Development and preliminary validation of a diagnostic prediction model to optimise outpatient management of patients with urolithiasis using urinary stones and intervention quality of life (USIQoL) measure

Patients with urinary calculi undergo resource-intensive follow-up. Application of a PROM, Urinary Stones and Intervention Quality of Life (USIQoL), can potentially optimise current practices if it matches the outcomes of traditional follow-up. Our objective was to develop, and conduct, a preliminary validation of the USIQoL based prediction model to aid triage.

We performed a two phase prospective cohort study. The 1st phase included development of the USIQoL-based decision model using multicentre data. The 2nd phase involved prospective single-blind external validation for the outpatient application. The aim was to evaluate correlations between the USIQoL scores and key predictors; clinical outcomes and global health ratings (EuroQoL EQ-5D). We used statistical analysis to validate USIQoL cut-off scores to aid triage and the decision to intervene.

Of 503 patients invited, 91% (n = 455, Development [305] and Validation [150]; M = 308, F = 147) participated. The relationship between USIQoL domain scores and clinical outcomes was consistently significant (estimated odds: PPH 1.24, p < 0.001, 95% CI 1.13–1.36; PSH 1.22, p < 0.001, 95% CI 1.12–1.33). The ROC values for the model were ≥ 0.75. The optimum domain cut-off scores were derived with rising scores implying increased need to intervene. The model demonstrated satisfactory sensitivity (0.81–0.89) and specificity (0.36–0.47).

The study demonstrates satisfactory correlation between the USIQoL and clinical outcomes making this model a valid aid for triage and optimising outpatient management with the cut-off scores able to identify high risk patients who need active treatment.