One of the major issues in antibiotic stewardship in nursing homes is the use of antibiotics to treat suspected UTIs [37–40]. Despite extensive research demonstrating a lack of benefit and a potential for harm for antibiotic use for ASB [9, 18, 41], this practice continues to be prevalent among clinicians serving nursing home residents [2, 42]. This study found a substantial proportion (50%) of antibiotics prescribed for a suspected UTI was given to asymptomatic residents. Our results were also consistent with previous research that identified fluoroquinolones as the most common type of antibiotic used to treat UTIs [37, 43].
Somewhat surprisingly, our results indicated that resident demographics or indicators of health and functional status did not affect the likelihood of receipt of an antibiotic despite the absence of physical symptoms for UTI. Several resident conditions such as diabetes, stroke and causes of urinary tract dysfunction were not included in these data. Nonetheless, these results imply that differences in health and functional status among residents are not a driving force behind prescribing antibiotic treatment for ASB.
Our results provide evidence of the overwhelming importance of the presence or absence of an indwelling urinary catheter in the use of antibiotics for ASB. Our results from these four homes indicate that over 80 percent of the antibiotics prescribed for individuals with a catheter were written in the absence of signs or symptoms of a UTI. However, they were usually written in the presence of urinalysis results.
Previously published infection surveillance criteria for UTIs in long term care facilities have given too little attention to laboratory data as part of the diagnostic paradigm . However, in these data, we found widespread use of urine testing in the absence of signs and symptoms recognized in clinical guidelines as indicating the presence of a UTI. These results suggest that diagnostic testing may play a major role in the use of antibiotics for ASB.
Our data highlight the need for further assessment of how the interpretation of these tests might drive prescribing decisions in this setting. The medical literature emphasizes that older persons with a UTI may present differently than younger persons [45–47]. Thus, a wide range of events may prompt the ordering of urinalyses - any change in cognitive status, change in behaviors, changes in the color or smell of urine, or even a fall . For cognitively impaired residents with limited communication abilities, any signs of discomfort or functional change may result in a urinalysis . However, given the prevalence of ASB, there is a high likelihood that any urinalysis will be abnormal and subsequent culture positive.
Given the receipt of a positive urinalysis, the attending clinician is faced with what can be viewed as a short and long-term risk assessment decision. For the clinician the calculation of risk can be almost entirely short-term. In terms of short-term risks, by not prescribing an antibiotic, the clinician may fail to treat a blossoming infection; the resident’s condition may worsen, possibly dramatically. The benefits of not prescribing an antibiotic, such as reduction in emergence of antibiotic-resistant pathogens or avoidance of adverse drug complications’ will usually be seen in rates for the entire population in the home (e.g. decreases in C. difficile rates in a facility over time). Thus, the value of good antibiotic stewardship may go unrecognized by the clinician who focuses on residents sequentially, rather than as a part of a population.
Further studies should explore how the level of engagement and types of authority wielded by nursing home clinicians in homes of different sizes may influence antibiotic prescribing practices. The longer term benefits of antibiotic stewardship may be more evident to nursing home clinicians with greater responsibility in the home. If that is the case, it may provide guidance to those seeking avenues to address effectively the overuse of antibiotics and the lack of good antibiotic stewardship in long-term care.
Our study has several limitations. Our sample was based on a log of antibiotic prescriptions driven by clinical suspicion of a UTI. We did not have a comparison of this cohort to residents in the facility who did not receive antibiotics, nor could we identify individuals who had ASB but were not suspected of having a UTI. Therefore, we could not provide a comparison between individuals treated with an antibiotic for ASB and individuals with ASB not treated with antibiotics, to explore risk factors related to receiving an antibiotic. Our definition of symptomatic UTI was based on criteria developed by a consensus panel of experts, with limited validation, so some may disagree with the criteria applied in this study. Our data came from homes that varied on a number of dimensions, but all were located in central Texas, potentially affecting whether these findings are more broadly representative of the nursing home setting. Finally, data collection was retrospective and dependent on the quality of residents’ medical records in nursing homes.