Association of Insulin Resistance With Cardiovascular Disease and All-Cause Mortality in Type 1 Diabetes: Systematic Review and Meta-analysis

OBJECTIVE: The association of insulin resistance (IR) with cardiovascular disease (CVD) and all-cause mortality in type 1 diabetes (T1D) remains unclear. PURPOSE: To investigate whether IR is associated with CVD and all-cause mortality among individuals with T1D. DATA SOURCES: PubMed, Embase, and the Cochrane Library databases were searched from inception to 31 October 2023. STUDY SELECTION: Observational studies reporting the associations between IR, as calculated by the estimated glucose disposal rate (eGDR), and the risk of CVD and all-cause mortality in individuals with T1D were eligible for inclusion. DATA EXTRACTION: Data from eight selected studies were extracted, pooled by random-effects models, and results are presented as hazard ratios (95% CIs). DATA SYNTHESIS: Eight studies involving 21,930 individuals were included, of which five studies involving 19,960 individuals with T1D reported the risk of CVD. During a median follow-up of 10 years, there were 2,149 cases of incident CVD. The pooled hazard ratio for composite CVD outcome per 1-unit increase in the eGDR index was 0.83 (95% CI 0.78-0.90, I2 = 58.9%). Five studies involving 19,403 individuals reported the risk of all-cause mortality. During a median follow-up of 10 years, 1,279 deaths were observed. The pooled hazard ratio for all-cause mortality per 1-unit increase in the eGDR index was 0.84 (95% CI 0.81-0.87, I2 = 0%). LIMITATIONS: The small number of available studies restricted our ability to perform meta-regression analyses or more detailed subgroup analyses. CONCLUSIONS: IR, as calculated by the eGDR, may be an additional risk factor for CVD and all-cause mortality in T1D.