Low serum testosterone is associated with an increased risk of first-time renal calculi in men without testosterone replacement therapy

The incidence of low serum testosterone has been increasing in men of all ages across a period which also corresponds to an increasing prevalence of kidney stones. Currently, the relationship between testosterone and kidney stones is unclear. Using the TriNetX Research Network, we performed a retrospective cohort study to evaluate the risk of developing an initial kidney stone in men based on their total testosterone level. Men aged ≥18 were divided into a low testosterone (<300 ng/dL) and normal testosterone (≥ 300 ng/dL) cohort. Men were excluded if they had a history of a kidney stone encounter diagnosis before testosterone measurement and a history of testosterone therapy prescription at any point. Propensity score matching was employed with an absolute standardized mean difference of less than 0.1 used as an indicator of successful matching. Our main outcome of interest was risk of developing an initial kidney stone in men aged ≥18 and within age-based subgroups. In men 18 and older, low testosterone was associated with a higher risk of one or more kidney stone encounter diagnoses (HR 1.12, 95% CI [1.09-1.15]). When stratified by age, no significant association between low testosterone and kidney stone encounter diagnoses was seen in men aged 18-24 (HR 1.09, 95% CI [0.85-1.39]). The highest risk was observed in men with low testosterone aged 34-44 (HR 1.29, 95% CI [1.17-1.38]). In this study, low serum testosterone was associated with an increased risk of initial kidney stone diagnosis in adult men without testosterone therapy prescriptions at any point in their life. Stratifying by age, the increased risk appears to begin in men aged 25, with the highest observed risk in men aged 33-44.