Incidence of Long COVID diagnoses in 3.6 million US Medicare beneficiaries with COVID-19.

Abstract

BACKGROUND Long COVID incidence and risk factors in older adults need to be better characterized to identify risk mitigation strategies. Our aim was to quantify the incidence of Long COVID in a population-based sample of older adults and to describe the association between COVID-19 vaccination and Long COVID risk. METHODS This cohort study included Medicare fee-for-service beneficiaries ≥ 66 years diagnosed with COVID-19 between October 1, 2021, and March 31, 2023 (index date). Long COVID diagnoses were identified from Medicare Part A-B claims based on ICD-10-CM code U09.9. We measured the number of COVID-19 vaccine doses administered prior to the index date using Medicare Part B claims and pharmacy records. Kaplan-Meier estimators, Cox proportional hazards, and Fine-Grey regression models were used to estimate the 1-year cumulative incidence and relative rate of Long COVID. RESULTS We identified 3,588,671 Medicare beneficiaries diagnosed with COVID-19. Overall, 3.89% of beneficiaries were diagnosed with Long COVID over one year. A gradient in the one-year cumulative incidence of Long COVID was observed according to the number of prior COVID-19 vaccine doses. Beneficiaries with four or more COVID-19 vaccine doses had a 39% lower adjusted rate of Long COVID relative to beneficiaries without a prior dose (aHR=0.61, 95%CI=0.60-0.62). CONCLUSIONS Long COVID diagnoses in Medicare claims were common in a large sample of older adults with COVID-19, and we observed a gradient in Long COVID risk across the number of prior COVID-19 vaccine doses. Promoting continued vaccination may be an effective strategy to mitigate the burden of Long COVID in older adults.