Impact of depressive symptoms on direct medical cost among medicare recipients with knee osteoarthritis

Objective: Depressive symptoms are prevalent among knee osteoarthritis (KOA) patients and may lead to additional medical costs. We compared medical costs in Medicare Current Beneficiary Survey (MCBS) respondents with KOA with and without self-reported depressive symptoms.

Methods: We identified a KOA cohort using ICD-9/10 diagnostic codes in both Part A and Part B claims among community-dwelling MCBS respondents from 2003 to 2019. We determined the presence of depressive symptoms using self-reported data on sadness or anhedonia. We considered three groups: 1) without depressive symptoms, 2) with depressive symptoms, no billable services, and 3) with depressive symptoms and billable services. We used a generalized linear model with log-transformed outcomes to compare annual total direct medical costs among the three groups, adjusting for age, gender, race, history of fall, Total Joint Replacement, comorbidities, and calendar year.

Results: The analysis included 4118 MCBS respondents with KOA. Of them, 27% had self-reported depressive symptoms, and 6% reported depressive symptoms and received depression-related billable services. The adjusted mean direct medical costs were $8598/year for those without depressive symptoms, $9239/year for those who reported depressive symptoms and received no billable services, and $14,229/year for those who reported depressive symptoms and received billable services.

Conclusion: While over one quarter of Medicare beneficiaries with KOA self-reported depressive symptoms, only 6% received billable medical services. The presence of depressive symptoms led to higher direct medical costs, even among those who did not receive depression-related billable services.