Survival in patients with type 2 diabetes in a Swedish community: skaraborg hypertension and diabetes project

OBJECTIVE: To explore risk factors for all-cause mortality in patients with type 2 diabetes treated in primary care. RESEARCH DESIGN AND METHODS:A prospective population-based study of 400 patients with type 2 diabetes who consecutively completed an annual checkup in primary care in Skara, Sweden, during 1992-1993. Vital status was ascertained to year 2000. Baseline characteristics as predictors for mortality were analyzed by Cox regression and expressed as relative risks (RRs), with 95% CIs. RESULTS: During a mean follow-up time of 5.9 years, 131 patients died (56 deaths per 1,000 patients per year). In both sexes, all-cause mortality was predicted by HbA(1c) (by 1%; RR 1.14, 95% CI 1.01-1.27), and by LDL-to-HDL cholesterol ratios (1.15, 1.00-1.32). Increased mortality was also seen with prevalent hypertension (1.72, 1.21-2.44), microalbuminuria (1.87, 1.27-2.76), and previous cardiovascular disease (1.70, 1.15-2.50). Subanalyses revealed that increased mortality related to HbA(1c) was restricted to hypertensive patients with type 2 diabetes (1.23, 1.04-1.47). Serum triglycerides (by 1 mmol/l) predicted all-cause mortality in women (1.25, 1.06-1.47). CONCLUSIONS: Poor glucose and lipid control and hypertension predicted all-cause mortality. Survival was also predicted by prevalent microalbuminuria and by previous cardiovascular disease. Confirming results from clinical trials, this population-based study has implications for primary and secondary prevention.