IRR	Standard error	z	P-values	95% CI
% Composite access score	0.962862	0.001558	−23.39	<0.001	0.959813 to 0.96592
Average age, years	0.989058	0.003703	−2.94	0.003	0.981827 to 0.996341
% Female	1.047712	0.007683	6.36	<0.001	1.032762 to 1.062878
Rank, proportion of population who were white	1.000025	9.23E-06	2.65	0.008	1.000006 to 1.000043
Rank IMD 2010 score	1.000001	8.06E-06	0.12	0.907	0.999985 to 1.000017
% Achievement Asthma 6 (asthma review within 15 months)	0.99354	0.001528	−4.22	<0.001	0.990551 to 0.996539
% Achievement Asthma 8 (measures of variability or reversibility)	0.997757	0.001498	−1.5	0.135	0.994825 to 1.000698
Distance to nearest hospital, km	1.001424	0.001873	0.76	0.447	0.99776 to 1.005102

Dependent variable: the rate of emergency admissions for asthma per 1000 patients on the asthma register. Weighted for practice size and clustered at the primary care trust level.

IRR = incidence rate ratio. IMD = Index of Multiple Deprivation.