Effect of educational outreach on general practice prescribing of antibiotics and antidepressants: A two-year randomised controlled trial

Figures & data

Figure 1. Study flowchart.

Table I. Baseline characteristics of study practices by intervention group (items per patient – numbers of prescriptions in six-month period per 1000 registered patients; ADQ per 1000 patients – average daily quantities [the assumed average maintenance dose per day] in six-month period per 1000 patients).

	Antibiotic intervention group(n = 14) Mean (95% CI)	Antidepressant intervention group (n = 14) Mean (95% CI)	p
Number of GPs per practice	3.3 (2.2, 4.5)	2.2 (1.4, 2.9)	0.08
Patients per practice
Females 0–18 years	930 (279, 1124)	424 (279, 580)	0.06
Females 19–65 years	2261 (857, 3198)	1156 (670, 1799)	0.15
Females 66 + years	693 (296, 899)	266 (164, 367)	0.06
Males 0–18 years	974 (317, 1159)	469 (308, 604)	0.06
Males 19–65 years	2088 (978, 3275)	1119 (670, 1768)	0.33
Males 66 + years	449 (219, 671)	194 (136, 282)	0.06
ID2004 Deprivation Score	20.6 (14.3, 26.8)	23.3 (16.2, 30.3)	0.46
Co-amoxiclav items per 1000 patients	10.9 (6.6, 15.2)	8.0 (4.4, 11.6)	0.31
Quinolone items per 1000 patients	11.4 (5.1, 17.8)	8.0 (5.2, 10.7)	0.38
Lofepramine ADQs per 1000 patients	256.4 (195.9, 316.8)	252.7 (109.4, 396.1)	0.36
Fluoxetine ADQs per 1000 patients	1832.7 (1278.4, 2387)	1629.1 (1227.3, 2030.9)	0.89

Table II. Effect of intervention combining data on all review periods using generalized mixed-effect model based on negative binomial regression distributions, with adjustment for baseline. Antibiotic prescribing - items per 1000 patients, antidepressant prescribing - average daily quantities.

Drug	RR^a	95% CI of RR	p
Co-amoxiclav	0.89	0.52, 1.50	0.65
Quinolones	0.98	0.63, 1.53	0.92
Lofepramine	2.85	1.92, 4.34	< 0.001
Fluoxetine	1.06	0.75, 1.52	0.74

Note: ^aRate ratio.

Table III. Percentage of co-amoxiclav and quinolones prescribed as a proportion of total antibiotic (number of items per 1000 patients), and lofepramine and fluoxetine as a proportion of total antidepressant prescribing (ADQs per 1000 patients).

	Antibiotic group Mean (CI)	Antidepressant group Mean (CI)	p-values
Co-amoxiclav and quinolones as percentage of total antibiotic prescribing
Average baseline	6.9 (4.6, 9.0)	5.8 (3.1, 8.3)
Review 1	4.6 (3.3, 5.9)	6.2 (3.7, 8.8)	0.40
Review 2	5.7 (4.2, 7.2)	6.2 (3.7, 8.7)	0.43
Review 3	5.4 (4.30, 6.4)	6.8 (4.0, 9.5)	0.97
Review 4	5.8 (4.3, 7.3)	6.4 (3.8, 9.0)	0.98
Lofepramine and fluoxetine as percentage of total antidepressant prescribing
Average baseline	20.9 (16.8, 25.1)	26.7 (22.6, 30.9)
Review 1	21.4 (17.3, 25.4)	27.7 (22.2, 33.2)	0.07
Review 2	21.3 (17.3, 25.3)	29.5 (24.0, 351)	0.01
Review 3	20.7 (16.6, 24.8)	29.4 (24.3, 34.5)	0.01
Review 4	20.8 (16.5, 25.2)	28.6 (23.0, 34.2)	0.01

Notes: Regression analysis adjusting for baseline. Review periods 1 to 4 were consecutive six-month periods, total follow up 24 months.