Pertinence between Preoperative Renal Function and Composition of Renal Calculi in Elderly Patients: A Retrospective Analysis

Background: Kidney stone disease poses a significant challenge in the geriatric population. Preoperative renal function has been speculated to influence the composition of renal calculi, and consequently, the management approach. We studied the correlation between preoperative renal function and the composition of renal calculi in elderly patients, which could have implications for optimizing therapeutic strategies.

Methods: This retrospective cohort study investigated patients aged 60 years and older who were hospitalized for kidney stones from January 2021 to December 2023. Based on their preoperative renal function, patients were categorized into two groups: Those with normal renal function (reduced glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m²) and those with abnormal renal function (eGFR <90 mL/min/1.73 m²). The composition of renal stones was determined through infrared spectroscopy. In addition, data on demographics, kidney stone size, location, number, and biochemical profiles were collected and analyzed.

Results: A total of 1154 elderly patients with kidney stones were included, comprising 903 patients with normal renal function and 251 with abnormal renal function. The mean ages for the normal renal and abnormal renal function groups were (72.25 ± 5.67) and (71.82 ± 4.92) years, respectively. Stone composition analysis revealed significant differences between the two groups. Patients with abnormal renal function had a higher occurrence of uric acid stones (11.16% vs. 6.76%, p = 0.029) and a lower occurrence of calcium oxalate stones (42.63% vs. 51.50%, p = 0.016). Moreover, the abnormal renal function displayed significantly elevated serum creatinine levels (1.92 ± 0.75 mg/dL vs. 0.87 ± 0.21 mg/dL, p < 0.001), lower eGFR (38.24 ± 12.67 mL/min/1.73 m² vs. 108.53 ± 15.42 mL/min/1.73 m², p < 0.001), and higher urea levels (32.18 ± 9.74 mg/dL vs. 16.25 ± 4.68 mg/dL, p < 0.001).

Conclusions: This study highlights a significant association between preoperative renal function and the composition of renal calculi in geriatric patients. Abnormal renal function is linked to a higher occurrence of uric acid stones and a reduced occurrence of calcium oxalate stones, alongside notable alterations in biochemical profile.