Redaction of Substance Abuse Claims in Medicare Research Files Affects Spending Outcomes for Nearly One in Five Beneficiaries with Serious Mental Illness

Abstract

Researchers who rely on Medicare claims to analyze spending outcomes for beneficiaries with serious mental illness should be aware of the potential for bias due to nonrandom redaction of substance abuse data.

Long-Term Implications Of A Short-Term Policy: Redacting Substance Abuse Data

“…Compared with one earlier study of Medicare beneficiaries with serious mental illness 7 and compared with ResDAC’s analyses of redaction for all patients in Medicare, 4 our study estimated how redaction affects the prevalence of conditions likely to be comorbid with substance abuse and the prevalence of inpatient admissions by diagnosis. Our study also quantified the concentrated effect of redaction among younger Medicare beneficiaries.…”

“…But redaction can affect a wide range of studies. Prior analyses highlighting this issue were limited to Medicaid recipients 2 or a subset of Medicare recipients with serious mental illness; 7 the impact on the full Medicare population is unknown.…”

Shifts in Alcohol‐Related Diagnoses After the Introduction of International Classification of Diseases, Tenth Revision, Clinical Modification Coding in U.S. Hospitals: Implications for Epidemiologic Research

“…Thus, the HCUP databases were not affected by the redactions of Medicare and Medicaid claims with substance‐related diagnoses and procedures from CMS research files. Previous work suggests that these redactions, which occurred between 2013 and 2017, had a substantial impact on healthcare expenditure estimates for Medicare beneficiaries with severe mental illness (Roberto et al., ), as well as prevalence estimates of chronic conditions that commonly co‐occur with substance use disorders (Austin et al., ). The all‐payer HCUP databases are a critical source of data on inpatient stays involving substance‐related diagnoses, particularly for the period during which CMS redaction policy was in effect.…”

Adherence to Antipsychotic Therapy: Association With Hospitalization and Medicare Spending Among Part D Enrollees With Schizophrenia

“…Data were obtained for a 5% random sample of Medicare beneficiaries from the Centers for Medicare and Medicaid Services (CMS) Chronic Conditions Data Warehouse (CCW) data set for 2011 and 2012, including demographic and enrollment information; Medicare Parts A, B, and D claims; and summarized annual utilization and spending data for each beneficiary from the Master Beneficiary Services Cost and Use file. The cost and use data are compiled by CMS by using the full set of Medicare claims and provide a source of beneficiary-level spending and utilization data that are unaffected by the substance abuse data redaction (13). Antipsychotic use was measured by using the Part D prescription drug event files, which include National Drug Code identifiers, service dates, and days of supply.…”

“…Efforts to examine the relationship among antipsychotic adherence, hospitalization, and spending among Medicare Part D enrollees are complicated because substance abuse claims are redacted from the Medicare Parts A and B research files. It has been estimated that one in five Part D enrollees with serious mental illness has claims data missing because of the redaction and that average Part A expenditures for beneficiaries affected by the redaction are underreported in the claims by 57% (13). Incomplete information about utilization and spending outcomes for antipsychotic users with substance abuse disorders-who often have poor medication adherence, higher Medicare spending, and increased risk of relapse-may produce biased estimates of the association between antipsychotic adherence and hospitalization.…”