Table 2.

Risk of ESRD among stone formers compared with control participants in Olmsted County, Minnesota, by stone former group

Group of Stone Formers IdentifiedNumber of Stone Formers (Events)Number of Controls (Events)HR (95% CI)Cumulative 15-Yr Incidence of ESRD (%)
Stone FormersControls
Group 1: ICD-9 codes (1984–2008)6911 (51)24,577 (75)2.36 (1.65, 3.37)1.30.7
Group 2: ICD-9 codes (1984–2003)4899 (46)17,465 (66)2.42 (1.66, 3.53)1.30.6
Group 3: Random subset of group 2 that underwent chart review2985 (29)10, 627 (42)2.35 (1.46, 3.78)1.40.7
Group 4: Those in group 3 with a validated symptomatic stone2453 (20)8711 (33)1.98 (1.13, 3.45)1.20.6
  • Table excludes participants with prevalent ESRD. HR, hazard ratio; 95% CI, 95% confidence interval; ICD-9, International Classification of Diseases, Ninth Revision.