Treatment complexity in cystic fibrosis: trends over time and associations with site-specific outcomes

Patients with cystic fibrosis (CF) have increasing treatment complexity and high treatment burden. We describe trends in treatment complexity and evaluate its relationship with health outcomes.

Using Epidemiologic Study of Cystic Fibrosis (ESCF) data, we developed a treatment complexity score (TCS) from 37 chronic therapies and assessed change by age group (6-13, 14-17, and 18+ years) over a three year period. Differences in average site TCS were evaluated by quartiles based on FEV1, BMI, or Treatment Burden score on the Cystic Fibrosis Questionnaire-Revised (CFQ-R).

TCS scores were calculated for 7252 individual patients (42% child, 16% adolescent, 43% adult) across 153 sites. In 2003, mean TCS was 11.1 for children, 11.8 for adolescents, and 12.1 for adults. In all 3 age groups, TCS increased over 3 years; the increase in TCS from 2003-2005 for children was 1.25 (95% CI 1.16-1.34), for adolescents 0.77 (0.62-0.93), and for adults 1.20 (1.08-1.31) (all P<0.001 for trend over time). At the site level, there were no significant differences in mean TCS based on FEV1 quartile. Mean TCS was higher in the highest BMI z-score quartile. Across all 3 versions of the CFQ-R, mean TCS was lower at sites in the highest quartiles (lowest burden) for CFQ-R treatment burden scores.

Treatment complexity was highest among adults with CF, although over 3 years, we observed a significant increase in treatment complexity in all age groups. Such increases in treatment complexity pose a challenge to patient self-management and adherence. Future research is needed to understand the associations between treatment complexity and subsequent health outcomes to reduce treatment burden and improve disease management.