P : Hospitalized patients ≥18 years with CAP who received initial NSBM or BSBM, with a severity score according to CRB-65≤2 (C=confusion, R=respiratory rate >30/min, B=systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg, 65= ≥65 years)
E : narrow-spectrum ß-lactam monotherapy (NSBM)
C : broad-spectrum ß-lactam monotherapy (BSBM)
BSBM was defined as empirical monotherapy with either a cephalosporin or piperacillin/tazobactam.
O : No significant differences in 30-day mortality were observed between NSBM and BSBM in patients with CRB-65≤1 or CRB-65=2, OR 1.41 (95% CI 0.94-2.14) and 0.88 (95% CI 0.59-1.32), respectively.
Fig and Tab
The strength of the study was the large number of patients from most regions of Sweden, and the complete data of outcome and exposure resulting from the accurate Swedish inpatient and death registers.
The estimated inclusion rate of 50 - 60% and lack of data on non-included patients is a limitation in terms of generalizability; however, for most characteristics the study population was similar to those in other pneumonia studies. We did not have data on sociodemographic status, alcohol habits, smoking, and time until administration of antibiotics, which have been associated with CAP, aetiology, and outcome [27e30]. Moreover, we cannot exclude some residual or unmeasured confounding under- estimating the relative effect of BSBM versus NSBM.
In this large national retrospective register-based cohort study of patients hospitalized with CAP, we compared outcomes with regard to different initial antibiotic regimens.
Our data suggest that BSBM is not more effective than NSBM as empirical treatment in patients with CRB-65 score 1 and also likely not in the majority of patients with a CRB-65 score of 2.