Patients with obstructive sleep apnea syndrome (OSAS) use health-care resources at higher rates than control subjects for years prior to diagnosis. Although obesity and certain cardiovascular disorders are more common in OSAS patients, the precise cause of increased health-care utilization is unclear.
To examine the causes of increased utilization, and what patients with OSAS were being treated for prior to this diagnosis.
We compared the records of 773 patients with OSAS to those of age-, gender-, geographic-, and physician-matched control subjects from the general population.
We found that sleep apnea patients used 23 to 50% more resources (defined by physician fees, physician visits, and hospital nights) in the 5 years prior to diagnosis than did control subjects. We examined the diagnoses made and found that apnea patients are at higher risk for hypertension (odds ratio [OR], 2.5; 95% confidence interval [CI], 2.0 to 3.3), congestive heart failure (OR, 3.9; 95% CI, 1.7 to 8.9), cardiac arrhythmias (OR, 2.2; 95% CI, 1.2 to 4.0), cardiovascular disease (OR, 2.6; 95% CI, 2.0 to 3.3), chronic obstructive airways disease (OR, 1.6; 95% CI, 1.2 to 2.0), and depression (OR, 1.4; 95% CI, 1.0 to 1.9). To control for the confounding effects of obesity and to determine the independent effects of body mass index (BMI), gender, age, degree of hypoxemia, apnea-hypopnea index, and sleepiness in the 773 patients, we performed a logistic regression analysis with the dependent variable being diagnosis, and a linear regression analysis with the dependent variable being measures of health-care utilization. Age and BMI were significant independent predictors of most cardiovascular diagnoses and arthropathy. Male gender predicted ischemic heart disease (OR, 2.98; 95% CI, 1.36 to 6.54), and female gender was predictive of chronic obstructive airways disease (OR, 2.63; 95% CI, 1.85 to 3.72) and depression (OR, 2.24; 95% CI, 1.45 to 3.44). The best model predicting health-care utilization measures was comprised of age, gender, and BMI, and explained 9%, 14%, and 8% of the variability in physician fees, number of physician claims, and number of physician visits, respectively.
Of all comorbid diagnoses, significantly increased utilization was found for cardiovascular disease and especially hypertension in the OSAS patients.