Clinical Characteristics Associated With Lung Function Decline in Individuals With Adult-Diagnosed Cystic Fibrosis: Contemporary Analysis of the Canadian CF Registry

Abstract

Individuals with cystic fibrosis (CF) diagnosed as adults represent a rare but growing subset of the CF population. Limited studies have described their lung function trajectories. What is the overall trajectory of lung function and clinical characteristics associated with lung function decline in people who receive a diagnosis of CF as adults? The Canadian CF Patient Registry (CCFR) was used to identify patients with CF who were≥ 18 years of age at diagnosis and received a diagnosis between 2000 and 2017. Linear mixed-effects models were used to quantify the change in lung function over age and to examine clinical characteristics associated with lung function decline. Lung function was stable in early adulthood, with a decline in middle adulthood (age 30-50 years) and a greater decline after 50 years of age. Individuals who receive a diagnosis at older ages (> 50 years: slope, -0.71%/y; 41-50 years: -0.68%/y; 31-40 years: -0.29%/y; 18-30 years: -0.28%/y) and those demonstrating pulmonary symptoms (slope, -0.41%/y) compared with no pulmonary symptoms at baseline were associated with faster rate of lung function decline. The lung function of who receive a diagnosis of CF as adults in the CCFR declines slowly compared with estimates from the overall adult CF population. Individuals with adult-diagnosed CF who are older and demonstrate pulmonary symptoms at diagnosis experience a faster rate of lung function decline and should be monitored more closely.