Table 1. Characteristics of control and case groups.
| Recurrence - | Recurrence + | p | |
|---|---|---|---|
| (n = 608) | (n = 152) | ||
| Age | 51.95 ± 18.71 | 56.94 ± 16.40 | 0.001 |
| Gender | |||
| Female (%) | 216 (36) | 28 (18) | - |
| Male (%) | 392 (64) | 124 (82) | < 0.0001 |
| Socio-economic status | |||
| NT$ 30300 or more | 94 (16) | 11 (7) | - |
| NT$ 19200 to NT$ 30300 | 245 (40) | 66 (43) | 0.01 |
| Less than NT$ 19200 | 33 (5) | 10 (7) | 0.04 |
| Dependents | 131 (22) | 30 (20) | 0.07 |
| Fixed amount | 105 (17) | 35 (23) | 0.004 |
| Residential area | |||
| Northern | 109 (18) | 26 (17) | - |
| Middle | 128 (21) | 31 (20) | 0.96 |
| Southern | 152 (25) | 33 (22) | 0.75 |
| Eastern | 219 (36) | 62 (41) | 0.51 |
| Comorbidities, n (%) | |||
| Diabetes | 121 (20) | 44 (29) | 0.02 |
| Dyslipidemia* | 77 (13) | 14 (9) | 0.24 |
| Hypertension | 171 (28) | 48 (32) | 0.40 |
| Ischemic cardiovascular disease | 89 (15) | 17 (11) | 0.27 |
| Cardiac arrhythmia* | 35 (6) | 5 (3) | 0.22 |
| Congestive heart failure | 30 (5) | 10 (7) | 0.42 |
| Cerebrovascular disease | 67 (11) | 20 (13) | 0.46 |
| Chronic obstructive pulmonary disease | 227 (37) | 81 (53) | 0.0003 |
| Asthma | 80 (13) | 24 (16) | 0.40 |
| Bronchiectasis | 59 (10) | 19 (13) | 0.31 |
| Silicosis* | 10 (2) | 5 (3) | 0.20* |
| Immuno-compromised diseases & | 5 (1) | 5 (3) | 0.20* |
- Without recurrence
+ With recurrence
*Fisher’s exact test for comparison of nominal variables.
&Immuno-compromised diseases included liver cirrhosis, end-stage renal disease, kidney transplant and connective tissue disease.