Relation between combining evidence-based medications on mortality following myocardial infarction in patients with and without renal impairment.

Background: Antiplatelet agents, beta-blockers, statins and ACE inhibitors have been shown to reduce mortality in patients following myocardial infarction (MI). However, it is uncertain if the combination of these agents has a similar impact on mortality following MI in patients with renal dysfunction.

Methods: We studied 5529 consecutive patients with confirmed MI between January 2000 and December 2003. Data on baseline demographics, co-morbidities and in-hospital management were collected prospectively. Glomerular filtration rate (GFR) was estimated using the 4-component Modification of Diet in Renal Disease equation. Based on discharge use of evidence-based medications, the patients were divided into those using 0, 1, 2, 3 or 4 medications. The impact of medication use on 1-year mortality was then assessed for patients with GFR > or =60 ml/min/1.73 m2 (group I) and GFR < 60 ml/min/1.73 m2 (group 2).

Results: Mean age was 63 +/- 13 years with 71% men.The prevalence of reduced GFR was 35% and the adjusted odds ratio for I-year mortality of patients in group 2 compared to those in group I was 1.86 (95% CI 1.54-2.25, P < 0.001). Compared with patients with no medication, the adjusted odds ratio for 1-year mortality was lower in patients with 1, 2, 3 and 4 medications in both groups. There was no significant interaction between the number of medications used and GFR.

Conclusion: Increased use of combined evidence-based medications was independently associated with a lower 1-year post MI mortality. Such therapies offer similar survival benefit in patients with and without renal dysfunction.