High perirenal fat thickness predicts a greater risk of recurrence in Chinese patients with unilateral nephrolithiasis.

Introduction: The aim of this study was to evaluate the association between recurrence-free survival (RFS) and perirenal fat thickness (PFT) in a cohort of Chinese population with unilateral nephrolithiasis.
Methods: We retrospectively reviewed the medical records of 81 patients with unilateral nephrolithiasis in our center from January 2019 to June 2019. PFT measured on computed tomography (CT) scans was evaluated. Kaplan-Meier curves and log-rank tests were used to assess significant differences in RSF between high-PFT and low-PFT groups within sexes. Univariable and multivariable Cox regression analyses were used to evaluate the potential risk factors for renal stone recurrence.
Results: High PFT was significantly associated with high BMI and hyperlipidemia ( p  = .003 and.047, respectively). The PFT of stone-bearing kidney was significantly greater than PFT of non-stone-bearing kidney (0.77 ± 0.60 cm vs. 0.67 ± 0.58 cm, p  = .002) . During the follow-up periods (median 31 months), 21 (25.9%) patients experienced ipsilateral renal stone recurrence. In addition, Kaplan-Meier survival curves showed that patients with low PFT had a significant better RFS than those with high PFT ( p  = .012). In the univariable Cox analyses, male sex and high PFT were significantly associated with a poor RFS ( p  = .042 and .018, respectively). Moreover, both male sex and high PFT retained significance in the multivariable analyses ( p  = .045 and .020, respectively).
Conclusions: Our findings suggested that PFT is a noninvasive and feasible parameter, which may help in the risk stratification of renal stone recurrence in the follow-up periods.