Table 2 Sequence symmetry results of the 1000 simulations for different scenarios of medicine utilisation trends and different effect sizes, for a population size of 1 million and 5% incidence of use of each drug in the population
Crude sequence ratio | Adjusted sequence ratio | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Medicine utilisation scenario | Pairs (N) | Null SR | Crude SR (95% CI) | Cover-age (%) | Power* (%) | Relative bias (%) | Adjusted SR (95% CI) | Cover-age (%) | Power* (%) | Relative bias (%) |
Expected ASR = 1.0 | ||||||||||
No trend | 225 | 1.00 | 1.01 (0.75-1.30) | 94.3 | 1.8 | 2.42 | 1.01 (0.75-1.30) | 94.5 | 1.6 | 2.42 |
Gradual | 41 | 0.85 | 0.90 (0.31-1.60) | 86.8 | 0.0 | −4.33 | 1.06 (0.37-1.88) | 94.5 | 0.1 | 12.18 |
Constant | 100 | 0.84 | 0.85 (0.52-1.23) | 81.1 | 0.1 | −12.58 | 1.01 (0.61-1.46) | 94.7 | 0.2 | 3.73 |
Rapid | 113 | 0.88 | 0.90 (0.57-1.27) | 87.3 | 0.0 | −7.75 | 1.03 (0.65-1.45) | 95.2 | 1.3 | 4.97 |
Expected ASR = 1.2 | ||||||||||
No trend | 247 | 1.00 | 1.21 (0.91-1.55) | 95.9 | 20.7 | 2.84 | 1.21 (0.91-1.55) | 95.7 | 20.8 | 2.84 |
Gradual | 44 | 0.85 | 1.08 (0.40-1.91) | 90.6 | 0.0 | −3.73 | 1.27 (0.47-2.24) | 96.9 | 0.5 | 12.90 |
Constant | 110 | 0.84 | 1.04 (0.65-1.47) | 81.5 | 1.3 | −11.45 | 1.23 (0.77-1.75) | 94.9 | 7.9 | 5.05 |
Rapid | 124 | 0.88 | 1.07 (0.70-1.49) | 87.4 | 1.4 | −8.70 | 1.22 (0.79-1.70) | 95.8 | 7.8 | 3.90 |
Expected ASR = 1.5 | ||||||||||
No trend | 280 | 1.00 | 1.51 (1.15-1.92) | 95.6 | 85.5 | 2.54 | 1.51 (1.15-1.92) | 95.4 | 85.8 | 2.52 |
Gradual | 50 | 0.85 | 1.36 (0.56-2.33) | 86.7 | 0.6 | −3.58 | 1.59 (0.66-2.74) | 95.6 | 5.6 | 13.10 |
Constant | 124 | 0.84 | 1.29 (0.84-1.82) | 81.1 | 13.3 | −11.39 | 1.54 (1.00-2.16) | 96.2 | 45.4 | 5.12 |
Rapid | 139 | 0.88 | 1.35 (0.90-1.87) | 86.9 | 24.6 | −7.53 | 1.54 (1.03-2.13) | 95.9 | 52.3 | 5.20 |
Expected ASR = 2.0 | ||||||||||
No trend | 337 | 1.00 | 2.03 (1.57-2.55) | 96.1 | 100.0 | 2.91 | 2.03 (1.57-2.55) | 96.2 | 100.0 | 2.89 |
Gradual | 60 | 0.85 | 1.79 (0.81-3.01) | 87.7 | 17.7 | −4.59 | 2.10 (0.95-3.53) | 95.6 | 40.6 | 11.87 |
Constant | 146 | 0.84 | 1.72 (1.15-2.39) | 80.6 | 76.1 | −11.44 | 2.04 (1.37-2.84) | 96.1 | 97.0 | 5.08 |
Rapid | 166 | 0.88 | 1.79 (1.23-2.45) | 87.5 | 90.7 | −7.96 | 2.04 (1.40-2.79) | 97.0 | 98.7 | 4.71 |
Expected ASR = 3.0 | ||||||||||
No trend | 450 | 1.00 | 3.03 (2.40-3.77) | 96.4 | 100.0 | 2.84 | 3.03 (2.40-3.77) | 96.2 | 100.0 | 2.85 |
Gradual | 78 | 0.85 | 2.67 (1.30-4.47) | 87.8 | 90.8 | −3.94 | 3.14 (1.52-5.24) | 96.3 | 97.9 | 12.66 |
Constant | 192 | 0.84 | 2.59 (1.79-3.55) | 80.5 | 100.0 | −11.16 | 3.07 (2.12-4.21) | 97.5 | 100.0 | 5.39 |
Rapid | 219 | 0.88 | 2.67 (1.90-3.59) | 83.4 | 100.0 | −8.50 | 3.03 (2.16-4.09) | 96.0 | 100.0 | 4.12 |
Expected ASR = 0.6 | ||||||||||
No trend | 300 | 1.00 | 0.61 (0.46-0.76) | 95.6 | 99.0 | 1.66 | 0.61 (0.46-0.76) | 95.6 | 99.0 | 1.68 |
Gradual | 56 | 0.85 | 0.53 (0.23-0.85) | 86.8 | 77.9 | −9.71 | 0.62 (0.27-1.00) | 95.2 | 57.0 | 5.92 |
Constant | 136 | 0.84 | 0.51 (0.33-0.70) | 79.2 | 98.2 | −14.48 | 0.61 (0.39-0.83) | 94.9 | 90.0 | 1.46 |
Rapid | 154 | 0.88 | 0.53 (0.35-0.71) | 83.7 | 98.6 | −11.09 | 0.60 (0.40-0.81) | 94.5 | 91.1 | 1.14 |
Expected ASR = 0.8 | ||||||||||
No trend | 254 | 1.00 | 0.81 (0.61-1.03) | 95.4 | 44.5 | 2.09 | 0.81 (0.61-1.03) | 95.7 | 44.5 | 2.10 |
Gradual | 46 | 0.85 | 0.72 (0.28-1.21) | 89.1 | 32.7 | −6.68 | 0.84 (0.33-1.42) | 95.9 | 16.6 | 9.43 |
Constant | 114 | 0.84 | 0.69 (0.43-0.97) | 79.5 | 60.4 | −13.09 | 0.82 (0.50-1.15) | 95.0 | 29.1 | 3.14 |
Rapid | 129 | 0.88 | 0.71 (0.46-0.98) | 83.2 | 55.8 | −9.95 | 0.81 (0.52-1.12) | 94.1 | 30.9 | 2.47 |