Factors associated with insulin-induced weight gain in an Australian type 2 diabetes outpatient clinic

Course of body weight before and after the initiation of insulin therapy in type 2 diabetes mellitus: Retrospective inception cohort study (ZODIAC 58)

Aims

The aim of this study was to explore the effect of insulin treatment initiation on weight by taking weight change prior to initiation into account.

Materials and methods

We performed an observational retrospective inception cohort study, concerning Dutch primary care. We identified all patients that initiated insulin treatment (n = 7967) and individually matched patients with a reference patient (n = 5213 pairs). We obtained estimated mean weight changes in the five years prior to five years post insulin therapy. We applied linear regression analysis on weight change in the first year after insulin therapy (T0 to T+1), with matched group as primary determinant adjusted for pre-insulin weight change and additional covariates.

Results

Estimated mean weight increased in the five consecutive years prior to insulin therapy (-0.23 kg in year T-5 to T-4, 0.01 kg in year T-4 to T-3, 0.07 kg in year T-3 to T-2, 0.24 kg in year T-2 to T-1, and 0.46 kg in year T-1 to T0) and continued to increase in the first year after, that is T0 to T+1, at a slightly lower rate (0.31 ± 3.9 kg). Pre-insulin weight change had the highest explained variance and was inversely and independently associated with weight change (p < .001). Starting insulin was associated with weight increase, independent of pre-insulin weight change (β-adjusted 1.228, p < .001). Stratification revealed that despite having a more or less similar baseline BMI, patients with substantial weight increase showed higher estimated mean BMI's followed by weight loss pre-insulin. In matched references, estimated mean weight changes were negative in all years concerning the study period, indicating consistent weight loss.

Conclusions

Initiation of insulin therapy was independently associated with weight increase; however, overall effect on weight was small and subject to substantial variation. Pre-insulin weight change is identified as a relatively strong inverse determinant of weight change after insulin initiation.

Association between insulin-induced weight change and CVD mortality: Evidence from a historic cohort study of 18,814 patients in UK primary care

BACKGROUND

This study explores the association of insulin-induced weight (wt) gain on cardiovascular outcomes and mortality among patients with type 2 diabetes (T2D) following insulin initiation using real-world data.

METHODS

A historical cohort study was performed in 18,814 adults with insulin-treated T2D derived from the UK The Health Improvement Network database. Based on the average weight change of 5 kg, 1 year postinsulin initiation, patients were grouped into 5 categories (>5 kg wt loss; 1.0-5.0 kg wt loss; no wt change; 1.0-5.0 kg wt gain; >5.0 kg wt gain) and followed-up for 5 years. Cox proportional hazard models and Kaplan-Meier estimators were fitted to estimate the hazards of a 3-point composite of nonfatal myocardial infarction, stroke, and all-cause mortality between categories.

RESULTS

The median age was 62.8 (IQR: 52.3-71.8) years, HbA_1c : 8.6% (IQR: 7.4-9.8) and mean BMI: 31.8 (6.5) kg/m² . The 5 year probability of survival differed significantly within the wt-change categories (log-rank test P value = .0005). Only 1963 composite events occurred. Compared with the weight-neutral group, the risk of composite events was 31% greater in the >5 kg wt-loss group (aHR: 1.31; 95% CI: 1.02, 1.68), the same in the 1.0 to 5.0 kg wt-gain category, but nonsignificantly increased in the 1.0 to 5.0 kg wt loss (15%) and >5.0 kg wt gain (13%) categories, respectively. In the obese subgroup, this risk was 50% (aHR: 1.50, 95% CI: 1.08-2.08) more in the >5 kg weight-loss group compared with the weight-neutral group.

CONCLUSION

Insulin-induced weight gain did not translate to adverse cardiovascular outcomes and mortality in patients with T2D. These data provide reassurance on the cardiovascular safety of insulin patients with T2D.

Determinants of weight change in patients on basal insulin treatment: an analysis of the DIVE registry

OBJECTIVE

We aimed to describe patterns of weight change in insulin-naive patients with type 2 diabetes mellitus (T2DM) starting basal insulin (BI) treatment.

RESEARCH DESIGN AND METHODS

Diabetes Versorgungs-Evaluation (DIVE) is an observational, multicenter, prospective registry in patients with T2DM. Patients were divided into those initiating BI therapy for the first time (with optional oral antidiabetic drugs (OADs)) and those initiating OADs only (OADo).

RESULTS

521 patients were included in the analysis, 113 in the BI arm and 408 in the OADo arm. Relative to baseline, the BI group gained an average of 0.98±7.1 kg at 1 year, compared with a loss of 1.52±11.8 kg in the OADo group (p<0.001). This difference remained statistically significant when expressed as a proportional change from baseline (+0.014±0.08 vs -0.015±0.12, respectively (p<0.001)). Baseline weight (regression coefficient (RC) 0.89; 95% CI 0.81 to 0.97; p<0.001) and diabetes duration (RC 2.52; 95% CI 0.53 to 4.52; p=0.01) were the only factors identified as significant predictors of weight gain between baseline and 1 year follow-up in BI patients.

CONCLUSIONS

Though BI therapy leads to modest weight gain over the subsequent year, this may be limited by BI initiation at an early stage of the disease. As such, delaying the start of insulin therapy based on fears of weight gain appears counter-productive, and should be reconsidered.