Aims: We assessed the association between risk factors and cardiovascular disease in an observational study of patients with Type 1 diabetes from the Swedish National Diabetes Register.
Methods: A derivation sample of 3661 patients, aged 30-65 years, 6.1% with previous cardiovascular disease, baseline 2002, and 197 cardiovascular disease events when followed for 5 years until 2007. A separate validation data set of 4484 patients, baseline 2003, 201 cardiovascular disease events when followed for 4 years.
Results: Adjusted hazard ratios at Cox regression for fatal/non-fatal cardiovascular disease were: diabetes duration 2.76 (2.21-3.44); onset age 1.47 (1.21-1.78); log ratio total cholesterol:HDL cholesterol 1.26 (1.09-1.45); log HbA(1c) 1.19 (1.03-1.38); log systolic blood pressure 1.17 (1.01-1.34) (1 SD increase in continuous variables); smoker 1.76 (1.27-2.46); macroalbuminuria (> 200 μg/min) 1.52 (1.10-2.10); previous cardiovascular disease 3.51 (2.54-4.84). All eight variables were used to elaborate a risk equation for 5-year cardiovascular disease risk. Regarding calibration in the derivation data set, ratio predicted 5-year risk (mean 5.4 ± 7.9%) to observed event rate was 1.0. Discrimination was sufficient, with C-statistic 0.83, sensitivity and specificity 72 and 77%, respectively, for the top quartile of predicted risk. Similarly, calibration and discrimination were adequate in the validation data set: ratio of predicted 4-year risk/observed rate 0.94, C-statistic 0.80, sensitivity and specificity 62 and 77%, respectively, for the top quartile.
Conclusions: This 5-year cardiovascular disease risk model from a large observational study of patients with Type 1 diabetes in routine care showed adequate calibration and discrimination and can be useful for clinical practice. It should also be tested in patients with Type 1 diabetes from other countries.
© 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.