Estimating Direct Cost of Cystic Fibrosis Care Using Irish Registry Healthcare Resource Utilisation Data, 2008-2012

Understanding the determinants of cost of cystic fibrosis (CF) care and health outcomes may be useful for financial planning for the delivery of CF services. Registries contain information otherwise unavailable to healthcare activity/cost monitoring systems. We estimated the direct medical cost of CF care using registry data and examined how cost was affected by patient characteristics and CF gene (CF Transmembrane Conductance Regulator [CFTR]) mutation.

Healthcare resource utilisation data (2008-2012) were obtained for CF patients enrolled with the Irish CF Registry by 2013 from linked registry and national hospitalisation database records. Mean annual hospitalisation and medication per-patient costs were estimated by demographic profile, CFTR mutation, clinical status, and CF co-morbidity, and were presented in 2014 euro values. A mixed-effects regression model was used to examine the effect of demographic, CFTR mutation, and clinical outcomes on the log₁₀ cost of direct medical CF care.

Using 4261 observations from 1100 patients, we found that the median annual total cost per patient increased over the period 2008-2012 from €12,659 to €16,852, inpatient bed-day cost increased from €14,026 to €17,332, and medication cost increased from €5863 to €12,467. Homozygous F508-CFTR mutation (class II) cost was highest and milder mutation (class IV/V) cost was 49% lower. Baseline estimated cost in 2008 for a hypothetical underweight, homozygous F508del-CFTR 6-year-old female without chronic Pseudomonas aeruginosa/Staphylococcus aureus, CF-related diabetes (CFRD) or methicillin-resistant S. aureus (MRSA), and with a poor percent predicted forced expiratory volume in 1 s (ppFEV₁) was €10,113, and was €21,082 in a 25-year-old with the same hypothetical profile. Chronic P. aeruginosa infection increased baseline cost by 39%, CF co-morbidity diabetes by 18%, and frequency of pulmonary exacerbation by 15%. Underweight, declining ppFEV₁, chronic S. aureus colonisation, and time also influenced cost.

CFTR mutation is an important factor influencing the cost of CF care. Costs differ among cohorts of CF patients eligible to access new and emerging CFTR repair therapies. These findings support the evaluation of outcome-associated cost in CFTR mutation-specific CF patient groups.