Associations between clinical variables and quality of life in adults with cystic fibrosis

Abstract

Background

The disease progression of cystic fibrosis (CF) is marked by an increase in clinical conditions and therapeutic interventions, which have the potential to affect health-related quality of life (HRQoL). This cross-sectional study explored associations between clinical variables and HRQoL.

Methods

HRQoL was measured using the Cystic Fibrosis Quality of Life (CFQoL) questionnaire, which consists of nine domains: physical, social, treatment, chest symptoms, emotional functioning, concerns for the future, relationships, body image, and career concerns. The CFQoL was completed by 223 adults with CF. Clinical and demographic data collected were: age, gender, FEV₁% predicted, BMI, Burkholderia cepacia status, lung transplant status, diabetic status, level of nutritional intervention, and presence of an intravenous access device. Multiple regression using forward selection was used to construct models relating these variables to each HRQoL domain.

Results

Despite many of the variables being inter-related, some variables were associated with CFQoL domains even in the presence of other important clinical factors. FEV₁% predicted was weakly positively associated with all nine domains. Strong evidence emerged that patients who had received a lung transplant reported a higher HRQoL in physical and social functioning, chest symptoms, and treatment issues. Females tended to report a lower quality of life for chest symptoms and career issues, but higher values for body image. Patients with an access device expressed more career concerns. There was no evidence of an association between B. cepacia and any of the nine CFQoL domains. The model for the body image domain explained a high percentage of the variance (R²=30%): negative body image was associated with lower BMI, having an access device, diabetes, and enteral feeding.

Conclusions

While important associations were identified, much of the variance in HRQoL remains unexplained. Other clinical and psychosocial variables merit investigation. A longitudinal study is required to investigate how the disease trajectory and associated treatments affect an individual's quality of life.