Ureteral colic is the most painful condition commonly encountered by urologists around the world. The goals of management are pain relief, stone removal, and preservation of renal function. Trial of SSP for four to six weeks along with MET is the current standard of care for small (≤ 10 mm), uncomplicated ureteral calculi (3, 15). Patient-reported pain outcomes are increasingly utilized as surrogate markers of successful SSP in multiple studies (9–12) and in contemporary practice. Our study documents the accuracy of patient-reported outcomes (PROs) in predicting SSP while also reporting non-pain-related symptoms in these patients.
The overall SSP rate was 66.4% (n = 99) in our cohort, and stone size and location were significantly associated with successful SSP. These findings paralleled those by Yallappa et al., who reported on the natural history of ureteral stones managed conservatively (1). Ureteral wall thickening was associated with failed SSP, as reported by Sahin et al., who reported on predictors of successful MET (16).
Patient-reported pain cessation, stone visualization, and stone capture were significantly associated with successful SSP. Pain cessation was found to have an accuracy of around 60% in predicting successful SSP. However, 25% of patients who reported complete cessation of pain still harbored ureteral calculus. While stone visualization and stone capture had a high specificity of 90% and 98%, respectively, they lacked adequate sensitivity. Only one-fourth of patients reported having seen or felt stone debris passing in their urine, and only one-tenth were able to capture the stone. No association between decreased pain and SSP was found.
Our results of PROs are in accordance with that of McLarty et al. (13), which reported 66% accuracy of pain cessation and 71% accuracy of reported stone passage in predicting SSP in a prospectively followed patient cohort. However, in our study, the mean stone size was larger; all patients received four weeks of MET and were followed up with a repeat NCCT. Another study by Meltzer et al. reported a secondary analysis of a prospective trial and concluded that stone visualization or capture, as reported by patients, was confirmed on NCCT in 93.8% of cases, and these patients may forgo repeat imaging (14). However, the mean stone size in the study was only 3.8mm, and 40% of patients reported stone visualization or capture as opposed to 26% of patients in our cohort. The stone capture rate in our cohort was only 10.7% (n = 16), and one patient had a persistent stone despite stone capture. Eight patients (5.4%) of our cohort had no pain and were incidentally diagnosed on an ultrasound done for LUTS evaluation.
Our results indicate that while PROs may indicate successful SSP, they cannot be taken as surrogate markers of successful SSP and a confirmatory imaging should be obtained. In our cohort, hydroureteronephrosis was not seen in 13 patients (8.7%) despite the presence of ureteral calculus on NCCT. Ultrasound imaging may overlook stones in such scenarios, and NCCT should be the preferred imaging modality, given its high accuracy (17). Clinical trials evaluating SSP should have objective outcomes based on imaging rather than relying on subjective pain-related outcomes.
Pain cessation may give a false sense of security to patients, and such silent stones may lead to persistent HUN and loss of renal function. One patient in our study had lost to follow-up and presented one year later with a non-functional kidney caused by obstructing ureteral calculus. Timely intervention for these silent stones has been reported to preserve renal function (8). Patients should be accordingly counseled to timely follow-up despite the resolution of pain to avoid risking the loss of renal function.
Despite the subjective nature of PROs, the patient’s perspective cannot be ignored in defining the treatment’s success. PROMIS® and CUSP® are two well-known validated sets of instruments designed to evaluate PROs in ureteral stone patients (18, 19). However, they predominantly focus on quantifying the pain while discounting other urological symptoms the patients may be more distressed about. We reported several non-pain-related symptoms including nausea, lower urinary tract symptoms (including urgency, frequency, and obstructive symptoms), burning micturition, hematuria, dysuria, and dyspareunia. We reported the symptom resolution rates for these individual non-pain-related symptoms indicating their utility as PRO measures. Pain resolved in 91% of patients at a four-month follow-up. While hematuria and nausea resolved in all patients, LUTS were not resolved in 17% of patients at the four-month follow-up. Further evaluation of these non-pain-related symptoms in ureteral calculus patients and their integration into PRO instruments will allow a holistic insight into the patients’ perspective and help define success of the treatment offered.
The study’s primary limitation was its non-randomized design with a single-center-based experience. All patients were recruited from the outpatient of a tertiary-care healthcare facility with a biased referral pattern, including patients with larger stones and co-morbidities. However, all patients received at least four weeks of MET and were followed up with a repeat NCCT.