Characteristics of hospital-recruited and population-recruited COPD cases and population-recruited control patients below 67 years of age in the EconCOPD study
| Hospital-recruited COPD cases | Population-recruited COPD cases | Population-recruited controls | Statistic | |
|---|---|---|---|---|
| N | 102 | 53 | 107 | |
| Male, N (%) | 57 (56) | 30 (57) | 54 (50) | χ2, p=0.662 |
| Age, mean years (SD) | 59 (5.2) | 58 (6.2) | 53 (6.9) | ANOVA, p<0.001 |
| Smoking status | χ2, p=0.054 | |||
| Current smoker, N (%) | 41 (40) | 31 (58) | 57 (53) | |
| Former smoker, N (%) | 61 (60) | 22 (42) | 50 (47) | |
| Education, N (%) | χ2, p<0.001 | |||
| Primary | 36 (35) | 22 (42) | 20 (19) | |
| Secondary | 54 (53) | 19 (36) | 48 (45) | |
| University | 12 (12) | 12 (23) | 39 (36) | |
| FEV1% predicted, N (%) | χ2, p<0.001 | |||
| ≥80% | 107 (100) | |||
| ≥50%, <80% | 51 (50) | 47 (89) | ||
| ≥30, <50% | 28 (27) | 4 (8) | ||
| <30% | 23 (23) | 2 (4) | ||
| Mean FEV1% predicted (SD) | 47.0 (12.6) | 65.5 (12.6) | 94.3 (8.33) | ANOVA, p<0.001 |
| Median FEV1% predicted (IQR) | 50.7 (29.7) | 68.4 (13.3) | 93.1 (10.1) | Kruskal–Wallis with ties, p<0.001; trend test p<0.001 |
| Number of comorbid conditions | ||||
| Mean (SD) | 1.5 (1.7) | 1.0 (0.9) | 0.7 (1.0) | ANOVA, p<0.001 |
| Median (IQR) | 1 (2) | 1 (1) | 0 (1) | Kruskal–Wallis with ties, p=0.003; trend test p=0.001 |
| Number of events of exacerbations of respiratory symptoms | ||||
| Mean (SD) | 6.8 (6.5) | 3.5 (7.3) | 0.8 (1.6) | ANOVA, p<0.001 |
| Median (IQR) | 5.5 (10) | 1 (4) | 0 (1) | Kruskal–Wallis with ties, p=0.001; trend test p<0.001 |
| Employment status at baseline, N (%) | χ2, p<0.001 | |||
| Paid job | 32 (31) | 29 (55) | 93 (87) | |
| Retired | 1 (1) | 4 (8) | 4 (4) | |
| Disability pension | 66 (65) | 16 (30) | 8 (7) | |
| Other* | 3 (3) | 4 (8) | 2 (2) | |
| Days in sick leave during 1 year | ||||
| Total number | 1287.7 | 1023.5 | 1676.5 | |
| Mean (SD) | 12.6 (30.0) | 19.3 (55.4) | 15.7 (36.4) | ANOVA, p=0.59 |
| Median (IQR) | 0 (5) | 0 (3) | 1 (14) | Kruskal–Wallis with ties, p=0.05; trend test p=0.03 |
| Days with disability pension during 1 year | ||||
| Any disability pension, N (%) | 69 (68) | 19 (36) | 9 (8) | χ2, p<0.001 |
| Total number | 23 322 | 5344.3 | 2504 | |
| Mean (SD) | 228.6 (170.3) | 100.8 (156.3) | 23.4 (83.1) | ANOVA, p<0.001 |
| Median (IQR) | 365 (365) | 0 (256) | 0 (0) | Kruskal–Wallis with ties, p<0.001; trend test p<0.001 |
| Days with productivity loss during 1 year | ||||
| Total number | 24 609.7 | 6367.8 | 4180.5 | |
| Zero days of productivity loss, N (%) | 8 (8) | 20 (38) | 44 (41) | χ2, p<0.001 |
| 365 days of productivity loss, N (%) | 57 (56) | 13 (25) | 5 (5) | χ2, p<0.001 |
| Mean (SD) | 241.3 (158.7) | 120.2 (158.5) | 39.1 (86.6) | ANOVA, p<0.001 |
| Median (IQR) | 365 (320) | 9 (329.3) | 5 (26) | Kruskal–Wallis with ties, p=0.0001; trend test p<0.001 |
Trend tests for hospital patients<population-based patients<control subjects.
*Students, unemployed, homemakers.
ANOVA, analysis of variance; COPD, chronic obstructive pulmonary disease; EconCOPD, COPD-related costs; FEV1, forced expiratory volume in 1 s.