Skip to main content

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

From: Adverse effects of Z-drugs for sleep disturbance in people living with dementia: a population-based cohort study

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
  1. Abbreviations: HR hazard ratio, CI confidence interval, GP general practitioner
  2. 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’
  3. bAdjusted for all covariates listed in Table 1
  4. cEstimates provided are rate ratios (95% confidence intervals)
  5. 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)