Intervention versus observation for asymptomatic kidney stones: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND

The detection rate of asymptomatic stones has increased with advances in imaging technology. Although many such stones remain stable, some patients later experience pain, obstruction, infection, stone growth, or need for intervention. Current guideline-based management generally favors surveillance for many asymptomatic stones while emphasizing individualized shared decision-making. We therefore conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to compare active stone-directed intervention versus observation for asymptomatic kidney stones.

METHODS

We systematically searched PubMed, Embase, and the Cochrane Library from database inception to April 22, 2026, using a broad concept-based strategy combining terms for asymptomatic kidney stones and stone-directed interventions. Procedure-specific terms such as ureteroscopy, shock wave lithotripsy, and ultrasonic propulsion were included to improve sensitivity. Only RCTs comparing active intervention with observation were eligible. The primary synthesis focused on a composite stone-related recurrence outcome, with subsequent surgery, unscheduled stone-related visits, stone growth, fragment passage, and adverse events analyzed as secondary outcomes.

RESULTS

Six RCTs involving 592 participants were included. Compared with observation, active intervention showed lower pooled odds of composite recurrence (OR 0.35, 95% CI 0.18-0.69; I²=56.3%) and subsequent surgery (OR 0.45, 95% CI 0.25-0.80; I²=0%). The pooled estimate for unscheduled visits favored intervention numerically but was not statistically significant (OR 0.31, 95% CI 0.07-1.28; I²=67.3%). Stone growth was reduced in two studies (OR 0.24, 95% CI 0.09-0.59; I²=0%), whereas fragment passage was highly heterogeneous and not statistically significant (OR 7.32, 95% CI 0.44-122.34; I²=90%). Adverse events were similar between groups (OR 1.16, 95% CI 0.66-2.03; I²=0.2%).

CONCLUSION

Active intervention may reduce subsequent stone-related surgery in selected patients with asymptomatic kidney stones, without a clear increase in adverse events. However, evidence for other outcomes remains uncertain because of the limited number of trials, heterogeneous interventions, variable outcome definitions, and imprecise estimates. When considering treatment strategies, individualized joint decision-making should be supported instead of applying routine intervention measures to all asymptomatic stones.