Minimum Threshold of Bariatric Surgical Weight Loss for Initial Diabetes Remission

Abstract

Objective: There are few studies testing the amount of weight loss necessary to achieve initial remission of type 2 diabetes mellitus (T2DM) following bariatric surgery and no published studies with use of weight loss to predict initial T2DM remission in sleeve gastrectomy (SG) patients.

Research design and methods: With Cox proportional hazards models we examined the relationship between initial T2DM remission and percent total weight loss (%TWL) after bariatric surgery. Categories of %TWL were included in the model as time-varying covariates.

Results: Of patients (N = 5,928), 73% were female; mean age was 49.8 ± 10.3 years and BMI 43.8 ± 6.92 kg/m2, and 57% had Roux-en-Y gastric bypass (RYGB). Over an average follow-up of 5.9 years, 71% of patients experienced initial remission of T2DM (mean time to remission 1.0 year). With 0-5% TWL used as the reference group in Cox proportional hazards models, patients were more likely to remit with each 5% increase in TWL until 20% TWL (hazard ratio range 1.97-2.92). When categories >25% TWL were examined, all patients had a likelihood of initial remission similar to that of 20-25% TWL. Patients who achieved >20% TWL were more likely to achieve initial T2DM remission than patients with 0-5% TWL, even if they were using insulin at the time of surgery.

Conclusions: Weight loss after bariatric surgery is strongly associated with initial T2DM remission; however, above a threshold of 20% TWL, rates of initial T2DM remission did not increase substantially. Achieving this threshold is also associated with initial remission even in patients who traditionally experience lower rates of remission, such as patients taking insulin.

Figure 1

Association between T2DM remission and %TWL after bariatric surgery: all a priori categories of %TWL (A) and upper categories collapsed into >20% TWL (B). Cox proportional hazards model results for T2DM remission as related to percentage of weight lost from surgery date until date of remission or censoring, as compared with patients who lost 0–5% of their surgery weight. %TWL was modeled as a time-varying covariate. Sample is comprised of ENGAGE CVD recipients of bariatric surgery who had T2DM at time of surgery and subsequently had their weight measured, had their weight measured at time of T2DM remission (if they remitted), and were not outliers (weight gain of >0% or weight loss of >50%). HRs: adjustment for surgery type, sex, race/ethnicity, age, age squared, HbA_1c (quartiles), DiaRem score (quartiles), Elixhauser score (quartiles), BMI (quartiles), weight at surgery (quartiles), BMI ≥50 kg/m² at surgery indicator, indicators for drug use in year and 3 months prior to surgery (aspirin, nonsteroidal anti-inflammatory drugs), number of diabetes drugs at surgery (indicators for 0, 1, and 2), drug use at surgery (dyslipidemia drugs, insulin), inpatient visits in year presurgery above median, emergency department visits in year presurgery above median, presurgery appointment attendance rate above median, presurgery weight change above median, and prior diagnosis indicators (hypertension, cirrhosis, sleep apnea, chronic kidney disease, serious mental condition, severe anxiety, mild-to-moderate anxiety).

Figure 2

Association between T2DM remission and %TWL after bariatric surgery, stratified by insulin use at surgery. Cox proportional hazards model results for T2DM remission as related to percentage of weight lost from surgery date until date of remission or censoring, as compared with patients who lost 0–5% of their surgery weight. %TWL was modeled as a time-varying covariate and interacted with binary insulin use. Sample is comprised of ENGAGE CVD recipients of bariatric surgery who had T2DM at time of surgery and subsequently had their weight measured, had their weight measured at time of T2DM remission (if they remitted), and were not outliers (weight gain of >0% or weight loss of >50%). HRs: adjustment for surgery type, sex, race/ethnicity, age, age squared, HbA_1c (quartiles), DiaRem score (quartiles), Elixhauser score (quartiles), BMI (quartiles), weight at surgery (quartiles), BMI ≥50 kg/m² at surgery indicator, indicators for drug use in year and 3 months prior to surgery (aspirin, nonsteroidal anti-inflammatory drugs), number of diabetes drugs at surgery (indicators for 0, 1, and 2), drug use at surgery (dyslipidemia drugs), inpatient visits in year presurgery above median, emergency department visits in year presurgery above median, presurgery appointment attendance rate above median, presurgery weight change above median, and prior diagnosis indicators (hypertension, cirrhosis, sleep apnea, chronic kidney disease, serious mental condition, severe anxiety, mild-to-moderate anxiety).

Figure 3

Association between T2DM remission and %TWL after bariatric surgery, stratified by race/ethnicity. Cox proportional hazards model results for T2DM remission as related to total weight loss (%TWL) from surgery date until date of remission or censoring, as compared with patients who lost 0–5% of their surgery weight. %TWL was modeled as a time-varying covariate and interacted with race/ethnicity. Sample is comprised of ENGAGE recipients of bariatric surgery who had T2DM at time of surgery and subsequently had their weight measured, had their weight measured at time of T2DM remission (if they remitted), and were not outliers (weight gain of >0% or weight loss of >50%). HRs: adjustment for surgery type, sex, age, age squared, HbA_1c (quartiles), DiaRem score (quartiles), Elixhauser score (quartiles), BMI (quartiles), weight at surgery (quartiles), BMI ≥50 kg/m² at surgery indicator, indicators for drug use in year and 3 months prior to surgery (aspirin, nonsteroidal anti-inflammatory drugs), number of diabetes drugs at surgery (indicators for 0, 1, and 2), drug use at surgery (dyslipidemia drugs, insulin), inpatient visits in year presurgery above median, emergency department visits in year presurgery above median, presurgery appointment attendance rate above median, presurgery weight change above median, and prior diagnosis indicators (hypertension, cirrhosis, sleep apnea, chronic kidney disease, serious mental condition, severe anxiety, mild-to-moderate anxiety).