Table 3. Crude mortality incidence rate ratio among the vascular dementia and non-vascular dementia groups.

Variables	Vascular dementia (n = 2,142)		Degenerative dementia (n = 10,051)
	No medication	Nootropics	No medication	Nootropics	Anti-dementia medication	Both medications
	(n = 750, 35.0%))	(n = 1,392, 65.0%)	(n = 4,130, 41.1%)	(n = 4,850, 48.3%)	(n = 240, 2.4%)	(n = 831, 8.3%)
Age (mean ± SD)	78.8 ± 6.8	77.9 ± 6.7	80.5 ± 7.4	78.8 ± 6.9	78.4 ± 6.3	76.7 ± 6.2
Charlson comorbidity index (CCI)	2.29 ± 2.49	2.52 ± 2.58	1.77 .77.58	1.93 .93.58	1.38 ±.38 5	1.60 ±.60 5
CCI except dementia	2.01 ± 2.34	2.20 ± 2.42	1.62 .62424	1.76 .76424	1.14 ±.1495	1.30 ±.30 5
Prescription cumulative days (IQR)
Nootropics	0	210 (63–577)	0	140 (44–420)	0.00	175 (58–511)
Anti-dementia medication	0	0	0	0	308 (90–739)	336 (126–805)
Median follow-up, years (IQR)	2.04 (0.86–3.80)	3.66 (1.91–6.03)	1.79 (0.68–3.62)	3.25 (1.57–5.41)	3.04 (1.50–5.11)	4.13 (2.35–6.37)
Person-years at risk	2,009	5,746	10,333	18,118	853	3729
Death	415	593	2,321	2,077	64	218
Mortality incidence (/1000 py)	207	103	225	115	75	58
Crude IRR (ref: non-dementia) (95% CI)	2.82 (2.54–3.12)	1.41 (1.29–1.54)	3.07 (2.91–3.23)	1.56 (1.48–1.65)	1.02 (0.79–1.31)	0.80 (0.69–0.91)

SD: standard deviation; IQR: interquartile range; py: person-year; IRR: incidence rate ratio; CI: confidence interval