Table 3 Adjusted hazard ratios for Z-drug prescription and adverse events for people with dementia according to prescribed daily defined dose of Z-drugs

 ≤ 0.5

117

1.30 (0.99–1.70)

1.22 (0.90–1.66)

1.33 (1.07–1.65)

1.28 (1.01–1.63)

 0.6–0.9

5

1.28 (0.51–3.20)

1.06 (0.39–2.89)

1.24 (0.50–3.05)

1.08 (0.42–2.76)

 ≥ 1

42

1.70 (1.19–2.42)

1.67 (1.13–2.46)^c

1.66 (1.18–2.34)

1.58 (1.09–2.28)^c

 ≤ 0.5

55

1.30 (0.88–1.93)

1.21 (0.78–1.90)

1.42 (1.03–1.97)

1.43 (1.00–2.06)

 0.6–0.9

< 5

1.10 (0.26–4.67)

0.79 (0.15–4.11)

1.27 (0.31–5.22)

1.05 (0.24–4.64)

 ≥ 1

27

2.30 (1.45–3.65)

1.96 (1.16–3.31)^c

2.50 (1.61–3.89)

2.36 (1.44–3.87)^c

 ≤ 0.5

20

1.66 (0.81–3.40)

1.22 (0.48–3.12)

1.28 (0.77–2.15)

1.29 (0.73–2.27)

 ≥ 0.6

9

2.18 (0.98–4.85)

1.91 (0.67–5.47)

1.53 (0.72–3.24)

1.42 (0.59–3.38)

 ≤ 0.5

335

1.05 (0.90–1.22)

0.95 (0.80–1.13)

1.43 (1.26–1.63)

1.35 (1.17–1.56)^c

 0.6–0.9

14

0.84 (0.49–1.44)

0.73 (0.41–1.29)

1.19 (0.70–2.02)

1.07 (0.61–1.87)

 ≥ 1

124

1.42 (1.15–1.74)

1.33 (1.06–1.66)^c

1.92 (1.58–2.35)

1.81 (1.46–2.34)^c

 ≤ 0.5

321

1.49 (1.26–1.77)

1.38 (1.14–1.68)^c

1.18 (1.03–1.34)

1.07 (0.93–1.24)

 0.6–0.9

16

1.56 (0.95–2.56)

1.60 (0.96–2.70)

1.25 (0.77–2.02)

1.22 (0.75–1.99)

 ≥ 1

99

1.56 (1.24–1.96)

1.33 (1.03–1.71)

1.26 (1.02–1.55)

1.06 (0.85–1.33)

 ≤ 0.5

297

1.15 (0.98–1.36)

1.00 (0.83–1.20)

1.37 (1.20–1.57)

1.23 (1.06–1.43)^c

 0.6–0.9

13

0.98 (0.56–1.72)

0.86 (0.47–1.57)

1.20 (0.69–2.08)

1.12 (0.63–1.99)

 ≥ 1

106

1.40 (1.12–1.76)

1.25 (0.98–1.60)

1.64 (1.32–2.04)

1.52 (1.21–1.91)^c

 ≤ 0.5

55

1.04 (0.72–1.51)

1.12 (0.71–1.75)

0.96 (0.71–1.30)

0.95 (0.68–1.31)

 0.6–0.9

5

1.97 (0.78–4.96)

1.98 (0.74–5.28)

1.74 (0.72–4.19)

1.71 (0.74–3.98)

 ≥ 1

33

2.07 (1.36–3.15)

1.88 (1.14–3.10)^c

1.90 (1.30–2.79)

1.61 (1.08–2.42)

 ≤ 0.5

26

2.01 (1.16–3.49)

2.00 (0.90–4.47)

1.35 (0.85–2.13)

1.26 (0.74–2.12)

 ≥ 0.6

< 5

0.78 (0.27–2.25)

0.85 (0.21–3.39)

0.56 (0.21–1.54)

0.66 (0.22–1.95)