A prospective trial of a novel, silicone-based, silver-coated foley catheter for the prevention of nosocomial urinary tract infections

OBJECTIVE. To evaluate the efficacy of silicone-based, silver ion-impregnated urinary catheters in the prevention of nosocomial urinary tract infections (NUTIs). DESIGN. Prospective, crossover study to compare the efficacy of a silicone-based, hydrogel-coated, silver-impregnated Foley catheter with that of a silicone-based, hydrogel-coated catheter in the prevention of NUTIs. SETTING. Adult medical and surgical wards of a university teaching hospital. RESULTS. A total of 3,036 patients with catheters were evaluated; 1,165 (38%) of the catheters were silver impregnated, and 1,871 (62%) were not silver impregnated. Study groups were not identical; there were more men, a shorter duration of catheterization, and fewer urine cultures per 1,000 catheter-days in the silver catheter group. The rate of NUTIs per 1,000 Foley-days was 14.29 in the silver catheter group, compared with 16.15 in the nonsilver catheter group (incidence rate ratio, 0.88; 95% confidence interval, 0.70-1.11; P = .29). The median length of catheterization prior to the onset of a urinary tract infection (ie, exposure time) was 4 days for each group. There were no differences in the recovery of gram-positive, gram-negative, or fungal organisms in NUTIs. In a multivariate survival analysis, no factors, including silver catheters, were protective against NUTI. CONCLUSIONS. Unlike previous trials of latex-based, silver ion-impregnated Foley catheters, we found that silicone-based, silver-impregnated Foley catheters were not effective in preventing NUTIs; however, this study was affected by differences in the study groups. Prospective trials remain important in assessing the efficacy and cost-effectiveness of new silver-coated products.