Table 3. Association between number of prescriptions per person per GP practice and GP practice IMD quintile
GabapentinPregabalinOxycodone
Univariate RR 95% CI P value RR (95% CI) P value RR P value
IMD quintile    
(least deprived) 11 (Ref)Ref1 (Ref)Ref1 (Ref)Ref
21.26 (1.22 to 1.31)<0.0011.2 (1.16 to 1.24)<0.0011.19 (1.13 to 1.25)<0.001
31.53 (1.48 to 1.58)<0.0011.35 (1.31 to 1.40)<0.0011.37 (1.31 to 1.44)<0.001
41.8 (1.745 to 1.86)<0.0011.56 (1.51 to 1.61)<0.0011.47 (1.40 to 1.54)<0.001
(most deprived) 52.29 (2.22 to 2.37)<0.0011.86 (1.80 to 1.92)<0.0011.71 (1.63 to 1.80)<0.001
Multivariate       
IMD quintile    
(least deprived) 11 (Ref)Ref1 (Ref)Ref1 (Ref)Ref
21.24 (1.21 to 1.28)<0.0011.2 (1.16 to 1.23)<0.0011.2 (1.15 to 1.25)<0.001
31.59 (1.54 to 1.63)<0.0011.39 (1.35 to 1.44)<0.0011.47 (1.40 to 1.53)<0.001
42.12 (2.06 to 2.18)<0.0011.79 (1.74 to 1.845)<0.0011.82 (1.74 to 1.90)<0.001
(most deprived) 53.13 (3.04 to 3.23)<0.0012.38 (2.30 to 2.45)<0.0012.54 (2.42 to 2.66)<0.001
Year    
20131 (Ref)Ref1 (Ref)Ref1 (Ref)Ref
20141.2 (1.175 to 1.22)<0.0011.24 (1.21 to 1.26)<0.0011.11 (1.07 to 1.14)<0.001
20151.36 (1.33 to 1.38)<0.0011.42 (1.40 to 1.45)<0.0011.19 (1.16 to 1.22)<0.001
20161.51 (1.48 to 1.54)<0.0011.62 (1.59 to 1.655)<0.0011.26 (1.225 to 1.30)<0.001
20171.55 (1.525 to 1.58)<0.0011.75 (1.72 to 1.79)<0.0011.27 (1.23 to 1.31)<0.001
Sex    
% female1 (0.10 to 1.00)0.0881 (0.10 to 1.00)0.2011.02 (1.02 to 1.03)<0.001
Age    
% ≥65 years1.04 (1.04 to 1.04)<0.0011.03 (1.03 to 1.03)<0.0011.04 (1.04 to 1.04)<0.001

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