Table 2. Hazard ratios, 95% confidence intervals and P-values for Cox proportional hazard models.

Dependent variable	Independent variable	HR (95% CI)	P-value
EOI	Number of RCTs	1.83 (1.58–2.12)	<0.001
	Number of individual RCTs	2.36 (1.86–2.99)	<0.001
	Number of cluster RCTs	1.91 (1.52–2.40)	<0.001
	Practice size (1,000's)	1.03 (0.99–1.07)	0.122
Randomised	Number of RCTs	1.81 (1.55–2.11)	<0.001
	Number of individual RCTs	2.36 (1.85–3.02)	<0.001
	Number of cluster RCTs	1.83 (1.45–2.32)	<0.001
	Practice size (1,000's)	1.04 (0.10–1.08)	0.054

Abbreviations: CI, confidence interval; EOI, expression of interest; OR, odds ratio; RCT, randomised controlled trial.