Aim: Bariatric surgery can provide significant weight loss but a complete resolution obstructive sleep apnoea (OSA) cannot be predicted. The aim of our audit was to assess the prevalence of OSA in bariatric clinics and outcomes after malabsorptive bariatric surgery.
Methods: Retrospective observational analysis was performed on patients who had undergone bariatric surgery (laparoscopic gastric bypass and sleeve gastrectomy) and completed a minimum of 6 months of follow up. Information from clinical letters, from first review in bariatric service and latest follow up appointment were compared. Referral for assessment of OSA was based on clinical index of suspicion.
Results: Records of 230 patients were analysed. Pre-operative mean age was 45 years (2069); mean weight 136 kg (85250); BMI 48.5 kg/m2 (3583); and 31% were men. Pre-op: 13.5% (n=31) had pre-established OSA on CPAP; 27.4% (n=63) had clinical possibility of OSA and referred for sleep studies. 21.7% (n=50) had no features to suggest OSA. There was no documentation on the rest of 86 patients. Respiratory assessment: Of the 63 patients referred, 57% (n=36) had no or mild OSA; 8% (n=5) had moderate OSA; 35% (n=22) have severe or very severe OSA. The BMI of those without OSA was lower than those with OSA (46.3 vs 52.0, P=0.014). Post-op follow-up: mean period of follow up was 236 days. 40 of the 58 patients (who had moderate to severe OSA or established CPAP treatment) had further respiratory follow-up. Mean BMI was 27.9 (2566). 15/40 had OSA resolved and hence CPAP discontinued; 22/40 had improvement in OSA but still warranted CPAP continuation; three patients were not compliant with CPAP. Comparing continued vs resolved OSA group: pre-op BMI (52 vs 49.6), latest BMI (38.5 vs 35.7), and weight loss achieved (44.0 vs 40.5) were comparable.
Conclusion: i) Screening for OSA needs to be universal in bariatric pathways (especially in patients with higher BMI) as clinical suspicion may not be accurate. ii) Prevalence of OSA is high in patients awaiting bariatric surgery (58 of 144 tested 40%). iii) 55% continue to have OSA after bariatric surgery and requiring CPAP despite good weight loss. iv) Periodic reassessment of OSA needs to be arranged post-bariatric surgery and spontaneous resolution should not be assumed.