Effect of Statins on the Risk of Poststroke Pneumonia: National Population-Based Cohort Study

Figures & data

Figure 1 Flowchart of patients included.

Abbreviation: NHIS-NSC, National Health Insurance Service national sample cohort.

Table 1 Baseline Characteristics of Patients with Acute Ischemic Stroke

	n=7,001
Sex, male	3,902 (55.7)
Age, years	65–69 (55–59 to 75–79)
Hypertension	5,083 (72.6)
Diabetes mellitus	1,862 (26.6)
Myocardial infarction	473 (6.8)
Atrial fibrillation	688 (9.8)
Chronic obstructive pulmonary disease	1,383 (19.8)
Thrombolysis	230 (3.3)
Household income
Low	2,314 (33.1)
Middle	2,551 (36.4)
High	2,136 (30.5)
Hospital type at index stroke
General hospital	5,844 (83.5)
Hospital or clinic	1,157 (16.5)
Duration of hospital stay following index stroke
≤16 days	3,690 (52.7)
>16 days	3,311 (47.3)

Note: Data presented as n (%) or medians (IQRs).

Table 2 Comparison of Characteristics Between Patients with Current Use of Statin and Those Without at 1-Year After Acute Ischemic Stroke

	No use of statins (n=4,254)	Current use of statins (n=1,386)	p-value
Sex, male	2323 (54.6)	817 (58.9)	0.005
Age, years	65–69 (55–59 to 75–79)	65–69 (55–59 to 70–74)	<0.001
Hypertension	2,965 (69.7)	1,046 (75.5)	<0.001
Diabetes mellitus	982 (23.1)	435 (31.4)	<0.001
Myocardial infarction	268 (6.3)	94 (6.8)	0.567
Atrial fibrillation	369 (8.7)	129 (9.3)	0.505
Chronic obstructive pulmonary disease	784 (18.4)	236 (17.0)	0.255
Thrombolysis	114 (2.7)	61 (4.4)	0.002
Household income			0.152
Low	1,409 (33.1)	421 (30.4)
Middle	1,540 (36.2)	515 (37.2)
High	1,305 (30.7)	450 (32.5)
Hospital type at index stroke			<0.001
General hospital	3,468 (81.5)	1,264 (91.2)
Hospital or clinic	786 (18.5)	122 (8.8)
Duration of hospital stay following index stroke			<0.001
≤16 days	2,389 (56.2)	624 (45.0)
>16 days	1,865 (43.8)	762 (55.0)

Note: Data presented as n (%) or medians (IQRs).

Figure 2 Proportion of patients with current of statin use throughout the poststroke period. The proportion was calculated by dividing the number of patients with current statin use by the number of patients still at risk of pneumonia at each time point.

Table 3 Effects of Treatment with Statins on Risk of Poststroke Pneumonia

	Unadjusted HR (95% CI)	Adjusted HR (95% CI)
Sex, male	0.95 (0.86–1.04)	1.18 (1.07–1.31)
Age, per 5-year interval	1.22 (1.19–1.24)	1.21 (1.18–1.23)
Hypertension	1.41 (1.26–1.58)	1.12 (1.00–1.25)
Diabetes mellitus	1.28 (1.15–1.42)	1.23 (1.11–1.37)
Myocardial infarction	1.17 (0.97–1.41)	1.09 (0.91–1.32)
Atrial fibrillation	1.40 (1.20–1.63)	1.17 (1.00–1.37)
Chronic obstructive pulmonary disease	1.63 (1.45–1.82)	1.29 (1.15–1.45)
Thrombolysis	1.02 (0.76–1.37)	1.10 (0.81–1.48)
Household income
Low	1 (ref)	1 (ref)
Middle	0.95 (0.84–1.06)	0.96 (0.86–1.08)
High	1.09 (0.97–1.22)	0.95 (0.84–1.07)
Hospital type at index stroke
General hospital	1 (ref)	1 (ref)
Hospital or clinic	1.41 (1.25–1.59)	1.20 (1.06–1.35)
Duration of hospital stay following index stroke
≤16 days	1 (ref)	1 (ref)
>16 days	0.95 (0.87–1.05)	0.92 (0.84–1.01)
Time-dependent variables
No use of statins	1 (ref)	1 (ref)
Current use of statins	0.81 (0.73–0.91)	0.86 (0.77–0.97)

Note: Data derived from Cox proportional hazard–regression model for the development of poststroke pneumonia.

Figure 3 Estimated pneumonia-free probability according to treatment with statins (A) and according to intensity of statins (B) during follow-up. HRs for pneumonia and 95% CIs were derived from the univariate time-dependent Cox proportional hazard–regression model.

Table 4 Risk of Poststroke Pneumonia According to Statin Intensity

Statin therapy	Adjusted HR (95% CI)	p-value	p-value for trend
No use of statins	1 (ref)	—	0.004
Current use of low- to intermediate-intensity statins	0.88 (0.78–0.99)	0.038
Current use of high-intensity statins	0.49 (0.27–0.87)	0.015

Note: Data derived from multivariate time-dependent Cox proportional hazard–regression model adjusted for the variables listed in Table 3.