IRR (95% CI) | P-value | |
PIPs at baseline (ref: control group) | ||
Intervention | 1.10 (0.97 to 1.25) | 0.15 |
Within-group reduction of PIPs relative to baseline | ||
Control | 0.93 (0.90 to 0.96) | <0.01 |
Intervention | 0.80 (0.78 to 0.82) | <0.01 |
aReduction of PIPs after intervention (ref: control group) | ||
Intervention | 0.86 (0.83 to 0.90) | <0.01 |
Subgroups: | ||
Age group, years (ref: 27–42 years) | ||
43–48 | 0.85 (0.81 to 0.89) | <0.01 |
49–52 | 0.92 (0.87 to 0.97) | <0.01 |
53–56 | 1.00 (0.95 to 1.05) | 0.94 |
57–68 | 1.21 (1.16 to 1.27) | <0.01 |
Specialist (ref: non-specialist) | ||
Specialist | 1.04 (0.99 to 1.08) | 0.13 |
Type of practice (ref: single-handed) | ||
Group practice | 1.04 (0.99 to 1.08) | 0.07 |
Sex (ref: female) | ||
Male | 1.40 (1.35 to 1.44) | <0.01 |
Practice setting (ref: rural) | ||
Urban | 1.15 (1.11 to 1.19) | <0.01 |
Mean PIPs p 100 prescriptions at baseline (ref: ≤1.6) | ||
1.7–2.0 | 1.40 (1.34 to 1.45) | <0.01 |
2.1–2.3 | 1.77 (1.71 to 1.84) | <0.01 |
2.4–2.9 | 2.10 (2.02 to 2.18) | <0.01 |
>2.9 | 2.40 (2.30 to 2.50) | <0.01 |
Prescriptions per patient at baseline (ref: <8.7) | ||
8.7–10.7 | 1.44 (1.38 to 1.51) | <0.01 |
10.8–12.8 | 1.96 (1.88 to 2.05) | <0.01 |
12.9–14.9 | 2.31 (2.20 to 2.42) | <0.01 |
≥15 | 2.97 (2.83 to 3.12) | <0.01 |
IRR = incidence rate ratio. PIP = potentially inappropriate prescription. Ref = reference. aPIPs were 14% (1.0 to 0.86) lower in the intervention arm compared to the control at after intervention.