The implementation of stop orders for removing urinary catheters among medical patients admitted to acute care hospitals using a prewritten order in the chart along with follow-up by a research nurse reduced duration of inappropriate urinary catheterization. Our data are consistent with recent observational studies, showing that simple interventions can significantly reduce total urinary catheterization in hospitalized patients17–19
. However, unlike the observational studies reported by Huang et al.19
and Topal et al.1
, we did not observe a significant reduction in incidence rates of urinary tract infections. Even though we do not show a significant difference in infection rates, our results demonstrate that stop orders are effective in reducing inappropriate use of indwelling urinary catheters, a practice that has been characterized as a “one-point restraint” for hospitalized patients20
, and may allow patients to achieve earlier mobilization and discharge. In this study, the research nurse played an important role in the implementation of the protocol but we believe that with minimal training and monitoring a similar protocol could be utilized with existing nursing staff.
Although our study did not find a statistically significant difference in urinary tract infection rates with the use of the auto-stop order, as the confidence intervals of our estimates indicate, we cannot rule out the possibility that the intervention reduces infection rates and larger studies with more precise estimates of effect may demonstrate this. Another possible explanation for the lack of effect on urinary tract infection rates is that the overall reduction in duration of catheterization, 1.34 days (95% CI, 0.64 to 2.05), may not have been sufficient to significantly reduce bacteriuria. Because it was not feasible to conduct an entirely blinded study, it is possible that nurses familiar with the protocol may have removed urinary catheters from usual care participants at higher rates than would otherwise have occurred without knowledge of the study. This is suggested by the mean duration of catheterization in our control group being slightly lower to that noted in our pilot study (5 versus 6 days respectively). Consequently, our estimates of reduction in duration of catheterization may be conservative. Our rates of colonization may also be affected by our method and timing of urine collection. Although this would not result in a differential effect in the two groups, future studies may wish to do more frequent sampling using a different method to ensure more accurate identification of bacterial growth and prevent potential contamination from existing catheters. Another possible factor contributing to the lack of difference in urinary tract infections between study groups is that 399 (58%) of study participants were exposed to antimicrobials. The fact that in multivariable analysis antimicrobial exposure showed a protective effect for urinary tract infection confirms the importance of controlling for this variable. Although urinary tract infection status could not be determined in 171 (25%) participants, we believe that bias on this basis is unlikely. The distribution of missing cultures along with the associated reasons (catheter removal prior to the visit by the research nurse, death unrelated to urine infection, or transfer or discharge with no catheter removal) were similar between study groups. A difference in rates of urinary tract infection between participants who could be assessed for urinary tract infection and those that could not would therefore have been unlikely.
We found no significant differences in symptomatic urinary tract infection or bacteremia between the study groups. It has been recently recognized that such events occur at a low rate21
, so it is not unexpected that we did not detect differences in these outcomes. We also found similar frequency of catheter reinsertion between study groups suggesting that urinary catheter stop orders do not lead to excessive reinsertion of catheters.
We acknowledge that this study has several limitations. The interpretation of the results is limited by the missing data, as discussed above. Furthermore, we did not assess variables such as mobilization and quality of life which may have demonstrated a potentially important benefit of reducing duration of urinary catheterization in hospital patients20
In conclusion, stop orders for urinary catheterization safely reduced the duration of urinary catheterization in hospitalized patients. Stop orders for urinary catheters should be considered for hospitalized patients because they can prevent prolonged unnecessary catheterization. Future studies should explore additional outcome variables that may be affected by catheterization as well as interventions to prevent inappropriate urinary catheter placement prior to insertion.