Pain is Independent of Stone Burden and Predicts Surgical Intervention in Patients with Ureteral Stones

Patients with obstructing ureteral stones typically experience sudden onset, severe pain. We examined the use of the NIH (National Institutes of Health) PROMIS® (Patient-Reported Outcome Measurement Information System) pain instruments in patients with acute ureteral stones.

PROMIS pain measures were obtained from a complete cohort of patients who presented to a subspecialty kidney stone clinic after emergency department discharge. Patients were followed longitudinally through the course of care. Raw scores were translated into population normed T-scores with a T-score of 50 indicating the mean pain population in the United States. Objective and patient centered factors were evaluated with reference to T-score thresholds for pain intensity with 60 equal to 1 SD above the mean and pain interference with 70 equal to 2 SD.

Multivariable logistic regression in 650 patients demonstrated an absent association between pain scores and stone size or location. Pain scores were associated with patient age, gender and emergency department pain scores (p <0.05). Initial stone surgery was predicted by a stone size less than 4 mm (OR 0.14, 95% CI 0.07-0.3), greater than 6 mm (OR 19.1, 95% CI 0.22-39.58), proximal location (OR 1.75, 95% CI 1.34-2.3) and pain intensity greater than 60 (OR 7.03, 95% CI 3.63-13.6) but not pain interference (p <0.001). Failed attempted stone passage was less likely for stones less than 4 mm (OR 0.26, 95% CI 0.14-0.48, p <0.001) and more likely for proximal stones (OR 1.61, 95% CI 1.21-2.14, p <0.01) and pain intensity greater than 60 (OR 2.74, 95% CI 1.23-6.07, p <0.05).

PROMIS pain scores are independent of stone size and location. Attention to emergency department discharge symptom control offers the potential to improve patient care. PROMIS pain intensity is an independent predictor of surgical intervention in patients with ureteral stones 1 cm or less.