Drug-eluting stents: meta-analysis in diabetic patients

Abstract

2A recent meta-analysis of six trials in patients receiving coronary angioplasty with bare-metal stents (BMS) reported that the odds ratio (OR) of restenosis associated with diabetes was 1.61 (95% CI 1.21-2.14, p = 0.004). 3 As DES significantly reduce restenosis rates, 4 especially in small vessels, it would be interesting to specifically analyse the potential impact of DES in diabetic patients. We performed a meta-analysis of the results from six recent trials comparing DES and BMS, using sirolimus (RAVEL, SIRIUS and E-SIRIUS) or paclitaxel (TAXUS II, TAXUS IV and TAXUS VI). These trials provided adequate figures which allowed us to recalculate the rate of in-stent restenosis (defined as a stenosis ≥ 50%) after a follow-up of 6-12 months in both diabetic (around 20% of the population) and non-diabetic patients (Fig. 1 ). OR of restenosis was markedly lower when comparing DES with BMS and similar in both non-diabetic (OR: 0.16; 0.12-0.20; p <0.00001) and diabetic (OR: 0.16; 0.11-0.24; p <0.00001) patients. However, as compared to non-diabetic individuals, the OR of in-stent restenosis associated with diabetes still averaged 1.96 (1.28-3.01) in the groups receiving DES (p = 0.002), a figure quite similar (although less consistent between studies) to that observed with BMS (OR = 1.90; 1.49-2.43; p <0.00001). Interestingly, in the SIRIUS substudy specifically devoted to diabetes, 5 in-lesion restenosis was significantly reduced with DES compared to BMS in the noninsulin-requiring patients (7.7% vs. 49.3%, p < 0.001 ), but not in the insulin-requiring patients (35% vs. 50%, p = 0.38). MACE incidence after 9 months was reduced from 25% with BMS to 9.2% with DES (p < 0.001 ) in diabetic patients and from 16.5% to 6.5% (p < 0.001) in non-diabetic patients, respectively. Finally, in the RESEARCH registry of DES use in the real world, 6 diabetes was a significant predictor of MACE (OR =1.62; 1.09-2.43; p = 0.02), especially clinically driven target vessel revascularization (OR =1.81; 1.10-2.99; p = 0.02). In conclusion, DES are associated with a 80% remarkable relative risk reduction of restenosis during the first year of follow-up in diabetic patients as compared to BMS, similar to that observed in non-diabetic subjects. However, despite the use of DES, diabetes mellitus still remains an independent risk factor of restenosis, need for revascularization and MACE. Further specific prospective studies with highly effective DES should be performed in this high risk diabetic population.