Clinician Versus Nomogram Predicted Estimates of Kidney Stone Recurrence Risk

Kidney stone recurrence rates vary between patients. A patient's risk informs the frequency and intensity of preventative interventions. Clinicians routinely use clinical experience to estimate risk. We sought to compare clinician estimated recurrence risk with the recurrence of kidney stones (ROKS) nomogram. We surveyed members of the Endourological Society with clinical expertise in kidney stones. Respondents estimated the risk of recurrence for patients in three clinical vignettes corresponding to low, intermediate, and high recurrence risk from the nomogram. Clinician estimates were compared with ROKS estimates. The majority of the 318 respondents were from North America (n = 127, 40%). The most commonly estimated recurrence was 50% at 5 years. The respondents' estimates were significantly different from the ROKS predicted recurrence rate for all cases (Case 1, 50% vs 93% p < 0.0001; Case 2, 50% vs 60% p < 0.0001; Case 3, 60% vs 22% p < 0.0001). The ROKS predicted estimates ranged from 22% to 93%, whereas the median urologist-derived 5-year risk estimates for each case ranged from 50% to 60%. The median range of estimates by respondents across cases was 20%, narrower than the 71% for the ROKS nomogram. The majority of respondents (95%) do not use nomograms in practice, mostly because of lack of awareness of useful nomograms (59%). This study suggests that clinicians may not be able to distinguish those with high and low recurrence risk when compared with peers and when compared with a nomogram. Clinical decision support tools are needed to enable clinicians to better estimate stone recurrence risk.