Silent myocardial ischemia and microalbuminuria in asymptomatic subjects with non-insulin-dependent diabetes mellitus

Microalbuminuria is an increase in urinary albumin not detected by conventi onal dipstick testing and is present in 20% of patients with non-insulin-de pendent diabetes mellitus (NIDDM). Mortality in NIDDM patients with microal buminuria is 60% at 8 years and is mainly due to cardiovascular disease. Be cause many deaths occur without warning symptoms, we have compared the prev alence and severity of silent myocardial ischemia in asymptomatic NIDDM pat ients with and without microalbuminuria. We have performed a cross-sectiona l, case-control study of asymptomatic NIDDM patients attending hospital dia betes clinics. Forty-three patients with microalbuminuria were matched for age, gender, diabetes duration, and smoking status with 43 normoalbuminuric patients. A symptom-limited exercise stress test was performed and reporte d blind to patient status. The degree of electrocardiographic ST-segment de pression, exercise time, work performed, and maximum heart rate with exerci se were recorded. patients with microalbuminuria had a higher prevalence of ischemic response (>1 mm ST depression) (65% vs 40%, p = 0.016), reduced t otal exercise time (5 vs 7 minutes, p <0.001), reduced work (6 vs 8 METs, p <0.001), and reduced age-predicted maximum heart rate (94% vs 101%, p = 0. 004), In multiple logistic regression, albumin excretion rate was shown to be the strongest independent predictor of ischemic response (p = 0.03), Sil ent myocardial ischemia is common in asymptomatic NIDDM patients but is mor e common in those with microalbuminuria. In these subjects, the higher prev alence of ischemic response at low workloads suggests a higher probability of future coronary events, and possibly a higher probability of potentially treatable coronary artery disease, (C)1999 by Excerpta Medica, Inc.