Antibiotic prescribing and associated diarrhoea: a prospective cohort study of care home residents.

BACKGROUND the risk factors for and frequency of antibiotic prescription and antibiotic-associated diarrhoea (AAD) among care home residents are unknown. AIM to prospectively study frequency and risks for antibiotic prescribing and AAD for care home residents. DESIGN AND SETTING a 12-month prospective cohort study in care homes across South Wales. METHOD antibiotic prescriptions and the development of AAD were recorded on case report forms. We defined AAD as three or more loose stools in a 24-h period occurring within 8 weeks of exposure to an antibiotic. RESULTS we recruited 279 residents from 10 care homes. The incidence of antibiotic prescriptions was 2.16 prescriptions per resident year (95% CI: 1.90-2.46). Antibiotics were less likely to be prescribed to residents from dual-registered homes (OR compared with nursing homes: 0.38, 95% CI: 0.18-0.79). For those who were prescribed antibiotics, the incidence of AAD was 0.57 episodes per resident year (95% CI: 0.41-0.81 episodes). AAD was more likely in residents who were prescribed co-amoxiclav (hazards ratio, HR = 2.08, 95% confidence interval, CI: 1.18-3.66) or routinely used incontinence pads (HR = 2.54, 95% CI: 1.26-5.13) and less likely in residents from residential homes (HR compared with nursing homes: 0.14, 95% CI: 0.06-0.32). CONCLUSION residents of care homes, particularly of nursing homes, are frequently prescribed antibiotics and often experience diarrhoea following such prescriptions. Co-amoxiclav is associated with greater risk of AAD.