Treatment burden in patients with at least one class IV or V CFTR mutation

Abstract

CFTR mutations are grouped according to disease-causing mechanism. Several studies demonstrated that patients having at least one mutation of class IV/V, present with a milder phenotype, but little is known about their relative treatment burden. We compared treatment burden between patients with two class I, II, or III mutations and patients with at least one mutation of class IV/V in the 2010 database of the Belgian CF Registry. We calculated a "Treatment Burden Index" (TBI) by assigning long term therapies to categories low, medium and high intensity, for differential weighing in the total score. There were 779 patients with two known class I/II/III mutations and 94 patients with at least one class IV/V mutation. Compared to class I/II/III, class IV/V patients had a lower median number of clinic visits (4 vs. 5; P < 0.001), a lower risk of hospitalization (24.7% vs. 50.8%; P < 0.001) and intravenous antibiotic treatment (23.5% vs. 46.0%; P < 0.001) and a lower median TBI (6 vs. 9; P < 0.001). These differences remained significant when only class IV/V patients with pancreatic insufficiency (n = 31) were considered. This study clearly demonstrates the significantly lower treatment burden in patients with CF and at least one class IV/V mutation compared to patients with two class I/II/III mutations and contributes to providing better individual counseling at time of diagnosis.

Cystic fibrosis in the year 2020: A disease with a new face

“…On average, patients with at least one mutation of class IV or V have later onset of disease, lower sweat chloride values, slower decline in lung function, less chronic Pseudomonas aeruginosa infections, less CF‐related diabetes and lower treatment burden . Together, these mutations are called residual function mutations, in contrast to mutations that confer no, or hardly any, CFTR function, which are jointly called minimal function mutations.…”

Cystic fibrosis lung environment and Pseudomonas aeruginosa infection

“…This is a result of neonatal screening and newer treatment modalities such as improved control of pulmonary infections and mucociliary clearance. However, recent years have also seen an increase in disease complexity [3] with newer, more resistant genetic variants [4] often emerging. Some of these have been covered very well in several excellent reviews [3, 5–7].…”

Treating the Underlying Cystic Fibrosis Transmembrane Conductance Regulator Defect in Patients with Cystic Fibrosis

“…11 Patients with at least one mutation of class IV or V have on average milder disease, later onset, lower sweat chloride, slower decline in lung function, less chronic Pseudomonas aeruginosa infections, less CF-related diabetes, and lower treatment burden. 12 The mutation classification is an oversimplification because most mutations cannot be strictly confined to one class. For example, the class II mutation F508del has also characteristics of class III and class VI.…”