Dr. David L. Greenburg of Walter Reed Army Medical Center in Washington, DC and team studied 12 reports involving 342 patients, including 5 prospective trials. Of all, one study had fewer than 50 participants.

The team reported that the random-effects mean pooled body mass index was reduced from 55.3 to 37.7.

The researchers found that the baseline rate of 54.7 events per hour with regard to the mean apnea-hypopnea index (AHI) was reduced by 71%.

The researchers explained that even with this substantial improvement, the mean residual AHI was 15.8 events per hour, which shows moderate disease severity and may contribute to adverse medical sequelae, such as hypertension, heart disease, stroke, and difficulty with weight control.

The investigators caution, Given the limitations of the pooled studies and the finding that the mean follow-up body mass indices in both aggregate and individual patient analyses were still in the obese range, additional larger, prospective studies are needed to better define patients for whom follow-up polysomnograms are warranted.

The team concluded that clinicians should have low thresholds for re-evaluating patients for obstructive sleep apnea after bariatric surgery.