Effect of diabetes on early and late survival after isolated first coronary bypass surgery in multivessel disease

Abstract

Objective: Diabetes has not yet been investigated as a risk factor for early and late cardiac-related death.

Methods: Patients operated on from January 1988 to December 1999 were considered; 767 were diabetic (group D) and 2593 were nondiabetic (group ND). Patients with preoperative hemodynamic deterioration were excluded. Early (30-day) mortality (any causes and cardiac causes) was evaluated with univariate analysis and stepwise logistic regression. Ten-year actuarial freedom from death of any cause and cardiac death was also assessed with univariate and Cox analyses.

Results: Early mortality was 2.2% (group D, 3.3%; group ND, 1.9%; P =.023). Early cardiac mortality was 1.3% (group D, 2.2%; group ND, 1.1%; P =.0016). Diabetes was an independent risk factor only for cardiac death and not for death of any cause. Five-year survival was 93.5% +/- 0.5% (group D, 92.5% +/- 1.1%; group ND, 93.9% +/- 0.6%; P =.0304). Diabetes was not an independent risk factor. Five-year freedom for cardiac death was 96.3% +/- 0.4% (group D, 94.9% +/- 0.9%; group ND, 96.6% +/- 0.4%; P =.0155). Diabetes was an independent risk factor. However, if only the patients who survived the first 30 days are considered, diabetes disappears as a risk factor (5-year freedom for cardiac death, 97.8% +/- 0.3%; group D, 97.3% +/- 0.8%; group ND, 97.9% +/- 0.4%; P = 0.2389).

Conclusions: Diabetes is an independent risk factor for early cardiac death only. Long-term survival in patients who survive the first 30 days is not statistically significantly different for diabetic and nondiabetic patients. In fact, the rates appear very similar.