Relation between OSA severity and the degree of diastolic dysfunction
Isovolumic relaxation time was significantly longer in severe vs mild OSA (mean difference 9.69 ms CI [5.16, 14.23]). The E/e’ ratio was not significantly different between mild vs control but was higher in moderate to severe OSA vs control (1.62 [0.06, 3.18]). Left ventricular mass was significantly higher in moderate to severe vs mild OSA (16.25 g [10.26, 22.23]). Although not statistically significant there was a trend towards inverse relationship between E/A ratio and severity of OSA, such that patients with more severe degree of sleep apnea had lower E/A ratio. Patients with moderate to severe sleep apnea tended to have greater LAVI as compared to controls or those with mild OSA but this association was not statistically significant. There was a trend toward higher left atrial volume index in both mild OSA vs control (1.71 [0.16, 3.26]) and moderate to severe vs control (5.49 [2.33, 8.64]) but the differences were not statistically significant. Forest plots are shown in Figure 4.