A Systematic Review of Factors Associated with Health-Related Quality of Life in Adolescents and Adults with Cystic Fibrosis

Rationale: As the life expectancy for individuals with cystic fibrosis (CF) continues to improve, an emphasis on optimizing health-related quality of life (HRQoL) has become increasingly important. The Cystic Fibrosis Questionnaire-Revised (CFQ-R 141) is the most widely accepted method to quantify HRQoL in this patient population. Objectives: Our objective was to systematically review the literature to identify sociodemographic and clinical factors associated with HRQoL among adolescents and adults with CF. Methods: Five major literature databases were searched (MEDLINE, EMBASE, CENTRAL, CINAHL, psychINFO) to identify studies published from January 1989 to April 2014 (n = 1,921). We included all full-text studies that: (1) focused on individuals 14 years of age or older, and (2) examined the relationship between sociodemographic (age, sex, body-mass index [BMI], socioeconomic status, and employment) and clinical (FEV1 % predicted, pulmonary exacerbation, comorbidities) factors with the CFQ-R 141. Effect estimates and levels of statistical significance in the association between sociodemographic and clinical factors with each of the 12 CFQ-R 141domains were analyzed, if examined in at least two studies. Measurements and Main Results: Twenty-eight articles met our inclusion/exclusion criteria, but 5 studies were excluded at the data synthesis stage, leaving 23 articles for analysis. In relation to the CFQ-R 141, 10 candidate factors were examined in at least two studies. The five most commonly studied factors were FEV1 % predicted (57.1% of 28 studies), sex (32.1%), BMI (28.6%), age (17.6%), and pulmonary exacerbations (13%). In studies incorporating multivariable methods, FEV1 % predicted was positively associated with all CFQ-R 141domains with the exception of Digestion, Social Functioning, and Emotional Functioning. Male subjects reported higher Physical Functioning and lower Body Image scores than female subjects, BMIwas positively correlated with Body Image and Weight, and age was negatively correlated with Treatment Burden. Pulmonary exacerbations were negatively associated with multiple domains, including Respiratory Symptoms, Physical, and Role Functioning. Conclusions: Although several factors have been found to be associated with the CFQ-R in adolescents and adults with CF, FEV1% predicted and pulmonary exacerbations have the broadest impact on HRQoL. Further research is required to investigate the impact of agerelated comorbidities, psychosocial factors, and treatment-related factors on HRQoL in adolescents/adults with cystic fibrosis.