Table 4 Subgroup analysis for persistent sputum production in subjects without post-nasal drip: multivariable analysis (N = 1766)
| Baseline factors | Persistent sputum production | ||
|---|---|---|---|
| OR | 95% CI | p value | |
| Age, per 10-year increase | 1.12 | 1.04–1.21 | 0.002 |
| Male sex | 1.37 | 1.07–1.74 | 0.01 |
| Smoking history (ex or current) | 1.32 | 1.04–1.68 | 0.03 |
| FSSG scores ≥ 8 | 1.68 | 1.34–2.11 | < 0.0001 |