Myeloperoxidase (MPO) is a lysosomal enzyme that may be involved in oxidative stress-mediated kidney injury. Using a two-step approach, we measured the association of four polymorphisms across the length of the MPO gene with systemic markers of oxidative stress: plasma MPO and urinary 15-F(2t)-isoprostane levels. Adverse outcomes were measured in a primary cohort of 262 adults hospitalized with acute kidney injury, and a secondary cohort of 277 adults undergoing cardiac surgery with cardiopulmonary bypass and at risk for postoperative acute kidney injury. Dominant and haplotype multivariable logistic regression analyses found a genotype-phenotype association in the primary cohort between rs2243828, rs7208693, rs2071409, and rs2759 MPO polymorphisms and both markers of oxidative stress. In adjusted analyses, all four polymorphic allele groups had 2-3-fold higher odds for composite outcomes of dialysis or in-hospital death or a composite of dialysis, assisted mechanical ventilation, or in-hospital death. The MPO T-G-A-T haplotype copy-number was associated with lower plasma MPO levels and lower adjusted odds for the composite outcomes. Significant but less consistent associations were found in the secondary cohort. In summary, our two-step genetic association study identified several polymorphisms spanning the entire MPO gene locus and a common haplotype marker for patients at risk for acute kidney injury.Kidney International advance online publication, 27 June 2012; doi:10.1038/ki.2012.235.

Previous studies have questioned the external validity of randomized controlled trial results of acute coronary syndrome (ACS) because of potential selection bias toward healthier patients. We sought to evaluate differences in clinical characteristics and management of patients admitted with non-ST-elevation ACS according to participation in clinical trials over the previous decade. The Canadian ACS I (1999 to 2001), ACS II (2002-2003), GRACE (2004-2007), and CANRACE (2008) were prospective, multicenter registries of patients admitted to hospitals with ACS. We examined 13,556 patients with non-ST-elevation ACS, of whom 1,126 (8.3%) participated in clinical trials. Data were collected on baseline characteristics, medication use at admission and discharge, in-hospital procedures, and in-hospital adverse events. Patients enrolled in clinical trials were younger, more likely to be men, and had fewer co-morbidities. They were significantly more likely to be on several guideline-recommended medications and were significantly more likely to undergo invasive procedures, including coronary angiography, percutaneous coronary intervention, and coronary bypass surgery (all p values <0.001). Unadjusted in-hospital (2.1% vs 0.7%, p = 0.001) and 1-year (8.9% vs 6.3%, p = 0.037) mortality rates were higher in non-enrolled patients. In multivariable analysis, patients who were older, women, had a history of heart failure, and increased creatinine levels on presentation were less likely to be enrolled into clinical trials. In conclusion, significant differences persist in baseline characteristics, treatment, and outcomes between patients enrolled and those not enrolled in clinical trials. Consequently, generalization of ACS clinical trials over the previous decade to the "real-world" patient may remain in question.

AIMS: To examine: (i) the temporal changes in the management pattern; (ii) the reasons for any treatment disparities; (iii) the relationship between invasive treatment and outcome, among acute coronary syndrome (ACS) patients with vs. without kidney dysfunction. METHODS AND RESULTS: Canadian ACS I, ACS II registries and Global Registry of Acute Coronary Events (GRACE) were prospective, multi-centre, observational studies of patients with ACS. From 1999 to 2007, non-ST elevation (NSTE) ACS patients were recruited in ACS I (n = 3295; 1999-2001), ACS II (n = 1956; 2002-2003), and GRACE (n = 6491; 2004-2007) in Canada. Using the four-variable Modified Diet in Renal Disease equation, we stratified the study population (n = 11,377) into three groups based on their estimated glomerular filtration rate (eGFR), and examined their treatment and outcome. While in-hospital use of coronary angiography and revascularization increased over time in all groups (P < 0.001), patients with kidney dysfunction were less likely to undergo invasive management (P < 0.001). Unadjusted 1 year mortality was lower among patients receiving in-hospital coronary angiography within all eGFR categories (> or =60 mL/min/1.73 m(2): 2.5 vs. 7.6%, P < 0.001; 30-59 mL/min/1.73 m(2): 8.0 vs. 14.6%, P < 0.001; <30 mL/min/1.73 m(2): 27.5 vs. 41.5%, P = 0.043). In-hospital revascularization was independently associated with lower 1-year mortality (adjusted OR = 0.52, 95% CI 0.36-0.77, P = 0.001), irrespective of eGFR (P for heterogeneity = 0.39). Underestimation of patient risk was the most common barrier to an invasive treatment strategy. CONCLUSION: Despite temporal increases in invasive management of NSTE-ACS, patients with kidney dysfunction are more commonly treated conservatively, with an associated worse outcome. In-hospital revascularization was independently associated with improved survival, irrespective of eGFR. Randomized controlled trials involving patients with kidney dysfunction are needed to confirm whether more aggressive treatment will improve their poor outcome.