Uncontrolled type II diabetes mellitus (DM) using single point hemoglobin A1c levels has been associated with poor cardiovascular outcomes. However, methods to quantify the effect of uncontrolled DM over time have been inconsistent. To quantify hyperglycemia over time and assess its cardiovascular effects we developed and tested a DM burden score which accounts for time in years prior to DM diagnosis, diagnostic HbA1c, and aggregate HbA1c levels thereafter. A retrospective cohort study was performed with patients (n = 188) from a single academic center with type II DM and no prior cardiac disease history. Patient scores were calculated from diagnosis until the year 2015 and were grouped into low (<5.3%; n = 55), moderate (5.3% to 5.5%; n = 80), and high (>5.5%; n = 53) DM burden score cohorts. At 48 months, the cohort with high DM burden scores correlated with significantly worse major adverse cardiovascular events (hazard ratio [HR] 3.07, p = 0.012), myocardial infarction (HR 12.78, p = 0.015), coronary revascularization (HR 4.53, p = 0.019), cardiovascular hospitalizations (HR 4.20, p = 0.005), and all-cause hospitalizations (HR 2.57, p = 0.01). Cardiovascular and all-cause mortality showed significant difference between groups in log-rank testing. Also, a multivariate regression model showed DM burden score (p = 0.045) to be an independent predictor of major adverse cardiovascular events (HR 9.38, p = 0.045). In conclusion, this study provides evidence that DM control over time impacts cardiovascular outcomes.
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