The effect of diabetes mellitus on in-hospital and long-term outcomes after heart valve operations

Abstract

Background: Diabetes mellitus (DM) is associated with adverse in-hospital and long-term outcomes in patients undergoing coronary artery bypass grafting. This study evaluated outcomes in patients with DM undergoing isolated heart valve operations.

Methods: From January 1, 1996, to March 31, 2008, 2964 consecutive patients underwent primary, isolated heart valve operations at Emory University Hospitals. Patients undergoing concomitant coronary bypass grafting were excluded. Of the heart valve patients, 424 (14.3%) had a diagnosis of DM, and 126 (29.7%) received insulin therapy. Long-term survival status was determined using the Social Security Death Index. Odds ratios and proportional hazards regression analysis (hazard ratio) were used to identify risk factors for in-hospital and long-term mortality, respectively.

Results: Thirty-four DM patients (8.0%) died in-hospital compared with 99 (3.9%) without DM (p < 0.001). In-hospital mortality was higher in DM patients who received insulin (12.7%) than in those without insulin therapy (6.0%, p = 0.021). DM patients had significantly reduced 10-year survival of 41.5% vs 70.5% for those without DM (p < 0.001). After risk adjustment, DM remained a strong risk factor for reduced 10-year survival (hazard ratio, 1.30; 95% confidence interval, 1.05 to 1.61; p = 0.018); other risk factors include advanced age, stroke, female gender, peripheral vascular disease, advanced heart failure, and renal failure.

Conclusions: DM is associated with significantly worse outcomes after valve operations. Given the reduced long-term survival observed in these patients, this information should be used when making operative decisions regarding surgical techniques and types of prosthesis in these complex patients.