Quality of life before and after Nasal Continuous Positive Airway Pressure (NCPAP) treatment for Obstructive Sleep Apnoea (OSA)
Although the benefits of treating OSA are obvious to patient and physician, purchasers of health care are not impressed by this subjective and anecdotal evidence. Controlled data are available, but not always using outcome measures that allow the estimation of health gain to be compared with other treatments in other conditions. This study compares the quality of life of OSA patients with a normal population, and measures the health gain from NCPAP treatment using two well accepted assessment techniques, the SF-36 and Functional Limitations Profile (FLP). The SF-36 provides a set of indices (eg energy/vitality), conveniently totalled as the Physical and Mental Component Summaries (PCS and MCS) standardised against a normal population. The FLP also provides a set of indices (eg alertness) summarised as the Total Score. 64 patients completed the SF-36 and FLP questionnaires prior to, and 6 weeks after, starting NCPAP for OSA. The response to treatment is quoted as 'effect size' (mean change in variable divided by SD of variable, where 0.2 is regarded as small, 0.5 moderate, and 0.8 large). Measure Before After Effect size SF-36 Energy/vitality* 38 (21) 60 (22) 1.0 Physical Component *x 39 (12) 47 (12) 0.6 Mental Component*x 40 (12) 49 (10) 0.8 FLP Sleep and Rest† 30 (24) 9 (18) 0.9 Alertness† 29 (28) 12 (24) 0.6 Social Interaction† 19 (20) 8 (16) 0.6 Total Score† 11 (9) 4 (7) 0.7 *100=best,0=worst. x50=normal population mean. †0=best, 100=worst. These results (all P<0.001) indicate a pre-treatment reduction in quality of life similar to many other severe disorders (e.g. Parkinson's, chronic heart failure) and a large response to treatment compared to other therapies in other disorders.