Predictors for Survival Rates for Adult-Diagnosed Cystic Fibrosis

Age at diagnosis, lung function, and diabetes are predictors of survival rates in adult-diagnosed cystic fibrosis (CF), according to a study published in Annals of the American Thoracic Society.

Researchers of this study examined demographic and clinical data on patients diagnosed with CF as adults (N=362; median age at diagnosis, 34.3 years) to create a guideline of characteristics for predicting outcomes and survival rates of this population. Clinical data included symptoms, genotype, chronic conditions, lung function, and body mass index. 

Of this cohort, 15 lung transplants and 33 deaths occurred; the rate of surviving for 10 years without a lung transplant was 87.7% (95% CI, 82.9%-91.3%), and the 15-year transplant-free survival rate was 86.1% (95% CI, 80.7%-90.1%). The researchers used the Kaplan-Meier method and multivariable Cox regression analysis and adjusted survival curves, determining that predictors of survival at baseline were age (hazard ratio [HR], 1.24 per 5-year increase; 95% CI, 1.09-1.43), lung function (HR, 1.35 per 5% decrease in forced expiratory volume in 1 second percent predicted; 95% CI, 1.24-1.48), and diabetes (95% CI, 1.35-13.01) (P <.05 for all predictors). Individuals diagnosed at younger ages with higher lung function had a higher predicted median survival time. Patients with diabetes were 4.19 (95% CI, 1.35-13.01) times more likely to need a transplant or die than those without.

“The mechanism by which developing diabetes impacts survival in CF remains unclear but it is hypothesized that it adds an additional inflammatory burden that together with CF-related pulmonary increases the risk of death,” the researchers noted. “The wide confidence intervals suggest some uncertainty in our estimate and therefore this association warrants further study.”

Future studies need to increase sample sizes, evaluate the relationship between diabetes and adult-onset CF for inflammatory-related complications, and include other variables as possible predictors.

The researchers concluded that survival rates of individuals who receive diagnoses of CF as adults can be predicted by factors that include their age at diagnosis, lung function, and the presence of diabetes. Younger patients with higher lung function had more years of survival, and those without diabetes were less likely to require lung transplants.

Reference

Desai S, Wong H, Sykes J, Stephenson AL, Singer J, Quon BS. Clinical characteristics and predictors of reduced survival for adult-diagnosed cystic fibrosis: analysis of the Canadian CF Registry [published online June 26, 2018]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201801-037OC