Effect of Continuous Positive Airway Pressure on Hemoglobin A1c in Patients with Obstructive Sleep Apnea: A Systematic Review and Meta-analysis

Abstract

There is little conclusive data regarding the effect of continuous positive airway pressure (CPAP) on glycated hemoglobin (HbA(1c)). An earlier meta-analysis included two randomized controlled trials (RCTs) and found no significant effect of CPAP on HbA(1c). The meta-analysis presented here was conducted to include all relevant observational studies and RCTs on the effect of CPAP on HbA(1c). We searched the PubMed database for all studies published prior to March 2012 for trials of the effect of CPAP on HbA(1c). Data from observational studies and RCTs that met the inclusion criteria were extracted for pre- and post-treatment HbA(1c). A total of nine studies that included 151 subjects met the inclusion criteria. The duration of the studies ranged from 41 days to 6 months. The mean net change in the HbA(1c) was -0.06 % [95 % CI: -0.24, 0.12] (p = 0.5). Five of the nine studies, with a total of 112 subjects, comprised patients with diabetes mellitus (DM) type 2. The mean net change in HbA(1c) for the subjects with DM type 2 was 0.08 % [95 % CI: -0.26, 0.42] (p = 0.65). The mean net change in HbA(1c) for subjects with DM type 2 in studies that were at least 3 months in duration was 0.16 % [95 % CI: -0.26, 0.58] (p = 0.45). This meta-analysis found that CPAP does not reduce HbA(1c) levels when used in the short term.