Reduction in motor vehicle collisions following treatment ofsleep apnoea with nasal CPAP

BACKGROUND—Patientswith untreated obstructive sleep apnoea (OSA) have increased motorvehicle collisions (MVCs). When successfully treated, they reportimproved driving and fewer mishaps, but there are few objective data toconfirm this. A study was therefore undertaken to examine actual MVCdata in a large group of patients with OSA before and after treatmentwith continuous positive airway pressure (CPAP) compared with a controlgroup matched for age, sex, and type of driver's licence (commercialor non-commercial).
METHODS—Two hundredand ten patients of mean (SD) age 52 (11) years, body mass index (BMI)35.5 (10) kg/m², apnoea/hypopnoea index (AHI) 54 (29)events/h were treated with CPAP for at least 3 years. MVC records wereobtained from the Ontario Ministry of Transportation (MTO) database forpatients and an equal number of randomly selected control drivers. MVC rates were compared for 3 years before and after CPAP therapy forpatients and for the corresponding time frames for controls.
RESULTS—Untreatedpatients with OSA had more MVCs than controls (mean (SD)MVCs/driver/year 0.18 (0.29) v 0.06 (0.17),p<0.001). Following CPAP treatment the number of MVCs/driver/year fellto normal (0.06(0.17)) while, in controls, the MVC rate was unchangedover time (0.06 (0.17) v 0.07 (0.18), p=NS).Thus, the change in MVCs over time between the groups was verysignificant (change = -0.12 (95% CI -0.17 to -0.06), p<0.001)).The MVC rate in untreated patients (n=27) remained high over time.Driving exposure was not different following CPAP.
CONCLUSIONS—The riskof MVCs due to OSA is removed when patients are treated with CPAP. Assuch, any restrictions on driving because of OSA could be safelyremoved after treatment.