Validation of the CFAbd-Score.kidⒸ, a Novel gastrointestinal patient reported outcome measure, specific for children with cystic fibrosis.

BACKGROUND

Abdominal symptoms (AS) relevantly impair quality of life (QoL) in people with Cystic fibrosis (CF). Following FDA guidelines, we previously developed and validated the CFAbd-Score©, the first CF-specific gastrointestinal patient-reported outcome-measure (PROM) for people with CF. Therewith, we demonstrated that AS significantly and markedly decrease during treatment with the new game-changing CF-therapy elexacaftor-tezacaftor-ivacaftor (ETI). However, for children with CF (cwCF), a pediatric-focused PROM could improve self- or proxy-assisted reporting of AS.

AIMS: Development and validation of the CFAbd-Score.kid©, the pediatric version of the CFAbd-Score©, following FDA- and COSMIN-guidelines, anticipating ETI approval in younger cwCF.

METHODS

We iteratively developed the CFAbd-Score.kid© together with CF-specialists from different fields, cwCF and their proxies. We implemented pictograms and easy language to optimize comprehension of questions by cwCF aged <12years, as well as adapted response strategies. We devised a scoring algorithm, weighting items (n = 29) and domains (n = 5) differently, to optimize the PROM´s sensitivity (range: 0-100pts).

RESULTS

In 5 German CF-centers, n = 102 cwCF (7.6 ± 2.3yrs) completed n = 257 CFAbd-Score.kid© questionnaires. For known-groups validity analysis, n = 72 healthy children (HC) were included. Good to excellent test-retest reliability was observed (intraclass correlation-coefficient=0.89, p < 0.001). Median total CFAbd-Score.kid© resulted significantly higher in cwCF, compared to HC (16.2 vs.10.1pts, p < 0.01). CwCF also scored significantly higher in domains "Disorders of bowel movement", "Disorders of appetite" and "Quality of life".

CONCLUSION

The novel CFAbd-Score.kid©, well accepted among children, allows recording of AS in cwCF. The total CFAbd-Score.kid© and three of its five domains reveal a significantly and markedly elevated burden of AS in cwCF, compared to HC.