Background
Clinical characteristics such as HbA1c, systolic blood pressure (SBP), albuminuria and estimated glomerular filtration rate (eGFR) are important when treating type 1 diabetes. We investigated the variability in these measures as risk markers for micro‐ and macrovascular complications.
Methods
This prospective study included 1062 individuals with type 1 diabetes. Visit‐to‐visit variability of HbA1c, SBP, albuminuria and eGFR was calculated as the SD of the residuals in individual linear regression models using all available measures in a specified period of 3 years (VV). Endpoints included were as follows: cardiovascular events (CVE) defined as myocardial infarction, non‐fatal stroke, or coronary or peripheral arterial intervention; end‐stage kidney disease (ESKD) defined as eGFR <15 ml/min/1.73 m2, chronic dialysis or kidney transplantation; eGFR decline ≥30%; and mortality. Adjustment included age, sex, cholesterol, HbA1c, SBP, body mass index, smoking, albuminuria, eGFR, and mean, intercept, slope of respective exposure variables and regression models.
Results
SBP VV was significantly associated with CVE (adjusted hazard ratio per 50% increase, (CI 95%); p: 1.21 [1.05–1.39]; p = 0.008), ESKD (1.51 [1.16–1.96]; p = 0.002) and mortality (1.25 [1.09–1.44]; p = 0.002). HbA1c VV was significantly associated with mortality (1.51 [1.30–1.75]; p < 0.001); albuminuria VV with eGFR decline (1.14 [1.08–1.20]; p = 0.024) and ESKD (1.14 [1.02–1.27]; p < 0.001), but neither CVE nor mortality. Adjusted eGFR VV was not associated with endpoints.
Conclusion
In type 1 diabetes, higher variability of basic clinical risk markers adds important risk stratification information for the development of micro‐ and macrovascular complications.