Table 2.
Cox regression analyses to determine the factors associated with overall mortality
| Variable | Univariate
|
Multivariate
|
||
|---|---|---|---|---|
| HR (95% CI) | P-value | aHR (95% CI) | P-value | |
| Disease entity | ||||
| OSA alone vs neither COPD nor OSA | 1.5 (0.9–2.3) | 0.113 | 1.1 (0.7–1.8) | 0.566 |
| COPD alone vs neither COPD nor OSA | 3.1 (2.4–4.0) | <0.001* | 1.5 (1.2–2.0) | 0.001* |
| OSA/COPD overlap vs neither COPD nor OSA | 5.8 (3.2–10.8) | <0.001* | 2.4 (1.3–4.3) | 0.007* |
| OSA/COPD overlap vs COPD alone | 1.9 (1.1–3.2) | 0.018* | 1.5 (0.8–2.8) | 0.160 |
| Demographic and socioeconomic status | ||||
| Age (years) | ||||
| 20–39 | Reference | Reference | ||
| 40–59 | 3.6 (2.1–6.3) | <0.001* | 2.9 (1.7–5.1) | <0.001* |
| 60–79 | 16.6 (10.3–26.9) | <0.001* | 9.1 (5.5–14.9) | <0.001* |
| 80+ | 74.4 (47.2–117.3) | <0.001* | 32.0 (18.8–54.3) | <0.001* |
| Gender | ||||
| Female | Reference | |||
| Male | 1.1 (0.9–1.3) | 0.407 | ||
| Race | ||||
| Non-Hispanic White | Reference | Reference | ||
| Non-Hispanic Black | 1.0 (0.8–1.2) | 0.935 | 1.0 (0.8–1.3) | 0.708 |
| Mexican American | 0.5 (0.3–0.6) | <0.001* | 0.8 (0.6–1.1) | 0.246 |
| Other Hispanic | 0.4 (0.2–0.8) | 0.016* | 0.6 (0.3–1.3) | 0.214 |
| Other race | 0.4 (0.2–0.9) | 0.038* | 0.7 (0.3–1.5) | 0.338 |
| Poverty income ratio | ||||
| >2 | Reference | Reference | ||
| 1–2 | 2.4 (1.9–3.1) | <0.001* | 1.3 (1.0–1.7) | 0.040* |
| <1 | 1.8 (1.3–2.5) | 0.002* | 1.3 (0.9–1.9) | 0.120 |
| Education | ||||
| Ever attend college | Reference | Reference | ||
| Never attend college | 2.2 (1.7–2.8) | <0.001* | 1.2 (0.9–1.5) | 0.172 |
| Lifestyles and behaviors | ||||
| Smoking | ||||
| Nonsmoker | Reference | Reference | ||
| Former | 2.0 (1.6–2.5) | <0.001* | 1.3 (1.0–1.8) | 0.052 |
| Current | 1.2 (0.9–1.7) | 0.177 | 2.0 (1.4–3.0) | 0.001* |
| Alcohol consuming | ||||
| Lifetime abstainer | Reference | Reference | ||
| Moderate drinker | 0.7 (0.5–1.0) | 0.103 | 0.9 (0.7–1.3) | 0.673 |
| Heavy drinker | 0.3 (0.2–0.4) | <0.001* | 0.8 (0.6–1.2) | 0.291 |
| Physical activity (MET min/week) | ||||
| ≥600 | Reference | Reference | ||
| <600 | 2.5 (1.9–3.4) | <0.001* | 1.3 (1.0–1.8) | 0.097 |
| Serum vitamin D | ||||
| Normal | Reference | Reference | ||
| Insufficiency | 1.2 (0.9–1.5) | 0.238 | 1.1 (0.8–1.4) | 0.595 |
| Deficiency | 1.8 (1.3–2.6) | 0.001* | 1.5 (1.1–2.1) | 0.011* |
| Comorbidities | ||||
| Obesity | ||||
| Underweight/normal | Reference | |||
| Overweight | 0.9 (0.7–1.1) | 0.276 | ||
| Obese | 0.8 (0.5–1.1) | 0.120 | ||
| Cancer history | ||||
| No | Reference | Reference | ||
| Yes | 4.2 (3.4–5.1) | <0.001* | 1.6 (1.3–1.9) | <0.001* |
| Cardiovascular disease | ||||
| No | Reference | Reference | ||
| Yes | 7.9 (6.3–9.9) | <0.001* | 1.9 (1.5–2.4) | <0.001* |
| Diabetes mellitus | ||||
| No/borderline | Reference | Reference | ||
| Yes | 3.9 (3.1–4.8) | <0.001* | 1.6 (1.2–2.1) | 0.002* |
| Hypertension | ||||
| No | Reference | Reference | ||
| Yes | 3.1 (2.4–4.0) | <0.001* | 1.0 (0.8–1.3) | 0.744 |
| Dyslipidemia | ||||
| No | Reference | |||
| Yes | 1.1 (0.9–1.3) | 0.451 | ||
| eGFR (mL/min/1.73 m2) | ||||
| ≥60 | Reference | Reference | ||
| <60 | 6.6 (5.5–8.0) | <0.001* | 1.4 (1.1–1.9) | 0.006* |
Note:
*
Statistically significant, P-value <0.05.
Abbreviations: aHR, adjusted hazard ratio; CI, confidence interval; eGFR, estimated glomerular filtration rate; HR, hazard ratio; MET, metabolic equivalent of task; OSA, obstructive sleep apnea.