Nephrolithiasis and Polycystic Ovary Syndrome: A Case-Control Study Evaluating Testosterone and Urinary Stone Metabolic Panels

INTRODUCTION: Both elevated testosterone and polycystic ovary syndrome (PCOS) have been speculated as possible risk factors for kidney stone formation; however, the details of this potential relationship with regards to 24-hour urine metabolic panels and stone composition have not previously been characterized. METHODS: A total of 74 PCOS patients were retrospectively identified and matched with a cohort of female stone formers at a 3 : 1 ratio (by age and BMI). All patients had 24-hour urinary metabolic panels and stone compositions. These groups were compared using Pearson chi-square and Student t-tests. Additionally, the PCOS group was differentiated based on free testosterone using multivariate analysis. RESULTS: The case-control cohort showed that PCOS patients had significantly lower sodium excretion (p=0.015) and hypernatriuria rates (28.9% vs 50.9%, p=0.009). The PCOS-testosterone cohort demonstrated that high testosterone patients had significantly higher citrate values (p=0.041) and significantly lower odds of hypocitraturia (36.7% vs 54.2%, OR = 0.2, p=0.042). The high testosterone group also had higher sodium excretion (p=0.058) with significantly higher odds of having hypernatriuria (40.0% vs 13.6%, OR = 13.3, p=0.021). No significant patterns were revealed based on stone composition analysis. CONCLUSIONS: Compared to healthy stone formers, PCOS patients did not demonstrate significant differences in 24-hour urine and stone composition values. Elevated free testosterone in PCOS patients has a significant association with higher urinary citrate and sodium values: findings that in and of themselves do not confirm the hypothesized increased risk of stone formation. This patient cohort may provide deeper insight into the interplay between androgens and stone formation; however, further study is needed to fully characterize the possible relationship between PCOS and stone formation.