Use of the Clinical Global Impression scale in sleep apnea patients - Results from the ESADA database

Objective/background: The Clinical Global Impression scale (CGI) reflects the clinician's assessment of the disease impact on patient's global functioning. We assessed predictors of CGI scale rating in patients with obstructive sleep apnea (OSA). Patients/methods: Consecutive patients with suspected OSA (n = 7581) were identified in the European Sleep Apnea Database (ESADA). Anthropometrics, comorbidities, apnea severity obtained by polygraphy or polysomnography, and daytime sleepiness [Epworth Sleepiness Scale (ESS)] were assessed. The CGI 7- point scale was completed at the end of the diagnostic process (CGI-severity, ie, CGI-S) and, in a subpopulation, at treatment follow-up (CGI- Improvement). Results: CGI-S was rated mild to moderate in 44% of patients. CGI rating at any given apnea intensity was worse in women than in men (p < 0.01). Patients undergoing polygraphy (n = 5075) were more frequently rated as severely ill compared to those studied with polysomnography (19.0% vs 13.0%, p < 0.001). In patients aged ≤65 years, CGI scoring was generally better than in the elderly despite a similar degree of OSA (eg, 'normal, not ill' 24.2% vs 15.3%, p < 0.01, respectively). Independent predictors of CGI rating included age, BMI, AHI, ESS, cardio- metabolic comorbidities, and diagnosis based on polygraphy. CGI-improvement rating (Beta = -0.406, p < 0.01) was superior to sleep apnea severity or ESS-score (Beta = 0.052 and -0.021, p = 0.154 and 0.538 respectively) at baseline for prediction of good CPAP compliance at follow-up. Conclusions: CGI rating is confounded by gender, age class and the type of sleep diagnostic method. As OSA phenotypes differ, CGI may contribute as a clinical tool to reflect the significance of clinical disease.