Associations Between Airflow Limitation According to Various Criteria and Outcomes
| Outcome | No Airflow Limitationa (n = 4,038) | Airflow Limitation | |
|---|---|---|---|
| FR+/LLN− (n = 297) | FR+/LLN+ (n = 532) | ||
| Chronic cough | 1.00 | 1.40 (0.99–1.98) | 2.54 (2.03–3.18) |
| Chronic phlegm | 1.00 | 1.43 (0.97–2.10) | 3.04 (2.39–3.87) |
| Chronic bronchitis | 1.00 | 1.59 (0.93–2.72) | 3.14 (2.25–4.37) |
| Wheeze | 1.00 | 1.54 (1.15–2.06) | 3.25 (2.65–3.97) |
| MRC dyspnea scaleb | 1.00 | 1.14 (0.86–1.52) | 2.33 (1.92–2.82) |
| SF-12 Physical component scalec | 1.00 | −0.78 (.17) | −3.31 (<.01) |
| SF-12 Mental component scalec | 1.00 | 0.47 (.40) | −0.30 (.49) |
| Exacerbation | 1.00 | 1.33 (0.98–1.81) | 1.90 (1.54–2.34) |
| Cardiovascular disease | 1.00 | 1.52 (1.14–2.04) | 1.21 (0.93–1.56) |
FR = fixed ratio; LLN = lower limit of normal; MRC = Medical Research Council; SF-12 = Short Form 12-item health survey.
Notes: Multiple logistic regression analysis, except as otherwise noted. All models adjusted for age-group (<60 years), sex, and ever smoking. Data are presented as odds ratios (95% CIs) or parameter estimates (P values) from regression analysis. Number of FR−/LLN+ patients was too small for inclusion.
↵a Reference group (FR−/LLN−).
↵b Ordinal logistic regression analysis.
↵c Multiple linear regression analysis.