Table 2.
Effect of total number of psychoactive medicines taken on fall risk
| Cohort | Script category | Number of falls | Person-years | Rate per 10 years (95 % CI) | IRR (95 % CI) | P value |
|---|---|---|---|---|---|---|
| Whole cohort | ||||||
| Unadjusted | 0 | 518 | 20,448 | 0.25 (0.23–0.28) | 1.00 (1.00–1.00) | – |
| 1 | 527 | 16,945 | 0.31 (0.29–0.34) | 1.23 (1.09–1.39) | 0.001 | |
| 2 | 246 | 5,231 | 0.47 (0.41–0.53) | 1.85 (1.59–2.16) | <0.001 | |
| 3–4 | 108 | 1,946 | 0.55 (0.46–0.67) | 2.18 (1.78–2.69) | <0.001 | |
| ≥5 | 16 | 189 | 0.84 (0.51–1.37) | 3.32 (2.02–5.47) | <0.001 | |
| Adjusteda | 0 | 518 | 20,448 | 0.17 (0.13–0.23) | 1.00 (1.00–1.00) | – |
| 1 | 527 | 16,945 | 0.21 (0.16–0.28) | 1.22 (1.08–1.38) | 0.002 | |
| 2 | 246 | 5,231 | 0.29 (0.22–0.40) | 1.70 (1.45–1.99) | <0.001 | |
| 3–4 | 108 | 1,946 | 0.34 (0.24–0.48) | 1.96 (1.58–2.43) | <0.001 | |
| ≥5 | 16 | 189 | 0.55 (0.31–0.96) | 3.15 (1.90–5.23) | <0.001 | |
| Cohort after exclusion of patients with anti-Parkinson medicines in the previous year | ||||||
| Unadjusted | 0 | 514 | 20,258 | 0.25 (0.23–0.28) | 1.00 (1.00–1.00) | – |
| 1 | 500 | 16,424 | 0.30 (0.28–0.33) | 1.20 (1.06–1.36) | 0.004 | |
| 2 | 219 | 4,849 | 0.45 (0.39–0.51) | 1.78 (1.52–2.08) | <0.001 | |
| 3–4 | 90 | 1,673 | 0.54 (0.44–0.66) | 2.11 (1.69–2.65) | <0.001 | |
| ≥5 | 9 | 147 | 0.61 (0.32–1.17) | 2.41 (1.24–4.66) | 0.009 | |
| Adjusteda | 0 | 514 | 20,258 | 0.17 (0.13–0.23) | 1.00 (1.00–1.00) | – |
| 1 | 500 | 16,424 | 0.21 (0.15–0.28) | 1.19 (1.05–1.35) | 0.006 | |
| 2 | 219 | 4,849 | 0.29 (0.21–0.39) | 1.63 (1.39–1.93) | <0.001 | |
| 3–4 | 90 | 1,673 | 0.33 (0.23–0.47) | 1.89 (1.50–2.39) | <0.001 | |
| ≥5 | 9 | 147 | 0.40 (0.20–0.82) | 2.30 (1.18–4.47) | 0.01 | |
CI confidence interval, IRR incidence rate ratio
aAdjusted for age, sex, socioeconomic index for area, time-varying co-morbidities, and numbers of medicines, prescribers, specialist visits and prior hospitalizations