Antibiotic prescribing frequency amongst patients in primary care: a cohort study using electronic health records.
Reducing inappropriate antibiotic prescribing in primary care is a public health priority.



We hypothesized that a subset of patients account for the majority of antibiotic prescriptions in primary care. We investigated the relationship between the total amount of antibiotics prescribed, individual-level antibiotic use and comorbidity.



This was a cohort study using electronic health records from 1 948 390 adults registered with 385 primary care practices in the UK in 2011-13. We estimated the average number of antibiotic prescriptions per patient and the association between prescribing and comorbidity. We modelled the impact on total prescribing of reducing antibiotic use in those prescribed antibiotics most frequently.



On average 30.1% (586 194/1 948 390) of patients were prescribed at least one antibiotic per year. Nine percent (174 602/1 948 390) of patients were prescribed 53% (2 091 496/3 922 732) of the total amount of antibiotics, each of whom received at least five antibiotic prescriptions over 3 years. The presence of any comorbidity increased the prescribing rate by 44% [adjusted incidence rate ratio (IRR) 1.44, 95% CI 1.43-1.45]; rates of prescribing to women exceeded those in men by 62% (adjusted IRR 1.62, 95% CI 1.62-1.63).



Half of antibiotics prescribed to adults in primary care were for <10% of patients. Efforts to tackle antimicrobial resistance should consider the impact of this on total prescribing.
UCL Institute of Health Informatics, 222 Euston Road, London NW1 2DA, UK.
Laura
L
Shallcross
Research Department of Primary Care and Population Health, University College London Medical School, Rowland Hill Street, London NW3 2PF, UK.
Nick
N
Beckley
Research Department of Primary Care and Population Health, University College London Medical School, Rowland Hill Street, London NW3 2PF, UK.
Greta
G
Rait
UCL Institute of Health Informatics, 222 Euston Road, London NW1 2DA, UK.
Andrew
A
Hayward
Research Department of Primary Care and Population Health, University College London Medical School, Rowland Hill Street, London NW3 2PF, UK.|Department of Clinical Epidemiology, Aarhus University, Olof Palmes Alle, 8200 Aarhus N, Denmark.
Irene
I
Petersen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D015897:Comorbidity; D000075202:Contraindications; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D057970:Inappropriate Prescribing / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011320:Primary Health Care; D012141:Respiratory Tract Infections / Q000188:drug therapy / Q000453:epidemiology; D012737:Sex Factors; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000453:epidemiology; D055815:Young Adult
D000900:Anti-Bacterial Agents