Patterns of medication use and factors associated with antibiotic use among adult fever patients at Singapore primary care clinics

Zaw Myo Tun, Mahesh Moorthy, Martin Linster, Yvonne C. F. Su, Richard James Coker, Eng Eong Ooi, Jenny Guek-Hong Low, Gavin J. D. Smith, Clarence C. Tam

Antimicrobial resistance is a public health problem of global importance. In Singapore, much focus has been given to antibiotic usage patterns in hospital settings. Data on antibiotic use in primary care is lacking. We describe antibiotic usage patterns and assess factors contributing to antibiotic usage among adults presenting with acute febrile illness (AFI) in primary care settings in Singapore. We analyzed data from the Early Dengue infection and outcome study. Adults with AFI presenting at 5 Singapore polyclinics were included. We used multivariable logistic regression to assess demographic, clinical and laboratory factors associated with antibiotic usage among adults with AFI. Between December 2007 and February 2013, 1884 adult AFI patients were enrolled. Overall, 16% of adult AFI patients reported antibiotic use. We observed a rise in the use of over-the-counter medications in late 2009 and a decrease in antibiotic use during 2010, possibly related to the outbreak of pandemic influenza A H1N1 virus. After adjusting for age, gender, polyclinic and year of enrolment, the following factors were associated with higher odds of antibiotic use: living in landed property (compared to public housing) (OR = 1.73; 95% CI: 1.06-2.80); body mass index (BMI) <18.5 (OR = 1.87; 95% CI: 1.19-2.93); elevated white blood cell (WBC) count (OR = 1.98; 95% CI: 1.42-2.78); and persistence of initial symptoms at 2-3 days follow-up with OR (95% CI) for categories of 1, 2, 3, and ≥4 persisting symptoms being 2.00 (1.38-2.92), 2.67 (1.80-3.97), 4.26 (2.73-6.64), and 2.79 (1.84-4.24) respectively. Our study provides insights on antibiotic usage among adult patients presenting to primary care clinics with febrile illness, and suggests that high socio-economic status, and risk factors of a severe illness, that is, low BMI and persistence of initial symptoms, are associated with higher antibiotic use. Further work to understand trends of antibiotic usage in both private and public primary care clinics, and factors that influence patient expectation and physician prescribing of antibiotics is important.