Sleep Apnea as a Risk Factor for Diastolic Dysfunction: A Systematic Review and Meta-Analysis

<b><i>Background:</i></b> This meta-analysis assessed the relationship between obstructive sleep apnea (OSA) and echocardiographic parameters of diastolic dysfunction (DD), which are used in the assessment of heart failure with preserved ejection fraction. <b><i>Methods:</i></b> We searched the databases including Ovid MEDLINE, Ovid Embase, Scopus, Web of Science, Google Scholar, and EBSCO CINAHL from inception up to December 26, 2020. The search was not restricted to time, publication status, or language. Two independent investigators screened the identified studies and extracted the data in duplicate. We conducted a meta-analysis using RevMan v.5. The risk of bias was assessed using Cochrane collaboration tools. Comparisons were made between patients with OSA, diagnosed in-laboratory polysomnography or home sleep apnea testing, and patients without OSA in relation to established markers of DD. <b><i>Results:</i></b> Primary search identified 2,512 studies. A total of 18 studies including 2,509 participants were included. The two groups were free of conventional cardiovascular risk factors. Significant structural changes were observed between the two groups. Patients with OSA exhibited greater left atrial volume index (LAVI) (3.94 95% CI [0.8, 7.07]; <i>p</i> = 0.000) and left ventricular mass index (11.10 95% CI [2.56, 19.65]; <i>p</i> = 0.000) as compared to control group. The presence of OSA was also associated with more prolonged deceleration time (10.44 ms 95% CI [0.71, 20.16]; <i>p</i> = 0.04), isovolumic relaxation time (IVRT) (7.85 ms 95% CI [4.48, 11.22]; <i>p</i> = 0.000), and a lower ratio of early to late mitral inflow velocities (E/A) ratio (−0.62 95% CI [−1, −0.24]; <i>p</i> = 0.001) suggestive of early DD. The early mitral inflow velocity to mitral annular early diastolic velocity (E/e′) ratio (0.94 95% CI [0.44, 1.45]; <i>p</i> = 0.000) was increased. Linear correlation between severity of OSA and LAVI and IVRT parameters was observed but this association did not sustain for the E/A and E/e′. The ejection fraction was not significantly different between patients with OSA and healthy controls (−0.48 95% CI [−1.18, 0.23]; <i>p</i> = 0.18). <b><i>Conclusion:</i></b> An association between OSA and echocardiographic parameters of DD was detected that was independent of conventional cardiovascular risk factors. OSA may be independently associated with DD perhaps due to higher LV mass. Investigating the role of continuous positive airway pressure therapy in reversing or ameliorating DD is recommended.