Cardiovascular and psychiatric morbidity in obstructive sleep apnea (OSA) with insomnia (sleep apnea plus) versus obstructive sleep apnea without insomnia: a case-control study from a Nationally Representative US sample.

Purpose: To evaluate cardiovascular and psychiatric morbidity in patient visits with obstructive sleep apnea (OSA) with insomnia (OSA+Insomnia) versus OSA without insomnia (OSA-Insomnia) in a nationally representative US sample.

Methods: A retrospective case-control study of epidemiologic databases (National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey) representing an estimated ± standard error (SE) 62,253,910 ± 5,274,747 (unweighted count=7234) patient visits with diagnosis of OSA from 1995-2010, was conducted. An estimated 3,994,104 ± 791,386 (unweighted count=658) were classified as OSA+Insomnia and an estimated 58,259,806 ± 4,849,800 (unweighted count=6576) as OSA-Insomnia. Logistic regression analysis was carried out using OSA+Insomnia versus OSA-Insomnia as the dependent variable, and age (>50 years versus ≤ 50 years), sex, race ('White' versus 'non-White'), essential hypertension, heart failure, ischemic heart disease, cardiac dysrhythmia, cerebrovascular disease, diabetes, obesity, hyperlipidemia, depressive, anxiety, and adjustment disorders (includes PTSD), hypersomnia and all medications used as independent variables. All comorbidities were physician diagnosed using the ICD9-CM.

Results: Among patient visits with OSA, an estimated 6.4%± 0.9% also had insomnia. Logistic regression analysis revealed that the OSA+Insomnia group was significantly more likely to have essential hypertension (all ICD9-CM codes 401) (OR=1.83, 95% CI 1.27-2.65) and provisionally more likely to have cerebrovascular disease (ICD9-CM codes 430-438) (OR=6.58, 95% CI 1.66-26.08). The significant OR for cerebrovascular disease was considered provisional because the unweighted count was <30.

Conclusions: In a nationally representative sample, OSA+Insomnia was associated significantly more frequently with essential hypertension than OSA-Insomnia, a finding that has not been previously reported. In contrast to studies that have considered patient self-reports of psychological morbidity, the absence of a significant association with psychiatric disorders in our study may be indicative of the fact that we considered only physician-rated psychiatric syndromes meeting ICD9-CM criteria. Our findings among the OSA+Insomnia group are therefore most likely conservative.