Body weight variability as a predictor of cardiovascular outcomes in type 1 diabetes: A nationwide cohort study.

Aim: Intraindividual body weight variability (BWV), that is, the degree of weight fluctuations over time, is associated with an increased risk of cardiovascular diseases (CVDs) in multiple settings. The impact of BWV on cardiovascular risk in type 1 diabetes (T1D) remains unclear, despite the issues relative to weight management in individuals with this condition.

Materials and methods: Using data from the Swedish National Diabetes Register, we identified individuals with T1D and without CVD at baseline with at least three measurements of body weight taken over three consecutive years. We estimated BWV as quartiles of the standard deviation of weight measures and explored its longitudinal association with the incidence of CVD during a 12.7 ± 4.6 year follow-up through adjusted Cox regression models. The primary endpoint was the composite of nonfatal myocardial infarction, nonfatal stroke and all-cause mortality. We modelled the function of risk in relation to the magnitude of BWV, testing also whether weight trends, that is, increasing, stable or decreasing, age, sex and glycaemic control modified the association between BWV and the outcome.

Results: Among the 36 333 individuals with T1D in the register, we identified 19 373 individuals with at least three measures of body weight and without CVD at baseline. Participants with the highest BWV had a 42% increased risk of reaching the primary endpoint compared to those with the lowest BWV (hazard ratio [HR] = 1.42, 95% confidence interval [CI]: 1.24-1.62). In addition, high BWV was significantly associated with a 51% increased risk of all-cause mortality (HR = 1.51, 95% CI: 1.28-1.78), a 37% increased risk of peripheral artery disease (HR = 1.37, 95% CI: 1.06-1.77) and a 55% increased risk of hospitalization for heart failure (HR = 1.55, 95% CI: 1.20-2.01). BWV showed a quasi-linear association with the primary endpoint. No interaction was observed when comparing subgroups for weight trends, sex or degree of glycaemic control. In the subgroup of elderly individuals, the association of BWV with the primary endpoint was no longer significant.

Conclusions: High BWV is associated with an increased risk of CVD and all-cause mortality in individuals with T1D, independently of canonical risk factors. Weight trends, sex and glycaemic control do not modify such association while older age attenuates it.