Box 4. Results of general practitioner enrolment and participant recruitment, by population demographic characteristics.

		Patients per GP, median (IQR)*			At least one randomised patient recruited by GP
	GPs enrolled	Screened by phone	Included after phone screen	Randomised participants	Adjusted odds ratio (95% CI)†	P
Remoteness classification (ASGS)‡
Major cities of Australia	1637	14 (6–30)	5 (2–11)	3 (1–7)	1
Inner regional Australia	864	14 (5–30)	8 (4–15)	4 (1–10)	1.45 (1.14–1.84)	0.002
Outer regional Australia	205	15 (5–32)	8 (4–18)	5 (1–13)	1.86 (1.19–2.88)	0.006
Remote	0	NA	NA	NA	NA
Age (per percentage point of local population aged 70 years or more)					1.10 (1.05–1.15)	< 0.001
Proportion of population ages 70 years or more
< 8%	627	12 (5–25)	5 (2–10)	2 (0–5)
8–9%	735	12 (4–25)	6 (3–12)	2 (0–7)
10%	657	18 (7–35)	8 (3–14)	4 (1–9)
≥ 11%	917	16 (6–34)	7 (3–14)	3 (1–8)
Socio-economic status of practice postcode (IRSAD), by percentile group§
Low (< 40%)	807	15 (3–36)	7 (3–13)	3 (1–9)	1
Moderate (40–74%)	845	14 (4–36)	6 (3–12)	3 (1–8)	1.30 (1.03–1.65)	0.025
High (75–100%)	889	18 (5–39)	7 (3–13)	4 (1–9)	1.83 (1.36–2.43)	< 0.001

ASGS = Australian Statistical Geography Standard; IQR = interquartile range; IRSAD = Index of Relative Socio-economic Advantage and Disadvantage.

^*Median number per enrolled GP per practice; 205 GPs were enrolled at more than one practice.

^†Adjusted for state.

^‡Data missing for 179 GPs.

^§Data missing for 175 GPs.