Background: Although there is accumulating evidence that renal insufficiency is an independent risk factor for mortality after acute myocardial infarction (AMI), it is not known whether renal dysfunction is associated with an increased mortality rate after a broad range of acute coronary syndromes, including unstable angina.
Methods: We examined consecutive patients from 24 Veterans Affairs hospitals with confirmed AMI or unstable angina between March 1998 and February 1999, who were categorized into groups according to estimated glomerular filtration rate (GFR). Multivariable regression was used to assess the independent association between GFR and the 7-month mortality rate, adjusting for differences in patient characteristics and treatment.
Results: Of the 2706 patients, 436 (16%) had normal renal function (GFR >90 mL/min/1.73 m(2)), 1169 (43%) had mild renal insufficiency (GFR 60-89 mL/min/1.73 m(2)), 864 (32%) had moderate renal insufficiency (GFR 30-59 mL/min/1.73 m(2)), and 237 (9%) had severe renal insufficiency (GFR <30 mL/min/1.73 m(2)). Patients with renal insufficiency were less likely to undergo coronary angiography or to receive aspirin or beta-blockers at discharge. In multivariable models, renal insufficiency was associated with a higher odds of death (mild renal insufficiency: odds ratio [OR] = 1.76; 95% CI, 0.93-3.33; moderate renal insufficiency: OR = 2.72; 95% CI, 1.43-5.15; and severe renal insufficiency: OR = 6.18; 95% CI, 3.09-12.36; all compared with normal renal function). The associations between renal insufficiency and mortality rate were similar in both the AMI and unstable angina subgroups (P value for interaction =.45).
Conclusions: Renal insufficiency is common and is associated with higher risks for death in patients with a broad range of ACS at presentation. Future efforts should be dedicated to determining whether more aggressive treatment will optimize outcomes in this patient population.