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TFFRS - Diabetes Prevention: Interventions Engaging Community Health Workers

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Community Preventive Services Task Force Finding and Rationale Statement

Intervention Definition

Community health workers (including promotores de salud, community health representatives,

community health advisors, and others) are frontline public health workers who serve as a bridge

between underserved communities and healthcare systems. They are from, or have an unusually

close understanding of, the community served. Community health workers often receive on-the-

job training, and work without professional titles. Organizations may hire paid community health

workers or recruit volunteers to act in this role.

Community health workers may address a broad range of health issues. Interventions that engage

community health workers to focus on diabetes prevention aim to reduce one or more risk factors

for type 2 diabetes among members of the community, primarily through improvements in diet,

physical activity, and weight management. Interventions are delivered to community groups or

individuals at increased risk for type 2 diabetes. Programs may include education about diabetes

prevention and lifestyle modification, or informal counseling, coaching, and extended support for

community members with a higher risk for diabetes. Community health workers deliver program

content through one-on-one interactions, group sessions, or a combination of the two.

Intervention activities take place in homes or community-based settings. Community health

workers may work alone or as part of an intervention team comprising counselors, clinicians, or

other health professionals.

CPSTF Finding

The Community Preventive Services Task Force (CPSTF) recommends interventions engaging community

health workers for diabetes prevention based on sufficient evidence of effectiveness in improving

glycemic control and weight-related outcomes among people at increased risk for type 2 diabetes.

Some evidence suggests interventions adapted from the U.S. Diabetes Prevention Program

The Community Guide (https://www.thecommunityguide.org)

(Diabetes Prevention Program Research Group 2002, NIDDK 2016) reduce rates of progression to

type 2 diabetes, though more research is needed. Interventions engaging community health

workers for diabetes prevention, which are typically implemented in underserved communities, can

improve health, reduce health disparities, and enhance health equity.

The economic evidence indicates that interventions engaging community health workers for

diabetes prevention are cost-effective.

Rationale

Basis of Finding

The CPSTF recommendation is based on evidence from a systematic review of 22 studies (search

period through May 2015). Studies evaluated the effectiveness of interventions in which community

health workers worked with community groups or individual members who had one or more risk

factors for type 2 diabetes. Included studies evaluated interventions that engaged community

health workers (CHWs) as health education providers (22 studies); outreach, enrollment, and

information agents (6 studies); members of care delivery teams (4 studies); and patient navigators

(3 studies) (HRSA 2007).

Findings demonstrated interventions engaging CHWs resulted in improved glycemic control

(HbA1c, fasting blood glucose [FBG]) and weight-related outcomes, and reduced rates of

progression to type 2 diabetes (Table 1). However, evidence on reduced progression to type 2

diabetes came from only 3 studies with small sample sizes, leading the CPSTF to downgrade the

strength of the supporting review to sufficient evidence on effectiveness.

Table 1. Outcomes Related to Glycemic Control and Weight

Outcome Measure Results by Study Design

Change in mean weight

Greatest suitability of study design (7 studies): Median decrease of 3.7 lbs

(IQI: -4.8 to -1.9)

Least suitable study design (7 studies): Median decrease of 2.8 lbs (IQI: -3.6

to -1.5)

Combined study design (14 studies): Median decrease of 3.0 lbs (IQI: -5.2 to

-1.8)

Greatest suitability of study design (6 studies): Median decrease of 0.6 kg/m

(IQI: -1.0 to -0.4)

A

B

C

2

2

Change in mean BMI Least suitable study design (7 studies): Median decrease of 0.5 kg/m (IQI:

-0.6 to -0.5)

Combined study design (13 studies): Median decrease of 0.5 kg/m (IQI: -0.7

to -0.5)

Change in mean waist circumference

Greatest suitability of study design (4 studies): (4 studies): Median decrease

of 1.1 inches (Range: -1.5 to -0.7)

Least suitable study design (6 studies): Median decrease of 1.4 inches (IQI:

-2.5 to -0.9)

Combined (10 studies): Median decrease of 1.4 inches (IQI: -1.6 to -0.9)

Progression to type 2 diabetes

Greatest suitability of study design (3 studies)

Two studies showed decreases of 5.1 percentage points (p-value=0.10) and

2.2 percentage points (p-value not reported)

One study showed an increase of 0.03 person years (p-value not reported)

Change in mean HbA1c

Greatest suitability of study design (3 studies): Median decrease of 0.07%

(range: -0.18 to 0)

Least suitable study design (3 studies): Median decrease of 0.10% (range:

-0.23 to 0.09)

Combined study design (6 studies): Median decrease of 0.09% (IQI: -0.19 to

0.02)

Change in mean fasting blood glucose

Greatest suitability of study design (5 studies): Median decrease of 1.0

mg/dL (IQI: -15.7 to 2.3)

Least suitable study design (2 studies): Decrease of 6.8 mg/dL (p<0.001) and

2.4 mg/dL (not significant)

Combined study design (7 studies): Median decrease of 2.4 mg/dL (IQI: -6.8

to 1.0)

2

2

A

Results shown in table were those reported at the end of each intervention

Includes the following study designs: group RCT, before-and-after with comparison group

Includes the following study design: before-and-after without comparison group

IQI = interquartile interval

Eight studies evaluated intervention effectiveness on risk factors for cardiovascular disease (CVD),

including changes in cholesterol and blood pressure outcomes. Overall, studies showed mixed

results (Table 2). This body of evidence included studies with a short duration (<6 months), limited

sample size (median=80 clients), and predominately female participants (80%). Of note, if lipids

and blood pressure measures are not elevated, participants might benefit from lifestyle

modifications. However, if lipids and blood pressure measures are elevated, studies do not attempt

to control or investigate these measures, as medical treatment was not part the intervention.

Table 2. CVD Risk Factors

Outcome Measure Results by Study Design

Change in mean total cholesterol

Greatest suitability of study design (2 studies): Increase of 25.2 mg/dL (p<0.01)

and a decrease of 3.9 mg/dL (not significant)

Least suitable study design (4 studies): Median decrease of 7.8 mg/dL (range:

-9.7 to -1.1)

Combined study design (6 studies): Median decrease of 5.7 mg/dL (IQI: -9.1 to

2.3)

Change in mean LDL

Greatest suitability of study design (1 study): Decrease of 5.0 mg/dL (not

significant)

Least suitable study design (4 studies): Median decrease of 5.3 mg/dL (range:

-9.2 to 2.8)

Combined study design (6 studies): Median decrease of 5.0 mg/dL (IQI: -8.3 to

-0.2)

Change in mean HDL

Least suitable study design (4 studies): Median increase of 0.3 mg/dL (range: -0.9

to 2.3)

A

B

C

A

B

C

Change in mean triglycerides

Least suitable study design (2 studies): Decrease of 13.8 mg/dL (p=0.005) and an

increase of 3.8 mg/dL (p=0.03)

Change in mean SBP

Greatest suitability of study design (3 studies): Median increase of 2.5 mmHg

(range: -1.7 to 6.0)

Least suitable study design (5 studies): Median decrease of 3.8 mmHg (IQI: -12.7

to -1.0)

Combined study design (8 studies): Median decrease of 2.6 mmHg (IQI: -5.5 to

2.3)

Change in mean DBP

Greatest suitability of study design (3 studies): Median increase of 1.0 mmHg

(range: -3.2 to 2.0)

Least suitable study design (5 studies): Median decrease of 2.8 mmHg (IQI: -8.1

to -1.7)

Combined (8 studies): Median decrease of 2.4 mmHg (IQI: -5.5 to 0.4)

Results shown in table were those reported at the end of each intervention

Includes the following study designs: group RCT, before-and-after with comparison group

Includes the following study design: before-and-after without comparison group

IQI = interquartile interval

Evidence measuring health behavior outcomes (20 studies) was largely self-reported. Increases in

physical activity and improvements in nutrition were seen across the included studies (Table 3).

Table 3. Health Behavior Change Outcomes

Outcome Measure

Results by Study Design

Physical activity

Greatest suitability of study design (8 studies)

One study reported statistically significant improvements, four studies reported non-

significant improvements, and three studies study showed no improvement

A

B

C

A

B

C

outcomes Least suitable study design (11 studies) Four studies reported statistically significant improvements, four studies reported non-

significant improvements, and three studies showed no improvement

Nutrition outcomes

Greatest suitability of study design (7 studies)

Two studies reported statistically significant improvements, two studies reported non-

significant improvements, and three studies showed no improvement

Least suitable study design (8 studies)

Two studies reported statistically significant improvements, four studies reported non-

significant improvements, and two studies showed no improvement

Results shown in table were those reported at the end of each intervention

Includes the following study designs: group RCT, before-and-after with comparison group

Includes the following study design: before-and-after without comparison group

Applicability and Generalizability Issues

Included studies were from the U.S. (21 studies) and New Zealand (1 study). Studies were conducted

in urban (7 studies) and rural (2 studies) areas. CHWs delivered services in communities (16

studies), community and home settings (4 studies), homes (1 study), and a worksite (1 study).

Fifteen studies reported the number of CHWs engaged and participants served. The median number

of CHWs per study was 6; the median number of clients served was 101, including one study that

served more than 500 clients.

In the included studies, CHWs served adults aged 18-64 (19 studies), and youth aged 17 years or

younger (2 studies); no studies included older adults aged 65 and older. Across all studies, more than

70% of participants were female, and 3 studies reported 100% female only study populations,

although overall results were similar in men and women. Included studies did not provide enough

information to draw conclusions about results by clients' sexual orientation, disability status, or

insurance status.

Ten included studies limited their population to clients at risk for diabetes, whereas 12 studies

allowed clients with diabetes to participate. However, the proportion of clients with diabetes in

these 12 studies was low (median: 22.8%; IQI: 13.0 to 27.1) Positive effects were similar for studies

that included clients at risk for diabetes and studies that included clients with diabetes.

Eighteen studies evaluated programs that enrolled clients from underserved groups as defined by

race/ethnicity, education, or annual income. Studies were limited to clients who were Hispanic (9

studies), African-American (3 studies), or Asian (3 studies), or had study populations that were at

C

A

B

C

least 75% Native Hawaiian or Pacific Islander (2 studies) or Native American (1 study). Five studies

were conducted in church-based settings and culturally tailored to target smaller groups in

underserved areas. In seven studies, most participants had less than a high school education; four

studies were evaluated in majority low-income populations. Based on this evidence, CHW

interventions targeted to underserved groups are likely effective in addressing health disparities.

Data Quality Issues

Study designs consisted primarily of before-and-after designs without comparison groups (12

studies), followed by group randomized controlled trials (7 studies) and before-and-after with

comparison (3 studies). Common limitations affecting this body of evidence were loss to follow-up,

insufficient reporting of sampling methods and intervention description, and self-selection bias.

Other Benefits and Harms

One study included in the review found that CHW engagement helped to increase the number of

program participants who obtained health insurance. Although not examined in the included

studies, CHWs are ideally positioned in communities to provide or assist members of the

community in completing diabetes risk assessments and assist those at high risk for type 2 diabetes

to obtain clinical follow-up and enrollment in appropriate community-based programs.

Experts noted that participants who increase their level of physical activity will be at increased risk

for associated injuries. These risks can be minimized, however, with graduated increases in physical

activity and by engaging in lower impact activities such as walking. No other potential harms to

patients, communities, or CHWs were identified.

Economic Evidence

Economic evidence indicates that interventions engaging community health workers for diabetes

prevention are cost-effective.

The economic review included seven studies from a search of the literature through July 2016.

Studies were based in the United States (6 studies) and the United Kingdom (1 study). All 7 studies

were implemented in community settings and most patients came from minority or low-income

populations. One study reported educational and exercise interventions that were followed by

CHW-facilitated support. The remaining 6 studies used interventions engaging CHWs alone. For

studies that did not report cost per quality adjusted life year (QALY) saved, reductions in A1c were

translated to QALY saved using published methods (Valentine et al. 2006) to generate cost-

effectiveness estimates. All costs and benefits were adjusted to 2015 U.S. dollars.

Intervention Cost

Seven studies reported on cost of intervention, with a median cost per person per year of $600 (IQI:

$369 to $731). The major drivers of cost were the cost of CHW time, supervision and training of

CHWs, and the cost of any additional staff or additional interventions. The cost most often missing

from studies was the cost of training and supervising CHWs. Based on the drivers of cost, two

studies provided complete estimates for the cost of intervention.

Healthcare Cost

The change in patients’ healthcare cost due to intervention was reported in 2 studies, with one

reporting a reduction of $1,242 per person per year and another reporting no change. A third study

modeled the impact on healthcare cost but did not report the estimate. The major drivers of

healthcare cost were outpatient and inpatient care, medication, and emergency room visits, with

two studies providing complete estimates for healthcare cost based on their inclusion of these

drivers.

Total Cost

Total cost is measured as the sum of change in healthcare cost due to intervention and the cost of

intervention. A negative value indicates averted healthcare cost exceeds the cost of intervention.

Three studies reported total cost of $48, $600, and -$856 per person per year. The study that

showed a negative total cost included the important intervention cost and healthcare cost drivers.

Cost-effectiveness

Two studies reported cost per QALY saved at $4,720 and $41,154. One study, for which translation of

reduction in A1c to QALY saved was feasible, was not included in the evidence for cost-effectiveness

because it did not account for change in healthcare cost.

The two studies that reported cost-effectiveness below the conservative benchmark of $50,000

likely overestimated net cost because they did not report averted emergency room visits and

increased productivity of patients. Also, the study that reported $4,720 per QALY saved did not

report the cost of CHW supervision and training. Replacing the intervention cost in this study with

the highest from the included studies ($780 per person per year), however, would still result in a

cost effectiveness estimate far less than $50,000. In conclusion, overall cost-effectiveness evidence

indicates that interventions engaging community health workers for diabetes prevention are cost-

effective.

Considerations for Implementation

The National Diabetes Prevention Program (National DPP) (https://www.cdc.gov/diabetes/prevention/index.html)

is a partnership of public and private organizations working to increase access for people with

higher diabetes risk to evidence-based, affordable, high-quality lifestyle change programs.

Through the National DPP, partner organizations:

Deliver CDC-recognized lifestyle change programs nationwide

Ensure quality and adherence to proven standards

The growing National DPP infrastructure provides the most promising avenue for implementation

of sustainable programs engaging CHWs for diabetes prevention, especially in diverse and

underserved communities. Trained CHWs may be potentially important providers of CDC-

recognized programs and could serve as lifestyle coaches for participants who are referred by

healthcare providers, or self-referred based on National DPP web-based risk assessment tools.

Recent rulings by the Centers for Medicare and Medicaid Services (CMS) provide emerging

opportunities for sustainable funding of CHW services. In 2013, the Centers for Medicare and

Medicaid Services began allowing states to provide Medicaid reimbursement for preventive services

recommended by the U.S. Preventive Services Task Force (USPSTF) when "recommended by a

physician or other licensed practitioner" and delivered by a broad array of health professionals,

including CHWs. States determine which services are covered, who provides them (including any

required education, training, experience, credentialing, certification, or registration), and how

providers are reimbursed.

In most studies identified in this review, CHWs functioned as the only provider of health education,

informal counseling, and extended support for program participants. The broader literature

suggests that CHWs are more typically engaged as a member of a team, providing a broader range of

services for community members in both community and clinical settings. For example, trained

CHWs could function as screening and enrollment agents, helping clients complete a simple risk

assessment for type 2 diabetes (ADA 2015, CDC 2016), and then connecting at-risk clients with

appropriate clinical follow-up and community services.

Consideration should be given to the frequency and settings for interactions between CHWs and

clients. Group sessions were the predominant delivery mechanism. Evaluated interventions were

delivered during group sessions (7 studies), one-on-one, in-person interactions (4 studies), or a

combination (8 studies; most often group sessions followed by one-on-one contact in person or by

telephone). Overall, studies reported improvements in glycemic and health behavior outcomes,

though there was not enough evidence to determine whether mode of delivery had an effect on

individual outcomes. Many studies reported on interaction frequency between CHWs and clients

(e.g., weekly, bimonthly), but there was not enough data to assess effects on outcomes.

CHWs are typically matched to the populations they serve and the specific services they deliver. In

the included studies, CHWs were frequently matched with populations by location, race or

ethnicity, or language. CHWs usually provided clients with culturally appropriate information and

education on diabetes prevention, lifestyle counseling to build individual capacity, and informal

counseling and social support. They also conducted home visits to ensure clients got the services

they needed. Most studies reported that CHWs received "some" training, usually focused on

diabetes prevention education, but there was limited evidence on specific types, methods, and

Train community organizations that can run the lifestyle change program effectively

Increase referrals to and participation in CDC-recognized lifestyle change programs

Increase coverage by employers and public and private insurers

duration of training.

Evidence Gaps

Most of the included studies included fewer than 100 participants and were conducted in urban or

suburban settings. More evidence is needed on effectiveness of large-scale programs (i.e., >500

participants), and programs conducted in rural settings. All studies in this review were funded by

public grants; it would be useful to understand whether CHW interventions funded by other

mechanisms are equally effective. Most included studies evaluated outcomes at <12 months. More

evidence is needed on programs evaluated over a longer time period to evaluate sustained effects

such as glycemic control and weight management.

More evidence is needed to understand effective methods for recruiting, training, and supervising

along with evaluating the impact of CHWs' experience and educational attainment. Additionally,

more information on frequency and duration of CHW–client interactions would be useful. Reporting

on CHWs' role as a member of care delivery team was limited. More evidence on the role and impact

of CHWs in a team-based care environment is needed. The population was majority female across

the lifestyle modification interventions. More evidence on the recruitment and retention of males

would be useful. CHWs usually delivered services in either community or home settings. Further

evaluations of community-worksite-clinic-health center linkages and the distribution and

implementation of diabetes prevention resources and their use in local communities including the

underserved would be useful.

In this body of evidence, positive, significant changes were seen in weight loss, indicating an

improvement in diet and physical activity behaviors. However, evidence was mixed for

improvements in other risk factors for cardiovascular disease, specifically blood pressure and

cholesterol. More comparative studies are needed.

Evaluations on models of care focused on providing culturally appropriate health education. There

was not enough evidence to draw conclusions on interventions engaging CHWs as navigators,

community organizers, outreach/enrollment/ information agent or member of a care delivery team.

More evidence is needed to assess intervention effects in communities at risk for type 2 diabetes.

Finally, more information is needed on reimbursement arrangements including CMS

implementation and funding of CHW services through clinical or community-based providers.

Studies that qualified for the economic review were incomplete in their reporting and inclusion of

the important drivers of intervention cost and healthcare cost. In addition to reporting this type of

information, future studies should assign a cost for the services of CHWs, whether such services are

voluntary or otherwise.

References

ADA. Are You at Risk for Type 2 Diabetes: Diabetes Risk Test. American Diabetes Association. Alexandria (VA); 2015. Available at URL: http://www.diabetes.org/are-you-at-risk/diabetes-risk-test/

The Community Guide

CDC. National Diabetes Prevention Program (National DPP). Centers for Disease Control and Prevention, U.S. Department of Health and Human Services. Atlanta (GA); 2016. Available at URL:

https://www.cdc.gov/diabetes/prevention/index.html (https://www.cdc.gov/diabetes/prevention/index.html) .

CDC. CDC Prediabetes Screening Test. National Diabetes Prevention Program. Centers for Disease Control and Prevention, U.S. Department of Health and Human Services. Atlanta (GA); 2016.

Available at URL: https://www.cdc.gov/diabetes/prevention/pdf/prediabetes-screening-test-tag508.pdf

(https://www.cdc.gov/diabetes/prevention/pdf/prediabetes-screening-test-tag508.pdf) .

Diabetes Prevention Program Research Group. (2002). Reduction in the incidence of type 2 diabetes

with lifestyle intervention or metformin. N Engl J Med 2002(346), 393-403. Available at URL:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1370926/pdf/nihms-5217.pdf

(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1370926/pdf/nihms-5217.pdf) .

Health Resources Services Administration (HRSA), Bureau of Health Professions. Community health

worker national workforce study. U.S. Department of Health and Human Services. Rockville (MD);

2007. Available at URL: http://bhpr.hrsa.gov/healthworkforce/reports/chwstudy2007.pdf

(http://bhpr.hrsa.gov/healthworkforce/reports/chwstudy2007.pdf) .

NIDDK. Diabetes Prevention Program (DPP). National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health. Bethesda (MA); 2016. Available at URL:

https://www.niddk.nih.gov/about-niddk/research-areas/diabetes/diabetes-prevention-program-

dpp/Pages/default.aspx (https://www.niddk.nih.gov/about-niddk/research-areas/diabetes/diabetes-prevention-

program-dpp/Pages/default.aspx) .

Valentine W, Palmer A, Nicklasson L, Cobden D, Roze S. Improving life expectancy and decreasing

the incidence of complications associated with type 2 diabetes: a modelling study of HbA1c targets.

International Journal of Clinical Practice 2006;60(9):1138-45.

@CPSTF (https://twitter.com/cpstf)

(404) 498-1827

[email protected]

Important Disclosures

August 23, 2017

August 20, 2018

The Guide to Community Preventive Services

The findings and conclusions on this page are those of the Community Preventive

Services Task Force and do not necessarily represent those of CDC. Task force evidence-based

recommendations are not mandates for compliance or spending. Instead, they provide

information and options for decision makers and stakeholders to consider when determining

which programs, services, and policies best meet the needs, preferences, available resources,

and constraints of their constituents.

Guide to Community Preventive Services. TFFRS - Diabetes Prevention: Interventions Engaging

Community Health Workers. https://www.thecommunityguide.org/content/tffrs-diabetes-

prevention-interventions-engaging-community-health-workers. Page last updated: August

20, 2018. Page accessed: April 24, 2019