The intervention group had better CPAP use ( higher daily CPAP usage by @ h/d -LSB- Cohen d = @ , P < @ -RSB- , a fourfold increase in the number using CPAP for @ % of days with @ h/d -LSB- P < @ -RSB- ) , and greater improvements in daytime sleepiness ( ESS ) by @ units ( P = @ ) and treatment self-efficacy by @ units ( P = @ ) compared with the control group .