Specific Variables Improve Disease Severity Discrimination Among CF Transplant Candidates

The inclusion of Cystic Fibrosis Foundation Patient Registry variables in the lung allocation score (LAS) calculation allowed for enhanced discrimination of disease severity among lung transplant waitlisted candidates with cystic fibrosis (CF), thus providing improved access for those at the highest risk for death. In addition, patients with chronic obstructive pulmonary disease (COPD) also had improved access to transplantation, specifically when forced expiratory volume in 1 second (FEV1) was included as one of the clinical parameters.

A multicenter, retrospective, population-based study was conducted among all lung transplant waitlist candidates aged ≥12 years between January 1, 2011, and December 31, 2014. Results of the analysis were published in the American Journal of Respiratory and Critical Care Medicine.

Using a novel database, investigators sought to identify those clinical variables associated with waitlist and posttransplant mortality in lung transplant recipients with CF. They also analyzed the effect of including new CF-specific variables in the LAS system. They used data from the US Scientific Registry of Transplant Recipients system, which includes information on all donors, transplant candidates, and transplant recipients in the United States, as submitted by members of the Organ Procurement and Transplantation Network.

A total of 9043 patients on the lung transplant waiting list and 6110 lung transplant receipts were evaluated, of whom 1020 and 677, respectively, had CF. Measured study outcomes included changes in LAS and lung allocation rank.

In lung transplant candidates with CF, the presence of any Burkholderia species (hazard ratio [HR], 2.8; 95% CI, 1.2-6.6; P =.02), hospitalization for 29 to 42 days in the previous 12 months (HR, 2.8; 95% CI, 1.3-5.9; P =.01), massive hemoptysis (HR, 2.1; 95% CI, 1.1-3.9; P =.02), and relative decline in FEV1 of ≥30% over 12 months (HR, 1.7; 95% CI, 1.0-2.8; P =.05) all significantly increased the waitlist mortality risk. In addition, pulmonary exacerbation time of 15 to 28 days before lung transplant (HR, 1.8; 95% CI, 1.1-2.9; P =.02) significantly increased the risk for posttransplant mortality.

Further, a relative decline in FEV1 of ≥10% among those with COPD who were candidates for lung transplantation was associated with a significantly increased risk for waitlist mortality (HR, 2.6; 95% CI, 1.2-5.4; P =.01). Moreover, variability in LAS and rank increased in patients with CF, and priority for receiving a lung transplant rose in those with COPD. Access to transplantation was not altered in any other diagnostic group. The researchers stated that the change for patients with COPD “likely reflects use of an updated cohort, arguing for more frequent updates to the cohorts used for LAS calculations.”

Reference

Lehr CJ, Skeans M, Dasenbrook EC, et al. Effect of including important clinical variables on accuracy of the lung allocation score for cystic fibrosis and chronic obstructive pulmonary disease [published online June 14, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201902-0252OC