Lina Palaiodimou, MD
The role of sleep-disordered breathing (SDB) is well established in the development of a first stroke or death from any cause. Previous studies have shown that SDB is associated with an increased incidence of stroke or death from any cause, and this association is independent of other cardiovascular and cerebrovascular risk factors. This condition appears both in prestroke patients and in poststroke patients, and is more often obstructive than central. An association between SDB and recurrent strokes is also being presumed, but there are no sufficient prospective data to demonstrate and support this association.
The study of Brown et al. is an attempt to enrich the scarce data regarding the interaction between SDB and recurrent strokes. More specifically, the primary endpoint of this study is to investigate the association between SDB and recurrent ischemic stroke and secondary endpoints are: possible association between SDB and all-cause poststroke mortality and possible influence of ethnicity on the interaction between SDB and outcome measures (recurrent stroke or mortality). For that purpose, the investigators designed a prospective study of 842 patients who suffered from an index ischemic stroke and underwent a sleep apnea study shortly after the event. Additionally, patients had to be above 45 years old and be a resident of Nueces County, as the study was limited in 7 acute care hospitals of this certain county. Demographics, stroke risk factors, clinical variables and the REI (which is the sum of apneas plus hypopneas per hour of sleep apnea study duration) were recorded. Patients were followed until the first recurrent stroke, death or the last follow-up date, whichever came first. Proportional hazard models were conducted, both unadjusted and adjusted, to assess the association between REI and recurrent stroke or death. Finally, the interaction of ethnicity, REI and each outcome was statistically analyzed.