Relationship of sleep apnea to functional capacity and length of hospitalization following stroke

STUDY OBJECTIVES: Recent evidence indicates that sleep apnea is common in patients with stroke. We hypothesized that the presence of sleep apnea among stroke patients would be associated with a greater degree of functional disability and longer hospitalization following stroke. DESIGN: Prospective study. SETTING AND PATIENTS: Sixty-one stroke patients admitted to a stroke rehabilitation unit. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Sleep studies were performed on all patients, and sleep apnea was defined as an apnea-hypopnea index of 10 or more per hour of sleep. Patients underwent functional assessments, including the Functional Independence Measure. Sleep apnea was found in 72% of patients; 60% had predominantly obstructive sleep apnea, while 12% had predominantly central sleep apnea. Although the severity of stroke was similar in the 2 groups, compared to patients without sleep apnea, those with sleep apnea had lower functional capacity Functional Independence Measure score (mean +/- SEM) 80.2 +/- 3.6 versus 94.7 +/- 4.3, p < 0.05 at admission, and 101.5 +/- 2.8 versus 112.9 +/- 2.7, p < 0.05 at discharge] and spent significantly more days in rehabilitation (45.5 +/- 2.3 versus 32.1 +/- 2.7 days, p < 0.005). In addition, multiple regression analysis showed that obstructive sleep apnea was significantly and independently related to functional impairment and length of hospitalization. CONCLUSIONS: Sleep apnea is very common among stroke patients undergoing rehabilitation, and its presence is associated with worse functional impairment and a longer period of hospitalization and rehabilitation. These data suggest that sleep apnea may be contributing to functional impairment and prolonged hospitalization following stroke.