Risk of chronic kidney disease in patients with kidney stones - A nationwide cohort study

Background: Chronic kidney disease (CKD) and kidney stones are common in Taiwan; in particular, CKD has a high prevalence but low self-awareness rate. CKD-related risk factors such as diabetes, hypertension, and nephrotoxic drugs are well-known and uncontested; however, kidney stones are relatively less studied and easily overlooked as a risk factor. The objective of this study was to investigate whether kidney stones are a risk factor for CKD. Methods: We conducted a nationwide population-based matched cohort study to assess the risk of incident CKD in people with kidney stones. Data on incident stones formers in the year 2001 - excluding those with a history of CKD - were obtained from Taiwan's National Health Insurance database. Stone formers were matched (1:4) to control subjects according to sex, age, and index date. The total observation period of the study was 10 years, and the primary end-point was the occurrence of CKD. Student's t-test and Chi-squared test were used to compare continuous and categorical data, respectively. Logistic regression was used to calculate the odds ratio of kidney stone patients with incident CKD relative to the control group. Cox proportional hazard regression model was used to obtain the hazard ratio for development of incident CKD among patients with kidney stones. Results: The incidence of CKD in the kidney stone cohort was 11.2%, which was significantly higher than that of the control group (P <.001). Survival analysis showed that the stones cohort was 1.82 times more likely to experience CKD than the controls. Age, sex, hypertension, diabetes mellitus, and hyperlipidemia increased the risk of CKD incidence (1.04, 1.27, 1.55, 3.31, and 1.25 times, respectively). Conclusion: Kidney stones are a definite risk factor for CKD; therefore, patients with stones are suggested to undergo regular renal function monitoring and receive appropriate treatment to avoid CKD.