The key factors in the vignettes of patients after CPAP treatment and the McNemar's test showing significant variability in what a patient will be told by the same clinician depending on whether the Driver and Vehicle Licensing Agency (DVLA) form asks about ‘irresistible’ or ‘excessive’ drowsiness
| Vignette | Pre CPAP AHI | Pre CPAP ESS | Post CPAP AHI | Post CPAP ESS | CPAP use | Other factors | ‘Compliance’ ‘Yes’ | ‘Excessive’ ‘Yes’ | ‘Irresistible’ ‘Yes’ | McNemar's test | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| p Value | OR (95% CI) | ||||||||||
| 7 | 35/h | 22 | 10 | 14 | 3.2 h | Had stopped driving (his decision) but has now restarted | 38 (21%) | 116 (65%) | 46 (26%) | <0.001 | 6.8 (3.7 to 13.7) |
| 8 | 28/h | 15 | 3 | 5 | 6 h | Does not use CPAP during weekend | 65 (37%) | 94 (53%) | 69 (39%) | 0.0009 | 2.3 (1.4 to 4.1) |
| 9 | 45/h | 14 | 7 | 9 | 4 h | Does not use CPAP for 2 days in a week | 45 (25%) | 128 (72%) | 92 (52%) | <0.001 | 2.7 (1.6 to 4.7) |
| 10 | 80/h | 22 | 10 | 12 | N/A | No longer having any problems driving but continues to fall asleep watching television, while reading and if a passenger in a car | 114 (64%) | 140 (79%) | 77 (43%) | <0.001 | 6.7 (3.5 to 14) |
| 11 | 35/h | 13 | Nil | 12 | N/A | Intolerant to CPAP, lifestyle modifications, weight loss 4 kg | 24 (13%) | 151(85%) | 87(49%) | <0.001 | 13.8 (5 to 43) |
AHI, apnoea/hypopnoea index; ESS, Epworth sleepiness scale.