https://immattersacp.org/weekly/archives/2016/07/12/2.htm

Reduced antibiotic prescribing for self-limiting respiratory tract infections not linked to large increase in serious bacterial infections, study finds

The authors estimated that a general practice with 7,000 patients could expect to see 1.1 additional case of pneumonia annually and 0.9 additional case of peritonsillar abscess per decade if it reduced the proportion of respiratory tract infections resulting in antibiotics prescribed by 10%.


Primary care practices in the United Kingdom that prescribe fewer antibiotics for self-limiting respiratory tract infections (RTIs) did not see large increases in complicated bacterial infections, according to a new study.

Researchers performed a cohort study using data from 610 general practices in the U.K. from 2005 to 2014, looking at antibiotics prescribed for RTIs and the rate of prescriptions per 1,000 registered patients. The main outcome measures were incidence of pneumonia, peritonsillar abscess, mastoiditis, empyema, meningitis, intracranial abscess, and Lemierre's syndrome. Outcome measures were adjusted for age group, sex, region, socioeconomic status, RTI consultation rate, and general practice. Results were published online by The BMJ on July 4.

The study included 45.5 million person-years of observation. The proportion of visits for an RTI that resulted in an antibiotics prescription decreased from 2005 to 2014 in both men and women (53.9% to 50.5% and 54.5% to 51.5%, respectively). New episodes of meningitis, mastoiditis, and peritonsillar abscess also decreased during this period, by 5.3%, 4.6%, and 1.0%, respectively, while new episodes of pneumonia increased by 0.4%. Practices were divided into fourths according to proportion of RTI consultations at which antibiotics were prescribed, with the highest fourth prescribing at a median rate of 65% and the lowest fourth prescribing at a median rate of 38%. Practices in the lowest fourth of antibiotic prescribing had higher age- and sex-standardized incidences of pneumonia and peritonsillar abscess versus practices in the highest fourth.

For a 10% reduction in antibiotic prescribing, adjusted relative risk increases for pneumonia and peritonsillar abscess were 12.8% (95% CI, 7.8% to 17.5%; P<0.001) and 9.9% (95% CI, 5.6% to 14.0%; P<0.001), respectively. All other outcome measures had similar frequencies at low- and high-prescribing practices. The authors estimated that a general practice with 7,000 patients could expect to see 1.1 additional case of pneumonia annually and 0.9 additional case of peritonsillar abscess per decade if it reduced the proportion of RTIs resulting in antibiotics prescribed by 10%.

Limitations of the study included that it did not look at variations in prescribing at the individual-physician level, that it did not evaluate the outcomes of patients who had complications, and that misclassification was possible, the authors acknowledged. However, they concluded that general practices adopting policies to decrease rates of antibiotic prescribing for RTIs can expect slight increases in incidence of treatable pneumonia and peritonsillar abscess but probably no increases in incidence of other potential adverse outcomes, such as mastoiditis and empyema.

“Even a substantial reduction in antibiotic prescribing was predicted to be associated with only a small increase in numbers of cases overall, but caution might be required in subgroups at higher risk of pneumonia,” the authors wrote. They called for further research to quantify associations by individual patient characteristics and primary care consultation patterns, as well as to evaluate safety outcomes.