Figure 4.

Adjusted Odds Ratios for Antibiotic Prescribing for Acute Respiratory Tract Infections at A) LAC+USC and B) OV-UCLA.

Odds ratios (ORs) during each time period were obtained from the within-group interrupted-time-series analysis consisting of segmented age- and sex-adjusted logistic regressions on the dependent variable (antibiotic prescribing) clustered by patient.

Results were interpretable as the OR of prescribing antibiotics during a post-intervention period divided by the OR of prescribing antibiotics during the period before all interventions (i.e., ratio of ORs). A ratio of ORs (rOR) equal to 0.60 indicated that the odds of prescribing antibiotics decreased by 40% from the pre-intervention period.

All interventions at LAC+USC were implemented during T2 (see Figure 2); Panel A depicts the change in odds of prescribing antibiotics after all interventions were implemented compared to before any interventions were implemented (i.e., T2 v. T1). At OV-UCLA some interventions were implemented during T2, while case-audit feedback (the main intervention) was implemented during T3; Panel B depicts both the change in odds of prescribing antibiotics after some interventions were implemented (post-partial interventions; T2 v. T1) as well as after all interventions were implemented (post-all interventions; T3 v. T1). Thus, LAC+USC had no “post-partial intervention” period.

Asterisks represent statistical significance by ITS analysis at the following levels: * if P≤.05, ** if P≤.01, *** if P≤.001. Error bars depict 95% CIs.