Table 5.
Adjusted hazard ratios for Z-drug prescription and new prescriptions, GP consultations, and hospital admissions for people with dementia according to prescribed daily defined doses (DDDs) of Z-drugs
| Outcome and daily defined dose prescribeda | No. events in the Z-drug cohort | No sedative-hypnotic, sleep disturbance (n = 1833) | No Z-drug, proximal GP consultation (n = 10,214) | ||
|---|---|---|---|---|---|
| Age, sex adjusted | Fully adjustedb | Age, sex adjusted | Fully adjustedb | ||
| Number of hospital admissionsc | |||||
| ≤ 0.5 | 1403 | 1.24 (1.10–1.39) | 1.18 (1.05–1.32) | 1.19 (1.07–1.31) | 1.10 (1.00–1.20) |
| 0.6–0.9 | 63 | 1.06 (0.76–1.49) | 1.22 (0.88–1.69) | 1.03 (0.74–1.43) | 1.10 (0.80–1.51) |
| ≥ 1 | 472 | 1.35 (1.15–1.58) | 1.29 (1.10–1.50)d | 1.32 (1.15–1.52) | 1.22 (1.06–1.39)d |
| Number of GP consultationsc | |||||
| ≤ 0.5 | 9230 | 1.21 (1.14–1.29) | 1.10 (1.05–1.16)d | 0.89 (0.85–0.94) | 1.00 (0.96–1.04) |
| 0.6–0.9 | 690 | 1.12 (0.96–1.32) | 1.10 (0.95–1.26) | 0.83 (0.71–0.97) | 1.02 (0.88–1.17) |
| ≥ 1 | 4823 | 1.23 (1.12–1.34) | 1.16 (1.08–1.25)d | 0.91 (0.84–0.98) | 1.06 (0.99–1.13) |
| Incident antipsychotic prescription | |||||
| ≤ 0.5 | 214 | 2.08 (1.64–2.62) | 2.00 (1.54–2.61)d | 3.09 (2.56–3.74) | 3.31 (2.69–4.07)d |
| 0.6–0.9 | 18 | 3.35 (2.04–5.50) | 2.75 (1.57–4.81)d | 5.15 (3.19–8.32) | 4.82 (2.81–8.25)d |
| ≥ 1 | 99 | 4.05 (3.10–5.31) | 3.56 (2.61–4.85)d | 5.81 (4.55–7.42) | 5.82 (4.44–7.63)d |
| Incident antidepressant prescription | |||||
| ≤ 0.5 | 124 | 1.25 (1.14–1.37) | 1.16 (1.05–1.28)d | 2.47 (1.91–3.19) | 2.39 (1.90–2.99)d |
| 0.6–0.9 | 8 | 1.20 (0.83–1.73) | 1.13 (0.76–1.68) | 2.67 (1.19–5.99) | 3.00 (1.49–6.01) |
| ≥ 1 | 40 | 1.37 (1.17–1.61) | 1.31 (1.11–1.54)d | 3.47 (2.32–5.18) | 2.93 (2.04–4.19)d |
| Incident antibiotic prescription | |||||
| ≤ 0.5 | 583 | 1.43 (1.27–1.63) | 1.30 (1.13–1.49)d | 1.25 (1.14–1.37) | 1.16 (1.05–1.28)d |
| 0.6–0.9 | 27 | 1.36 (0.93–2.00) | 1.20 (0.79–1.81) | 1.20 (0.83–1.73) | 1.13 (0.76–1.68) |
| ≥ 1 | 181 | 1.57 (1.32–1.88) | 1.46 (1.21–1.76)d | 1.37 (1.17–1.61) | 1.31 (1.11–1.54)d |
Abbreviations: HR hazard ratio, CI confidence interval, GP general practitioner
aThe reference group for all comparisons is no Z-drug prescription. Most patients assigned to the ‘0.6–0.9 DDD’ Z-drug group were prescribed 3.75 mg zopiclone with instructions similar to ‘TAKE ONE OR TWO AT NIGHT’
bAdjusted for all covariates listed in Table 1
cEstimates provided are rate ratios (95% confidence intervals)
dFully adjusted HR remaining statistically significant after controlling the false discovery rate to < 5% (based on 37 tests; 11 outcomes with three dose categories and two outcomes with two dose categories)