Abstract
BACKGROUND: Kidney stones are a common urological disease with rising global prevalence and are influenced by immune, metabolic, and nutritional factors. The ratio of serum albumin to globulin, a marker of inflammation and nutritional status, has been linked to various inflammatory and chronic conditions, but its role in kidney stone risk and outcomes remains unclear. We aimed to determine the association between ratio of serum albumin to globulin and risk of kidney stones, as well as the impact of ratio of serum albumin to globulin on all-cause mortality in participants with kidney stones. METHODS: Multivariable logistic regression was used to explore the association between ratio of serum albumin to globulin and the risk of kidney stones. Multivariate Cox regression and restricted cubic spline (RCS) were performed to clarify the relationship between ratio of serum albumin to globulin and the risk of all-cause mortality. RESULTS: Among 31,091 study participants, 2,955 (9.5%) individuals had kidney stones. Multivariable logistic models demonstrated that each standard deviation (SD) increase in the ratio of serum albumin to globulin (SD =0.30) was associated with a 6% reduction in kidney stone risk. A total of 387 (13.1%) participants with kidney stones died for any reasons during a median follow-up of 6.2 years. The multivariable Cox model showed a significantly lower risk of all-cause mortality in the quartile (Q)2, Q3, and Q4 groups as compared to Q1 [Q2: adjusted hazard ratio (aHR) =0.84, 95% confidence interval (CI): 0.63-1.11; Q3: aHR =0.65, 95% CI: 0.48-0.86; Q4: aHR =0.63, 95% CI: 0.46-0.86; P for trend =0.04]. CONCLUSIONS: A lower ratio of serum albumin to globulin was associated with an increased risk of kidney stones. Additionally, our study showed that at a cutoff point of 1.5, the association between ratio of serum albumin to globulin and all-cause mortality in participants with kidney stones was nonlinear L-shaped. However, due to the observational nature of the study, our study results should be interpreted with caution.