Objective
This study examined the role of coping in explaining health-related quality of life (HRQoL) in cystic fibrosis (CF).

Methods
Coping, quality of life, and clinical variables were assessed. The CF Coping Scale measures four ways of coping: optimistic acceptance, hopefulness, distraction, and avoidance. The Cystic Fibrosis Quality of Life Questionnaire (CFQoL) comprises 9 domains: physical, social, treatment, chest symptoms, emotional, body image, relationships, career, and future. Step-wise multiple regression and path analysis were used to model the associations between coping and CFQoL domains, taking into account important demographic and clinical factors.

Results
One hundred and sixteen people with CF were recruited to the study. Their mean FEV1% predicted and BMI were 59.3% and 21.2 kg/m2, respectively. Mean scores were highest for optimism and lowest for distraction coping. Coping had an inequitable influence across the CFQoL domains: it had negligible influence on domains that incorporate symptoms and aspects of physical functioning but considerable influence on psychosocial domains. Optimism and distraction were strongly associated with emotional responses, social functioning, and interpersonal relationships. A high level of optimism was associated with a better HRQoL and high levels of distraction with a poorer HRQoL. For some domains, optimism and distraction had a counterbalancing effect so the difference between them could be an important predictor of HRQoL.

Conclusion
Coping has emerged as an important factor in explaining some quality-of-life domains but not others. This has important implications especially when employing HRQoL as an outcome measure in clinical trials.