discussion #13 disease

Maintaining Lasting Improvements: One-Year Follow-Up of Children With Severe Chronic Pain Undergoing Multimodal Inpatient Treatment

Gerrit Hirschfeld,1 PHD, Tanja Hechler,1 PHD, Michael Dobe,1 PHD, Julia Wager,1 MSC,

Pia von Lützau,1 MSCN, Markus Blankenburg,1,2 MD, Joachim Kosfelder,3 PHD, and

Boris Zernikow,1 MD, PHD 1German Peadiatric Pain Centre and Department of Children’s Pain Therapy and Paediatric Palliative Care,

Children’s and Adolescents’ Hospital, Datteln, Witten/Herdecke University, Faculty of Health, School of

Medicine, Germany, 2Center for Child Neurology, Clinic for Children and Adolescent Hospital, Witten/

Herdecke University, and 3Department of Social Sciences and Cultural Studies, University of Applied Sciences,

Düsseldorf, Germany

All correspondence concerning this article should be addressed to Tanja Hechler, PHD, German Paediatric

Pain Centre and Department of Children’s Pain Therapy and Paediatric Palliative Care, Children’s and

Adolescents’ Hospital, Datteln, Witten/Herdecke University, Dr-Friedrich-Steiner-Str. 5, Datteln 45711,

Germany. E-mail: [email protected]

Received April 4, 2012; revisions received October 7, 2012; accepted October 13, 2012

Objective To investigate the long-term effectiveness of a 3-week multimodal inpatient program for children

and adolescents with chronic pain. Methods 167 adolescents were evaluated at pretreatment baseline, 3-,

and 12-month follow-up. Long-term effectiveness was investigated for pain-related variables (pain-related

disability, school absence, pain intensity) and emotional distress. Results We found statistically and

clinically significant changes in all variables. After 1 year, the majority (56%) showed overall improvement as

indexed by decreased pain-related disability or school absence. 22% had an unsuccessful treatment

outcome. Those showing only short-term improvements had higher levels of emotional distress at baseline.

Conclusions 1 year after completing a multimodal inpatient program adolescents report less chronic pain,

disability, and emotional distress. Clinically significant changes remain stable. Adolescents with high levels of

emotional distress at admission may require special attention to maintain positive treatment outcomes.

Specialized inpatient therapy is effective for children with chronic pain.

Key words adolescents; clinical significance; headache; inpatient pain treatment; somatoform pain disorder.

Introduction

Chronic pain is a pervasive problem for the health care

system that may begin in childhood and adolescence

with �5% suffering from severe and disabling chronic

pain (Huguet & Miro, 2008).

Intensive multimodal pain treatment is considered as

an adequate treatment options for these severely disabled

children because then professionals from several discip-

lines can see the child daily in various situations, and a

systematic change in pain-related disability and distress

can be achieved. There are only few inpatient programs

or intensive day care programs to date, and their concep-

tualization and labeling is diverse (Eccleston, Bruce, &

Carter, 2006; Hechler, Dobe, & Zernikow, 2010b; Logan

et al., 2012a; Logan, Conroy, Sieberg, & Simons, 2012b).

Here, we follow the definition of a multimodal inpatient

treatment (MIT) set out by the German Pain Society

(Arnold et al., 2009) defined as a treatment provided

by a minimum of three health care disciplines including

medical, psychological, and physical therapy, which

Journal of Pediatric Psychology pp. 1–13, 2012 doi:10.1093/jpepsy/jss115

Journal of Pediatric Psychology � The Author 2012. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: [email protected]

Journal of Pediatric Psychology Advance Access published November 17, 2012 at U

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are provided concurrently, generally lasting for 3 weeks.

This treatment addresses underlying pain mechanisms,

adapts pain medication, treats specific symptoms such as

emotional distress, and teaches active coping skills

(Hechler et al., 2010c; Maynard, Amari, Wieczorek,

Christensen, & Slifer, 2009a).

Effectiveness of MIT has rarely been investigated and if

so, comparison is hampered by the diversity of the pro-

grams. The few studies are diverse in terms of setting (some

programs provide inpatient and outpatient treatment

[Chalkiadis, 2001]), length of stay (ranging from 3-8 days

to 3 weeks), and interventions provided (exercise therapy

[Sherry, Wallace, Kelley, Kidder, & Sapp, 1999] compared

with multimodal interventions (Eccleston, Malleson,

Clinch, Connell, & Sourbut, 2003). The program

described by Maynard and colleagues can be classified as

MIT. There are, however, other intensive multidisciplinary

rehabilitation programs, which can not be classified as MIT

as defined earlier but which share similarities in thera-

peutic approaches and program philosophy (e.g. [Logan

et al., 2012a]). In addition, long-term follow-up has

rarely been investigated. However, extended follow-ups

are necessary to investigate the stability of treatment effects

and factors that influence the stability of treatment effects

(Maynard et al., 2009a). The only study that investigated

long-term effects has been conducted by Sherry and col-

leagues (1999). This study followed 96 children for up to 7

years after a short exercise therapy and found high stability

of treatment results, i.e. after 2 years, 88% of the children

were still symptom free. However, their program was an

exercise-based program, focused on children with complex

regional pain syndrome (CRPS), and suffered from a large

amount of dropout (50% after 2 years).

It is yet unclear which factors influence long-term

treatment outcome. Given that there is numerous empirical

support for the role of emotional variables on the mainten-

ance and exacerbation of pediatric chronic pain and dis-

ability (e.g., [Cohen, Vowles, & Eccleston, 2010; Kashikar-

Zuck, Goldschneider, Powers, Vaught, & Hershey, 2001;

Sieberg, Williams, & Simons, 2011; Vervoort et al., 2011]),

emotional distress may be an important factor. Vervoort

et al. (2011) demonstrated recently that pain catastro-

phizing in schoolchildren was related to pain and disability

6 months later. They also found that children with

increased anxiety at baseline were more inclined to

report catastrophizing at follow-up. Whether this pattern

holds true for children with chronic pain has not yet been

investigated.

In addition, very few of the previous treatment studies

analyzed the clinical significance (Jacobson & Truax, 1991)

of treatment results as recommended by the Initiative for

Methods, Measurement, and Pain Assessment in Clinical

Trials (IMMPACT) (Dworkin et al., 2009). Jacobson and

Truax (1991) proposed a method for defining clinically

significant change and suggest two criteria: (1) the magni-

tude of change between pre- and post-treatment scores

should be statistically reliable. (2) By the end of the ther-

apy, patients should move from a dysfunctional to a func-

tional level to render them indistinguishable from healthy

people. Thus far, only one study reported on the clinical

significance of their treatment results 3 months after inpa-

tient treatment (Hechler et al., 2009). They found that 3

months after treatment, 72% of the patients had clinically

significant changes in pain intensity, and 45% had clinic-

ally significant changes in pain-related disability.

The present article aims to add to our limited know-

ledge on the long-term effects of MIT by investigating

long-term treatment outcome 12 months after treatment

compared with the pre-treatment status at admission.

There were four objectives of the study: First, to assess

12 month outcomes of three primary outcomes (pain in-

tensity, pain-related disability, school absences), with a

focus on clinically significant changes. We expected signifi-

cant and clinically relevant decreases in primary outcomes

from admission to 12-month follow-up. Second, to classify

children into two groups based on the composite measure

of ‘‘overall improvement.’’ Third, to predict clinically rele-

vant levels of overall improvement. We hypothesized that

patient- and pain characteristics at admission would pre-

dict overall improvement at 12-month follow-up. Fourth,

to assess the stability of change over time. Therefore, we

defined the following groups based on overall improvement

status at 3- and 12-month follow-up: (1) ‘‘stable long-term

improvers’’ (improved on both assessments), (2)

‘‘short-term improvers’’ (improved at 3-month follow-up

only), (3) ‘‘long-term improvers’’ (improved at 12-month

follow-up only), and (4) ‘‘children with unsuccessful treat-

ment results’’ (not improved at both follow-ups). We also

aimed to investigate the influence of pain characteristics

and emotional distress at admission on stability of change.

Materials and Methods Participants

In the present study, we report data from extended

12-months follow-up of our earlier study (Hechler et al.,

2009). Data from this sample have been described previ-

ously (Dobe, Damschen, Reiffer-Wiesel, Sauer, & Zerni-

kow, 2006; Dobe, Hechler, Behlert, Kosfelder, &

Zernikow, 2011; Hechler et al., 2009; Hechler, Blanken-

burg, Dobe, Kosfelder, Hübner, & Zernikow, 2010a;

Hechler et al., 2010c), but this is the first time that the

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clinical significant long-term outcomes are described.

The study was a naturalistic longitudinal effectiveness

study, with assessment at admission, 3 and 12 months

after treatment. Between January 2004 and December

2006, adolescents that completed the 3-week inpatient

chronic-pain treatment program at the German Paediatric

Pain Centre were included. All children and their guardians

were informed and agreed to their data being anonymously

stored and processed for research purposes. The study was

approved by the Ethics Committee of the Witten/Herdecke

University.

During the study, 200 children and adolescents

completed the program. Thirty-three were excluded from

this analysis because they were aged <11 years. At admis-

sion, the 167 adolescents included in the final analysis

were between the ages 11 and 18.3 years, mostly female

(62%), and the majority (50%) had recurrent headache (see

Table I for complete demographic information, and Table II

for information about the level of functioning). In all, 141

(84%) provided data at the 3 months follow-up, and 136

(81%) provided data at the 12 months follow-up (see

Figure 1). Participants completed the 12 month follow-up

data on average 394 days after therapy.

Comparing those who dropped out of the study at

12-month follow-up to those who remained in the study,

we found that dropouts were significantly older than

completers (14 vs. 15 years; p < .01) and had higher

levels of school aversion compared to dropouts (51 vs.

58; p < .01). There were no differences in pain character-

istics at admission (all p > .1). At the 12-month follow-up,

data were collected via mail for n¼105 patients (63%), via

telephone for n¼13 patients (8%), and during a scheduled

appointment at the German Paediatric Pain Centre for

n¼18 (11%) patients. Chi-square tests found no differ-

ences in sample characteristics (age, sex, diagnosis) and

the way of responding (mail, phone, in-person, or

drop-out) at the 12-month follow-up. We found however

a difference between the way of responding and overall

improvement (w2¼12.91; p¼ .002); responses given via telephone indicated less improvement than those given

via post and in-person.

Outcome Measures

We assessed the following three measures as primary out-

come measures: (1) mean pain intensity in the past 7 days,

(2) pain-related disability comprising disability in daily life

assessed by the Pediatric Pain Disability Index (Hübner et

al., 2009), and (3) school absence assessed via parental

report through the German Pain Questionnaire for

Children and Adolescents (DSF-KJ) (Schroeder et al.,

2010). Emotional distress and use of analgesics were

secondary outcome measures. We thus cover three core

outcome domains (pain intensity, role functioning, and

emotional functioning) from the recent IMMPACT recom-

mendations for pediatric patients (PedIMMPACT)

(McGrath et al., 2008).

Pain Intensity

Adolescents’ pain-intensity was assessed using a 11-point

numeric rating scale (NRS) (Denecke & Hünseler, 2000)

ranging from 0 (no pain) to 10 (maximal pain). This scale

has been shown to be valid and sensitive to change in

pediatric samples (von Baeyer et al., 2009).

Pain-Related Disability

Pain-related disability was assessed using the P-PDI

(Hübner et al., 2009). The P-PDI assesses disability in

daily activities owing to pain on 12 items rated on a

5-point scale (1 [never] to 5 [always]). Daily activities com-

prise activities such as going to school, doing homework,

engaging in physical activity, and sleeping. The total score

is computed by summing all items and ranges from 12 to

60 (Cronbach’s alpha in this sample¼ .85). The 2-way

imputation method (Sijtsma & van der Ark, 2003) was

Table I. Demographic Characteristics at Admission

Variable Value

Age (mean�SD; [range]) 14.1�1.91 (11–18.3)

Sex (n [%])

Female 103 (62)

Diagnosis (n [%])a

Headache 84 (50)

Recurrent abdominal pain 22 (13)

Back pain 16 (10)

Diffuse idiopathic pain 15 (9)

Disease-related pain 11 (7)

Fibromyalgia 8 (5)

Localized idiopathic pain 6 (4)

CRPS 5 (3)

Pain duration in months

(mean�SD, range)

42�37

Patients on pain medication at

preassessment n (%)

70 (62)

Mean pain intensity (mean�SD, range) 6.7�1.7

Pain intensity categories (%)b

Mild pain 4

Moderate pain 42

Severe pain 55

Note. NRS¼Numeric Rating Scale. aCumulative percentage > 100% owing to rounding up. bThe NRS was categorized into four categories: no pain (NRS 0), mild-to-moderate

pain (NRS 1–3), severe pain (NRS 4–6), and very severe pain (NRS 7–10).

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used to impute missing values when at least 9 of 12 items

were responded to.

School Absence

Parents were asked how many days their child missed

school owing to ongoing pain within the past 4 weeks

(i.e., 20 school days excluding weekends and holidays)

as part of the DSF-KJ (Schroeder et al., 2010). Thus, for

children admitted short after public holidays, some parents

had to report school absence before the holidays, but the

number of expected school days was similar for all chil-

dren, i.e., 20 days. Logan and colleagues provided evidence

for a high correlation between parent report and official

school attendance records (Logan, Conroy, Sieberg, &

Simons, 2008b).

Emotional Distress

Emotional distress was assessed using the Anxiety

Questionnaire for Pupils (AFS; [Wieczerkowski, Nickel,

Janowksi, Fittkau, & Rauer, 1981]) and the Depression

Inventory for Children and Adolescents (DIKJ;

[Stiensmeier-Pelster, Schürmann, & Duda, 2000a]). Both

measures are frequently used in adolescent samples and

allow a norm-based comparison with non-clinical school

children. We used these norms to transform individual

raw-scores to T values with a mean of 50 and standard

deviation of 10. We investigated three subscales of the

AFS; (1) fear of exams, (2) generalized anxiety, and (3)

school aversion, which all have good internal consistency

(Cronbachs alpha between .75 and .85; Wieczerkowski

et al., 1981) The DIKJ consists of 26 items measuring de-

pression with good reliability (internal consistency: 0.84)

and validity (Stiensmeier-Pelster, Schürmann, & Duda,

2000b). Raw scores > 18 are indicative of depression

(Stiensmeier-Pelster et al., 2000b). Individual missing

items (up to two for the DIKJ and the scale school aversion,

and up to three for the scales fear of exams and generalized

anxiety) were replaced as suggested by the test authors.

Use of Analgesics

Parents indicated whether the children used analgesics

before and after treatment as part of the DSF-KJ. Use of

analgesics was then classified into five groups: (1) non-

steroidal anti-inflammatory drugs (NSAID), (2) other

non-opioid analgesics, (3) triptans, and (4) opiods.

Procedure

Data on the initial status were collected by sending a bat-

tery of questionnaires via mail before admission. Data for

the follow-up were collected at the 3-month follow-up,

which was regularly scheduled with the patients. Data for

the 12-month follow-up were collected in three different

ways: (a) either during a scheduled appointment at the

German Paediatric Pain Centre for those participants who

were still in treatment, (b) via mail, or (c) via structured

telephone interview for those participants who did not

return their questionnaires. Children still in treatment

were seen for follow-up visits scheduled 3, 6, or 12

months after inpatient treatment (see also Hechler et al.,

Table II. Functioning

Variable Value

P-PDI (n¼160; mean�SD, range)a 40�9

School absence of >2 days (10%) within the

preceding 4 weeks (n [%])b 122 (73)

School absence because of pain (n [%])

<15% (3 days) school absence 45 (27)

15–50% (3–10 days) school absence 57 (34)

No school attendance at all 42 (25)

Significant emotional distress (n [%])

Fear of examination (n¼167)c 35 (21)

General anxiety (n¼167)c 61 (36)

School aversion (n¼167)c 34 (26)

Depression (n¼161)d 51 (31)

Note. P-PDI¼Pediatric Pain Disability Index. aCumulative percentage >100% owing to rounding up. P-PDI values ranged

between 12 and 60; the higher the value, the more disabled the child. bSchool absence was assessed as days absent from school within the past 4 weeks

(parental report). cSignificant values in the anxiety questionnaire were assigned if the patient

demonstrated T > 60 compared with a non-clinical population. dSignificant values in the depression questionnaire were assigned if the patient

demonstrated raw values > 18.

Figure 1. Flow of patients through the stages of the study.

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2011a). Responses were included if they were given max-

imum 18 months post discharge. The structured interview

was conducted by a research assistant not involved in

treatment.

Pain intensity and pain-related disability were assessed

via self-report. School absence and use of analgesics were

assessed by the parents. The sample size differs between

the variables (see Table II) owing to >2 missing items on

the questionnaires.

MIT at the German Paediatric Pain Centre

The MIT at the German Paediatric Pain Centre lasts 3

weeks. Children are referred to our specialized treatment

center by primary physicians due to persisting pain. The

treatment is based on operant and cognitive behavioral

principles throughout all modules. Parents are actively

engaged in the treatment as part of weekly family sessions

and coaching sessions during which parents were taught to

actively support their child to engage in healthy daily

activities. Furthermore, reintegration into the child’s daily

life is initiated from the second week onwards comprising

visits home and to their home school on one appointed

day. Patients complete various treatment modules such as

education, individual sessions on pain-related coping and

related problems, family sessions on parental cognitions

and reactions towards the child’s pain, and group sessions

on peer relationships that sum up to �5–8 hr per day. The

treatment is provided by a multiprofessional team

including clinical psychologists, pediatricians, children

and adolescent psychiatrists, pediatric nurses, physiother-

apists, occupational therapists, and social workers. A

scheduled appointment is arranged for each child and its

family 3 months after discharge. More information can be

taken from our earlier study (Hechler et al., 2009).

Statistical Analysis

Descriptive statistics (means, SD, and frequencies) of pa-

tients’ characteristics at admission were computed. Group

differences between the different ways of responding at the

12 months follow-up were tested with chi-square tests.

Treatment Effects at 12-Month Follow-Up—Statistical Significance

Statistically significant changes between admission and

12-month follow-up in all continuous variables (pain in-

tensity, pain-related disability, school absence, fear of

exam, generalized anxiety, school aversion, and depres-

sion) were assessed using repeated-measures analysis of

variance (ANOVA). Effect-sizes were calculated according

to Grawe and colleagues by dividing the difference between

12-month follow-up scores from prescores by the SD of the

scores at admission (Grawe, Bernauer, & Donati, 1994).

Effect sizes were interpreted according to established

standards (Cohen, 1988). Significant changes in the use

of analgesics (yes or no) were assessed using McNemar’s

test for paired proportions (McNemar, 1947).

Treatment Effects at 12-Month Follow-Up—Clinical Significance

The clinically significant changes in the core variables were

defined using the method developed by Jacobson and

Truax (1991). This procedure entails two steps; (1)

Computation of the reliable change index (RCI) to estimate

whether the change for an individual patient is due to

chance fluctuations or real change; (2) Calculation of

cut-off points that need to be crossed to count as clinically

relevant. The RCI was calculated using Jacobsen and

Truax’s formular and resulted in three outcome groups:

‘‘no reliable change,’’ ‘‘reliable deterioration,’’ and ‘‘reli-

able improvement’’ for each patient and test. Cut-off

points were defined using different methods, depending

on whether normative data for a test existed.

1. If no normative data were available, a cut-off point

at 90% of the patient population (mean before

treatment þ/� 1.6 SD) was used.

2. If a cut-off point already existed that indicates a

clinically relevant point, (e.g., a t-value, which in-

dicates that a score lies outside of the distribution

of the healthy population), this was used.

3. If no cut-off score existed, but distribution of the

healthy population was known, a cut-off point was

chosen, at which a value is more likely to belong

to a healthy than a clinical population.

In the present article, criterion 1 was used for

pain-related disability, resulting in a cut-off score of

25.58. Criterion 2 was used for pain intensity, school ab-

sence, and the three anxiety scales. Specifically, we used

the same the cut-off point for pain-intensity that has been

identified in adult research, where a raw change of �1.74

on the 11-point NRS was found to be clinically significant

(Farrar, Young, LaMoreaux, Werth, & Poole, 2001). This

resulted in a cut-off point of 5 (6.82–1.74) for our sample.

The cut-off point for school absence could not be

based on a clear definition, as there are no official data

on school absence in Germany, and was thus based on

our previous definition that school absence of >10%

(i.e, 2 days) during a 4-week period would be considered

as unacceptable by the teaching staff. The cut-off point for

the three anxiety scales (60) was taken from published

research with these scales (Wieczerkowski et al., 1981).

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Criterion 3 was used for depression where data on the

distribution of a healthy sample were available, and a raw

score of >18 has been indicative of depression

(Stiensmeier-Pelster et al., 2000b). Using these cut-offs to-

gether with the RCI, five outcome groups were defined for

all variables;

1. ‘‘Clinically significant change’’: Patients who reli-

ably improved and whose post-scores were below

the cut-off.

2. ‘‘Significant but not clinically relevant’’: Patients

who reliably improved but did not cross the

cut-off.

3. ‘‘No change unproblematic’’: Patients who showed

no reliable change and had prescores below or

equal to the cut-off.

4. ‘‘No change problematic’’: Patients who showed

no reliable change and had prescore above the

cut-off.

5. ‘‘Reliable deterioration’’: Patients who showed

change in the undesired direction that was larger

than the RCI.

To make our results comparable with other reports

using only individual reductions in pain ratings as index

for clinically significant change, we also calculated the

number of patients who reduced their pain rating by at

least 2 points on the NRS and at least 50% of their initial

score.

Treatment Effects at 12-Month Follow-Up—Overall Improvement

We also computed an overall improvement score based on

the clinically significant changes between admission and

12-month follow-up in the primary outcome variables

(pain intensity, pain-related disability, school absence

[Hechler et al., 2009]). Patients were classified as showing

overall improvement if they did not show deterioration in

any pain-related variable (i.e. in pain intensity, pain-related

disability, and school absence) and had clinically signifi-

cant improvements in one or both disability-related

variables (pain-related disability or school absence). All

other patients were classified as showing no overall

improvement.

Furthermore, we compared the levels of overall im-

provement for patient and pain characteristics.

Chi-square tests were used to compare diagnostic groups.

Owing to the low group size, a mixed group of adolescents

with fibromyalgia, localized idiopathic pain, and CRPS

(n¼19) was formed in addition to the other five groups

(headache, recurrent abdominal pain, back pain, diffuse

idiopathic pain, disease-related pain). A logistic regression

was used to predict overall improvement with pain inten-

sity, pain-related disability, and emotional distress at ad-

mission, as well as sociodemographic variables such as age

and sex.

Maintenance Groups Over the Two Time Points (3- and 12-Month Follow-Up)

First, we investigated whether there was a systematic

change in the overall improvement status of the adoles-

cents from 3- to 12-month follow-up using McNemar’s

test. Specifically, we investigated whether more adolescents

changed from no overall improvement at 3-month

follow-up to overall improvement at 12-month follow-up

or vice versa.

Second, we subdivided the children into four mainten-

ance groups according to the stability of their overall im-

provement status at 3- and 12-months follow-up:

1. ‘‘stable long-term improvers’’: Patients who

showed stable overall improvement both at 3- and

12-month follow-up.

2. ‘‘long-term improvers’’: Patients who showed no

overall improvement at 3-month follow-up, but

overall improvement at 12-month follow-up.

3. ‘‘short-term improvers’’: Patients who showed

overall improvement at 3-month follow-up, but no

overall improvement at 12-month follow-up.

4. ‘‘children with unsuccessful treatment results’’:

Patients who showed stable no overall improve-

ment both at 3- and 12-month follow-up.

To investigate pre-treatment influences on mainten-

ance status, univariate ANOVA were used to compare the

four maintenance groups in terms of pain-related and

demographic variables; post-hoc tests (Tukey’s honestly

significant difference [HSD]) were computed to test

which of the four groups differed. Data were analyzed

using R. We defined p < .05 as significant.

Results Treatment Effects at 12-Month Follow-Up— Statistical Significance

Participants showed statistically significant reductions in

all variables 12 months after treatment (see Table III).

Participants showed statistically significant reductions in

all variables 12 months after treatment such that they re-

ported less pain, disability, and fewer school absences.

Similarly, adolescents reported less emotional distress

with lower levels of fear of exams, generalized anxiety,

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school aversion, and depression. Effect-sizes for primary

outcome measures were large. Effect-sizes for secondary

outcome measures were of medium size.

We found a significant decrease in the number of ado-

lescents taking pain medication (McNemar’s w2¼10.26; p¼ .001; Table IV).

Treatment Effects at 12-Month Follow-Up—Clinical Significance

In terms of the clinical significance of the changes, 74% of

patients showed clinically significant changes in pain in-

tensity, 53% in pain-related disability, and 39% in school

absence (see Figure 1). For the secondary outcome vari-

ables, ‘‘unchanged unproblematic’’ was the most frequent

category. Specifically, there were 27% who improved clin-

ically significant in depression and 24% in generalized anx-

iety. Across all measures, between 1% (for fear of exams)

and 7% (for depression), showed reliable deterioration.

There were 62% of the children who showed a de-

crease of at least 50% from the initial NRS score and

80% of the children who showed reductions of �1.74

from the initial NRS score.

Treatment Effects at 12-Month Follow-Up—Overall Improvement

Twelve months after treatment, 74 patients (56%)

demonstrated ‘‘overall improvement.’’ Of these, only four

(5%) showed unchanged problematic pain-related disabil-

ity while displaying a clinically significant change in school

absence, and 11 (15%) showed unchanged problematic

school absence while displaying clinically significant

changes in pain-related disability. There were no differ-

ences between the diagnostic groups (w2¼5.5; p¼ .36). The logistic regression (method:enter) identified school ab-

sence at admission as the sole significant predictor for

overall improvement (Table V). Specifically, adolescents

with higher school absence at admission were more likely

to demonstrate overall improvement after 12 months

(OR¼1.073, p < .05).

Maintenance Groups Over 3- and 12-Month Follow-Up

Over the two time points, 53 (46%) of the adolescents were

‘‘stable long-term improvers,’’ 16 (14%) were ‘‘long-term

improvers,’’ 22 (19%) were ‘‘short-term improvers,’’ 25

(22%) had an ‘‘unsuccessful treatment outcome.’’ There

was no systematic change in the overall improvement

status (either decrease or increase) between 3 and 12

months follow-up (McNemar’s w2¼ .66; p¼ .4). Specifically, there were as many short-term improvers, as

there were long-term improvers.

There were no differences between the maintenance

groups in terms of diagnosis (w2¼16.76; p¼ .33) and those who participated versus those who did not partici-

pate in the 3-month follow-up (w2¼0.56; p¼ .45). ANOVAs comparing the four improvement groups in

terms of pretreatment psychosocial variables found that

the four groups significantly differed in school absence

(F¼3.03; p < .05), generalized anxiety (F¼2.90;

p < .05), and depression (F¼2.95; p < .05). Post-hoc

tests revealed that ‘‘stable long-term improvers’’ adoles-

cents had significantly higher rates of school absence at

admission than ‘‘unsuccessful’’ adolescents. Furthermore,

‘‘short-term improvers’’ had higher levels of generalized

anxiety and depression than ‘‘stable long-term improvers’’

adolescents (both p < .05).

Discussion

The present study presents data on the statistical and clin-

ical significance of treatment effects 1 year after an inter-

disciplinary MIT (Hechler et al., 2009). Our results show

that the majority of children exhibit statistically and clin-

ically significant changes in core outcome measures 12

months after treatment. Changes in secondary outcomes

were also observable albeit smaller. Importantly, the ma-

jority of adolescents reported no significant emotional dis-

tress at admission. The majority of children showed overall

Table III. Statistically Significant Changes in Outcomes From Admission to One-Year Follow-Up

Admission 3 months follow-up 12 months follow-up

M (SD) M (SD) p ES M (SD) p ES

Pain intensity (n¼120) 6.83 (1.78) 2.83 (2.66) <.001 2.25 2.49 (2.74) <.001 2.44

Pain-related disability (n¼109) 39.19 (8.51) 22.82 (9.06) <.001 1.92 24.11 (10.45) <.001 1.77

School absence (n¼120) 9.25 (7.76) 1.8 (3.92) <.001 .96 1.39 (3.08) <.001 1.01

Fear of exams (n¼72) 47.43 (12.37) 43.18 (11.05) <.001 .34 41.46 (1.32) <.001 .48

Generalized anxiety (n¼72) 52.96 (12.73) 46.6 (11.67) <.001 .5 45.72 (12.09) <.001 .57

School aversion (n¼72) 51.94 (10.87) 47.92 (9.95) <.001 .37 48.54 (10.13) <.001 .31

Depression (n¼73) 13.19 (7.89) 8.59 (6.92) <.001 .58 8.92 (8.69) <.001 .54

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improvement 12 months after treatment. During 3- and

12-month follow-up, approximately half of the adolescents

were classified as stable long-term improvers; 30% showed

either short-term or long-term improvements, and �20%

had an overall unsuccessful treatment outcome. The stable

long-term improvers reported more days absent from

school at admission; the short-term improvers reported

more emotional distress at admission.

Treatment Outcomes After 12 Months

The treatment outcomes at 12-month follow-up were re-

markably similar to the outcomes 3 months after treatment

(Hechler et al., 2009). We found statistically significant

changes in primary outcomes with large effect sizes and a

majority of patients showing clinically significant improve-

ments. The secondary outcomes changed to a lesser

degree. This is in line with the results at 3-month follow-up

(Hechler et al., 2009) but contrasts with other studies

(McCracken, MacKichan, & Eccleston, 2007) that found

large improvements in emotional distress in adults.

The most likely explanation for this is that only a minority

of our sample exhibited clinically relevant levels of depres-

sion and anxiety at admission and thus could not show

clinical improvements. Also, the program may have pre-

vented an aggravation of emotional distress so that most

children could maintain a low level of emotional distress.

We extend previous studies (Hechler et al., 2009;

Eccleston et al., 2003; Lanzi et al., 2007; Maynard et al.,

2009a; Palermo & Scher, 2001) by showing that adoles-

cents are able to maintain these positive treatment effects

over a period of 1 year. Here, positive long-term outcomes

for a 12-month period could be replicated with a lower

drop-out rate (32% compared with 50% by Sherry et al.,

1999) and a stricter definition of overall improvement

(based on the concept of clinical significance of Jacobson

and Truax) compared with previous studies (Sherry et al.,

1999). Hence, in line with existing studies, the present

study highlights the importance of MITs for severely

disabled children. Several possible explanations accounting

for the effectiveness have previously been discussed: The

treatment intensity of the inpatient setting, changes in

coping strategies, the ability to engage in activities with

peers, and experiences of success (Eccleston et al., 2003;

Hechler et al., 2009; Hechler et al., 2010c; Lanzi et al.,

2007; Maynard, Amari, Wieczorek, Christensen, & Slifer,

2009b; Palermo & Scher, 2001; Sherry et al., 1999;).

Future studies are warranted to examine the exact mech-

anisms of change, i.e., which changes for instance in cog-

nitive or emotional variables such as pain catastrophising

(Vervoort et al., 2011), or treatment adherence (Simons,

Logan, Chastain, & Cerullo, 2010) may moderate changes

in primary outcomes (Keefe, Buffington, Studts, &

Rumble, 2002).

In addition, future research should address two prac-

tical issues (Jensen & Foster, 2010): First, the cost-benefit

ratio needs to be assessed in a large group of patients to

make possible financial incentives more obvious (Maynard

Table IV. Changes in Medication Between Pretreatment and 12

Months Follow-Up

Admission

(n¼90)

12 months

follow-up

(n¼90)

Number of patients who

reported using

n (%a) na % p¼ .001

Any pain medication (yes, no)a 56 (62) 35 (39)

NSAID 29 (32) 25 (28)

Other non-opioid analgesics 21 (23) 5 (6)

Triptanes 3 (3) 10 (11)

Opioid 3 (3) 3 (3)

Anti-depressants

Note. aThe cumulative number of patients taking a specific medication is larger

than the number of patients taking medications overall owing to intake of mul-

tiple medications.

Table V. Predictors of Overall Amelioration at 12 Months Follow-Up

Predictors Coefficient SE OR (standardized OR) 95% CI lower 95% CI upper p

School absence at admission 0.07 0.03 1.07 (1.73) 1.02 1.14 <.05

Pain intensity �0.1 0.13 0.91 (.84) 0.7 1.16 n.s.

Pain-related disability 0.03 0.03 1.03 (1.34) 0.98 1.09 n.s.

Fear of examinations 0 0.02 1 (.99) 0.95 1.05 n.s.

General anxiety �0.01 0.03 0.99 (.86) 0.93 1.04 n.s.

School aversion �0.03 0.03 0.97 (.74) 0.92 1.02 n.s.

Depression �0.02 0.04 0.98 (.84) 0.89 1.07 n.s.

Age �0.22 0.12 0.8 (.67) 0.63 1.02 n.s.

Sex �0.08 0.5 0.92 (.96) 0.34 2.47 n.s.

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et al., 2009a). Second, it is important to investigate inpa-

tient treatment in the context of other treatment options.

Most participants proceed through the health care system

in various steps of treatment intensity, such as starting with

primary care, and proceeding to specialized treatment if the

pain persists. Here, they may be referred to outpatient or

intensive inpatient treatment dependent on their clinical

status (Hechler et al., 2011a; Von Korff & Moore, 2001).

Further research should investigate the feasibility of a

stepped-care approach in which treatment can be

intensified over time (Hechler et al., 2011a). Within such

a framework, screening tools that detect children at risk of

developing chronic pain and explicit decision criteria for

treatment allocation can be developed (Vowles, Jordan, &

Eccleston, 2009).

Maintenance of Improvement

We found that 50% showed improvement at both

follow-ups, 20% were not significantly improved at any

of the two follow-ups, and �30% of the participants

showed improvement 3 months after treatment, but not

12 months after treatment or vice versa. Our analysis of

pre-admission differences between these groups revealed

important differences. First, stable long-term improvers

had the highest levels of school absence at admission.

This is in accordance with the finding that adolescents

with high school absence at admission were more likely

to display overall improvement at 3-month follow-up

(Hechler et al., 2009). These children may have been en-

trenched in the vicious cycle of pain, disability, and school

absence at admission. As demonstrated by Logan et al.

(2008b), their academic achievement may have decreased

and contributed to long-term disability. These children

may, however, be highly academically competent (Logan

et al., 2008b). Once these children have surmounted

their disability and pain, they may therefore be able to

quickly reintegrate into school functioning. This may lead

to experiences of success, positive contact with peers, and

teachers, which may prevent deterioration and relapse over

time. These suggested mechanisms need to be further

explored in future studies.

Second, short-term compared with stable long-term

improvers had higher levels of emotional distress at admis-

sion. Possibly, deterioration in their emotional distress over

time, especially from 3- to 12-month follow-up, may have

lead to increases in pain and disability at 12-month

follow-up. The relationship between increased emotional

distress and pain and disability has been extensively

studied in children (Cohen et al., 2010; Kashikar-Zuck

et al., 2001). Our findings suggest that children with

increased emotional distress at admission benefit from

the intensive inpatient treatment as suggested by

Figure 2. Percentage of adolescents demonstrating clinically significant changes in the seven outcome variables at 12-month follow-up. Displayed

are the percentages of children for the five outcome groups: Clinically significant change; Positive change, but not clinically significant; No

change—unproblematic; No change—problematic; Reliable deterioration.

Effectiveness of Multimodal Chronic Pain Treatment 9

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improvements in primary outcomes. They deteriorate,

however, with time. The patterns of these deteriorations

need to be further investigated. On the basis of these

findings, additional treatments for these children may

need to be conceptualized specifically addressing the

aspect of emotional distress to prevent relapse and deteri-

oration such as how to cope with pain when emotional

distress increases again.

Finally, children with unsuccessful outcome did not

show particularly high levels of emotional distress or high

levels in school absence. Different to children high in

school absence at admission, they did not experience suc-

cess when being able to attend school again. Whether these

children really do not experience emotional distress, or

whether these children are high in social desirability and

deny emotional distress (Logan, Claar, & Scharff, 2008a)

needs to be investigated in future studies. In addition,

other potential candidates that may account for unsuccess-

ful treatment results such as the child’s pain-specific emo-

tions (fear of pain [Simons, Sieberg, Carpino, Logan, &

Berde, 2011]) or pain-specific cognitions (Vervoort et al.,

2011) and parental reactions such as adherence to treat-

ment (Simons et al., 2010) or parental cognitions and re-

actions (Hechler et al., 2011b; Vervoort et al., 2011)

warrant further investigation.

Limitations

There are some limitations inherent of the present study.

First, the study is limited by the lack of a control group.

However, there is little reason to suspect spontaneous

changes in the participants we studied (Perquin et al.,

2003), and the inclusion of a waiting-list control group

would have been highly unethical, given the known effect-

iveness of our program. Second, we found unexpected dif-

ferences in the overall improvement rates depending on the

way in which participants responded. Improvement rates

were lower for those who responded by phone, compared

with those who responded in person at a scheduled

follow-up visit. The latter group had contacted the tertiary

institute for a follow-up visit. During this follow-up visit,

the current status of the child is evaluated. Dependent on

the child’s status, further pain management strategies are

adjusted to the needs of the child (Hechler et al., 2011b).

At this stage, we do not if the difference in improvement

rates is due to the additional treatment or a social desir-

ability effect. Possibly, families who were interviewed by a

research assistant were more willing to report negative as-

pects than those faced with the clinicians in person. In

light of the small sample size, only 13 responded by tele-

phone; this pattern needs to be replicated before any

strong conclusions can be drawn. Third, our outcome

measures relied on self-report. More objective measures

of pain-related disability have only recently been used in

samples with chronic pain (Wilson & Palermo, 2012).

Similarly, this study did not include a measure of the eco-

nomic benefit. Fourth, we dichotomized our outcome vari-

ables. This greatly enhances the communication of results.

On the other hand, this clearly leads to a drop in power. At

present, there is no statistical method that maintains max-

imal power, and can be easily interpreted for binary out-

comes and predictors; thus the use of the Jacobson and

Truax method is recommended (Lambert & Ogles, 2009).

It will be most important to develop methods that classify

individuals’ change over time, and at the same time retain

the comparability across studies. On a similar note, cut-off

points for clinically relevant relative changes in pain inten-

sity need to be determined for children and adolescents

(Farrar et al., 2001). Also absolute levels of clinical signifi-

cant pain that are required according to Jacobsen and

Truax to differentiate the ‘‘no change problematic’’ from

the ‘‘no change unproblematic’’ group are not established

for children and adolescents. At present, it is not clear

whether methods based on relative or absolute cut-offs

are more relevant to patients. Although relative cutpoints

may overestimate small changes in almost healthy patients,

absolute cutpoints may overestimate small changes near

the border between healthy and diseased. The application

of the adult cut-off score may have hampered results. For

better study comparison, we therefore integrated report on

children displaying a 50% pain reduction. Finally, we as-

sessed general emotional distress and no pain-specific emo-

tions such as fear of pain (Simons et al., 2011). Future

treatment studies should implement assessment of

pain-specific emotions to investigate its potential influence

on treatment results.

The clinical implications of our results can be

summarized as follows: (1) the MIT is effective in improv-

ing the overall status of children over long periods. (2)

However, there were 20% with an overall unsuccessful

treatment result and 30% who showed only short-term

or long-term improvement. (3) Emotional distress seems

to play a crucial role for long-term improvement, given that

adolescents with high levels of emotional distress displayed

a risk to relapse after short-term improvements. These ado-

lescents may require special attention and interventions

that are useful in enhancing maintenance of positive out-

comes for this particular group of patients.

Acknowledgments

The authors, H.G. and H.T., contributed equally to the study.

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Conflicts of interest: None declared.

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