Methodology Score: 2.5/5
Usefulness Score: 2.5/5
Little P, et al. BMJ. 2017 May 22;357:j2148.
Editorial: Controlling antibiotic prescribing for lower respiratory tract infections Scott AM et al. BMJ. 2017 May 22;357:j2398. doi: 10.1136/bmj.j2398.
Question and Methods: This is a large, prospective, observational study of ambulatory patients with acute cough treated with no, immediate or delayed antibiotics that compared rates of re-consultation, admission and death in each group.
Findings: There was no change in admission or death with antibiotics, but re-consultation for new, worsening, or non-resolving symptoms decreased with delayed antibiotics (RR 0.64, 95% CI 0.57 to 0.72, P<0.001).
Limitations: Limitations include lack of randomization, non-standardized antibiotic regimes, no blinding to treatment, no discussion of antibiotic associated adverse events, and rates of compliance were not measured.
Interpretation: In patients presenting with a cough without signs of pneumonia if you are considering prescribing antibiotics, use a delayed prescription to decrease rates of re-consultation.
By: Dr. Erica Lee
Impact of Clusters in Analyses
Most statistical analyses assume that all observations (data) are independent from each other. On occasion, groups share similarities (for e.g. patients of a same physician) which makes the contribution of each patient slightly less valuable or different from the others. The amount of similarity within a group is called “intra-class correlation” and can be measured statistically. This can be used to calculate a slightly larger required sample size, or to adjust analyses accordingly.
By: Dr. Christian Vaillancourt