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Kidney Week

Abstract: TH-PO858

Risk of Hospital Encounters for Kidney Stones in Autosomal Dominant Polycystic Kidney Disease: A Cohort Study

Session Information

Category: Genetic Diseases of the Kidneys

  • 1001 Genetic Diseases of the Kidneys: Cystic

Authors

  • Kalatharan, Vinusha, Western University, London, Ontario, Canada
  • Welk, Blayne, Western University, London, Ontario, Canada
  • Nash, Danielle Marie, London Health Sciences Centre, London, Ontario, Canada
  • Dixon, Stephanie, Institute for Clinical Evaluative Sciences, London, Ontario, Canada
  • Slater, Justin, Institute for Clinical Evaluative Sciences, London, Ontario, Canada
  • Pei, York P., University Health Network and University of Toronto, Toronto, Ontario, Canada
  • Sarma, Sisira, Western University, London, Ontario, Canada
  • Garg, Amit X., London Health Sciences Centre, London, Ontario, Canada
Background

Patients with autosomal dominant polycystic kidney disease (ADPKD) are may be more likely to develop kidney stones than the general population. However, empirical evidence to this effect is lacking in the current literature. We studied the incidence of (i) a de novo hospital encounter with kidney stones, and (ii) stone interventions among patients with ADPKD compared to patients without ADPKD who were similar in their baseline health indicators.

Methods

Using large healthcare databases from Ontario, Canada, patients with and without ADPKD were identified using hospital encounters between April 1st, 2002 and March 31st, 2016. We used inverse probability of treatment weighting (IPTW) based on propensity score to ensure characteristics of baseline health indicators between the two groups were similar. We followed patients from cohort entry until the first recorded hospital encounter with a de novo stone, death, emigration from Ontario, or March 31st, 2017. We used a weighted Cox proportional hazards model to compare stone rates between the two groups. Death was treated as a censoring event in the primary analysis, and as a competing event in secondary analyses. We also performed analyses for time to first recorded stone intervention and abdominal imaging across all settings. Patients were followed for a mean (maximum) of 7.5 (15.6) years.

Results


ADPKD compared to no ADPKD was not associated with a higher risk of a hospital encounter with stones (92 patients of 2094 with ADPKD [4.3%] vs 80 patients of 2096 without ADPKD [3.8%]; 7.4 vs 6.2 events per 1000 person-years; hazard ratio 1.2 [95% CI, 0.9 to 1.6]. Similarly, ADPKD compared to no ADPKD was not associated with a higher risk of stone intervention (52 of 2094 [2.5%] vs 62 of 2096 [3.0%]; 4.1 vs 4.7 events per 1000 person-years; hazard ratio 0.9 [95% CI 0.6 to 1.2]). The results were similar when treating death as a competing event. ADPKD compared to no ADPKD was associated with a significantly higher rate of abdominal imaging (hazard ratio 1.2 [95% CI 1.1 to 1.3]).

Conclusion


ADPKD was not a significant risk factor for a hospital encounter with kidney stones. The perception that patients with ADPKD are more likely to develop stones may be due to increased surveillance.

Funding

  • Government Support - Non-U.S.