Association of insulin resistance with cardiovascular disease and all-cause mortality in type 1 diabetes: systematic review and meta-analysis

Background: 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 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 8 selected studies were extracted, pooled by random- effects models, and results were presented as hazard ratios (95% CI). Data Synthesis: Eight studies involving 21,930 individuals were included, of which 5 studies involving 19,960 T1D individuals 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 T1D 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 eGDR, may be an additional risk factor for CVD and all-cause mortality in T1D.