Table 1 Baseline characteristics of enrollees in the National Health Insurance and Medical Aid programs

Medical Aid

   Class I^a, n (%)

-

17,248 (80.1)

-

   Class II^b, n (%)

-

4,291 (19.9)

-

Age in years, mean (SD)

61.6 (11.7)

68.1 (11.9)

<0.0001

Male, n (%)

130,398 (42.9)

6,000 (27.9)

<0.0001

Insurance-covered medical costs in Korean won^c, mean (SD)

   All causes

228,566 (838,665)

541,699 (1,359,656)

<0.0001

   Hypertension related^d

171,249 (616,724)

375,440 (995,523)

<0.0001

No. outpatient visits, mean (SD)

   All causes

4.8 (2.6)

5.4 (2.7)

<0.0001

   Hypertension related

4.3 (2.3)

4.6 (2.0)

<0.0001

Elixhauser comorbidity index^e, mean (SD)

2.3 (1.3)

3.0 (1.7)

<0.0001

   n (%)

   1

103,722 (34.1)

4,074 (18.9)

<0.0001

   2

92,830 (30.5)

5,614 (26.1)

   3

57,212 (18.8)

4,684 (21.8)

   4

28,815 (9.5)

3,160 (14.7)

   ≥5

21,448 (7.1)

4,007 (18.6)

Type of institution, n (%)

<0.0001

   Tertiary-care hospital

19,101 (6.3)

536 (2.5)

   General hospital

28,703 (9.4)

3,586 (16.7)

   Hospital

14,174 (4.7)

2,185 (16.7)

   Long-term care facility

1,026 (0.3)

368 (1.7)

   Clinic

203,556 (67.0)

11,432 (53.1)

   Public health center

36,740 (12.1)

2,288 (10.6)

Type of ownership, n (%)

<0.0001

   Government owned

40,031 (13.2)

3,086 (14.3)

   Non-government owned

263,947 (86.8)

18,449 (85.7)

   Missing

49 (0.0)

4 (0.0)

Bed size, n (%)

<0.0001

   <100

248,378 (81.7)

15,818 (73.4)

   100 ~ 299

17,077 (5.6)

2,790 (13.0)

   300 ~ 799

24,925 (8.2)

2,281 (10.6)

   800 ~ 999

7,377 (2.4)

435 (2.0)

   ≥1,000

6,270 (2.1)

215 (1.0)

Location, n (%)

<0.0001

   Seoul

72,002 (23.7)

3,190 (14.8)

   Six major cities

73,653 (24.2)

5,329 (24.7)

    Kwangju

7,457 (2.5)

761 (3.5)

    Daegu

14,106 (4.6)

1,056 (4.9)

    Daejeon

8,787 (2.9)

641 (3.0)

    Pusan

22,703 (7.5)

1,706 (7.9)

    Ulsan

5,261 (1.7)

264 (1.2)

    Incheon

15,339 (5.1)

901 (4.2)

   Nine provinces

158,323 (52.1)

13,016 (60.4)

    Kangwon

11,442 (3.8)

1,084 (5.0)

    Kyonggi

59,167 (19.5)

3,065 (14.2)

    Kyungsangnam

17,754 (5.8)

1,432 (6.7)

    Kyungsangbuk

16,935 (5.6)

1,680 (7.8)

    Jeollanam

13,100 (4.3)

1,921 (8.9)

    Jeollabuk

12,466 (4.1)

1,706 (7.9)

    Jeju

3,279 (1.1)

236 (1.1)

    Chungcheongnam

14,200 (4.7)

1,058 (4.9)

    Chungcheongbuk

9,980 (3.3)

834 (3.9)

   Missing

49 (0.0)

4 (0.0)