- Design
- Prospective randomised controlled trial, two centres
- Population
- 100 patients with ureteric stents for urolithiasis (95 analysed)
- Primary outcome
- Stent encrustation weight at 30 days
- Effect
- 49.7% less encrustation; mean difference 22.8 mg (95% CI 2.4–43.2)
This randomised controlled trial at two German centres assigned 100 patients needing a ureteric stent for stones to an identical 6 F stent with or without a covalent sulfonic acid coating. Stents were removed at 30 days at the time of definitive stone treatment.
In 95 analysed patients, encrustation weight was about half with the coated stent (mean difference 22.8 mg, 95% CI 2.4 to 43.2). The rise in lower urinary tract symptoms was smaller (3.6 vs 7.8 points), light physical activity was better, and fewer patients needed antibiotics (7.1% vs 31.8%).
Stent discomfort is one of the commonest complaints in endourology, so a coating that eases it is relevant. This is a small two-centre trial of one coating over 30 days; it does not show effects with longer dwell times, and availability and cost in India are unknown.
- Consider coated stents where available for patients needing a stent before definitive stone treatment.
- Keep stent dwell time as short as possible regardless of stent type.
- Warn patients about stent symptoms and give clear advice on when to seek help.
- Do not assume benefits extend beyond 30 days; longer dwell was not studied.
Why it matters
It targets stent discomfort, one of the most common reasons for unplanned contact after endourology.
Don't overread it
This was a 95-patient, two-centre trial over 30 days; the antibiotic and symptom findings are secondary outcomes.
The statistics, in plain English
The encrustation interval (2.4 to 43.2 mg) is wide, so the true reduction could be small or large. The antibiotic finding (OR 6.1, 1.11 to 33.1) rests on few events and should be read cautiously.
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