Table 3. Adjusted odds ratio for each independent variable associated with sleep apnea.
| Independent variables associated with sleep apnea | Unadjusted odds ratio (CI) | P value | Adjusted odds ratio (CI) | P value |
| Sex | ||||
| Male | Reference | |||
| Female | 0.53 (0.53–0.54) | <0.001 | 0.55 (0.54–0.55) | <0.001 |
| Age in years | ||||
| 18–19 | Reference | |||
| ≥20 and <30 | 1.10 (0.99–1.22) | 0.056 | 1.03 (0.93–1.15) | 0.589 |
| ≥30 and <40 | 3.16 (2.86–3.50) | <0.001 | 2.23 (2.01–2.48) | <0.001 |
| ≥40 and <50 | 10.9 (9.88–12.09) | <0.001 | 4.54 (4.09–5.04) | <0.001 |
| ≥50 and <60 | 15.12 (13.7–16.72) | <0.001 | 4.82 (4.34–5.34) | <0.001 |
| ≥60 and <70 | 17.27 (15.7–19.10) | <0.001 | 4.32 (3.89–4.79) | <0.001 |
| ≥70 and <80 | 15.96 (14.43–17.7) | <0.001 | 3.52 (3.17–3.91) | <0.001 |
| ≥80 and <90 | 9.02 (8.15–9.98) | <0.001 | 2.15 (1.94–2.39) | <0.001 |
| ≥90 and <100 | 3.37 (3.04–3.74) | <0.001 | 0.97 (0.87–1.08) | 0.606 |
| Cushing’s syndrome | ||||
| No | Reference | |||
| Yes | 2.94 (2.66–3.24) | <0.001 | 1.79 (1.60–2.01) | <0.001 |
| Diabetes | ||||
| No | Reference | |||
| Yes | 2.70 (2.68–2.71) | <0.001 | 1.38 (1.37–1.39) | <0.001 |
| Obesity | ||||
| No | Reference | |||
| Yes | 5.84 (5.80–5.97) | <0.001 | 4.59 (4.56–4.62) | <0.001 |
| Hypertension | ||||
| No | Reference | |||
| Yes | 3.73 (3.70–3.75) | <0.001 | 1.70 (1.68–1.71) | <0.001 |
| Chronic lung disease | ||||
| No | Reference | |||
| Yes | 2.54 (2.52–2.55) | <0.001 | 1.96 (1.94–1.97) | <0.001 |
| Chronic kidney disease/ESRD | ||||
| No | Reference | |||
| Yes | 1.97 (1.95–1.98) | <0.001 | 1.05 (1.04–1.06) | <0.001 |
| Liver disease | ||||
| No | Reference | |||
| Yes | 1.20 (1.19–1.22) | <0.001 | 1.05 (1.04–1.07) | <0.001 |
| Cerebral infarction | ||||
| No | Reference | |||
| Yes | 0.87 (0.85–0.89) | <0.001 | 0.77 (0.75–0.78) | <0.001 |
| Heart failure | ||||
| No | Reference | |||
| Yes | 2.68 (2.66–2.70) | <0.001 | 1.43 (1.42–1.44) | <0.001 |
| Obesity hypoventilation syndrome | ||||
| No | Reference | |||
| Yes | 2.54 (2.48–2.61) | <0.001 | 0.39 (0.38–0.40) | <0.001 |
| Thyroid disorders | ||||
| No | Reference | |||
| Yes | 1.54 (1.53–1.55) | <0.001 | 1.28 (1.27–1.29) | <0.001 |
| Fluid, electrolyte, and acid–base disorders | ||||
| No | Reference | |||
| Yes | 1.07 (1.06–1.08) | <0.001 | 0.80 (0.79–0.80) | <0.001 |
| Atrial fibrillation/flutter | ||||
| No | Reference | |||
| Yes | 2.25 (2.23–2.26) | <0.001 | 1.42 (1.41–1.43) | <0.001 |
| Other cardiac arrhythmias | ||||
| No | Reference | |||
| Yes | 1.64 (1.61–1.67) | <0.001 | 1.14 (1.12–1.16) | <0.001 |
| RLS | ||||
| No | Reference | |||
| Yes | 3.86 (3.79–3.92) | <0.001 | 2.68 (2.63–2.73) | <0.001 |
| Smoking | ||||
| No | Reference | |||
| Yes | 0.75 (0.74–0.76) | <0.001 | 0.69 (0.69–0.70) | <0.001 |
| Alcohol use | ||||
| No | Reference | |||
| Yes | 0.52 (0.51–0.53) | <0.001 | 0.61 (0.60–0.62) | <0.001 |
| Household income (percentile) | ||||
| 0–25th | Reference | |||
| 26th–50th | 1.12 (1.12–1.13) | <0.001 | 1.10 (1.09–1.11) | <0.001 |
| 51st–75th | 1.17 (1.16–1.18) | <0.001 | 1.18 (1.17–1.19) | <0.001 |
| 76th–100th | 1.08 (1.07–1.09) | <0.001 | 1.24 (1.22–1.25) | <0.001 |
| Race | ||||
| White | Reference | |||
| Black | 0.81 (0.80–0.82) | <0.001 | 0.86 (0.85–0.87) | <0.001 |
| Hispanic | 0.48 (0.482–0.493) | <0.001 | 0.64 (0.63–0.64) | <0.001 |
| Asian/Pacific Island | 0.34 (0.340–0.358) | <0.001 | 0.50 (0.49–0.51) | <0.001 |
| Native American | 0.70 (0.67–0.72) | <0.001 | 0.80 (0.76–0.83) | <0.001 |
| Other | 0.48 (0.47–0.49) | <0.001 | 0.64 (0.62–0.65) | <0.001 |
| Pay | ||||
| Medicare | Reference | |||
| Medicaid | 0.384 (0.38–0.388) | <0.001 | 0.69 (0.68–0.70) | <0.001 |
| Private | 0.71 (0.71–0.72) | <0.001 | 0.99 (0.98–1.00) | 0.763 |
| Self-pay | 0.30 (0.29–0.30) | <0.001 | 0.52 (0.51–0.53) | <0.001 |
| No charge | 0.25 (0.23–0.27) | <0.001 | 0.43 (0.39–0.47) | <0.001 |
| Other | 0.72 (0.71–0.74 | <0.001 | 0.96 (0.94–0.98) | <0.001 |
| Location of hospital/teaching status | ||||
| Rural | Reference | |||
| Urban non-teaching | 1.05 (1.03–1.06) | <0.001 | 1.05 (1.03–1.06) | <0.001 |
| Urban teaching | 1.13 (1.12–1.14) | <0.001 | 1.20 (1.18–1.21) | <0.001 |
| Bed size | ||||
| Small | Reference | |||
| Medium | 0.99 (0.98–1.00) | <0.001 | 1.03 (1.02–1.04) | <0.001 |
| Large | 1.03 (1.02–1.04) | <0.001 | 1.06 (1.06–1.07) | <0.001 |
| Hospital region | ||||
| Northeast | Reference | |||
| Midwest | 1.54 (1.53–1.56) | <0.001 | 1.40 (1.39–1.42) | <0.001 |
| South | 1.06 (1.05–1.07) | <0.001 | 1.10 (1.09–1.11) | <0.001 |
| West | 1.04 (1.05–1.06) | <0.001 | 1.23 (1.22–1.24) | <0.001 |