Introduction: The management of incidentally discovered, asymptomatic renal stones is controversial. Options include watchful waiting (WW) or pre-emptive surgical treatments. Shock wave lithotripsy (SWL), ureteroscopy with basket extraction of fragments (URS-B), and ureteroscopy with laser "dusting” (URS-D) are options which come with different levels of invasiveness, stone free rates (SFR), and postoperative quality of life (QOL). We performed decision analysis to assess optimal quality adjusted life-years (QALY) associated with each option
Methods: A Markov Model was constructed with TreeAge Pro software (Fig 1) representing potential outcomes for a single 1cm renal stone with each possible intervention. The cohort was followed for 1 month cycles over three years. Toll-penalties for ureteral stents and undergoing surgery were incorporated into each subtree when indicated. Probabilities, utilities, and toll-penalties were derived from existing literature and clinical extrapolation if no published data was available. One-way sensitivity analyses were performed to determine probabilities and utilities that may alter preferred options
Results: WW was the preferred intervention, preserving 2.82 QALYs over three years. Remaining options had similar but decreasing QALYs: URS-B at 2.78, SWL at 2.72, and URS-D at 2.67 QALYs. One-way sensitivity analysis was performed for the range of expected stone free probabilities per intervention and for range of disutility related to ureteral stents (Fig 2). URS-D was preferred when SFR with URS-B dropped below 37% (Figure 2). SWL was preferred over URS-B when the SFR with URS-B dropped below 62%. As stents became progressively less bothersome, WW is preferred, followed by URS-B, SWL, and URS-D
Conclusions: When accounting for SFR and utilities of associated health states over a three year period, WW is a preferred strategy for asymptomatic renal stones. However, these results are sensitive to both actual stone free rate and individual stent tolerance, emphasizing the importance of shared decision making Source of
