Adverse cardiovascular outcomes between insulin-treated and non-insulin treated diabetic patients after percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND: Type 2 diabetes mellitus (DM) patients have worse adverse cardiovascular outcomes after Percutaneous Coronary Intervention (PCI). However, the adverse cardiovascular outcomes between insulin-treated and non-insulin treated DM patients have been a subject of debate. We sought to compare the short-term (<1 year) and long-term (≥1 year) cardiovascular outcomes between insulin-treated and non-insulin treated DM patients after PCI. METHODS: Medline and Embase databases were searched for studies by typing ‘diabetes and percutaneous coronary intervention/PCI’ or ‘insulin-treated and non-insulin treated diabetes mellitus and PCI’. Endpoints included adverse cardiovascular outcomes reported in these DM patients during the corresponding follow-up periods. Odd Ratio (OR) with 95 % confidence interval (CI) was used to express the pooled effect on discontinuous variables and the pooled analyses were performed with RevMan 5.3. RESULTS: 21 studies have been included in this meta-analysis consisting of a total of 21,759 diabetic patients (6250 insulin-treated and 15,509 non-insulin treated DM patients). Short term mortality, myocardial infarction, target lesion revascularization, major adverse cardiac effects and, stent thrombosis were significantly higher in insulin-treated diabetic patients (OR 1.69, 95 % CI 1.40–2.04, p < 0.00001), (OR 1.40, 95 % CI 1.16–1.70, p = 0.0005), (OR 1.37, 95 % CI 1.06–1.76, p = 0.02), (OR 1.46, 95 % CI 1.22–1.76, p < 0.0001) and (OR 1.66, 95 % CI 1.16–2.38, p = 0.005) respectively. Long-term cardiovascular outcomes were also significantly higher in insulin-treated DM patients. CONCLUSION: Insulin treatment in these DM patients was associated with a significantly higher short and long-term adverse cardiovascular outcomes after PCI compared to those DM patients not treated by insulin therapy.