- Design
- Two-centre prospective randomised controlled trial
- Population
- 95 analysed patients with ureteric stents for urolithiasis
- Primary outcome
- Encrustation weight at 30 days
- Effect
- 49.7% less encrustation (mean difference 22.8 mg, 95% CI 2.4–43.2)
In this two-centre randomised trial in Germany, 100 patients needing a ureteric stent for stones received identical 6 F stents, with or without a covalent sulfonic acid coating, removed after 30 days at definitive stone treatment.
In 95 analysed patients, coated stents carried about half the encrustation weight (mean difference 22.8 mg, 95% CI 2.4 to 43.2). The rise in lower urinary tract symptoms was smaller with the coating (3.6 vs 7.8 points), light activity scores were better, and antimicrobial treatment was needed less often (7.1% vs 31.8%).
Stent symptoms are one of the commonest complaints after endourology, so a better-tolerated stent matters. This is a small trial with dwell times of 30 days, and several benefits rest on secondary outcomes, so it is a reason for interest rather than a change in purchasing.
- Keep stent dwell time as short as possible, whatever the stent.
- Warn patients about urgency, frequency and flank pain with stents and offer an alpha-blocker if needed.
- Coated stents may reduce encrustation and symptoms; availability and cost will vary.
- Register every stent with a removal date to prevent forgotten stents.
Why it matters
Stent discomfort is one of the most common complaints in urology, and options to reduce it are few.
Don't overread it
A 100-patient trial with 30-day dwell; benefits beyond encrustation are secondary outcomes.
The statistics, in plain English
The encrustation interval (2.4 to 43.2 mg) excludes zero but is wide. The antimicrobial odds ratio of 6.1 has an interval from 1.1 to 33, which tells you the result is uncertain in size even if real in direction. Secondary outcomes were not the trial's main question.
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