Effectiveness of an intervention to improve antibiotic-prescribing behaviour in primary care: a controlled, interrupted time-series study

Abstract Background High rates of antibiotic misprescribing in primary care, with alarming clinical and economic consequences, highlight the urgent need for interventions to improve antibiotic prescribing in this setting. Objectives To assess the effectiveness on antibiotic prescribing quality indicators of a multifaceted intervention targeting health professionals’ and patients’ behaviour regarding antibiotic use. Methods We conducted a pragmatic cluster-randomized controlled trial in the catchment area covered by Portugal’s Central Regional Health Administration. The intervention consisted of a multidisciplinary, multifaceted programme involving physicians, pharmacists and patients, and comprising outreach visits for physicians and pharmacists, and educational materials for health professionals and patients. The following were assessed: relative ratios of prescription of penicillins sensitive to β-lactamase, penicillin combinations including β-lactamase inhibitors, third- and fourth-generation cephalosporins and fluoroquinolones; and the ratio of broad- to narrow-spectrum antibiotics. An interrupted time-series analysis for multiple-group comparisons was performed. The study protocol was registered on Clinical.trials.gov (NCT02173509). Results The participation rate in the educational intervention was 64% (197/309 GPs) in a total of 25 counties. Statistically significant improvements were obtained, not only in the relative prescription of penicillins sensitive to β-lactamase (overall relative change of +896%) and penicillin combinations including β-lactamase inhibitors (−161%), but also in the ratio of broad- to narrow-spectrum antibiotics (−200%). Statistically significant results were also obtained for third- and fourth-generation cephalosporins, though only in the immediate term. Conclusions This study showed that quality indicators of antibiotic prescribing can be improved by tackling influences on behaviour including knowledge and attitudes surrounding physicians’ clinical practice. Accordingly, these determinants must be considered when implementing interventions aimed at improving antibiotic prescribing.