Table 3.
Risk of falls and fractures in different study periods
| No of events | Follow-up time | Incidence rate (95% CI)/100 person years | Crude incidence rate ratio (95% CI) compared with non-treatment | Adjusted incidence rate ratio (95% CI) | |||
|---|---|---|---|---|---|---|---|
| Total person years | Median (interquartile range) years | Compared with non-treatment | Compared with pretreatment* | ||||
| All events (n=15 278): | |||||||
| Non-treatment | 10 208 | 122 963.00 | 8.55 (4.01) | 8.30 (8.14 to 8.46) | Reference | Reference | 0.16 (0.15 to 0.18) |
| Pretreatment | 657 | 1254.90 | 0.07 (0.03) | 52.35 (48.46 to 56.47) | 6.31 (5.83 to 6.82) | 6.17 (5.69 to 6.69) | Reference |
| Cholinesterase inhibitor alone | 1790 | 19 018.33 | 0.96 (1.92) | 9.41 (8.98 to 9.86) | 1.13 (1.08 to 1.19) | 1.17 (1.10 to 1.24) | 0.19 (0.17 to 0.21) |
| Antipsychotic drug alone | 1353 | 13 087.45 | 0.35 (1.21) | 10.34 (9.80 to 10.89) | 1.25 (1.18 to 1.32) | 1.33 (1.24 to 1.43) | 0.22 (0.20 to 0.24) |
| Combination | 1270 | 12 037.35 | 0.56 (1.31) | 10.55 (9.98 to 11.14) | 1.27 (1.20 to 1.35) | 1.35 (1.26 to 1.45) | 0.22 (0.20 to 0.24) |
| Falls (n=766): | |||||||
| Non-treatment | 341 | 6750.84 | 9.28 (3.32) | 5.05 (4.54 to 5.61) | Reference | Reference | 0.10 (0.07 to 0.12) |
| Pretreatment | 84 | 62.84 | 0.07 (0.03) | 134.70 (107.30 to 164.70) | 26.46 (20.84 to 33.60) | 10.39 (8.08 to 13.37) | Reference |
| Cholinesterase inhibitor alone | 120 | 968.87 | 1.01 (2.11) | 12.39 (10.31 to 14.76) | 2.45 (1.99 to 3.02) | 0.91 (0.71 to 1.18) | 0.09 (0.06 to 0.12) |
| Antipsychotic drug alone | 107 | 554.99 | 0.28 (0.93) | 19.28 (15.88 to 23.20) | 3.82 (3.07 to 4.74) | 1.36 (1.02 to 1.82) | 0.13 (0.09 to 0.18) |
| Combination | 114 | 518.55 | 0.49 (1.16) | 21.98 (18.22 to 26.31) | 4.35 (3.52 to 5.38) | 1.55 (1.17 to 2.05) | 0.15 (0.11 to 0.21) |
| Fractures (n=14 874): | |||||||
| Non-treatment | 9998 | 119 543.18 | 8.53 (4.02) | 8.36 (8.20 to 8.53) | Reference | Reference | 0.16 (0.15 to 0.18) |
| Pretreatment | 627 | 1222.01 | 0.07 (0.03) | 51.31 (47.41 to 55.45) | 6.13 (5.66 to 6.65) | 6.11 (5.62 to 6.63) | Reference |
| Cholinesterase inhibitor alone | 1735 | 18 491.49 | 0.96 (1.91) | 9.16 (8.74 to 9.60) | 1.12 (1.07 to 1.18) | 1.18 (1.11 to 1.26) | 0.19 (0.18 to 0.21) |
| Antipsychotic drug alone | 1299 | 12 764.29 | 0.35 (1.21) | 10.18 (9.64 to 10.74) | 1.22 (1.15 to 1.29) | 1.34 (1.24 to 1.43) | 0.22 (0.20 to 0.24) |
| Combination | 1215 | 11 759.94 | 0.56 (1.31) | 10.33 (9.76 to 10.93) | 1.24 (1.16 to 1.31) | 1.35 (1.25 to 1.45) | 0.22 (0.20 to 0.24) |
| Events in hospital (n=7364): | |||||||
| Non-treatment | 4382 | 58 310.22 | 8.44 (4.15) | 7.51 (7.30 to 7.74) | Reference | Reference | 0.10 (0.09 to 0.11) |
| Pretreatment | 516 | 608.77 | 0.07 (0.04) | 84.76 (77.68 to 92.32) | 11.28 (10.30 to 12.36) | 10.20 (9.28 to 11.21) | Reference |
| Cholinesterase inhibitor alone | 909 | 9005.44 | 0.94 (1.85) | 10.09 (9.45 to 10.77) | 1.34 (1.25 to 1.44) | 1.27 (1.17 to 1.39) | 0.12 (0.11 to 0.14) |
| Antipsychotic drug alone | 782 | 6584.79 | 0.36 (1.26) | 11.88 (11.07 to 12.73) | 1.58 (1.46 to 1.71) | 1.55 (1.41 to 1.71) | 0.15 (0.13 to 0.17) |
| Combination | 775 | 5905.85 | 0.57 (1.34) | 13.12 (12.22 to 14.07) | 1.75 (1.62 to 1.88) | 1.73 (1.57 to 1.90) | 0.17 (0.15 to 0.19) |
Combination=combination of cholinesterase inhibitors and antipsychotic drugs.
*
Pretreatment period was considered as reference group and the analysis repeated.