Table 2

Factorial Analysis: Efficacy of Interventions in Reducing Antibiotic Prescribing at 12 Months

MeasureNo CRP Training
(n = 2,360)
CRP Training
(n = 2,462)
No Communication
Training (n = 2,246)
Training (n = 2,576)
Patients prescribed antibiotics, No. (%)1,078 (45.7)1,097 (44.6)1,069 (47.6)1,106 (42.9)
Basic risk ratio (95% CI) [P value]aref0.91 (0.77-1.05) [.22]ref0.90 (0.77-1.04) [.17]
Fully adjusted risk ratio (95% CI) [P value]bref0.87 (0.68-1.06) [.18]ref0.81 (0.64-1.00) [.049]
  • CRP = C-reactive protein; ref = reference group.

  • a The basic model adjusted for baseline prescribing and clustering by physician and practice.

  • b The fully adjusted model controlled for diagnosis (lower respiratory tract infection, upper respiratory tract infection, pneumonia), sex, age, presence of cough, phlegm, shortness of breath, blocked/runny nose, chest pain, fever, muscle ache, headache, disturbed sleep, feeling generally unwell, interference with social activities, earache, sore throat, facial/sinus pain, crackles, wheeze, pulse >100 beats per minute, temperature >37.8°C, respiratory rate, physician’s rating of severity, low blood pressure, duration of cough, and duration of illness before consultation.