Health-related quality of life in children and adolescents with cystic fibrosis: Convergent validity with parent-reports and objective measures of pulmonary health

Patient-reported outcome (PRO) measures inform medical interventions and evaluate their effectiveness.1 Health-related quality of life (HRQOL) instruments represent PROs that measure perceived health of patients with cystic fibrosis (CF) and provide clinicians and scientists valuable disease-specific information across multiple functional dimensions.2 However, when patients are children, it is unclear whether children or parents are more appropriate and reliable informants. Although children with CF are typically encouraged to recognize symptoms and increasingly assume responsibilities for self-care, child development theory and research suggest their emergent cognitive and psychosocial capacities still put them in need of parent proxies for medical care, decision-making, and research.3 This study compared the concordance of parent proxy-reports and child self-reports on HRQOL for children with CF relative to objective pulmonary measures across three time points. Parent-Child Concordance Research across clinical populations, e.g., asthma, attention deficit hyperactivity disorder, cancer, central nervous system problems, chronic pain, CF, dermatitis, diabetes, epilepsy, eye or ear problems, heart disease, obesity, rheumatoid problems, and healthy pediatric samples shows mixed findings concerning domains of function on which parents and their children agree. Some studies show greater parent-child concordance for observable physical versus psychosocial HRQOL domains.4–7 Others report higher levels of parent-child agreement for psychosocial domains.8–9 Yet another study of healthy children and their parents shows significant parent-child discordance on physical and psychosocial domains. Parents tend to perceive their children’s HRQOL to be higher than children’s reports.10 However, children with CF report higher overall HRQOL compared to their parents’ proxy appraisals; while parents of children with CF tend to report greater treatment burden than their children report.11–12 Objective measures of pulmonary health and frequency of pulmonary exacerbations are associated with HRQOL for patient-reported illness-specific symptoms, general health, physical functioning, and pain.11–14 One study shows no relationship between changes in pulmonary status and changes in patient-reported HRQOL over time,14 whereas another shows changes in patient-reported respiratory symptoms and weight congruent with changes in related HRQOL.15 Gender and age also may play a role in children’s and adolescents’ perceptions about HRQOL. Research shows that female adolescents with CF 16 as well as those in the general population17 tend to report lower HRQOL than their male counterparts. These gender differences in HRQOL have been associated with more severe pulmonary disease among female adolescent and adults with CF.18 Additionally, differences between children and adolescents on self-reported HRQOL have been documented in normative samples.17 For example, younger children are more likely to report digestive problems than adolescents. By contrast, body image may more likely to become an issue during adolescence than childhood. Similarly, age differences have been found in CF populations. Children with CF in late childhood (ages 8 to 12 years) report less favorable HRQOL in the HRQOL domains of Psychosocial, Social, Emotional, and School.19 However, a study of pain shows no associations between child age, gender and parent-child concordance.20 Thus, the influence of age and gender of perceived HRQOL remains unclear. Given the conflicting reports from previous research, designed a study to test the following hypotheses: (a) parent reports would have greater concordance with objective pulmonary measures than child reports; that parent-child concordance would (b) be higher on domains associated with observable symptoms, and (c) show adolescent gender differences. Based on theories of child development we predicted that parent-child concordance would (b) be inversely related to child age.