Assng 5
© 2018 Laureate Education, Inc. Page 1 of 6
Case 9: Coding Accuracy
BACKGROUND
In our recent report, Using Software to Detect Upcoding of Hospital Bills
(OEI-01-97-00010), we examined the ability of commercially available software to
identify DRG upcoding through analysis of electronic claims data. We used two software
products to identify 299 hospitals with a high predicted rate of upcoding. We then had
accredited medical records professionals perform a blinded DRG validation on a sample
of over 2,600 claims from 50 of these hospitals and a control group of 20 hospitals.
In the course of conducting this study, we developed serious concerns about the
potential for abuse of the DRG system through upcoding and about the Healthcare
Financing Administration’s (HCFA) oversight of the accuracy of DRG coding.
Specifically, we found that, although the hospital payment system is functioning well as a
whole, the system has significant vulnerabilities to upcoding that can easily be avoided.
We also found that, despite these vulnerabilities, HCFA is not performing routine,
ongoing monitoring and analysis of DRG coding to detect problematic DRGs, hospitals,
and coding situations that require administrative, educational, or law enforcement
intervention.
FINDINGS
The DRG system is vulnerable to abuse by providers who wish to increase
reimbursement inappropriately through upcoding, particularly so within certain DRGs.
Our analysis found noticeable, detectable, and curable upcoding abuses among
providers and within specific DRGs.
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In a focused sample from a group of 299 hospitals that computer software
identified as high upcoders, we found that an average of 11% of DRG bills submitted
during 1996 were upcoded, versus 5% of bills among a control sample of hospitals.
Identifying Hospitals That Upcode
Average
Upcoding
Rate
Average
Downcoding
Rate OIG experimental sample: hospitals
with a high predicted rate of upcoding
(n=50)
11.4%
5.1%
OIG control sample: hospitals without
a high predicted rate of upcoding
(n=20)
5.2%
3.9%
Source: U.S. Department of Health and Human Services, Office of
Inspector General. (1998). Using software to detect upcoding of
hospital bills (Report no. OEI-01-97-00010). Retrieved from
https://oig.hhs.gov/oei/reports/oei-01-97-00010.pdf
The average rate of upcoding in the control sample of hospitals (those without a
high predicted rate of upcoding) was not statistically different from the average
downcoding rate. However, among hospitals that the software predicted would have a
high rate of upcoding, the average upcoding rate was more than twice that of
downcoding. The difference between upcoding and downcoding in these hospitals
suggests intentional abuse of the DRG system by some providers.
© 2018 Laureate Education, Inc. Page 3 of 6
Using data from both our focused review and the more broadly representative
1996 DRG validation performed by HCFA’s clinical data abstraction centers (CDAC), we
found that certain DRGs are particularly susceptible to upcoding.
Three Highly Vulnerable DRGs
OIG Experimental
Sample
OIG Control
Sample
CDAC
Sample Up-
coded
Down-
coded
Up-
coded
Down-
coded
Up-
coded
Down-
coded
DRG 79: Respiratory
Infections
37.7%
(n=60)
0.0%
(n=0)
18.5%
(n=5)
0.0%
(n=0)
11.0%
(n=48)
0.7%
(n=3)
DRG 416:
Septicemia
21.2%
(n=14)
0.0%
(n=0)
16.7%
(n=3)
0.0%
(n=0)
13.3%
(n=49)
1.1%
(n=4)
DRG 14: Specific
Cerebrovascular
Disorders
10.1%
(n=10)
0.0%
(n=0)
6.7%
(n=2)
0.0%
(n=0)
3.5%
(n=24)
0.4%
(n=3)
Claims billed for these three DRGs show a clear pattern that exemplifies the
upcoding seen in a group of over half a dozen DRGs we examined. These DRGs were
© 2018 Laureate Education, Inc. Page 4 of 6
upcoded disproportionately, especially by our experimentally identified upcoding
hospitals and also among hospitals from the general population represented by the
CDAC review and our control sample.
The HCFA does not routinely analyze readily available billing and clinical data
that could be used to proactively identify problems in DRG coding. Additionally, the
HCFA does not routinely analyze data from the annual validation of DRG coding
performed by its clinical data abstraction centers.
Since 1995, HCFA has used two specialized contractors called clinical data
abstraction centers to validate the DRGs on an annual national sample of over 20,000
claims billed to Medicare. On a monthly basis, the CDACs report detailed data on each
claim reviewed to HCFA’s Office of Clinical Standards and Quality. These data include
original and validated diagnostic coding, original and validated DRGs, and reasons for
any variance between the DRGs. The purpose of this validation effort is to provide
HCFA with insight as to the accuracy of DRGs billed to Medicare.
However, we found that HCFA performs no routine, ongoing analysis of CDAC
data. In our interviews with staff at the two HCFA components that have responsibility
for DRGs—the Office of Clinical Standards and Quality and the Center for Health Plans
and Providers—staff were unable to identify any routine monitoring and analysis of
CDAC data. In our review of HCFA’s instructions to the peer review organizations
(PROs), contractors who have statutory responsibility for DRG oversight, we found no
instructions advising them to perform regular analysis of CDAC data.
We believe that analysis of CDAC data can be of great value to HCFA in
overseeing the accuracy of DRG coding. For example, in HCFA’s 1996 DRG validation,
© 2018 Laureate Education, Inc. Page 5 of 6
the CDACs found a 4% upcoding rate with estimated net overpayment of $183 million.
Some may suggest that overpayments of $183 million in an $80 billion program (less
than one-quarter percent) indicate that the DRG payment system does not have major
problems with upcoding and warrants no further analysis. However, our analysis
presented above shows that upon digging below the immediate surface, upcoding
problems are readily apparent.
The HCFA does not routinely analyze data from hospitals, despite the fact that these
data are ideally suited for monitoring and analysis of DRGs.
The HCFA maintains valuable clinical, demographic, and administrative data that
form the underlying basis of each of the over 10 million DRG-based claims billed to
Medicare each year. Data for each hospitalization include diagnosis codes, procedure
codes, beneficiary demographics, admission and discharge detail, cost reporting data,
and hospital identifiers for linkage with provider demographics. Whether used on their
own to monitor billing patterns and trends or used to further explore potential problem
areas identified within CDAC data, data from hospital claims can provide valuable
information to assist in HCFA’s oversight of DRG coding.
However, we found that HCFA does not make routine use of data from hospital
claims for monitoring and analysis of DRG coding. In our interviews with staff at both
HCFA’s Office of Clinical Standards and Quality and its Center for Health Plans and
Providers, staff were unable to identify any routine monitoring and analysis of DRG
billing data. Interviews at HCFA’s Program Integrity unit, within the Office of Financial
Management, revealed that HCFA conducts some limited analysis of billing data.
© 2018 Laureate Education, Inc. Page 6 of 6
However, this analysis is done on a very broad level, primarily to identify coverage
issues.
We also reviewed HCFA’s current instructions to the Medicare PROs. We found
no instructions to the PROs advising them to perform any routine monitoring and
analysis of DRG coding, despite the fact that PROs already have a complete set of
inpatient billing data provided to them by HCFA. In fact, HCFA staff told us that the
PROs were instructed not to do “coding projects” within their current contract. We did
find that PROs are involved in sporadic activity around DRG oversight; however, this
activity often is in support of an OIG investigation.