Association of nephrolithiasis with the risk of cardiovascular diseases: a longitudinal follow-up study using a national health screening cohort

OBJECTIVES: The aim of this study was to explore the associations of stroke and ischaemic heart disease in patients with nephrolithiasis. DESIGN: A longitudinal follow-up study. SETTING: Data from the Korean National Health Insurance Service-Health Screening Cohort (2002-2013) were retrieved to identify the occurrence of nephrolithiasis. PARTICIPANTS AND INTERVENTIONS: In total, 19 103 patients with nephrolithiasis were matched at a 1:4 ratio with control participants for age, sex, income and region of residence. PRIMARY AND SECONDARY OUTCOME MEASURES: The occurrence of stroke and ischaemic heart disease was analysed in both patients with nephrolithiasis and control participants. The primary outcome was HRs of stroke and ischaemic heart disease in a stratified Cox proportional hazards model. Smoking, alcohol consumption, obesity and Charlson Comorbidity Index were adjusted for as covariates. Subgroup analyses according to age and sex were also performed. RESULTS: Eight per cent (1615/19 103) of patients with nephrolithiasis and 7.2% (5476/76 412) of control participants had stroke. Nine per cent (1879/19 103) of patients with nephrolithiasis and 7.7% (5895/76 412) of control participants had ischaemic heart disease. Patients with nephrolithiasis had risks of stroke and ischaemic heart disease that were 1.18 times (95% CI=1.11 to 1.24) and 1.24 times (95% CI=1.18 to 1.31) those of the control participants, respectively. The age and sex subgroups showed consistent results. CONCLUSIONS: Nephrolithiasis was associated with increased risks of stroke and ischaemic heart disease.