BackgroundRecent studies have suggested a potential increased risk of acute kidney injury (AKI) among proton-pump inhibitor (PPI) users. However, the present results are conflicting. Thus, we performed a meta-analysis to investigate the association between PPI therapy and the risk of AKI.MethodsEMBASE, PubMed, Web of Science, and Cochrane Library databases (up to September 23, 2016) were systematically searched for any studies assessing the relationship between PPI use and risk of AKI. Studies that reported relevant risk ratios (RRs), odds ratios, or hazard ratios were included. We calculated the pooled RRs with 95% confidence intervals (CI) using a random-effects model of the meta-analysis. Subgroup analysis was conducted to explore the source of heterogeneity.ResultsSeven observational studies (five cohort studies and two case–control studies) were identified and included, and a total of 513,696 cases of PPI use among 2,404,236 participants were included in the meta-analysis. The pooled adjusted RR of AKI in patients with PPIs use was 1.61 (95% CI: 1.16–2.22; I2=98.1%). Furthermore, higher risks of AKI were found in the subgroups of cohort studies, participant’s average age <60 years, participants with and without baseline PPI excluded, sample size <300,000, and number of adjustments ≥11. Subgroup analyses revealed that participants with or without baseline PPI excluded might be a source of heterogeneity.ConclusionPPI use could be a risk factor for AKI and should be administered carefully. Nevertheless, some confounding factors might impact the outcomes. More well-designed prospective studies are needed to clarify the association.

BackgroundRecent studies have shown associations between contrast-induced acute kidney injury (CI-AKI) and increased risk of adverse clinical outcomes in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI); however, the estimates are inconsistent and vary widely. Therefore, this meta-analysis aimed to evaluate the precise associations between CI-AKI and adverse clinical consequences in patients undergoing PCI for ACS.MethodsEMBASE, PubMed, Web of Science™ and Cochrane Library databases were systematically searched from inception to December 16, 2016 for cohort studies assessing the association between CI-AKI and any adverse clinical outcomes in ACS patients treated with PCI. The results were demonstrated as pooled risk ratios (RRs) with 95% confidence intervals (CI). Heterogeneity was explored by subgroup analyses.ResultsWe identified 1857 articles in electronic search, of which 22 (n = 32,781) were included. Our meta-analysis revealed that in ACS patients undergoing PCI, CI-AKI significantly increased the risk of adverse clinical outcomes including all-cause mortality (18 studies; n = 28,367; RR = 3.16, 95% CI 2.52–3.97; I2 = 56.9%), short-term all-cause mortality (9 studies; n = 13,895; RR = 5.55, 95% CI 3.53–8.73; I2 = 60.1%), major adverse cardiac events (7 studies; n = 19,841; RR = 1.49, 95% CI: 1.34–1.65; I2 = 0), major adverse cardiovascular and cerebrovascular events (3 studies; n = 2768; RR = 1.86, 95% CI: 1.42–2.43; I2 = 0) and stent restenosis (3 studies; n = 130,678; RR = 1.50, 95% CI: 1.24–1.81; I2 = 0), respectively. Subgroup analyses revealed that the studies with prospective cohort design, larger sample size and lower prevalence of CI-AKI might have higher short-term all-cause mortality risk.ConclusionsCI-AKI may be a prognostic marker of adverse outcomes in ACS patients undergoing PCI. More attention should be paid to the diagnosis and management of CI-AKI.Electronic supplementary materialThe online version of this article (10.1186/s12882-018-1161-5) contains supplementary material, which is available to authorized users.