Although the use of pneumococcal urinary antigen tests (UATs) was not associated with a decreased rate of treatment with broad-spectrum ß-lactam monotherapy (BSBM) in patients hospitalized with community-acquired pneumonia (CAP), treatment with BSBM was less likely among those with nonsevere disease and positive UAT results. These findings were from a retrospective cohort study published in the Journal of Infection.
This study was conducted in Sweden, where national guidelines recommend pneumococcal UAT for all adult patients hospitalized with CAP. Researchers obtained UAT results from adults hospitalized with their first episode of CAP between July 2011 and December 2014. The researchers assessed the rate of treatment with BSBM vs narrow-spectrum ß-lactam monotherapy (NSBM) among patients on the basis of UAT results. Treatment with BSBM was defined as monotherapy with cephalosporin, piperacillin/tazobactam, or amoxicillin/clavulanic acid, and NSBM was defined as monotherapy with penicillin G, penicillin V, or amoxicillin. They also assessed the rate of atypical antibiotic coverage, defined as treatment with macrolide or quinolone, alone or in combination with BSBM or NSBM. Propensity score and nearest neighbor matching was performed to assign patients who did and did undergo UAT in a 1:1 fashion into subgroups on the basis of patient characteristics. The same method was used to compare antibiotic treatment among patients with positive vs negative UAT results. The primary outcome was patients’ medication regimen at hospital day 3, with multinomial regression used with NSBM as a reference to compare the matched groups.
There were 14,590 patients with unique CAP episodes included in the analysis, of whom UAT was performed in 4,996 (34.2%). Of these patients, 603 (12.1%) had a positive UAT result. Propensity score matching revealed no difference between patients with positive vs negative UAT results; however, performance of UAT was more likely among those who were younger and those with fewer comorbidities.
Among patients who did (n=3506) and did not undergo UAT (n=3506), 18.1% and 16.1% received treatment with BSBM on hospital day 3 (odds ratio [OR], 1.07; 95% CI, 0.94-1.23). When stratified by CRB-65 (new-onset confusion; respiratory rate ≥30/min; systolic blood pressure <90 mm Hg or diastolic blood pressure ≤60 mm Hg; age, ≥65 years) scores, performance of UAT was not associated with an increased rate of BSBM treatment in any patient group. However, patients with CRB-65 scores of 2 were more likely to receive atypical antibiotic treatment. At hospital day 1, patients who underwent UAT and had CRB-65 scores of either 2 (OR, 2.60; 95% CI, 1.69-3.98) or between 3 and 4 (OR, 3.69; 95% CI, 1.55-8.79) were more likely to receive atypical antibiotic treatment.
At hospital day 3, patients with a positive UAT result were less likely to receive BSBM vs those with a negative result (9% vs 15%; OR, 0.39; 95% CI, 0.25-0.60). Atypical antibiotic treatment also was less likely among patients with positive UAT results at day 3 (OR, 0.25; 95% CI, 0.16-0.37). A decreased rate of BSBM and atypical antibiotic treatment was observed among patients with CRB-65 scores of between either 0 and 1 or 2. At day 1, a positive UAT result was associated with an increased use of BSBM in patients with CRB-65 scores between 3 and 4.
No associations were observed between either the performance of UAT or for UAT results and the rate of in-hospital mortality, with similar results noted after stratification by CRB-65 scores.
This study was limited by the relatively small number of patients (34%) who underwent UAT, and the lack of data on UAT availability and UAT manufacturers across hospitals.
“The indications for performing UAT should be carefully considered in CAP guidelines in order to improve the sensitivity and specificity and to identify patients who may benefit from antibiotic guidance based on a positive test result,” the study researchers concluded.
Athlin S, Magnuson A, Spindler C, Hedlund J, Strålin K, Nauclér P. Pneumococcal urinary antigen testing for antimicrobial guidance in community-acquired pneumonia-A register-based cohort study. J Infect. Published online May 23, 2022. doi:10.1016/j.jinf.2022.05.021