Impact of bariatric surgery on the resolution of obesity hypoventilation syndrome at 1-year follow-up: a retrospective study.

Abstract

Study objectives: This study aimed to assess the effectiveness of metabolic and bariatric surgery in patients with obesity comorbid with obesity hypoventilation syndrome (OHS) at 1-year follow-up.

Methods: This retrospective study was conducted between January 2020 and June 2023 at a metabolic and bariatric surgery center in a university-affiliated tertiary hospital in China. Clinical data, including body mass index, arterial blood gas values, portable sleep study results, and anthropometric parameters, were recorded pre- and postoperatively. Correlations between variables and risk factors for OHS resolution were analyzed.

Results: Among 1,134 candidates for metabolic and bariatric surgery, 187 (16.5%) had comorbid OHS; 151 patients with OHS met inclusion criteria and completed the 1-year follow-up visit (body mass index 39.1 ± 6.8 kg/m² with partial pressure of carbon dioxide in arterial blood [PaCO₂] 48.6 ± 3.0 mmHg). At 1-year follow-up, body mass index decreased to 29.0 ± 6.0 kg/m² (P < .001) and PaCO₂ dropped to 43.8 ± 5.5 mmHg (P < .001). Resolution of OHS, defined as awake PaCO₂ < 45 mmHg with discontinuation of positive airway pressure therapy for a minimum of 6 months before obtaining the arterial blood gas at the 12-month visit, was achieved in 105 (69.5%) of the patients. Nonlinear analysis indicated that PaCO₂ did not significantly decrease until the percentage of total weight loss exceeded approximately 20%. A larger reduction in waist circumference was associated with a greater reduction in PaCO₂, particularly when waist circumference reached less than 25 cm. Beyond this point, ΔPaCO₂ reached a plateau. In multivariate analysis, a larger preoperative waist circumference (odds ratio: 1.046, 95% confidence interval: 1.031-1.118, P = .025) and arterial blood gas pH < 7.35 (odds ratio: 3.921, 95% confidence interval: 2.305-9.140, P < .001) were associated with lack of resolution of OHS, and a larger percentage of total weight loss after bariatric surgery (odds ratio: 0.917, 95% confidence interval: 0.846-0.965, P = .001) was independently associated with OHS resolution.

Conclusions: Metabolic and bariatric surgery is an effective treatment for OHS. Achieving a sufficient percentage of total weight loss is critical for the resolution of OHS.

Citation: Ma S, Yu W, Yang C, et al. Impact of bariatric surgery on the resolution of obesity hypoventilation syndrome at 1-year follow-up: a retrospective study. J Clin Sleep Med. 2025;21(10):1665-1678.