Through this cross sectional study of antibiotic prescribing events for NH residents, we have identified important differences in prescribing patterns between those initiated in-facility and other outpatient settings (clinic, ED) for this vulnerable population. Consistent with previously published data, overall we observed nearly 50% inappropriate antibiotic initiation for NH residents using the Loeb consensus criteria [3, 14]. Although this study was limited to 5 facilities in the state of Wisconsin, it does indicate the persistent nature of the challenge to improve judicious antibiotic use in NHs, even in the setting of increased efforts by the Centers for Disease Control (CDC) to address this issue . Although the vast majority of antibiotic courses were initiated within the NHs themselves, nearly 13% (1 of 8) were initiated in either outpatient clinics or the ED. This highlights the need to consider interventions to improve prescribing not only within NHs, but also when these residents receive care outside of the facility.
When examining inappropriate prescribing in our regression model, prescriptions in the outpatient clinic setting were observed to have nearly 3 times the odds of being inappropriate. There were no increased odds with prescriptions initiated in the ED setting, which is consistent with results from several recently published reports [19,20,21]. Although our data do not provide insight into why the outpatient clinics might be particularly high risk for inappropriate antibiotic initiation, we hypothesize it is related to the well-established challenges associated with diagnosing acute infections in elders . Providers in outpatient clinics and the ED may be significantly disadvantaged as they are often not familiar with a patient’s baseline (e.g. chronic venous stasis dermatitis mimicking cellulitis) and are not afforded time to observe the individual’s clinical trajectory that might emerge from serial examinations. However, ED providers have universal access to rapid diagnostic testing which can provide objective data and reduce diagnostic uncertainty (e.g. chest radiographs and urinalysis with microscopy). This finding highlights the need for increased efforts to establish outpatient clinic antimicrobial stewardship programs based on the CDC’s recently published guidelines for this setting .
Another potential factor in the observed setting variability is disagreement between medical specialties when it comes to diagnosing infections in older adults. Caterino et al. observed that nearly 20% of ED patients admitted with suspected infection were not diagnosed as such by the inpatient physicians . Additionally, emergency physicians were found to over diagnose pulmonary infections and underdiagnose UTIs relative to the inpatient team’s determination . This important finding highlights the need for interdisciplinary collaboration to enhance consensus in terms of diagnostic criteria and appropriate initiation of empiric antibiotics.
In addition to setting, infection type was also significantly associated with increased odds of inappropriate prescribing. UTIs increased the odds of inappropriate prescribing by nearly 4.5 times, which is consistent with prior literature highlighting the clinical uncertainty which surrounds the diagnosis of UTI in elders [24,25,26,27]. The vast majority of UTI related antibiotics were initiated in-facility with lower rates of inappropriate prescribing as compared to the ED and outpatient clinics. This perhaps reflects uptake of published methods to improve antibiotic prescribing for suspected UTI among NH residents . There is also emerging evidence to suggest UTIs are often misdiagnosed in the ED setting resulting in unnecessary empiric antibiotic administration [29, 30]. A recent cohort study of elders admitted through the ED to general medical services found that 62% underwent urinalysis at the time of admission while 84% of these patients did not have symptoms of UTI . Overuse of diagnostic testing, such as urinalysis, in the ED has recently come to the forefront of national discussions and certainly may play a role in the observed overtreatment of UTIs in this setting . However, any attempt to improve diagnostic testing in the ED must consider both provider and system level factors such as protocol driven ordering of urinalysis in triage by nurses prior to physician evaluation .
Similar to UTI, LRTIs increased the odds of inappropriate prescribing by nearly 3.5 times in our regression model. This again reflects the diagnostic challenges specific to LRTIs in the older adult population. Previous literature suggests that nearly 75% of elders with pneumonia will not have fever and less than half report cough, with increased risk of atypical presentations among NH residents specifically [34,35,36,37,38,39,40]. Although the Loeb criteria for suspected LRTI offers five distinct sets of signs and symptoms to meet the minimum criteria to initiate antibiotics, we observed high rates of prescribing outside of these parameters. This is likely to indicate ongoing clinical concerns for atypical presentations among this high-risk population. The vast majority of LRTIs were managed in the NHs which is potentially indicative of practice patterns informed by a published clinical pathway that demonstrated similar clinical outcomes for NH residents with LRTIs treated in-facility as compared to those who were hospitalized .
Relative to UTIs and LRTIs, SSTIs had the lowest overall rate of inappropriate antibiotic prescribing and were therefore selected as the reference condition in the regression model. This is likely because the Loeb criteria for initiating of antibiotics for SSTIs focus more on signs of infection which are readily identified by conducting a basic physical exam as opposed to patient reported symptoms . Despite this finding, antibiotic stewardship in the management of SSTIs should remain an area of great concern. This is emphasized by a recent study reporting that nearly 50% of empiric antibiotic use among NH residents with suspected SSTI failed to meet the Loeb criteria . SSTIs made up a higher relative percentage of infections managed in the ED and outpatient clinics. Although the reason for this is unclear, we hypothesize that NH residents may be sent to these settings for advanced imaging if clinical uncertainty exists around the presence of a purulent SSTI. In addition, purulent SSTIs often require surgical drainage for source control, which may necessitate transfer out of the NH.
In comparing the classes of antibiotics between settings (Table 3), we observed areas of consistency and variation in practice patterns. The most common class of antibiotic used for UTIs in each care setting was fluoroquinolones, with the ED having the highest prescribing rate (53.3%). However, the second most common class used for UTIs differed by setting with NHs favoring sulfonamides while the ED and outpatient clinics favoring cephalosporins. Interestingly, these results conflict with a prior report out of Canada indicating nitrofurantoin was the most commonly used agent for treatment of UTIs in the NH setting . Fluoroquinolones were also the most common class of antibiotic used for LRTIs, with the ED having the highest prescribing rate. Cephalosporins and penicillins were the two most common classes of antibiotics used for SSTIs in all settings. The observed variability in antibiotic prescribing by class again points to the need for enhanced bidirectional communication between NHs and other care settings around local resistance patterns and best practice guidelines in terms of recommended first line empiric antibiotics.
This study has several important limitations that we would like to mention. First, this study was conducted using data from 5 NHs in one US state which limits generalizability. Local practice patterns vary which highlights the need for additional investigation into antibiotic prescribing appropriateness for NH residents by setting. The small number of antibiotic starts occurring in the ED and outpatient clinic setting as compared to the NHs is also a limitation. The small sample size may have reduced our ability to detect true differences in appropriateness when present. Another limitation of this study is that our reported inappropriateness rates are likely underestimates because we did not assess the appropriateness of antibiotic selection or duration. In contrast, although we reviewed all clinical records available at the NH, documentation of care provided at outside settings (ED or outpatient clinic) was not always available. Without reviewing these records directly, it is unknown if additional symptom documentation or diagnostic testing would have satisfied the criteria for antibiotic initiation. However, our approach accurately reflects appropriateness assessed from the NH perspective based on all records available to providers in that setting. The bidirectional transfer of information for NH residents treated in the ED has already been highlighted as an important area of focus to improve the quality of care in this population [43, 44]. Although this quality concern is not specific to antibiotics, the transfer of information that enables the receiving NHs to understand the rationale for initiation of antibiotics is critical to support ongoing stewardship programs and enhancing safe transitions of care.