Metabolic syndrome in non-obese patients with OSA: learning points of across-sectional study from atertiary care hospital in Central India.

Abstract

Study objectivesObesity is often considered mandatory for the diagnosis of Metabolic Syndrome (MS). Data on the prevalence of MS in non-obese patients with Obstructive Sleep Apnea (OSA) is scarce. This study was aimed to determine the prevalence of MS in non-obese patients with OSA.MethodologyAll consecutively diagnosed patients with OSA between October 2018 and November 2019 were screened for metabolic syndrome. Patients with OSA and BMI < 25 kg/m2 (NOOSA) vs BMI > 25 kg/m2 (obese OSA) were compared. Lean waist NOOSA was defined as BMI < 25 kg/m2 and WC < 80 cm (32 in.) for women or < 90 cm (36 in.) for men.ResultsDuring the study period, 502 patients were diagnosed with OSA. MS was observed in 35% of patients with NOOSA compared to obese patients with OSA (79%). In the NOOSA group, hypertension, impaired fasting glucose, diabetes mellitus and dyslipidemia were observed in 65, 48, 14 and 61% respectively and all of these parameters were significantly more common in the obese group (p < 0.001). Parameters of OSA severity (apnea-hypopnea index or AHI, time spent below 90% saturated or T90, and nadir oxygen) were significantly more severe in the obese group with OSA. Approximately 83% of patients in the NOOSA group had at least two metabolic risk factors, compared to the obese OSA group, in which 95% had two or more metabolic risk factors. Sixty-four percent of patients with NOOSA with lean waist had at least two metabolic risk factors. At BMI cut-offs of < 25, < 27 and < 30 kg/m2; 35, 46 and 57% of patients with OSA respectively had metabolic syndrome.ConclusionMetabolic syndrome was observed in approximately one in three patients with OSA and BMI < 25 kg/m2. Approximately two of every three lean waist non-obese patients with OSA had at least two markers of metabolic syndrome. The role of OSA in the development of metabolic syndrome in non-obese individuals needs further exploration.