Study suggests it does when using standard claims-based risk adjustment

While dual Medicare and Medicaid status is associated with hospital readmission when using standard claims-based risk adjustment, that association weakens when additional clinical measures are included in the risk adjustment, researchers found.

According to a study by Benjamin A. Y. Cher, MS, University of Michigan Medical School, Ann Arbor, Michigan, and colleagues, which was published in JAMA Network Open, this suggests that dual-eligibility status reflects unmeasured clinical risk instead of social risk factors associated with readmission after surgery.

Cher and colleagues pointed out that CMS (Centers for Medicare and Medicaid Services) is contemplating adjusting for social risk factors when evaluating hospital performance under value-based purchasing (VBP) programs. While adjusting for patient health status and other clinical factors is widely accepted, according to Cher and colleagues, “it is unknown whether dual eligibility represents a unique domain of social risk or instead represents clinical risk unmeasured by variables available in traditional Medicare claims.”

In this study, Cher and colleagues wanted to see whether dual eligibility for Medicare and Medicaid is associated with risk-adjusted hospital readmission rates after surgery.

The retrospective cohort study included 55,651 Medicare patients who underwent common general, vascular, and gynecologic procedures at 62 Michigan hospitals from Jan. 1, 2014-Dec. 1, 2016. From these patients, the authors generated representative patient cohorts from traditional Medicare claims (29,710 patients) and the Michigan Surgical Quality Collaborative (MSQC) clinical registry (25,941 patients) — a prospective clinical registry formed by a partnership between Blue Cross Blue Shield of Michigan and 73 Michigan hospitals.

The Medicare claims data source included patient demographic characteristics, baseline comorbidities, dual eligibility, and 30-day readmission rates. The MSQC included additional measures of clinical risk, specifically results from a preoperative clinical examination by the surgical team that provided assessments — functional status and American Society of Anesthesiologists (ASA) classification of physical status — not available in Medicare fee-for service claims.

The authors compared the association between dual eligibility and risk-adjusted 30-day readmission rates after surgery between the two models, inclusive and exclusive of the additional measurements of clinical risk. The main outcome was risk-adjusted all-cause 30-day readmission after surgery.

Of the 29,710 patients in the Medicare claims cohort, there were a total of 3,986 dual-eligible beneficiaries in the Medicare claims cohort (2,554 women; mean age 72.9 years). The MSQC cohort included 1,608 dual-eligible beneficiaries (990 women; mean age 72.9 years).

In the Medicare claims cohort, dual-eligible beneficiaries were more likely to be readmitted than Medicare-only beneficiaries (15.5% compared with 13.3% — a difference of 2.2 percentage points), while in the MSQC cohort dual eligibility was not significantly associated with readmission (difference, 0.6 percentage points).

The authors also found that adding dual eligibility to the risk-adjustment models had little association with hospital rankings in either of the 2 data sets. In the Medicare claims cohort 44.3% did not experience a change in ranking by risk-adjusted readmission rate, while in the MSQC cohort 72.6% of hospitals did not experience a change in ranking.

Thus, Cher and colleagues pointed out, while dual eligibility status was associated with hospital readmission when using standard claims-based risk adjustment, that association diminished when they adjusted for additional clinical risk factors as measured by the MSQC.

“This study suggests that dual eligibility for Medicare and Medicaid may reflect unmeasured clinical risk of readmission in claims data,” Cher and colleagues concluded. “Policy makers should consider incorporating more robust measures of social risk into risk-adjustment models used by value-based purchasing programs.”

In a commentary accompanying the study, Linda Diem Tran, Stanford-Surgery Policy Improvement Research & Education (S-SPIRE) Center, Stanford University School of Medicine, Palo Alto, California, observed that the issue of including social factors such as socioeconomic position and racial/ethnic contexts in risk adjustment for performance measures is controversial.

For example, she wrote, critics are concerned that social risk adjustment can conceal disparities in care and that accounting for social risk factors “tacitly lowers quality standards for disadvantaged patients.” On the other hand, proponents argue hospitals and physicians shouldn’t be penalized if their patients have different risk profiles, and that excluding social risk factors from performance metrics would penalize those hospitals that care for poorer and sicker patients.

Tran suggested that in addition to social risk adjustment, financial incentives can be targeted to reward improvements in health equity and clinical outcomes for the most vulnerable patients, and that CMS can adopt and support initiatives — within and outside of health care systems — addressing social determinants of health.

  1. Dual eligibility status was associated with hospital readmission when using standard claims-based risk adjustment, and that association diminished when researchers adjusted for additional clinical risk factors, suggesting that dual eligibility for Medicare and Medicaid may reflect unmeasured clinical risk of readmission in claims data.

  2. More robust measures of social risk should be incorporated into risk-adjustment models used by value-based purchasing programs.

Michael Bassett, Contributing Writer, BreakingMED™

Cher and Tran reported no disclosures.

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