Study design, materials and methods
A total of 49 patients underwent DJ stent insertion or exchange during June 2020 to June 2021 were randomized 1:1 into control ( taking placebo 1 tab once daily ) and treatment group ( Mirabegron 50 mg once daily ) for the duration of 30 days. These patients had their stents inserted due to several reasons: after urologic procedures i.e., Ureteroscopic lithotripsy (URSL) or Retrograde Intrarenal Surgery (RIRS), diverting ureteric obstruction from renal or ureteric calculi, correcting obstructive uropathy from colorectal malignancies, gynecological malignancies, bladder and prostate malignancies, and stenting ureteric strictures from other benign causes. At enrollment dates, both groups took OABSS (Overactive Bladder Symptoms Scores) and EQ5D5L questionnaires, for comparing their baseline urinary symptoms and general health. After one month of drugs administration, the patients then again took EQ5D5L questionnaire and USSQ (Urinary Stent Symptoms Questionnaire). All the questionnaires used are validated and translated into Thai language. The primary outcome is the difference of USSQ scores between the two groups.
Results
Among 49 patients, the median age in control group was 63 years old (P25,P75 = 56, 67.5) and 64 years old (P25,P75 = 50, 70) in treatment group. The genders, BMI, Glomerular filtration rates, underlying diseases including hypertension and diabetes mellitus, pre-intervention systolic and diastolic blood pressures, and the reasons for having stent inserted were the same in both groups. The pre-intervention OABSS and EQ5D5L scores in both groups were also similar. Patients in Mirabegron group responded that there is no difficulty performing light physical activities ( Median(P25, P75) = 1 (1, 1))* while control group responded that they usually have some difficulty performing light physical activity ( Median (P25, P75) = 2 (1, 2)), with P value of 0.002 after the end of intervention. Both groups have relatively similar urinary symptoms scores, pain scores, work performance scores, sexual performance scores, additional problem scores and post-intervention EQ5D5L scores. Post-intervention systolic and diastolic blood pressures did not differ significantly. One patient (4%) in Mirabegron group encountered tachycardia and one patient (4%) experienced dry mouth. Both have mild symptoms and could complete taking the medication for the required period of this research.
Interpretation of results
Compared to the control group, the Mirabegron group had significantly better general health symptoms regarding less difficulty in performing light physical activities. No serious side effect was found in Mirabegron group.