Table 2. Correlation between rates of practice prescribing cost per practice patient of LAMA and LABA+ICS (with partial correlation of log of the cost of LAMA and the log of the cost of LABA+ICS when controlling for the log of the practice list size).

	Rate LAMA versus	Log LAMA cost versus
Year	Rate LABA+ICS	Log LABA+ICS cost
	R1 (±95% CI)	R2 (±95% CI)
2007 (n=798)	0.52 (0.47–0.57)	0.56 (0.52–0.61)
2008 (n=801)	0.60 (0.55–0.64)	0.63 (0.59–0.67)
2009 (n=804)	0.63 (0.59–0.67)	0.67 (0.63–0.71)
2010 (n=796)	0.68 (0.64– 0.72)	0.73 (0.69–0.76)

R₁ is Pearson’s correlation (unadjusted for practice list size). R₂ is Partial correlation (adjusted for log practice list size). n is number of practices.

Abbreviations: CI, confidence interval; LABA+ICS, combined inhaled long-acting β₂-agonist and corticosteroid; LAMA, long-acting anti-muscarinic.