Obesity and BMI score as risk factors for urolithiasis: a systematic review over 30 years

To examine association between high BMI, obesity, and kidney stone disease (KSD). For this, systematic review of empirical studies was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA) guidelines. Cochrane Library, EMBASE, MEDLINE, CINAHL, AMED, Emcare, Clinicaltrials.gov, and WHO ICTRP were searched for English language population-based studies published from inception to October 2024, including adults aged at least 18 years reporting on high BMI, obesity and overweight, with incidence of KSD.

The search identified 943 records, of which 15 relevant articles with 97 645 participants and 17 158 cases in total were enrolled in the narrative synthesis. A high heterogeneity and imbalance were observed among baseline distribution of cohorts in most studies. Thirteen studies provided comparative data on stone occurrence in obese and nonobese participants, and on per-patient analysis, three studies demonstrated a lower risk (RR < 1; 95% CI: 0.78-1.03), four studies a higher risk (RR>1; 95% CI: 0.77-2.32), and six studies depicted similar risk (RR = 1; 95% CI: 0.94-1.06) of stone occurrence between the two cohorts.

Evidence in this study suggests an association between high BMI, being overweight, obesity, and increased risk of developing kidney stone disease. In the context of optimizing treatment, KSD should be considered a metabolic disease, with treatment to include dietary regimes, exercise intervention alongside pharmacotherapy to help reduce renal stone disease recurrence risk, alongside managing associated chronic diseases such as hypertension, type 2 diabetes mellitus, and coronary artery disease.