Association between Korean Medicine Hospital Utilization and Cardiovascular Risks in Patients with Hypertension: a National Korean Cohort Study

Hyunjoo Cho; Hyejin Jung; Sabina Lim; Cho, Hyunjoo; Jung, Hyejin; Lim, Sabina

doi:10.13048/jkm.19024

JKM > Volume 40(3); 2019 > Article

Cho, Jung, and Lim: Association between Korean Medicine Hospital Utilization and Cardiovascular Risks in Patients with Hypertension: a National Korean Cohort Study

Original Article

The Journal of Korean Medicine 2019; 40(3): 1-20.

Published online: September 30, 2019

DOI: https://doi.org/10.13048/jkm.19024

Association between Korean Medicine Hospital Utilization and Cardiovascular Risks in Patients with Hypertension: a National Korean Cohort Study

Hyunjoo Cho¹

, Hyejin Jung²

, Sabina Lim¹^{, 2}^{, *}

¹Department of Health Science, Graduate School of Applied Korean Medicine, Kyung Hee University

²Department of Meridian and Acupoint, Graduate School of Science in Korean Medicine, Kyung Hee University

Correspondence to: (Sabina Lim), Graduate School of Applied Korean Medicine, and Graduate School of Science in Korean Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea, Tel: +82-2-961-0324, Fax: 0504-072-7831, E-mail: lims@khu.ac.kr

Received June 3, 2019 Revised July 25, 2019 Accepted July 26, 2019

Abstract

Objectives

This study aims to investigate the effects of Korean Medicine Hospital Utilization (KMHU) on major adverse cardiovascular events (MACE), myocardial infarction (MI), stroke, and death in hypertensive patients taking antihypertensives.

Methods

Using the Korean National Health Insurance Service-National Sample Cohort database, this study identified and diagnosed 68,457 hypertensive patients taking antihypertensives between 2003 and 2006. They were divided into KMHU and non-KMHU groups. The follow-up period ended with the diagnosis of myocardial infarction, stroke, or death. After propensity score matching (PSM), there were 18,242 patients each in the non-KMHU and KMHU groups. We calculated the incidence rate, hazard ratio (HR), and 95% confidence interval (CI) for MACE, myocardial infarction, stroke, and death in patients with hypertension using a stratified Cox proportional hazard model. In addition, secondary outcome analyses for stroke and cardiovascular mortality were performed.

Results

After PSM, the HRs for MACE (HR: 0.84, 95% CI: 0.81–0.87), all-cause mortality (HR: 0.75, 95% CI: 0.72–0.79), and myocardial infarction (HR: 0.90, 95% CI: 0.83–0.97) were significantly lower in the KMHU group than in the non-KMHU group. Moreover, the HRs for stroke-related mortality, haemorrhage and ischaemic stroke-related mortality, and ischaemic heart disease-related and circulatory system disease-related mortality were significantly lower in the KMHU group than in the non-KMHU group.

Conclusions

On long-term follow-up observation, this study supported the effect of KMHU for managing hypertension and reducing the burden of cardiovascular diseases.

Keywords: hypertension, Korean medicine hospital utilization, myocardial infarction, stroke, Death, National Health Insurance Service database

Fig. 1

Flowchart of sample selection process. From 1 million sampled data, patients who were newly diagnosed with hypertension, between 2003 and 2006, were included in this study. Except for subjects that did not meet the criteria, the korean medicine hospital utilization group and the non-korean medicine hospital utilization group group matched with propensity score at a 1:1 ratio.

Fig. 2

Kaplan-Meier Curves on MACE, all-cause mortality, myocardial infarction, and stroke in Korean medicine hospital utilization group and non-Korean medicine hospital utilization group before PSM, after PSM and after stabilized IPTW. MACE indicates Major Adverse Cardiovascular Events; PSM, Propensity Score Matching; and s IPTW, Stabilized Inverse Probability of Treatment Weighting.

Fig. 3

Kaplan-Meier curves on cerebro-cardio vascular mortality in Korean medicine hospital utilization group and non-Korean medicine hospital utilization group before PSM, after PSM and after stabilized IPTW. CSD indicates Circulatory System Disease ; IHD, Ischemic Heart Disease; PSM, Propensity Score Matching; and s IPTW, stabilized Inverse Probability of Treatment Weighting.

Table 1

Baseline characteristics of subjects

	Before PSM			After PSM			After stabilized IPTW

Demographics	non-korean medicine hospital utilization	korean medicine hospital utilization	absolute standardized difference	non-korean medicine hospital utilization	korean medicine hospital utilization	absolute standardized difference	non-korean medicine hospital utilization	korean medicine hospital utilization	absolute standardized difference
N	40798	18328		18242	18242		40832	18311

Age (y)	57.5±10.3	59.2±10.2	0.1729	59.1±10.2	59.2±10.2	0.0116	58.0±10.4	58.0±10.2	0.0055
40–49	11007 (27.0)	3842 (21.0)	0.1413	3927 (21.5)	3838 (21.0)	0.0119	10321 (25.3)	4637 (25.3)	0.0011
50–59	11914 (29.2)	5223 (28.5)	0.0156	5173 (28.4)	5207 (28.5)	0.0041	11653 (28.5)	5454 (29.8)	0.0274
60–69	11755 (28.8)	5816 (31.7)	0.0636	5753 (31.5)	5786 (31.7)	0.0039	12114 (29.7)	5386 (29.4)	0.0056
70–79	6122 (15.0)	3447 (18.8)	0.1016	3389 (18.6)	3411 (18.7)	0.0031	6744 (16.5)	2835 (15.5)	0.0282

Female sex	18829 (46.2)	11754 (64.1)	0.3676	11631 (63.8)	11674 (64.0)	0.0049	21099 (51.7)	9426 (51.5)	0.0039

Male sex	21969 (53.8)	6574 (35.9)	0.3676	6611 (36.2)	6568 (36.0)	0.0049	19733 (48.3)	8885 (48.5)	0.0039

Household income
Low	11696 (28.7)	4981 (27.2)	0.0332	4899 (26.9)	4967 (27.2)	0.0084	11501 (28.2)	5139 (28.1)	0.0023
Middle	13857 (34.0)	6181 (33.7)	0.0051	6199 (34.0)	6160 (33.8)	0.0045	13857 (33.9)	6234 (34.0)	0.0023
High	15245 (37.4)	7166 (39.1)	0.0356	7144 (39.2)	7115 (39.0)	0.0033	15475 (37.9)	6938 (37.9)	0.0002

Residence Urban	34021 (83.4)	15300 (83.5)	0.0024	15283 (83.8)	15230 (83.5)	0.0079	34065 (83.4)	15284(83.5)	0.0010

Residence Rural	6777 (16.6)	3028 (16.5)	0.0024	2959 (16.2)	3012 (16.5)	0.0079	6767 (16.6)	3028 (16.5)	0.0010

CCI	2.5±1.9	3.1±2.1	0.3074	3.0±2.1	3.0±2.1	0.0007	2.7±2.1	2.7±1.9	0.0008
0	5494 (13.5)	1454 (7.9)	0.1797	14362 (8.0)	1454 (8.2)	0.0016	4936 (12.1)	2016 (11.0)	0.0337
1	8383 (20.5)	2805 (15.3)	0.1370	2820 (15.5)	2805 (15.4)	0.0023	7787(19.1)	3404 (18.6)	0.0123
2	9456 (23.2)	3779 (20.6)	0.0619	3813 (20.9)	3779 (20.7)	0.0046	9103 (22.3)	4125 (22.5)	0.0056
3	7768 (19.0)	3747 (20.4)	0.0353	3772 (20.7)	3747 (20.5)	0.0034	7864 (19.3)	3652 (19.9)	0.0172
4	4600 (11.3)	2692 (14.7)	0.1017	2690 (14.7)	2692 (14.8)	0.0003	4898 (12.0)	2332 (12.7)	0.0224
5	2455 (6.0)	1694 (9.2)	0.1217	1654 (9.1)	1689 (9.3)	0.0067	2767 (6.8)	1331 (7.3)	0.0192
6	1279 (3.1)	1009 (5.5)	0.1168	928 (5.1)	980 (5.4)	0.0128	1531 (3.7)	735 (4.0)	0.0137
7	616 (1.5)	530 (2.9)	0.0943	459 (2.5)	499 (2.7)	0.0137	794 (1.9)	357 (1.9)	0.0004
8	341 (0.8)	298 (1.6)	0.0717	260 (1.4)	293 (1.6)	0.0148	469 (1.1)	185 (1.0)	0.0134
9	186 (0.5)	157 (0.9)	0.0496	168 (0.9)	156 (0.9)	0.0070	286 (0.7)	91 (0.5)	0.0264
≥10	220 (0.5)	160 (0.9)	0.0416	216 (1.2)	148 (0.8)	0.0375	397 (1.0)	83 (0.5)	0.0617

IPTW indicates Inverse Probability of Treatment Weighting; and PSM, Propensity Score Matching.

* Data are expressed as the mean ± standard deviation, or number (%).

Table 2

Incidence rate of MACE, all-cause mortality, myocardial infarction, and stroke by acupuncture

	Before PSM			After PSM			After stabilized IPTW

	Events (n)	Follow-up duration (person years)	Incidence rate (per 1000 person years)	Events (n)	Follow-up duration (person years)	Incidence rate (per 1000 person years)	Events (n)	Follow-up duration (person years)	Incidence rate (per 1000 person years)
MACE
non-korean medicine hospital utilization	8921	408,268	21.85	4225	181,387	23.29	9153	407,385	22.47
korean medicine hospital utilization	3542	180,099	19.67	3521	179,301	19.64	3401	180,666	18.83

All-cause mortality
non-korean medicine hospital utilization	6145	426,213	14.42	2938	189,896	15.47	6372	425,551	14.97
korean medicine hospital utilization	2209	188,369	11.73	2197	187,527	11.72	2104	188,577	11.16

Myocardial infarction
non-korean medicine hospital utilization	1561	419,244	3.72	744	186,559	3.99	1585	418,522	3.79
korean medicine hospital utilization	695	185,274	3.75	690	184,450	3.74	671	185,580	3.62

Stroke
non-korean medicine hospital utilization	3098	414,448	7.48	1457	184,355	7.90	3159	413,605	7.64
korean medicine hospital utilization	1402	182,871	7.67	1395	182,055	7.66	1328	183,364	7.24

IPTW indicates Inverse Probability of Treatment Weighting; MACE, Major Adverse Cardiovascular Events; and PSM, Propensity Score Matching.

Table 3

Hazard ratios of MACE, all-cause mortality, myocardial infarction and stroke treated with acupuncture

	Crude analysis		Multivariable analysis		PSM		stabilized IPTW

	HR (95% CI)	P-value	HR* (95% CI)	P-value	HR† (95% CI)	P-value	HR‡ (95% CI)	P-value
MACE	0.91 (0.87–0.94)	<.0001	0.84 (0.81–0.88)	<.0001	0.84 (0.81–0.87)	<.0001	0.84 (0.81–0.88)	<.0001
All-cause mortality	0.82 (0.78–0.86)	<.0001	0.75 (0.71–0.78)	<.0001	0.75 (0.72–0.79)	<.0001	0.75 (0.72–0.79)	<.0001
Myocardial infarction	1.00 (0.92–1.10)	0.9676	0.96 (0.87–1.05)	0.3380	0.90 (0.83–0.97)	0.0076	0.95 (0.87–1.05)	0.3180
Stroke	1.03 (0.97–1.10)	0.3766	0.96 (0.90–1.02)	0.1825	0.98 (0.92–1.03)	0.3860	0.95 (0.89–1.02)	0.1471

CI indicates Confidence Interval; HR, Hazard Ratio; IPTW, Stabilized Inverse Probability of Treatment Weighting; MACE, Major Adverse Cardiovascular Events; and PSM, Propensity Score Matching.

* Adjusted for variables listed in the table 1.

† Cox proportional hazards model stratifying on matched pairs.

‡ Weighted Cox proportional hazards model with robust standard errors.

Table 4

Incidence rate of cerebro-cardiovascular mortality by acupuncture

	Before PSM			After PSM			stabilized IPTW

	Events (n)	Follow-up duration (person years)	Incidence rate (per1000 person years)	Events (n)	Follow-up duration (person years)	Incidence rate (per 1000 person years)	Events (n)	Follow-up duration (person years)	Incidence rate (per 1000 person years)
Stroke-related mortality
non-korean medicine hospital utilization	670	426,213	1.57	333	189,896	1.75	704	425,551	1.65
korean medicine hospital utilization	263	188,369	1.40	263	187,527	1.40	241	188,577	1.28

Hemorrhage stroke-related mortality
non-korean medicine hospital utilization	163	426,213	0.38	90	189,896	0.47	170	425,551	0.40
korean medicine hospital utilization	59	188,369	0.31	59	187,527	0.31	52	188,577	0.28

Ischemic stroke-related mortality
non-korean medicine hospital utilization	193	426,213	0.45	93	189,896	0.49	204	425,551	0.48
korean medicine hospital utilization	78	188,369	0.41	78	187,527	0.42	72	188,577	0.38

IHD-related mortality
non-korean medicine hospital utilization	366	426,213	0.86	167	189,896	0.88	379	425,551	0.89
korean medicine hospital utilization	139	188,369	0.74	139	187,527	0.74	135	188,577	0.72

CSD-related mortality
non-korean medicine hospital utilization	1465	426,213	3.44	730	189,896	3.84	1541	425,551	3.62
korean medicine hospital utilization	580	188,369	3.08	578	187,527	3.08	539	188,577	2.86

CSD indicates Circulatory System Disease ; IHD, Ischemic Heart Disease; IPTW, Inverse Probability of Treatment Weighting; and PSM, Propensity Score Match

Table 5

Hazard ratios of cerebro-cardiovascular mortality by acupuncture

	Crude analysis		Multivariable analysis		PSM		stabilized IPTW
	HR (95% CI)	P-value	HR* (95% CI)	P-value	HR†(95% CI)	P-value	HR‡(95% CI)	P-value
Stroke-related mortality	0.90 (0.78–1.04)	0.1400	0.78 (0.67–0.90)	0.0009	0.80 (0.71–0.91)	0.0008	0.78 (0.67–0.90)	0.0010
Hemorrhage stroke-related mortality	0.83 (0.62–1.12)	0.2195	0.72 (0.53–0.97)	0.0325	0.72 (0.56–0.92)	0.0097	0.70 (0.52–0.95)	0.0236
Ischemic stroke-related mortality	0.93 (0.71–1.20)	0.5629	0.80 (0.61–1.04)	0.0988	0.79 (0.61–1.01)	0.0622	0.80 (0.61–1.05)	0.1146
IHD-related mortality	0.87 (0.72–1.06)	0.1655	0.79 (0.65–0.97)	0.0225	0.79 (0.66–0.94)	0.0097	0.81 (0.66–1.00)	0.0474
IHD-related mortality	0.87 (0.72–1.06)	0.1655	0.79 (0.65–0.97)	0.0225	0.79 (0.66–0.94)	0.0097	0.81 (0.66–1.00)	0.0474
CSD-related mortality	0.91 (0.83–1.00)	0.0508	0.79 (0.71–0.87)	<.0001	0.79 (0.72–0.86)	<.0001	0.80 (0.72–0.88)	<.0001

CI indicates Confidence interval; CSD, Circulatory System Disease, HR, Hazard Ratio; IHD, Ischemic Heart Disease; IPTW, Inverse Probability of Treatment Weighting; and PSM, Propensity Score Matching.

* Adjusted for variables listed in the table 1.

† Cox proportional hazards model stratifying on matched pairs.

‡ Weighted Cox proportional hazards model with robust standard errors.

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