ASSOCIATION OF OUT-OF-POCKET COSTS AFTER CHRONIC OBSTRUCTIVE PULMONARY DISEASE HOSPITALIZATION WITH SIX-MONTH READMISSION: AN INSTRUMENTAL VARIABLE ANALYSIS

Background: Out-of-pocket costs (OOPCs) have risen considerably, increasing the financial burden even among insured individuals. Higher cost-sharing is linked with decreased medication adherence and delayed or foregone care, but the impact of acute financial burden following hospitalization on subsequent readmission is not well established. This study examined the association between OOPCs incurred during chronic obstructive pulmonary disease (COPD) hospitalizations and six-month readmission rates among commercially insured adults.

Methods: This retrospective cohort study used the Merative MarketScan Database to analyze 9,327 COPD hospitalizations in January–March and October–December of 2016–2021. We used an instrumental variable (IV) approach, with discharge month as an instrument for OOPCs, leveraging annual deductible resets in January. The primary exposure was OOPCs incurred from the index COPD hospitalization. The primary outcome was all-cause readmission within 6 months of discharge. Secondary outcomes included six-month readmission requiring intensive care unit (ICU) utilization, COPD-specific readmission, and readmission due to motor vehicle crash (MVC) or trauma.

Results: Mean OOPC was $1,106 (SD $1,531) for October–December and $1,891 (SD $1,837) for January–March hospitalizations. In the IV analysis, each $1,000 increase in OOPCs was associated with a 13.5 percentage point higher risk of all-cause readmission (95% CI, +7.0 to +20.0) and a 12.7 percentage point higher risk of COPD-specific readmission (95% CI, +4.1 to +21.4). No significant association was found for readmission requiring intensive care unit (ICU) utilization (+1.7 percentage point per $1,000; 95% CI -8.7 to +12.1) or MVC or trauma-related readmission (-3.4 percentage point per $1,000; 95% CI, -30.0 to +25.3).

Conclusions: Higher OOPCs incurred from COPD hospitalizations were associated with increased readmission risk among commercially insured adults. Findings highlight the need for reforms to protect patients from cost-related harms after acute illness.