Recurrence of sleep apnea without concomitant weight increase 7.5 years after weight reduction surgery

In this study we report on a long-term follow-up of 14 morbidly obese sleep apneic patients, 11 of whom were male and 3 female. The mean age was 46 +/- 8.5 years. These patients had undergone weight reduction surgery. Before surgery, body mass index (BMI) and apnea index (AI) were 45 +/- 7.2 kg/m2 and 40 +/- 28.8 (SD) h-1, respectively. Four and a half months after surgery (range, 2 to 7 months), both BMI and AI significantly decreased to 33 +/- 7.5 kg/m2 and 11 +/- 16.4 h-1, respectively. Seven and half years after surgery (range, 5 to 10 years), BMI increased only slightly to 35 +/- 6.0 kg/m2 (p > 0.2), while AI increased significantly to 24 +/- 23 h-1 (p < 0.05). There were poor and insignificant correlations between changes in BMI and AI prior to 4.5 months after operation (r = 0.23; p > 0.4). and 4.5 months to 7.5 years after operation (r = 0.41; p > 0.1). We conclude that morbid obesity is not the only causative factor in the sleep apnea syndrome for these patients. Weight reduction surgery alone does not "cure" their sleep apnea, and they are still at risk.