The different subtypes of obstructive sleep apnea (OSA) have different cardiovascular outcomes, and it would benefit clinicians to know that patients with the Excessively Sleepy subtype of sleep apnea have a significantly increased risk for heart failure, according to study results published in the American Journal of Respiratory and Critical Care Medicine.
This study was designed to characterize the symptom subtypes of OSA and identify associations with incidence and prevalence of cardiovascular disease (CVD). The study used data on 1207 patients from the community-based Sleep Heart Health Study (SHHS) with an apnea-hypopnea index (AHI) ≥15 events/h, and 2830 patients with an AHI <5. Patients were classified by symptom subtype, then logistic regression was used to assess associations between these subtypes and overall CVD prevalence and its individual components (heart failure, coronary heart disease, and stroke). Researchers used Cox proportional hazards models and Kaplan-Meier survival analysis to evaluate whether the symptom subtypes were associated with cardiovascular mortality and other incident events.
Similar to prior studies, 4 subtype groups were identified: Moderately Sleepy (38.5%), Minimally Symptomatic (32.6%), Excessively Sleepy (16.7%), and Disturbed Sleep (12.2%). The Excessively Sleepy subtype was associated with >3 times the risk for prevalent heart failure compared with the other apnea subtypes. After adjusted analysis, the Excessively Sleepy subtype was the only subtype associated with significantly increased risk for prevalent CVD (odds ratio [OR], 2.00; 95% CI, 1.21-3.31; P =.007) and prevalent heart failure (OR, 4.64; 95% CI, 2.17-9.92; P =.0001) when compared with individuals without sleep apnea.
Limitations to this study included participants with more severe symptoms, older participants, a lack of data on underlying risks, and a lack of accurate continuous positive airway pressure therapy data.
Study investigators concluded that “patients with the Excessively Sleepy subtype are at increased risk of CVD compared not only to patients without OSA, but also relative to other patients with similar AHI in other subtypes. This concept should be introduced into routine clinical practice, by developing appropriate and validated clinical support tools and training clinicians in identifying the subtype at increased risk.”
Mazzotti DR, Keenan BT, Lim DC, Gottlieb DJ, Kim J, Pack AI. Symptom subtypes of obstructive sleep apnea predict incidence of cardiovascular outcomes [published online February 15, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201808-1509OC