Cardiac Versus Non-Cardiac Related Mortality Following Percutaneous Coronary Intervention in Patients with Insulin-Treated Type 2 Diabetes Mellitus: A Meta-Analysis

INTRODUCTION: Cardiovascular mortality is a major concern for patients with type 2 diabetes mellitus (T2DM). Insulin therapy significantly contributes to a high rate of death in these patients. We have performed a meta-analysis comparing cardiac and non-cardiac-related mortality following percutaneous coronary intervention (PCI) in a sample of patients with insulin-treated type 2 diabetes mellitus (ITDM). METHODS: Studies were included in the meta-analysis if: (1) they were trials or cohort studies involving patients with T2DM post-PCI; (2) the outcomes in ITDM were separately reported; and (3) they reported cardiac death and non-cardiac death among their clinical endpoints. ITDM patients with any degree of coronary artery disease were included. The analysis was carried out using RevMan version 5.3 software, and data were reported with odds ratios (OR) and 95% confidence intervals (CI) as the main parameters. RESULTS: A total of 4072 participants with ITDM were included, of whom 1658 participants and 2414 participants were extracted from randomized controlled trials and observational cohorts, respectively. Analysis of all data showed that death due to cardiac causes was significantly higher in patients with ITDM (OR 2.16, 95% CI 1.79–2.59; P = 0.00001). At 1 year of follow-up, cardiac death was still significantly higher compared to non-cardiac death (OR 2.39, 95% CI 1.47–3.88; P = 0.0004), and this result did not change with a longer follow-up period (3–5 years) (OR 2.09, 95% CI 1.70–2.56; P = 0.00001). Death due to cardiac causes was still significantly higher in the subpopulations of patients with everolimus-eluting stents (OR 2.31, 95% CI 1.26–4.26; P = 0.007), paclitaxel-eluting stents (OR 2.36, 95% CI 1.63–3.39; P = 0.00001), sirolimus-eluting stents (OR 2.11, 95% CI 1.67–2.67; P = 0.00001), and zotarolimus-eluting stents (OR 2.12, 95% CI 1.11–4.05; P = 0.02), respectively. CONCLUSIONS: Mortality due to cardiac causes was significantly higher than that due to non-cardiac causes in patients with ITDM who had undergone PCI. The same conclusion could be drawn from analyses focused on different follow-up periods, types of coronary stents, and type of study data used.