A randomized controlled trial comparing two ways of providing evidence-based drug information to GPs

Figures & data

Figure 1. Flow of participating GPs through the study.

Table I. Baseline characteristics of 991 GPs in the intervention and control groups at baseline.

	Intervention group (n = 408)	Control group (n = 583)	Difference between groups (p-value)
Medical information officers^1	6 pharmacists, 1 GP 4 males, 3 females	5 pharmacists, 2 GPs 3 males, 4 females	–
Primary healthcare centres	28	38	–
GPs’ age; years^2	46 (11)	47 (11)	0.19
GPs’ sex; male/female^3	248/153	328/250	0.13
Number of GPs working at private/public clinic^3	31/377	0/583	< 10^26
Proportion of GPs receiving allocated treatment^3	29%	29%	0.96
Average proportion of female patients among GPs’ patients^2	0.54 (0.19)	0.57 (0.20)	0.016
Average age of GPs’ patients; years^1	69 (6.5)	68 (6.4)	0.13

Notes: ¹Description of medical information officers’ profession (first line) and sex (second line). ²Mean (standard deviation). Difference between groups analysed with Student's t-test. ³Difference between groups analysed with chi-squared with Yates correction. Significant differences are shown in bold.

Table II. Proportion of ACE inhibitors prescribed by all GPs and change in this proportion over time (intention-to-treat).

	Intervention group	Control group
	n = 408	n = 583
Proportion of ACE inhibitors at 3 months before intervention, baseline^1, 2	0.64 (0.26) 0.67 (0.50–0.83)	0.63 (0.28) 0.65 (0.45–0.85)
Relative change in proportion of ACE inhibitors 0–3 months after intervention^2,3	+ 0.12 (0.43) + 0.029 (–0.11–0.32)	+ 0.12 (0.59) ± 0.00 (–0.17–0.27)
Relative change in proportion of ACE inhibitors 4–6 months after intervention^2,3	+ 0.12 (0.47) + 0.051 (–0.13–0.25)	+ 0.13 (0.56) + 0.0040 (–0.14–0.26)

Notes: ¹Proportion = number of ACE inhibitors prescribed divided by the sum of ACE inhibitors and ARBs. ²Upper line means (standard deviation). Lower line median (interquartile range). ³Relative change in proportion = Change in proportion of ACE inhibitors at follow-up divided by baseline proportion.

Table III. Change in proportion of ACE inhibitors prescribed by GPs actually receiving assigned intervention over time (per protocol).

	Intervention group	Control group
	n = 117	n = 168
Relative change in proportion of ACE inhibitors 0–3 months after intervention^1,2,3	+ 0.14 (0.41) + 0.024 (–0.11–0.30)	+ 0.11 (0.49) + 0.053 (–0.17–0.25)
Relative change in proportion of ACE inhibitors 4–6 months after intervention^1,2,3	+ 0.11 (0.47) + 0.049 (–0.13–0.24)	+ 0.14 (0.48) + 0.031 (–0.12–0.32)

Notes: ¹Proportion = number of ACE inhibitors prescribed divided by the sum of ACE inhibitors and ARB. ²Upper line means (standard deviation). Lower line median (interquartile range). ³Relative change in proportion = change in proportion of ACE inhibitors at follow up divided by baseline proportion.