Income level and antibiotic misuse: a systematic review and dose–response meta-analysis

OBJECTIVES: To quantify the association between income and antibiotic misuse including unprescribed use, storage of antibiotics and non-adherence. METHODS: We identified pertinent studies through database search, and manual examination of reference lists of selected articles and review reports. We performed a dose–response meta-analysis of income, both continuous and categorical, in relation to antibiotic misuse. Summary odds ratios (ORs) and their 95% confidence intervals (CIs) were estimated under a random-effects random effects model. RESULTS: Fifty-seven studies from 22 countries of different economic class were included. Overall, the data are in agreement with a flat linear association between income standardized to socio-economic indicators and antibiotic misuse (OR per 1 unit increment = 1.00, p-value = 0.954, p-value non-linearity = 0.429). Data were compatible with no association between medium and high income with general antibiotic misuse (OR 1.04; 95% CI 0.89, 1.20 and OR 1.03; 95% CI 0.82, 1.29). Medium income was associated with 19% higher odds of antibiotic storage (OR 1.19; 95% CI 1.07, 1.32) and 18% higher odds of any aspect of antibiotic misuse in African studies (OR 1.18; 95% CI 1.00, 1.39). High income was associated with 51% lower odds of non-adherence to antibiotic treatment (OR 0.49; 95% CI 0.34, 0.60). High income was also associated with 11% higher odds of any antibiotic misuse in upper-middle wealth countries (OR 1.11; 95% CI 1.00, 1.22). CONCLUSIONS: The association between income and antibiotic misuse varies by type of misuse and country wellness. Understanding the socioeconomic properties of antibiotic misuse should prove useful in developing related intervention programs and health policies.