Evaluating the natural history of incidentally recognized clinically silent nephrolithiasis in healthy adults: an updated systematic review with meta-analysis.

The incidental detection of asymptomatic renal stones has risen with increased use of imaging and screening programs. While guidelines exist for treating kidney stones, managing asymptomatic stones remains controversial due to limited understanding of their natural history. A systematic search of the PubMed, Web of Science, Embase, and Scopus databases was conducted on 3rd June 2024 with a distinct search strategy and citation tracking to identify English language publications evaluating the natural history of asymptomatic renal stones in healthy adults. systematic report of the included studies was provided; besides, meta-analysis of proportions and meta regression was conducted to find the pooled estimation of stone-related events and to evaluate factors affecting natural history of these stones. Quality assessment of the included articled was conducted by means of the Newcastle-Ottawa Scale. This study was registered on PROSPERO (CRD42023409454). Out of 4,574 identified publications, twelve studies met inclusion criteria. Reported outcome rates ranged from 28.12% to 32.27% for symptomatic events, 7.1% to 31.88% for requiring intervention, 7.5% to 32.08% for spontaneous passage, 11.11% to 45.9% for stone growth, 31.77% to 77% for stone-related events, and 23% to 68.22% for remaining asymptomatic. Meta-analysis identified the pooled proportion of 30% (95% CI 27% to 33%) for developing symptoms, 22% (95% CI 18% to 27%) for requiring intervention, 25% (95% CI 16% to 36%) for stone growth, 18% (95%CI 13% to 23%) for spontaneous stone passage, 49% (95% CI 39% to 59%) for all stone-related events, 50% (95% CI 48% to 52%) for remaining asymptomatic. Notably, our investigation done by meta-regression did not reveal any specific risk factor for developing symptoms and stone growth. However, multiple and bilateral stones were less likely to pass spontaneously. Moreover, the analyses indicated a positive correlation between multiple stones and requiring intervention and between male sex and all stone-related events, albeit it trended toward significance. The findings offer some guidance for managing asymptomatic renal stones, suggesting that active surveillance could be a potentially viable option. However, further meta-analysis incorporating additional studies with consistent criteria for patient inclusion, standardized stone size categorization, and uniform reporting of effect sizes is needed to validate our findings. Unfortunately, this is not currently feasible due to the limitations outlined above.