Time dependent effect on mortality of drug-eluting stents versus bare metal stents

Abstract

Objective. The comparison of all-cause long-term mortality between the use of drug-eluting stents versus bare metal stents in patients treated with percutaneous coronary interventions. Design. Observational data from patients treated at Feiring Heart Clinic from 1999 until 2010 with a follow-up of survival at March 8, 2011. The survival was compared using Cox regression with ordinary covariates, propensity score used as covariate and 1:1 propensity score matching. Results. The analyses included 5690 patients treated solely with bare metal stents and 2916 with drug-eluting stents. During the study period (October 2002 to March 2011), 996 deaths were observed. Due to nonproportional hazard effect on mortality of drug-eluting stents compared to bare metal stents, a landmark analysis splitting time at 9 months was employed. All analyses indicated a significantly reduced mortality by drug-eluting stents in the first 9 months with hazard ratios ranging from 0.42 to 0.51 with no difference in mortality from 9 months to 8 years of follow-up. Conclusions. Short-term mortality was significantly reduced in the drug-eluting stent group compared to the bare metal stent group. A selection bias could not be ruled out as an explanation for this effect. No difference was observed in mortality after 9 months. © 2012 Informa Healthcare.