Effects of metabolic parameters' variability on cardiovascular outcomes in diabetic patients

Background: Metabolic abnormalities such as dyslipidemia, glucose and high blood pressure are common in diabetic patients. Visit-to-visit variabilities in these measures have been reported as potential residual cardiovascular risk factors. However, the relationship between these variabilities and their effects on cardiovascular prognosis have not been studied.

Methods: A total of 22,310 diabetic patients with ≥ 3 measurements of systolic blood pressure (SBP), blood glucose, total cholesterol (TC), and triglyceride (TG) levels during a minimum of three years at three tertiary general hospitals were selected. They were divided into high/low variability groups for each variable based on the coefficient of variation (CV) values. The primary outcome was the incidence of major adverse cardiovascular events (MACE), a composite of cardiovascular death, myocardial infarction, and stroke.

Results: All high CV groups had a higher incidence of MACE than those with low CV (6.0% vs. 2.5% for SBP-CV groups, 5.5% vs. 3.0% for TC-CV groups, 4.7% vs. 3.8% for TG-CV groups, 5.8% vs. 2.7% for glucose-CV groups). In multivariable Cox regression analysis,, high SBP-CV (HR 1.79 [95% CI 1.54-2.07], p < 0.01), high TC-CV (HR 1.54 [95% CI 1.34-1.77], p < 0.01), high TG-CV (HR 1.15 [95% CI 1.01-1.31], p = 0.040) and high glucose-CV (HR 1.61 [95% CI 1.40-1.86], p < 0.01) were independent predictors of MACE.

Conclusion: Variability of SBP, TC, TG and glucose are important residual risk factors for cardiovascular events in diabetic patients.