Kidney stones and kidney function loss: a cohort studyBMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e5287 (Published 30 August 2012) Cite this as: BMJ 2012;345:e5287
- R Todd Alexander, assistant professor1,
- Brenda R Hemmelgarn, associate professor2,
- Natasha Wiebe, research associate1,
- Aminu Bello, research fellow1,
- Catherine Morgan, assistant professor1,
- Susan Samuel, assistant professor2,
- Scott W Klarenbach, associate professor1,
- Gary C Curhan, professor3,
- Marcello Tonelli, professor1
- for the Alberta Kidney Disease Network
- 17-129 Clinical Science Building, University of Alberta, 8440 112 Street, Edmonton, Alberta T6B 2G3, Canada
- 2University of Calgary, Calgary, Canada
- 3Channing Laboratory, Harvard University, Boston, USA
- Correspondence to: M Tonelli
- Accepted 25 July 2012
Objective To investigate whether the presence of kidney stones increase the risk of end stage renal disease (ESRD) or other adverse renal outcomes.
Design A registry cohort study using validated algorithms based on claims and facility utilisation data. Median follow-up of 11 years.
Setting Alberta, Canada, between 1997 and 2009.
Participants 3 089 194 adult patients without ESRD at baseline or a history of pyelonephritis. Of these, 1 954 836 had outpatient serum creatinine measurements and were included in analyses of chronic kidney disease and doubling of serum creatinine level.
Exposure One or more kidney stones during follow-up.
Main outcome measures Incident ESRD, development of stage 3b–5 chronic kidney disease (estimated glomerular filtration rate <45 mL/min/1.73 m2), and sustained doubling of serum creatinine concentration from baseline.
Results 23 706 (0.8%) patients had at least one kidney stone, 5333 (0.2%) developed ESRD, 68 525 (4%) developed stage 3b–5 chronic kidney disease, and 6581 (0.3%) experienced sustained doubling of serum creatinine. Overall, one or more stone episodes during follow-up was associated with increased risk of ESRD (adjusted hazard ratio 2.16 (95% CI 1.79 to 2.62)), new stage 3b–5 chronic kidney disease (hazard ratio 1.74 (1.61 to 1.88)), and doubling of serum creatinine (hazard ratio 1.94 (1.56 to 2.43)), all compared with those without kidney stones during follow-up. The excess risk of adverse outcomes associated with at least one episode of stones seemed greater in women than in men, and in people aged <50 years than in those aged ≥50. However, the risks of all three adverse outcomes in those with at least one episode of stones were significantly higher than in those without stones in both sexes and age strata. The absolute increase in the rate of adverse renal outcomes associated with stones was small: the unadjusted rate of ESRD was 2.48 per million person days in people with one or more episodes of stones versus 0.52 per million person days in people without stones.
Conclusion Even a single kidney stone episode during follow-up was associated with a significant increase in the likelihood of adverse renal outcomes including ESRD. However, the increases were small in absolute terms.
Contributors: RTA conceived the study. RTA, NW, AB, and MT designed the analysis plan. NW performed the statistical analyses. RTA, NW, and MT wrote the first draft of the study. All authors contributed to the design, interpretation of results, and critical revision of the article for intellectually important content.
Funding: This work was supported by a team grant to the Interdisciplinary Chronic Disease Collaboration from the Alberta Heritage Foundation for Medical Research (AHFMR), the Kidney Foundation of Canada, and by the University Hospital Foundation. RTA is supported by a Clinician-Scientist award from the Canadian Institute of Health Research, a KRESCENT New Investigator award, and an Alberta Innovates Health Solutions Clinical Investigator Award. SS is supported by a KRESCENT New Investigator award and a Canadian Child Health Clinician Scientist Program Career Development award. GCC is supported by grant DK070756 from the National Institutes of Health. MT is supported by an AHFMR Population Health Scholar award and a Government of Canada Research Chair in the optimal care of people with chronic kidney disease.
Competing interests: All authors have completed the ICMJE uniform disclosure form at ww.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: Our protocol was approved by the University of Alberta Health Research Ethics Board and the University of Calgary Conjoint Health Research Ethics Board.
Data sharing: No additional data available.
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