[1] Vet Affairs Med Ctr, Clin Epidemiol Res Ctr, West Haven, CT 06516 USA
[2] Yale Univ, Sch Med, Dept Med, New Haven, CT 06510 USA
[3] Univ Rochester, Sch Med, Dept Med, Rochester, NY USA
[4] Univ Western Ontario, Dept Nephrol, London, ON, Canada
[5] Univ Western Ontario, Dept Epidemiol & Biostat, London, ON, Canada
[6] Inst Clin Evaluat Sci, Toronto, ON, Canada
[7] Yale Univ, Sch Med, Dept Anesthesiol, New Haven, CT 06510 USA