Objective: Comorbid insomnia and sleep apnea (COMISA) is a frequent but underrec-ognized condition in patients with obstructive sleep apnea (OSA). While OSA is strongly linked to hypertension, the independent contribution of COMISA to resistant hyper-tension (RH) remains unclear. This study aimed to investigate the association between COMISA and RH in hypertensive OSA patients and to identify independent predictors of RH.

Methods: This retrospective cross-sectional study included 131 patients diagnosed with both OSA and hypertension who underwent full-night polysomnography (PSG) at a ter-
tiary sleep center. The Insomnia Severity Index (ISI) was used to define COMISA (ISI ≥15). Resistant hypertension (RH) was defined as uncontrolled blood pressure despite the use of at least 3 antihypertensive agents of different classes, including a diuretic. Demographic, clinical, and polysomnographic data were analyzed using multiple logistic regression to determine independent predictors of RH.

Results: Of 131 hypertensive OSA patients, 39 (29.8%) met criteria for COMISA. The preva-lence of RH was 43.5%. COMISA was significantly more frequent in the RH group (66.7% vs. 33.3%, P = .006). In the multiple logistic regression analysis, COMISA (OR = 5.26, P < .001, 95% CI: 2.04-13.57) and male sex (OR = 3.24, P = .010, 95% CI: 1.36-7.72) were identi-fied as independent predictors of RH, while age, apnea–hypopnea index (AHI), and body mass index (BMI) were not significantly associated.

Conclusion: Comorbid insomnia and sleep apnea (COMISA) markedly increases the risk of RH in hypertensive OSA patients, independent of apnea severity and obesity. These find-ings highlight COMISA as a distinct cardiovascular phenotype within the OSA spectrum. Routine screening and targeted treatment of insomnia in OSA may represent a critical approach to improving blood pressure control and cardiovascular outcomes.