Mortality in diabetic patients undergoing non-cardiac surgery: a 7-year follow-up study

The prognosis of diabetic patients after non-cardiac surgery remains controversial. This study was designed to compare the long-term mortality between diabetic and non-diabetic control patients undergoing non-cardiac surgery and to evaluate the possible risk factors.

We investigated 274 consecutive diabetic patients and 282 non-diabetic control patients who underwent non-cardiac surgery within 1 year in a tertiary care hospital in Finland. The control group was matched for the same type of operations. Patients were followed for up to 7 years on average. The main outcome measure was mortality within 7 years.

Mortality both in the short-term postoperatively (< or =21 days) and in the long-term (up to 87 (1/2) months) was significantly higher in the diabetic patients compared with the non-diabetic group: 3.5 vs. 0% (P<0.05) and 37.2 vs. 15% (P<0.00001), respectively. The major causes of death among diabetic subjects were diseases of the cardiovascular system (56.8%) compared with non-diabetic patients (18.6%), P<0.0001. We found that diabetes mellitus per se is not a risk factor for post-operative mortality but a combination of variables had a significant effect on both short- and long-term mortality.

Diabetic patients undergoing non-cardiac surgery had a significantly higher incidence of short-term post-operative and long-term mortality compared with non-diabetic subjects. We propose a model of predictors of death among diabetic individuals undergoing non-cardiac surgery within a 7-year follow-up. The majority of deaths were associated with cardiovascular diseases.