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The association between obstructive sleep apnea (OSA) and cardiovascular disease is well recognized. The impact of OSA on the outcomes of patients hospitalized with diastolic heart failure remains unexplored. In this analysis of National Inpatient sample, we intended to assess the prevalence and impact of OSA and mitral valve insufficiency (MVI) in patients admitted with diastolic heart failure.
We used nationwide inpatient sample database years 2005-2012 to identify patients admitted with diastolic heart failure (ICD9: 428.30-428.32) and concomitant diagnosis of mitral valve insufficiency (ICD9: 424.0). Within these patients, a diagnosis of obstructive sleep apnea (OSA; ICD9: 327.23) was identified. Mortality rates, patient charges, hospital cost, and length of stay were compared between patients with diastolic heart failure and MVI with or without OSA. Mortality data was evaluated using a logistic regression model, whereas charges, cost, and length of stay were compared using log-normal regression models given heteroscedastic residuals. All analyses accounted for NIS sampling design. SAS v. 9.4 was used for statistical analysis and p < 0.05 indicated statistical significance.
From 2005 to 2012, 5,438,471 patients were hospitalized with diastolic heart failure. Of these patients, 396,812 (7.3%) had MVI and 29,490 (7.4%) of these had a diagnosis of OSA. The mortality rate of patients with MVI and OSA was 2.1% compared to 3.8% in patients with MVI but no OSA. As such, patients with MVI and OSA had 44% lower odds of dying compared to patients with MVI without OSA (95% CI = 32% to 53%, p < 0.001). Total patient charges for patients with MVI and OSA were 15.9% higher than patients with MVI without OSA (95% CI = 12.6% to 19.3%, charges = $32,742 vs. $28,246, respectively, p < 0.001). Similarly, total hospital cost for patients with MVI and a diagnosis of OSA was about 11.4% higher than patients with MVI without OSA (95% CI = 8.8% to 14.1%, cost = $10,281 vs. $9,229, respectively, p < 0.001). Finally, hospital length of stay (LOS) for patients with MVI and a diagnosis of OSA was about 3.7% higher than patients with MVI without OSA (95% CI = 1.6% to 5.9%, LOS = 5.0 days vs. 4.8 days, respectively, p < 0 .001).
In this large sample of diastolic heart failure patients, we observed that in hospital mortality was significantly lower in those with mitral insufficiency and obstructive sleep apnea,though they had increased cost of care and length of stay.