New‐onset metabolic risk factors and the incidence of kidney stones: a prospective cohort study

OBJECTIVE To examine the association of kidney stones with new-onset hypertension, diabetes and obesity. PARTICIPANTS AND METHODS This prospective cohort study included participants in the Qingdao Port Cardiovascular Health Study who were aged ≥18 years and had abdominal ultrasonography results in 2013 that were negative for kidney stones. Multivariable Cox regression models with time-dependent covariates were used to estimate the effects of new-onset hypertension, diabetes and obesity on the incidence of kidney stones. RESULTS There were 9667 participants without kidney stones in 2013 (mean age 46.2 years; 75.6% men). During a mean (range) follow-up of 33.5 (6-42) months, 676 (7.0%) incident cases of kidney stones were identified. Kidney stones were more frequent among those who had new-onset of a metabolic factor vs those who did not (hypertension: 7.7 vs 6.0%; diabetes: 8.4 vs 6.6%; obesity: 7.4 vs 6.8%). Adjusted Cox models identified that increased risk of kidney stones was associated with new-onset hypertension (adjusted hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.25-2.27), new-onset diabetes (HR 1.78, 95% CI 1.07-2.96), and new-onset obesity (HR 1.78, 95% CI 1.15-2.74). CONCLUSIONS New-onset of hypertension, diabetes and obesity were all strongly associated with an increased risk of kidney stones in this prospective cohort study. Results suggest that a substantial proportion of kidney stones are potentially preventable by appropriate control of these metabolic risk factors.