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

Insulin-induced weight gain is a key concern for people with type 2 diabetes (T2D) and their treatment team. This study aimed to document the prevalence of insulin-induced weight gain and its impact on cardiovascular risk factors in patients attending the Royal Melbourne Hospital diabetes clinic.

Clinical and biochemical data were extracted from a prospective clinic database and from the hospital record. These variables were correlated with the percentage weight change 1 year after starting insulin and compared between groups with or without clinically significant weight gain, defined as more than 7% of the baseline bodyweight.

The population comprised 340 patients (184 male), representing 36% of people with T2D who commenced insulin at our clinic. Their mean ± SD age and duration of diabetes was 63 ± 11 and 13 ± 8 years respectively. The mean (95% CI) change in bodyweight at 1 year was 3.0 (2.5-3.5) kg, but this was not associated with deleterious changes in blood pressure or lipid profile. Weight gain was associated with higher insulin doses, the use of short-acting insulin and with lower baseline bodyweight. Clinically significant weight gain occurred in 87 patients and was associated with glucose-lowering regimens that included short-acting insulin or a thiazolidinedione, whereas regimens that incorporated other oral agents, particularly sulfonylureas, were associated with less weight gain.

In this Australian tertiary hospital population with T2D, insulin-induced weight gain was common but was not associated with deleterious changes in blood pressure or lipids. Treatment regimens that avoid short-acting insulin but include oral agents other than thiazolidinediones might prevent insulin-induced weight gain in T2D.