A new model for 5-year risk of cardiovascular disease in Type 1 diabetes; from the Swedish National Diabetes Register (NDR)

Diabet. Med. 28, 1213–1220 (2011) 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 HbA1c 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.