Long-term outcomes in gastric bypass patients with and without type 2 diabetes--Waitemata District Health Board experience.

BACKGROUND/

OBJECTIVES

Dramatic early postoperative improvement or resolution of type 2 diabetes mellitus (T2DM) has been widely reported after bariatric surgery but there is limited long-term data on T2DM outcome. Moreover, data on long-term weight outcomes of government funded bariatric surgery in New Zealand is lacking. We report weight and glycaemic outcomes in subjects with and without T2DM who underwent gastric bypass surgery (GBP) at Waitemata District Health Board (WDHB).

METHODS

Clinical records of those who underwent a GBP (Roux-en-Y gastric bypass or loop gastric bypass) at WDHB between 2001 and 2007 were reviewed. Relevant pre- and postoperative data, including weight and diabetes related parameters, were collected from hospital records and analysed. Missing clinical data was attained by contacting patients, their primary practitioners and local laboratories, and also by performing HbA1c in T2DM subjects in whom latest diabetes status was unclear.

RESULTS

Data of 126 subjects was analysed. Their mean age was 43.7 years, 73% were female and 83% were Pakeha/European. Mean preoperative weight was 136.2 kg (SD plus or minus 29.1, range 81.3-241) with a mean BMI of 48.3 kg/m². Postoperative nadir weight was 80.6 kg (SD plus or minus 18.1, range 48.0-132.8) at 20.8 months (SD plus or minus 14.6, range 4-98) (BMI 28.6) with percentage of excess body weight loss (%EBWL) of 84.7%. Latest mean weight was 90.5 kg (SD plus or minus 18.8, range 57-140) (BMI 32.2, %EBWL 70.7%) at a mean of 63.4 months (SD plus or minus 19.7, range 12-109) post-op. Thirty four subjects (27.0%) had preoperative diagnosis of T2DM, of whom 29 (85.3%) had complete remission at some stage postoperatively. At the latest follow-up, 19 of 33 (57.6%) remained in complete remission, and the rest had either never remitted or had evidence of T2DM relapse after an initial remission. Weight loss outcomes were comparable between T2DM and non-T2DM subjects, and also between European and Maori and Pacific Islanders.

CONCLUSION

GBP resulted in substantial weight loss in essentially all subjects, and weight loss was well maintained over time. GBP also had dramatic and favourable effect on T2DM but did not uniformly result in prolonged diabetes remission. Long-term glycaemic surveillance is desirable.