Table 3. Association between number of prescriptions per person per GP practice and GP practice IMD quintile.

	Gabapentin	Pregabalin	Oxycodone
Univariate	RR 95% CI	P value	RR (95% CI)	P value	RR	P value
IMD quintile
(least deprived) 1	1 (Ref)	Ref	1 (Ref)	Ref	1 (Ref)	Ref
2	1.26 (1.22 to 1.31)	<0.001	1.2 (1.16 to 1.24)	<0.001	1.19 (1.13 to 1.25)	<0.001
3	1.53 (1.48 to 1.58)	<0.001	1.35 (1.31 to 1.40)	<0.001	1.37 (1.31 to 1.44)	<0.001
4	1.8 (1.745 to 1.86)	<0.001	1.56 (1.51 to 1.61)	<0.001	1.47 (1.40 to 1.54)	<0.001
(most deprived) 5	2.29 (2.22 to 2.37)	<0.001	1.86 (1.80 to 1.92)	<0.001	1.71 (1.63 to 1.80)	<0.001
Multivariate
IMD quintile
(least deprived) 1	1 (Ref)	Ref	1 (Ref)	Ref	1 (Ref)	Ref
2	1.24 (1.21 to 1.28)	<0.001	1.2 (1.16 to 1.23)	<0.001	1.2 (1.15 to 1.25)	<0.001
3	1.59 (1.54 to 1.63)	<0.001	1.39 (1.35 to 1.44)	<0.001	1.47 (1.40 to 1.53)	<0.001
4	2.12 (2.06 to 2.18)	<0.001	1.79 (1.74 to 1.845)	<0.001	1.82 (1.74 to 1.90)	<0.001
(most deprived) 5	3.13 (3.04 to 3.23)	<0.001	2.38 (2.30 to 2.45)	<0.001	2.54 (2.42 to 2.66)	<0.001
Year
2013	1 (Ref)	Ref	1 (Ref)	Ref	1 (Ref)	Ref
2014	1.2 (1.175 to 1.22)	<0.001	1.24 (1.21 to 1.26)	<0.001	1.11 (1.07 to 1.14)	<0.001
2015	1.36 (1.33 to 1.38)	<0.001	1.42 (1.40 to 1.45)	<0.001	1.19 (1.16 to 1.22)	<0.001
2016	1.51 (1.48 to 1.54)	<0.001	1.62 (1.59 to 1.655)	<0.001	1.26 (1.225 to 1.30)	<0.001
2017	1.55 (1.525 to 1.58)	<0.001	1.75 (1.72 to 1.79)	<0.001	1.27 (1.23 to 1.31)	<0.001
Sex
% female	1 (0.10 to 1.00)	0.088	1 (0.10 to 1.00)	0.201	1.02 (1.02 to 1.03)	<0.001
Age
% ≥65 years	1.04 (1.04 to 1.04)	<0.001	1.03 (1.03 to 1.03)	<0.001	1.04 (1.04 to 1.04)	<0.001

IMD = Index of Multiple Deprivation. Ref = reference. RR = rate ratio.