Association of hemoglobin glycation index with all-cause and cardiovascular mortality in patients with diabetes or prediabetes and comorbid cardiovascular disease: a population-based cohort study.

The relationship between HGI and mortality in patients with diabetes or prediabetes who have comorbid CVD has not yet been clearly established. Therefore, the aim of this study was to investigate the correlation between baseline HGI and all-cause and cardiovascular mortality in US adults with diabetes or prediabetes and comorbid CVD. This study analyzed data from 1,760 patients with diabetes or prediabetes and comorbid CVD from the NHANES from 1999 to 2018. Three models were constructed considering covariates to evaluate the correlation between HGI and mortality risk. Additionally, we used RCS and threshold effects to analyze the nonlinear relationship. During the follow-up of 1,760 patients with diabetes or prediabetes and comorbid CVD, there were 793 all-cause deaths and 274 cardiovascular-related deaths recorded. Restricted cubic spline analysis results showed that baseline HGI was U-shapedly associated with all-cause and cardiovascular mortality rates. Threshold effect analysis indicated that the turning points of HGI for all-cause and cardiovascular mortality rates were - 0.382 and - 0.380, respectively. Specifically, when baseline HGI was below the turning point, HGI was negatively correlated with all-cause mortality rate (HR: 0.6, 95% CI: 0.5-0.7) and cardiovascular mortality rate (HR: 0.6, 95% CI: 0.4-1.0), while when baseline HGI exceeded the turning point, HGI was positively correlated with all-cause mortality rate (HR: 1.2, 95% CI: 1.1-1.4) and cardiovascular mortality rate (HR: 1.3, 95% CI: 1.1-1.5). We found that in US adults with diabetes or prediabetes and comorbid CVD, baseline HGI was U-shapedly associated with all-cause and cardiovascular mortality rates. Specifically, the turning points for all-cause and cardiovascular mortality rates were - 0.382 and - 0.380, respectively.