NEW YORK (Reuters Health) – A newer ureteral stent, designed to be more comfortable than an older stent, actually isn’t, according to results of a randomized controlled trial. And it’s also more expensive than the older stent, according to the UK-based study team.

While ureteral stents are highly effective in facilitating urinary drainage, it is recognized that they are often associated with pain and decreased quality of life, which has fueled extensive efforts by manufacturers to design more comfortable stents, the study team notes in the November 15 online issue of The Journal of Urology.

In a prospective, randomized study, Dr. Kim Davenport and colleagues from the Bristol Urological Institute in the UK compared symptoms and quality of life after insertion of the Polaris ureteral stent (Boston Scientific) in 53 patients and the InLay (C. R. Bard) ureteral stent in 45 patients.

In an e-mail to Reuters Health, a spokesman for Boston Scientific pointed out that “the Polaris stent utilized in this study that began in 2002 was the first generation dual durometer stent and has been subsequently replaced by our Polaris ultra technology.”

The Polaris stent was designed to “combine the ease of placement benefits of a firm stent with the comfort benefits of a softer stent,” by providing a firm proximal aspect with a softer distal aspect, Dr. Davenport and colleagues note in their report. The stent uses a HydroPlus coating to facilitate advancement and improve the stent-ureter interface. The softer bladder coil is meant to minimize bladder discomfort.

The InLay stent, they note, has been thoroughly investigated in terms of its impact on patient quality of life. It also has a hydrophilic coating to ease insertion and it softens at body temperature it softens as much as 50%. High retention coils at each end of the stent prevent migration, according to the manufacturer. A study published in 2005 suggested that it may be better tolerated than many other stents.

The two study groups were well matched in terms of age, gender and other demographic features. Patients were asked to complete the validated Ureteral Stent Symptom Questionnaire two weeks after stent placement and one week after removal.

Responses revealed no significant between-group differences on any health domain assessed. Pain was the most common symptom experienced by with the stent in situ, reported by 94% of patients with the Polaris stent and 91% of those with the InLay group. Hematuria was the next most common symptom reported by 62% and 73% or Polaris and InLay users, respectively. These differences were not statistically significant.

More patients in the Polaris group than the InLay group had the sensation of urinary tract infection (77% vs 70%) and received antibiotics from their physician (39% vs 29%) when the stent was in place. Again, the difference was not significant.

Forty-three percent of patients in the Polaris group and 36% in the InLay group sought the help of a health care professional for stent-related side effects (p = 0.81). Sixty-six percent of patients in the Polaris group and 60% in the InLay group said they wouldn’t want a further stent due to symptoms (p = 0.79).

“This study reveals no significant difference in health related quality of life between the InLay and the Polaris ureteral stents despite the different composition and physical properties,” Dr. Davenport and colleagues conclude.

“The softer distal coil and HydroPlus coating of (the Polaris) stent did not appear to improve patient tolerability or decrease lower urinary tract symptoms. Each stent remains responsible for significant symptoms,” they say.

“Ultimately,” they conclude, it’s best to try to avoid placing a ureteral stent. If a stent is judged to be essential, symptoms may be minimized by limiting the time that the stent is left in place since there is “little evidence to date that one stent design is better than another.”

“The results of this small patient study indicated no statistically significant difference between the Inlay and the Polaris ureteral stents,” Boston Scientific noted in an e-email to Reuters Health. “There are many factors that could influence this result, including the small study size and difficulties with the subjective nature of measuring patient discomfort.”

“Boston Scientific is committed to advancing stent technology to improve patient comfort. To this end, we have consulted with urologists for decades to develop next generation stent technology,” the company stated.