Comparison between false negative (FN) and true positive (TP) patients when cut off points in the oxygen desaturation index (ODI) of ⩾5, ⩾10, and ⩾15 were considered to analyse the nocturnal oximetry
| FN | TP | p value | |
|---|---|---|---|
| ODI ⩾5 | |||
| Age (years) | 51 (10) | 53 (10) | NS |
| Duration of symptoms (months) | 53 (52) | 72 (72) | 0.053 |
| BMI (kg/m2) | 29 (4) | 33 (5) | <0.001 |
| Epworth sleepiness scale | 12 (4) | 14 (5) | <0.01 |
| Neck circumference (cm) | 41 (4) | 44 (4) | <0.01 |
| Cephalometric abnormalities | 6/37 | 56/175 | 0.08 |
| AHI (n) | 22 (7) | 46 (20) | <0.001 |
| Baseline Sao 2(kPa) | 12.5 (0.3) | 12.1 (0.4) | <0.001 |
| Minimal Sao 2 (kPa) | 11.6 (0.7) | 9.4 (1.6) | <0.001 |
| ODI ⩾10 | |||
| Age (years) | 53 (10) | 53 (10) | NS |
| Duration of symptoms (months) | 52 (52) | 74 (74) | <0.01 |
| BMI (kg/m2) | 29 (4) | 33 (6) | <0.001 |
| Epworth sleepiness scale | 12 (5) | 15 (5) | <0.001 |
| Neck circumference (cm) | 42 (3) | 44 (4) | <0.01 |
| Cephalometric abnormalities | 11/61 | 52/152 | <0.05 |
| AHI (n) | 24 (11) | 49 (19) | <0.001 |
| Baseline Sao 2(kPa) | 12.4 (0.4) | 12.1 (0.4) | <0.01 |
| Minimal Sao 2 (kPa) | 11.2 (0.9) | 9.6 (1.6) | <0.001 |
| ODI ⩾15 | |||
| Age (years) | 52 (10) | 53 (10) | NS |
| Duration of symptoms (months) | 49 (49) | 65 (65) | <0.05 |
| BMI (kg/m2) | 30 (4) | 33 (5) | <0.001 |
| Epworth sleepiness scale | 12 (5) | 15 (5) | <0.001 |
| Neck circumference (cm) | 42 (3) | 44 (4) | <0.001 |
| Cephalometric abnormalities | 15/80 | 47/133 | <0.05 |
| AHI (n) | 26 (12) | 51 (18) | <0.001 |
| Baseline Sao 2(kPa) | 12.4 (0.4) | 12.1 (0.4) | <0.01 |
| Minimal Sao 2 (kPa) | 11 (0.9) | 9.3 (1.6) | <0.001 |
BMI = body mass index; AHI = apnoea hypopnoea index; Sao 2 = oxygen saturation.