Differences in the composition of urinary stone in metabolically healthy and unhealthy obese patients

초록

Introduction & Objectives To investigate whether the effects of metabolic health status on stone composition were different between obese or normal weight individuals. Materials & Methods We retrospectively reviewed data of 711 patients (490 males, 221 females) with urinary stone removed between 2013 and 2020 in 2 medical centers. Normal-weight and obesity were defined as body mass index (BMI) < 25 kg/m2 and ≥ 25 kg/m2, respectively. Metabolically obese was defined as the presence of ≥3 components of metabolic syndrome. Patients were stratified into metabolically healthy, normal-weight (MHNW); metabolically obese, normal-weight (MONW); metabolically healthy, obese (MHO); metabolically obese, obese (MOO). All urinary stones were analyzed using infrared spectrophotometry and categorized according to their main component. This study was approved by Ethical Committee of the Korea University Hospital. Results Patient’s mean age was 58.6 years (range 16 – 96). Of 715 patients, 268 (37.7%) were MHNW, 102 (14.3%) were MONW, 235 (33.1%) were MHO and 106 (14.9%) were MOO. The prevalence of stone components for each group was presented in Figure 1. When we analyzed using MHNW group as a reference, the multivariable adjusted HRs (95% CIs) for uric acid stone comparing MONW, MHO and MOO groups were 3.33 (1.89–5.89, p < 0.01), 0.72 (0.40–1.29, p=0.269), and 4.49 (2.59–7.80, p < 0.01), respectively, whereas the corresponding HRs (95% CIs) for calcium oxalate stone were not significantly different between groups. Conclusions Metabolic health status was associated with higher prevalence of uric acid stone in both normal-weight and obese individuals, indicating metabolic syndrome per se as an independent risk factor for uric acid stone rather than obesity.