Undiagnosed obstructive sleep apnea increases risk of hospitalization among a racially diverse group of older adults with comorbid cardiovascular disease.

STUDY OBJECTIVES: Undiagnosed obstructive sleep apnea (OSA) is associated with increased risk for subsequent cardiovascular events, hospitalizations, and mortality. The primary objective of this study was to determine the association between undiagnosed OSA and subsequent hospitalizations among older adults with pre-existing cardiovascular disease (CVD). A secondary objective was to determine the risk of 30-day hospital readmission associated with undiagnosed OSA among older adults with CVD.

METHODS: This was a retrospective cohort study of a 5% sample of Medicare administrative claims data for years 2006-2013. Beneficiaries aged 65 and older diagnosed with CVD were included. Undiagnosed OSA was defined as the 12-month period prior to OSA diagnosis. A similar 12-month period among beneficiaries not diagnosed with OSA was used for the comparison group (no OSA). Our primary outcome was the first all-cause hospital admission. Among beneficiaries with a hospital admission, 30-day readmission was assessed for the first hospital admission only.

RESULTS: Among 142,893 beneficiaries diagnosed with CVD, 19,390 had undiagnosed OSA. Among beneficiaries with undiagnosed OSA, 9,047 (46.7%) experienced at least one hospitalization while 27,027 (21.9%) of those without OSA experienced at least one hospitalization. Following adjustment, undiagnosed OSA was associated with increased risk of hospitalization (odds ratio (OR) 1.82; 95% confidence interval (CI) 1.77, 1.87) relative to no OSA. Among beneficiaries with ≥1 hospitalization, undiagnosed OSA was associated with a smaller but significant effect in weighted models (OR 1.18; 95% CI 1.09, 1.27).

CONCLUSIONS: Undiagnosed OSA was associated with significantly increased risk of hospitalization and 30-day readmissions among older adults with pre-existing CVD.