Abstract
BACKGROUND: Perioperative corticosteroid use may reduce acute kidney injury. We sought to test whether methylprednisolone reduces the risk of acute kidney injury after cardiac surgery.
METHODS: We conducted a prespecified substudy of a randomized controlled trial involving patients undergoing cardiac surgery with cardiopulmonary bypass (2007–2014); patients were recruited from 79 centres in 18 countries. Eligibility criteria included a moderate-to-high risk of perioperative death based on a preoperative score of 6 or greater on the European System for Cardiac Operative Risk Evaluation I. Patients (n = 7286) were randomly assigned (1:1) to receive intravenous methylprednisolone (250 mg at anesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients, caregivers, data collectors and outcome adjudicators were unaware of the assigned intervention. The primary outcome was postoperative acute kidney injury, defined as an increase in the serum creatinine concentration (from the preoperative value) of 0.3 mg/dL or greater (≥ 26.5 μmol/L) or 50% or greater in the 14-day period after surgery, or use of dialysis within 30 days after surgery.
RESULTS: Acute kidney injury occurred in 1479/3647 patients (40.6%) in the methylprednisolone group and in 1426/3639 patients (39.2%) in the placebo group (adjusted relative risk 1.04, 95% confidence interval 0.96 to 1.11). Results were consistent across several definitions of acute kidney injury and in patients with preoperative chronic kidney disease.
INTERPRETATION: Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery. Trial registration: ClinicalTrials.gov, no. NCT00427388
About 20% of the 4 million cardiopulmonary bypass surgeries performed worldwide each year are complicated by acute kidney injury, defined as a sudden reduction in kidney function.1 Acute kidney injury is associated with longer hospital stays, higher health care costs and death.2,3 In the most severe cases, dialysis is needed to sustain life. An intervention that can reduce the risk of acute kidney injury has, to date, proven elusive.
Cardiopulmonary bypass can initiate a systemic inflammatory response, which is associated with adverse clinical outcomes including acute kidney injury.1 Several lines of evidence support testing whether corticosteroids can mitigate perioperative inflammation and acute kidney injury.1,4 Corticosteroids can attenuate the systemic inflammatory response to cardiopulmonary bypass by reducing inflammatory mediators, cytokines, transcription factors and adhesion molecules.3,5–8 Physicians commonly use intravenous corticosteroids to treat acute conditions that involve renal inflammation, including glomerulonephritis and vasculitis.9 In a post-hoc analysis of the Dexamethasone for Cardiac Surgery Trial, use of intravenous dexamethasone (a corticosteroid) was associated with a significant relative risk (RR) reduction for dialysis use during the hospital stay (although there were few outcome events and all occurred in patients with chronic kidney disease).5,10
We conducted a prespecified substudy of the Steroids in Cardiac Surgery (SIRS) trial11 to test the effect of intraoperative methylprednisolone versus placebo on acute kidney injury after cardiopulmonary bypass surgery. The protocol and outcomes for this substudy were prespecified and published before the results of the main trial were known,4 and the substudy received separate grant funding from the Canadian Institutes of Health Research. We hypothesized that methylprednisolone would reduce the risk of acute kidney injury, and that the RR reduction would be greater in patients with preoperative chronic kidney disease.
Methods
Design and setting
This was a parallel-group (1:1) randomized controlled trial that evaluated intraoperative intravenous methylprednisolone versus placebo in 7507 patients (including 490 pilot patients enrolled between June 19, 2007, and Sept. 10, 2010) from 18 countries who had cardiac surgery with cardiopulmonary bypass (2007–2014).11,12 Eligible patients were aged 18 years and older with a moderate-to-high risk for perioperative death (based on a preoperative score of ≥ 6 on the European System for Cardiac Operative Risk Evaluation I [patients from China and India were eligible if their score was ≥ 4 and they were having valvular surgery]),13 were not taking or expecting to take aprotinin or systemic steroids in the immediate postoperative period, had no history of bacterial or fungal infection in the last 30 days, and had no intolerance or allergy to steroids.
The primary results are reported elsewhere; briefly, methylprednisolone did not alter the risk of 30-day mortality, myocardial injury, stroke, renal failure or respiratory failure.11
Acute kidney injury substudy
The original protocol for this substudy was published previously (minor changes are summarized in Appendix 1, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1).4 The following patients (< 3%) were excluded from this substudy: those with prerandomization end-stage kidney disease (i.e., patients with an estimated glomerular filtration rate of < 15 mL/min/1.73 m2 [calculated using the Chronic Kidney Disease Epidemiology Collaboration equation14] or patients receiving dialysis), those missing a prerandomization serum creatinine measurement (which is needed to define acute kidney injury) and those who did not undergo surgery.
Interventions
Patients were randomly assigned to receive either intravenous methylprednisolone (250 mg at anesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or matching placebo. Prior randomized trials suggested that this steroid regimen, compared with placebo, decreased plasma concentrations of inflammatory biomarkers, improved hemodynamic stability, and reduced the need for vasopressors in patients having cardiac surgery with cardiopulmonary bypass.8
Data sources
Research personnel at each site collected patient data from medical charts, hospital discharge notes and patient interviews. Preoperative serum creatinine levels were recorded in the 30-day period before surgery and the peak postoperative serum creatinine level was recorded in the 14-day period after surgery. Beginning on Mar. 1, 2012 (after receipt of substudy grant funding), centres began recording all postoperative serum creatinine measurements taken in routine care in the 14-day period after surgery for eligible patients. No data on urine output were collected given difficulties with the accurate measurement of urine output in the setting of international data collection.
Substudy outcomes
The primary outcome of postoperative acute kidney injury (prespecified when enrolment began in 2007) was defined as an increase in the serum creatinine concentration (from the preoperative value) of 0.3 mg/dL or greater (≥ 26.5 μmol/L) or 50% or greater within 14 days after surgery, or receipt of dialysis within 30 days after surgery.4
Prespecified secondary definitions of acute kidney injury
To determine whether the primary results were robust, we examined 6 secondary definitions of acute kidney injury (comparing the peak postoperative serum creatinine concentration in the 14-day period after surgery to the preoperative value).
The primary definition of acute kidney injury or death within 48 hours after surgery (to account for the potential impact of early deaths on outcome ascertainment).
Stage 2 acute kidney injury or higher, defined as an increase in postoperative serum creatinine of 100% or greater, or an increase to an absolute value of 4.0 mg/dL or greater (≥ 353.6 μmol/L) (while meeting the primary definition), or receipt of dialysis within 30 days after surgery.
Stage 3 acute kidney injury, defined as an increase in postoperative serum creatinine of 200% or greater, or an increase to an absolute value of 4.0 mg/dL or greater (≥ 353.6 μmol/L) (while meeting the primary definition), or receipt of dialysis within 30 days after surgery.
Receipt of dialysis within 30 days after surgery.
Percentage change in serum creatinine, defined as [(peak postoperative serum creatinine – preoperative serum creatinine)/preoperative serum creatinine] × 100.
Absolute change in serum creatinine defined as peak postoperative serum creatinine – preoperative serum creatinine.
In 2012, Kidney Disease Improving Global Outcomes published a guideline15 defining acute kidney injury with an increase in serum creatinine of 0.3 mg/dL or greater (≥ 26.5 μmol/L) within 48 hours, or an increase of 50% or greater within 7 days. We examined this definition in a subsample of patients who were randomly assigned on or after Mar. 1, 2012 (when the study began recording all serum creatinine values measured during routine care). Acute kidney injury that was present on (i) at least 2 days and (ii) at least 3 days within 7 days after surgery was also examined in this subsample.4
Randomization procedures
Patients were randomly assigned (1:1) using a central 24-hour computerized randomization system. Patients were assigned to either intravenous methylprednisolone or placebo by block randomization with random block sizes of 2, 4 or 6, stratified by centre. The study drug was prepared and masked by local pharmacies at the study centres. Patients, health care providers, data collectors and outcome adjudicators were unaware of treatment allocation.
Sample size
We anticipated that at least 7000 patients enrolled in the main trial would be eligible for the kidney substudy, providing at least 90% power to detect a 10% RR reduction for the primary outcome of acute kidney injury (2-sided α = 0.05), assuming an incidence of 38% in the placebo group. With the inclusion of 7286 patients (97% of 7507 randomly assigned in the main trial), this substudy had 94% power to detect a 10% RR reduction in the primary outcome.
Statistical analysis
We conducted analyses using the intention-to-treat principle. Data were analyzed using SAS version 9.2. A modified Poisson regression model (accounting for centre) was used to estimate the RR and 95% confidence interval (CI) for acute kidney injury in patients randomly assigned to methylprednisolone versus placebo; a sandwich variance estimator was used to account for the effect of centre and to incorporate a robust error estimator in the modified Poisson regression approach for a binary response variable.16,17
We determined unadjusted and adjusted estimates. The adjusted models included 10 prespecified covariates: age, sex, left ventricular function less than 50%, diabetes, prerandomization medication use, estimated glomerular filtration rate less than 60 mL/min/1.73m2, surgery type and evidence of nonelective surgery. We used multiple imputation to impute missing data on left ventricular ejection fraction (a covariate; missing for 0.9%) and in a sensitivity analysis of acute kidney injury (missing for 0.8%); further details are provided in Appendices 2 and 3, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1. We estimated the adjusted percentage change and absolute change in postoperative serum creatinine using linear regression models. The risk of acute kidney injury in patients with preoperative chronic kidney disease (defined by an estimated glomerular filtration rate of < 60 mL/min/1.73 m2) was examined by including an interaction term in the model.
We conducted 3 other prespecified analyses. First, the between-group difference in adherence was examined, where adherence was defined as the percentage of patients receiving the treatment as randomly assigned, and the percentage using nonstudy corticosteroids in the operating room and in the first 3 days after surgery. Second, the possibility of differential outcome ascertainment was assessed in the subgroup of patients who had multiple serum creatinine measurements within 7 days of surgery (those randomly assigned on or after Mar. 1, 2012). Third, the primary analyses were repeated after excluding patients who underwent emergent or urgent surgery (defined based on preoperative use of inotropes, vasopressors, an intra-aortic balloon pump, or a ventricular assist device, or evidence of myocardial infarction in the 30 days before surgery).
Ethics approval
Ethics approval to conduct the trial was obtained at all participating centres, and all participants provided written informed consent before enrolment; SIRS was centrally coordinated at the Population Health Research Institute at McMaster University and Hamilton Health Sciences, Hamilton, Ontario. In some countries with more than 3 centres recruiting, a national coordinating office was responsible for obtaining the national regulatory approvals and coordinating research ethics application at each site.11,12
Results
Trial enrolment began on June 19, 2007, and the last patient was randomly assigned on Dec. 19, 2013. Of 7507 patients randomly assigned in the main trial, 7286 met the eligibly criteria for this substudy (3647 methylprednisolone and 3639 placebo) (Figure 1). The median time from the prerandomization serum creatinine assessment to surgery was 2 (interquartile range [IQR] 1–7) days. The median time from randomization to surgery was 1.0 (IQR 0.0–1.0) day in the methylprednisolone group and 1.0 (IQR 0.0–1.0) day in the placebo group. The lowest prerandomization estimated glomerular filtration rate was 15 mL/min/1.73m2. Surgeries were completed between June 2007 and January 2014, and the last day of follow-up was Mar. 21, 2014. Baseline characteristics are shown in Table 1. Both groups had a mean age of 68 (standard deviation [SD] 14) years and a mean prerandomization estimated glomerular filtration rate of 73 (SD 22) mL/min/1.73m2.
The flow of patients in the subsample with serial postoperative serum creatinine assessments is shown in Appendix 4, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1. Differences in baseline characteristics between patients in the main trial, the kidney substudy and the subsample with serial postoperative creatinine assessments are shown in Appendix 5, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1.
Postoperative acute kidney injury
Postoperative acute kidney injury occurred in 1479 of 3647 patients (40.6%) in the methylprednisolone group and in 1426 of 3639 patients (39.2%) in the placebo group (unadjusted RR 1.03, 95% CI 0.98 to 1.09; adjusted RR 1.04, 95% CI 0.96 to 1.11) (Table 2). Results were consistent across 4 other categorical definitions of acute kidney injury (Table 2) and in sensitivity analyses using different methods to handle missing outcome data (Appendix 6, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1). The adjusted mean difference in the percentage change in serum creatinine was 0.02% (95% CI −3.7% to 3.7%), and the adjusted mean difference in the absolute change was −0.01 mg/dL (0.6 μmol/L), 95% CI −0.04 to 0.02 (Table 3). The RR of acute kidney injury did not differ significantly in patients with and without preoperative chronic kidney disease (Figure 2 and Table 4). In the subsample of 4824 patients with serial postoperative serum creatinine assessments, postoperative acute kidney injury (serum creatinine threshold defined according to guidance from Kidney Disease Improving Global Outcomes) occurred in 832/2405 patients (35%) in the methylprednisolone group and in 819/2419 patients (34%) in the placebo group; adjusted RR, 1.02 (95% CI 0.92 to 1.12) (Table 5).
The treatment was received as assigned for 96% in each group. Nonstudy corticosteroids were received in the operating room by 2.9% and 2.7% in the methylprednisolone versus placebo group, respectively, and by 4.1% in each group in the first 3 days after surgery. In the subsample of patients with serial postoperative serum creatinine measurements, 98% of each group had at least 1 measurement, and each group had a median of 5 (IQR 3–6) measurements (Appendix 7, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1). The primary results were consistent when patients who underwent emergent or urgent surgery were excluded from the analysis (Appendix 8, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1).
Interpretation
In this randomized controlled trial involving patients who underwent cardiopulmonary bypass surgery, allocation to perioperative methylprednisolone did not alter the risk of acute kidney injury. Results were consistent across several definitions of acute kidney injury, and in patients with preoperative chronic kidney disease.
This study provides reliable, generalizable effect estimates from a sample of more than 7000 patients recruited from 79 centres in 18 countries. The lower bound of the 95% CI of the treatment estimates suggests that clinically important benefits of perioperative steroids on the risk of acute kidney injury are unlikely. Although inflammatory markers were not measured in this study, we used the same steroid regimen that was used in the pilot study that resulted in decreased plasma concentrations of inflammatory biomarkers, improved hemodynamic stability and a reduced need for vasopressors.8
Our findings are discordant with a post-hoc analysis of a similar but smaller trial (n = 4465) in which dexamethasone (1 mg/kg, maximum 100 mg) versus placebo significantly reduced the risk of in-hospital dialysis (10/2229 [0.4%] v. 23/2236 [1.0%], RR 0.44, 95% CI 0.19 to 0.96).5,10 However, the wide CI and low number of dialysis events (33 v. 183 in our study) means this result is statistically fragile (i.e., the result would be statistically nonsignificant if 1 more event occurred in the intervention group).18
To understand the effect of corticosteroids on acute kidney injury better, we updated a previous meta-analysis of placebo-controlled trials involving adult patients undergoing cardiac surgery.7 In these trials, acute kidney injury was usually defined as a 50% or greater increase in serum creatinine from the preoperative value or receipt of dialysis. The updated forest plot is shown in Appendix 9, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.181644/-/DC1. The pooled RR of acute kidney injury (steroids [1564 events] v. placebo [1533 events]) was 0.93 (95% CI 0.68 to 1.28). The lack of evidence of a protective effect of steroids combined with some adverse effects suggests that prophylactic use of steroids during cardiopulmonary bypass surgery is not warranted.11,19
Limitations
Although serum creatinine measurement is part of routine care after cardiac surgery, sole reliance on routine measures could introduce ascertainment bias. For example, if methylprednisolone altered the incidence of myocardial infarction or other events, this could alter the frequency of serum creatinine assessment and influence the detection of acute kidney injury. Also, multiple measures of serum creatinine are preferred for the accurate assessment of kidney function. To address these concerns, we examined several definitions of acute kidney injury, and we collected multiple postoperative serum creatinine measurements in a subsample of 4824 patients (66%). Results were consistent across all sensitivity analyses, and no between-group differences in the frequency of serum creatinine measurements were observed. Results were also consistent after excluding patients having urgent surgery (baseline concentrations of serum creatinine may have been unstable in these patients).
Conclusion
Prophylactic intravenous steroids administered in the operating room did not alter the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Strategies focusing on other noninflammatory contributors of perioperative acute kidney injury, such as improving renal perfusion and decreasing hemolysis20 warrant future consideration.
Footnotes
SIRS Investigators: The following list includes investigators who participated in acute kidney injury substudy of SIRS by country: Canada — Hamilton Health Sciences: R. Whitlock, A. Lamy, L. Semelhago, V. Chu, A. Dyub, I. Cybulsky, R. Van Oosteen, G. Cordova; London Health Sciences Centre: M.A. Quantz, F.N. McKenzie, S. Fox, L. Chase; Centre Hospitalier de l’Université de Montréal: N. Noiseux, L.M. Stevens, I. Prieto, F. Basile; University of Alberta Hospital: B.A. Finegan, C. Bryden, S. Meyer, A. Chappell; St. Michael’s Hospital: C.D. Mazer, J. Dixon, S. Yagnik, C. Crescini, S. Verma; Queen Elizabeth II Health Sciences Centre: J.F. Legaré; Centre hospitalier universitaire de Sherbrooke: F. Lamontagne, D. Greentree, M. Coutu, J. Teijeira; Southlake Regional Health Centre: K.H. Teoh, W. Wiley, C. Peniston, C. Teng; Montreal Heart Institute: A.G. Rochon, Y. Lamarche, A. Deschamps; Institut universitaire de cardiologie et de pneumelogie de Québec: P. Voisine, F. Dagenais; St. Boniface General Hospital: R.K. Singal; New Brunswick Heart Centre: C.D. Brown; Foothills Medical Centre: T.M. Kieser, R. Robinson; Sunnybrook Health Sciences Centre: S.E. Fremes, G.T. Christakis; Eastern Health: K.N. Melvin, M. Parsons; China — First Teaching Hospital of Xinjiang Medical University: H. Zheng, J. Yu, W. Xu, Q. Zhang, C. Chen; West China Hospital, Sichuan University: H. Yu, J. Zeng, Y. Zuo, J. Liu; General Hospital of Shenyang Military Command: T. Zhang, Y. Sun, D. Song; Xijing Hospital: H. Dong, M. Chen, J. Zhao; Wuhan Asia Heart Hospital: L. Tao, W. Huang, Y. Cheng; Union Hospital: Y.S. Long, W. Lei; First Affiliated Hospital of Zhengzhou University: W. Zhang; Shanghai Thoracic Hospital: M.Y. Xu; Anzhen Hospital, Beijing: E. Qing; Third Military Medical University: Y.B. Xiao; India — Sree Chitra Tirunal Institute for Medical Sciences and Technology: J. Karunakaran, V.V. Pillai, P.B. Reddy, S. Kundan; SAL Hospital and Medical Institute: A.R. Jain, S.S. Mallya, C.B. Mehta; Christian Medical College: V. Shukla, K. Kuruvila; All India Institute of Medical Sciences: G. Karthikeyan, V. Devagourou, M.P. Hote, B. Airan; G. Kuppuswamy Naidu Memorial Hospital: C. Padmanabhan, M. Srinivasan; Sanjay Gandhi Postgraduate Institute of Medical Sciences: S.K. Agarwal, S. Pande; Sri Jayadeva Institute of Cardiovascular Sciences and Research: P. Simha Mohan Rao, R. Math; Frontier Lifeline Hospital: B.P.R. Shankar, P.H. Vaijyanath; Amrita Institute of Medical Sciences: S.K. Nair; Nizam’s Institute of Medical Sciences: D.R. Ayapati; United States — Cleveland Clinic: J.P. Yared, A. Kurz, A. Awais, K. Panjasawatwong, B.K. Kashy; University of Virginia Health System: J.L. Huffmyer, D.C. Scalzo, A. Kazemi; St. Johns Medical Research/Mercy Hospital: K.F. Huang, S.V. Parvathaneni; Wake Forest University Health Sciences: J.C. Gardner; Hillcrest Hospital: M.R. Malik, Y. Eshraghi; Maine Medical Center: R.S. Kramer; The Ohio State University: M.K. Essandoh, J. Portillo; Fairview Hospital: S.S. Ayad, Z. Akhtar; Georgia Regents University: M.R. Castresana; Texas Heart Institute/CHI Baylor St. Luke’s Medical Center: C.D. Collard; University of Miami: Y.F. Rodriguez-Blanco; University of Rochester: M.P. Eaton; Colombia — Fundación Cardioinfantil Instituto de Cardiologia: J.C. Villar, J.P. Umaña, C.L. Dominguez, P.A. Alvarado, D. Zuluaga; Fundación Clínica Shaio: M. Abello, T. Sarquis, E. Vaquiro, C.A. Oliveros; Instituto del Corazón de Bucaramanga: E.J. Manrique, S. Vasquez, L.M. Ortiz; Australia — Princess Alexandra Hospital: P.J. Shah, J. Holliday, R. Griffin; Royal Melbourne Hospital: A.G. Royse, C.F. Royse, Z. Williams; Italy — Universita degli Studi Aldo Moro di Bari: D. Paparella, C. Rotunno, M. De Palo, V. Margari; San Raffaele University Hospital: O. Alfieri, D. Ferrara, D. Schiavi; Centro Cardiologico Monzino IRCCS: A. Parolari, V.A. Myasoedova, A. Daprati; V. Monaldi Hospital: M. De Feo, C. Bancone; University of Bologna: R. Di Bartolomeo, D. Pacini; Azienda Ospedaliera Citta della Salute e della Scienza: M. Ribezzo; Iran — Tehran Heart Center: S.H. Abbasi, A. Karimi, A. Salehiomran, A. Hajighasemi, P. Bina; Czech Republic — University Hospital Královské Vinohrady: Z. Straka, J. Hlavička, P. Lukáč; University Hospital Motol: K. Vik, F. Mosna; Greece — University Hospital of Thessaly: G.I. Tagarakis, N.B. Tsilimingas, V.N. Simopoulos, F. Tsolaki; Spain — Hospital de la Santa Creu i Sant Pau: M.T. Rivilla, J. Galan, J.A.F. Nuñez; Hospital Universitari Vall d’Hebron: A. Gonzalez, D. Ruiz; Hospital Universitario de La Princesa: M. Orts Rodríguez; Brazil — Instituto Dante Pazzanese de Cardiologia: M. Issa, D.C. Vila Nova; Fundação Faculdade de Medicina de São José do Rio: L.N. Maia, M.A. Nakazone; Real e Benemérita Associação Portuguesa de Beneficência: G.V. Lico e Cividanes; Instituto do Câncer do Estado de São Paulo: L.A. Hajjar; Cardioclinica Paulista: V. Ávila Neto; São Francisco Hospital: F.A. Lucchese; Unidade de Doenças Torácicas Stolf SA Ltda: N.A. Stolf; Austria — Medical University of Vienna: D. Hutschala, K. Ruetzler, B. Sima; Belgium — ZNA Middelheim: S. Engelen, S. Borms; University Hospital Leuven: M. Van de Velde, S. Rex; Ghent University Hospital: S.G. De Hert; Hong Kong — The Chinese University of Hong Kong: A.M.H. Ho, M.T.V. Chan, M.J. Underwood; Argentina — Sociedad Italiana de Beneficencia en Buenos Aires: D. Deluca Bisurgi; Chile — Clinica Sante Maria: D. Torres; Ireland — Mater Misericordiae University Hospital: D.J. Buggy.
Competing interests: P.J. Devereaux has received grants from Abbott Diagnostics, Boehringer Ingelheim, Covidien, Octapharma, Philips Healthcare, Roche Diagnostics and Stryker for projects outside the work reported here. Chirag Parikh reports personal fees from AbbVie Pharmaceutical Research and Development and GENFIT Biopharmaceutical Company; funding from Renalytix AI; and grants from the National Institute of Diabetes and Digestive and Kidney Diseases, and the National Heart, Lung and Blood Institute. Vlado Perkovic reports receiving personal fees for advisory boards or scientific presentations from Retrophin, Janssen, Merck and Servier. Vlado Perkovic was a member of the SONAR Steering Committee; has served on steering committees for trials funded by AbbVie, Boehringer Ingelheim, GlaxoSmithKline, Janssen, Novo Nordisk, Retrophin and Tricida; and has participated in scientific presentations and advisory boards with AbbVie, Astellas, Astra-Zeneca, Bayer, Baxter, Bristol-Myers Squibb, Boehringer Ingelheim, Dimerix, Durect, Eli Lilly, Gilead, GlaxoSmithKline, Janssen, Merck, Mitsubishi Tanabe, Novartis, Novo Nordisk, Pfizer, PharmaLink, Relypsa, Retrophin, Sanofi, Servier, Vifor and Tricida. Richard Whitlock reports grants and personal fees from Boehringer Ingelheim. No other competing interests were declared.
This article has been peer reviewed.
Contributors: All of the authors contributed to the concept and design of the study, and the acquisition, analysis or interpretation of data. Amit Garg, Jessica Sontrop and Richard Whitlock drafted the manuscript. All of the authors contributed to the critical revision of the manuscript for important intellectual content. Meaghan Cuerden performed the statistical analysis. Amit Garg and Richard Whitlock obtained funding. Amit Garg and Richard Whitlock provided administrative, technical or material support. Amit Garg and Richard Whitlock supervised the study. Amit Garg had full access to all data in the study and had final responsibility for the decision to submit for publication. All of the authors gave final approval of the version to be published and agreed to be accountable for all aspects of the work.
Funding: The Steroids in Cardiac Surgery (SIRS) trial and this substudy on acute kidney injury were financially supported by grants from the Canadian Institutes of Health Research (CIHR). Amit Garg was supported by the Dr. Adam Linton Chair in Kidney Health Analytics and a CIHR Clinician Investigator Award. Chirag Parikh was supported by the National Institutes of Health grant RO1HL-085757. Michael Walsh is supported by a CIHR New Investigator Award.
Data sharing: The study protocol and statistical analysis plan are available on request from Amit Garg (amit.garg{at}lhsc.on.ca). Additional questions about the trial data can be directed to Richard Whitlock (Richard.Whitlock{at}phri.ca).
- Accepted February 1, 2019.