Table 4.
Quantile Regression (Continuous Parameters) and Logistic Regression (Binary Parameters) for the Effects of Restrictive or Obstructive/Mixed Impairments of Spirometry Against the Reference of “Normal” Spirometry, Adjusting for Age, Sex, Body Mass Index, Remoteness and Smoking Status
| Polysomnography Data | Polysomnography Parameters | Restrictive Impairment (n=95) | p-value | Obstructive/Mixed Impairments (n=31) | p-value |
|---|---|---|---|---|---|
| Sleep related variables | Sleep latency | 6.5 (−2.8, 15.81) | 0.170 | 10.14 (−3.29, 23.56) | 0.138 |
| REM latency | −1.49 (−38.09, 35.1) | 0.936 | −14.39 (−68.12, 39.34) | 0.598 | |
| Wake after sleep onset | 2.91 (−19.24, 25.05) | 0.796 | 19.29 (−12.46, 51.04) | 0.232 | |
| Sleep efficiency | −2.2 (−6.35, 1.95) | 0.298 | −5.7 (−11.73, 0.33) | 0.064 | |
| Sleep efficiency <80% | 1.36 (0.73, 2.52) | 0.335 | 2.59 (1.04, 6.44) | 0.041* | |
| Total sleep time | 19.09 (−13.77, 51.95) | 0.253 | −22.62 (−70.59, 25.35) | 0.354 | |
| Architecture | N1 (%) | −0.64 (−3.95, 2.66) | 0.703 | −1.97 (−6.81, 2.87) | 0.423 |
| N2 (%) | 3.84 (−1.38, 9.06) | 0.149 | 5.49 (−2.09, 13.08) | 0.155 | |
| N3 (%) | −1.46 (−4.69, 1.77) | 0.374 | 0.19 (−4.51, 4.89) | 0.936 | |
| REM (%) | −2.35 (−5.19, 0.49) | 0.104 | 0.82 (−3.3, 4.94) | 0.695 | |
| Arousals | Respiratory arousal index | −0.03 (−5.45, 5.4) | 0.993 | 2.13 (−5.83, 10.1) | 0.598 |
| Spontaneous arousal index | −0.7 (−1.84, 0.44) | 0.227 | −0.44 (−2.11, 1.23) | 0.606 | |
| Total arousal index | 1.13 (−4.07, 6.33) | 0.669 | 2.07 (−5.56, 9.7) | 0.593 | |
| Apnoea-hypopnea index | Total | 4.77 (−5.29, 14.82) | 0.351 | 8.99 (−5.62, 23.6) | 0.227 |
| NREM | 1.31 (−9.26, 11.88) | 0.807 | 7.56 (−7.71, 22.82) | 0.330 | |
| REM | 7.82 (−4.33, 19.97) | 0.206 | 20.69 (2.8, 38.58) | 0.024* | |
| Obstructive sleep apnoea | Presence and severity | 0.99 (0.56, 1.74) | 0.976 | 1.67 (0.71, 3.92) | 0.240 |
| Oxygen saturation | Total | −0.5 (−1.45, 0.45) | 0.302 | −1.63 (−3, −0.27) | 0.019* |
| Wake | −0.12 (−0.92, 0.67) | 0.758 | −0.99 (−2.1, 0.13) | 0.082 | |
| NREM | −0.8 (−1.99, 0.39) | 0.185 | −2.14 (−3.85, −0.43) | 0.015* | |
| REM | −0.05 (−1.76, 1.65) | 0.951 | −2.19 (−4.58, 0.2) | 0.072 | |
| Nadir | −2.63 (−6.28, 1.02) | 0.156 | −2.56 (−7.81, 2.7) | 0.338 | |
| Continuous positive airway pressure (CPAP) | Trialled CPAP | 1.78 (0.9, 3.51) | 0.097 | 1.17 (0.45, 3.04) | 0.753 |
| CPAP > 30 days | 1.3 (0.54, 3.11) | 0.557 | 0.7 (0.19, 2.61) | 0.597 | |
| Days used (%) | −19.59 (−53.93, 14.75) | 0.259 | −29.63 (−93.23, 33.98) | 0.356 | |
| Average hours used | 0.31 (−1.4, 2.02) | 0.716 | −0.38 (−3.55, 2.79) | 0.812 | |
| Days used >4 hours (%) | −26.91 (−60.53, 6.71) | 0.115 | −33.07 (−95.35, 29.21) | 0.293 | |
| Adherent | 0.52 (0.16, 1.73) | 0.287 | 0.68 (0.04, 11.19) | 0.788 |
Notes: Data were beta (95% confidence interval (CI)) or odds ratio (95% CI). p-values obtained via multivariate quantile regression for continuous outcomes, multivariate logistic regression for binary outcomes and ordered logistic regression for ordinal outcomes (OSA presence and severity), utilising “no spirometry impairment” as baseline reference. *Indicates significance at p<0.05.
Abbreviations: N1/N2/N3, non-rapid eye movement stages 1, 2, 3; NREM, Non-rapid eye movement; REM, Rapid eye movement.