Health-Related Quality of Life for Adults with Cystic Fibrosis: A Regression Approach to Assessing the Impact of Recombinant Human DNase

Study Objectives. To examine the general health‐related quality of life (HRQOL) of adults with cystic fibrosis (CF) using available generic instruments, and to determine important predictors of change in HRQOL, including therapy with recombinant human Dnase (rhDNase). Design. Prospective, observational study. Patients. Fifty‐nine adults with CF. Intervention. The Medical Outcomes Study Short‐Form 36 (SF‐36) and the EuroQol (EQ‐5D) were mailed to patients; follow‐up surveys were mailed 1 year later. Measurements and Main Results. Multivariate regression analyses assessed the relationships between clinical and demographic variables and change in health status. The 39 respondents reported lower HRQOL scores compared with general population norms for generic instruments. Regression analyses indicated that age (p=0.010), percentage predicted forced expiratory volume in 1 second (p=0.005), hospital admission (p=0.023), and rhDNase therapy (p=0.026) were positively associated 1998 EQ‐5D index scores, whereas body mass index was negatively associated (p=0.025) with 1998 EQ‐5D index scores after controlling for baseline 1997 scores. The size of the regression coefficients indicated that only 1997 scores and hospital admission in the year were quantitatively importantly associated with 1998 scores. Baseline HRQOL assessments showed that adults with CF reported important decrements in health status and functioning. An interesting relationship between functional status and total household income was observed. Conclusion. Although a statistically significant association between rhDNase and 1‐year change in HRQOL was found on multivariate regression analysis, the magnitude of this relationship may not be clinically important.