Table 1.

Effect of intervention on prescribing rates of simple analgesia^a

Medication group	Reduction, %	aIRR	95% CI	P-value	Pre-intervention slope (by month)	Post-intervention slope (by month)
All simple analgesia	4.4	0.956	0.919 to 0.995	0.027b	−0.22	−0.18
Paracetamol tablet/capsule	3.9	0.961	0.925 to 0.999	0.05b	−0.15	−0.12
Paracetamol suspension	9.3	0.907	0.827 to 0.995	0.045b	−0.02	−0.02
Ibuprofen tablet/capsule	0.9	0.991	0.931 to 1.055	0.772	−0.06	−0.04
Ibuprofen suspension	13.2	0.868	0.758 to 0.993	0.045b	−0.01	−0.01
Topical NSAID	9.0	0.910	0.873 to 0.948	<0.001b	0.03	0.03

^aFor all, and for each subgroup of, simple analgesia the percentage reduction in prescribing rates associated with the intervention is given for the time and seasonally adjusted model, along with the aIRR and 95% CIs. The slope coefficients for the linear trends before and after the intervention are shown (as change in prescribing rate per 1000 registered patients per month).

^bP <0.05. aIRR = adjusted incidence rate ratio. CI = confidence interval. NSAID = non-steroidal anti-inflammatory drug.