Is There an “Ideal” Cystic Fibrosis Candidate for Lung Transplantation?

As diagnostics become more sophisticated, more adults are being diagnosed with cystic fibrosis (CF). Although patients with CF tend to have shorter expected life expectancies than the general population, researchers are exploring methods that predict outcomes, even in patients who are diagnosed well into adulthood.¹

Why Are Patients Being Diagnosed With CF in Adulthood?

Diagnosing CF early is critical because prompt treatment can lead to better survival, yet universal newborn screening (NBS) in the United States has been around for less than a decade.²

“From the time the evidence supporting NBS appeared in 2005, it took until late 2009 for all 50 states to adopt NBS,” said Philip M. Farrell, MD, PhD, professor of pediatrics and population health sciences at the University of Wisconsin School of Medicine and Public Health in Madison, in an email interview with Pulmonology Advisor. “That is among the fastest time that any NBS program has been implemented.”

Because of this relatively late adoption of NBS, some patients are diagnosed with CF as adults after they present to their clinicians with respiratory and gastrointestinal complaints.¹ In a Canadian registry study of 362 adults with CF, the median age at diagnosis was 34.3 years.¹

To better characterize this growing population of patients with CF, Desai and colleagues reported the top predictors of poor outcomes. Age at diagnosis (hazard ratio [HR], 1.24 per 5-year increase; 95% CI, 1.09-1.43), diabetes (HR, 4.19; 95% CI, 1.35-13.01), and lung function at baseline (HR, 1.35 per 5% decrease in forced expiratory volume in 1 second [FEV_­1 %] predicted; 95% CI, 1.24-1.48) were among the primary factors for decreased survival.¹ Of the adult-diagnosed patients in the registry who did not have a lung transplant, 88% survived 10 years and 86% were alive 15 years after diagnosis.¹

“It is too early to gauge the impact of our research, but we certainly believe that our study will provide insights on adult-diagnosed patients at risk [for] worse outcomes,” said coauthor Bradley S. Quon, MD, from the Centre for Heart Lung Innovation at the University of British Columbia in Vancouver, Canada, in an interview with Pulmonology Advisor. “This new information will allow clinicians to target therapies accordingly to improve health outcomes. This study does not impact on decisions regarding lung transplantation for CF patients, but it does appear that a minority of adult-diagnosed patients develop progressive disease requiring lung transplantation.”

Comorbid Diabetes Increases Likelihood of Transplantation

One of the most common comorbidities is CF-related diabetes (CFRD), which leads to poor outcomes. Lewis and colleagues discovered that in a chart review of 664 patients with CF, those with diabetes who were ≥40 years old not only had lower forced vital capacity but were also more likely to have had a lung transplant within a decade compared with patients with CF who did not have diabetes (24% vs 0%, respectively; P =.046).³