Table 3.
Comparisons of patients with decreased FVC (restricted) and normal spirometry
| Definition of AFL | ||||||
|---|---|---|---|---|---|---|
|
|
||||||
| FR | LLN | |||||
|
|
|
|||||
| Normal | Restriction | P-value | Normal | Restriction | P-value | |
| n | 92 | 68 | 104 | 77 | ||
| Age (mean ± SEM) | 55.1 ± 1.22 | 64.1 ± 1.4 | <0.001 | 56.6 ± 1.2 | 64.9 ± 1.3 | <0.001 |
| Symptom score (mean ± SEM) | 4.9 ± 0.55 | 6.4 ± 0.7 | 0.09 | 4.8 ± 0.54 | 6.1 ± 0.64 | 0.12 |
| BMI (mean ± SEM) | 30.4 ± 0.67 | 31 ± 0.9 | 0.6 | 30 ± 0.6 | 30.9 ± 0.82 | 0.37 |
| FVC (mean ± SEM) | 4.3 ± 0.08 | 3.0 ± 0.07 | <0.001 | 4.3 ± 0.08 | 3.0 ± 0.07 | <0.001 |
| FEV1 (mean ± SEM) | 3.3 ± 0.06 | 2.3 ± 0.06 | <0.001 | 3.24 ± 0.06 | 2.29 ± 0.06 | <0.001 |
| Cardiovascular disease | 15 (16) | 29 (43) | <0.001 | 16 (15) | 35 (45) | <0.001 |
| Health care utilization | ||||||
| ED visits/year (mean ± SEM) | 0.09 ± 0.04 | 0.13 ± 0.03 | 0.45 | 0.09 ± 0.03 | 0.12 ± 0.03 | 0.49 |
| Hospitalizations/year (mean ± SEM) | 0.03 ± 0.02 | 0.16 ± 0.12 | 0.22 | 0.03 ± 0.02 | 0.15 ± 0.11 | 0.22 |
| Annual mortality (% dead/year ± SEM) | 1.7 ± 0.7 | 2.8 ± 1 | 0.35 | 2.2 ± 0.8 | 2.89 ± 1 | 0.59 |
Notes: AFL as defined by FR: FR = FEV1/FVC < 0.70. AFL as defined by LLN: (FEV1/FVC)/LLN < 1.0.
Abbreviations: AFL, airflow limitation; BMI, body mass index; ED, emergency department; FEV1, forced expiratory volume in 1 second; FR, fixed ratio; FVC, forced vital capacity; LLN, lower limit of normal; SEM, standard error of the mean.