Annual assessment spirometry, plethysmography, and gas transfer in cystic fibrosis: do they predict death or transplantation.
OBJECTIVE
The long- and short-term prognostic value of pediatric spirometry, plethysmography, and gas transfer measurements in cystic fibrosis (CF) were assessed.


METHODS
Two hundred ninety-eight children with CF and >or=4 annual assessment lung function measurements at a single institution were analyzed in mid childhood. Long-term outcome was death or lung transplantation (D/T) before 2007. Short-term outcome was forced expired volume in one second (FEV(1)) z-score 1 year after the previous lung function measurements.


RESULTS
26/298 had a D/T outcome at median 19.5 years. A zFEV(1) < -2 aged 8 years had a positive predictive value of 67% (sensitivity 67%) for D/T in those homozygous for DeltaF508 but zFEV(1) at older ages and all genotypes was unhelpful. The ratio of residual volume to total lung capacity z-score could also predict a few D/T individuals when zFEV(1) was normal in mid childhood. Most other lung function measurements were not helpful. Matching D/T with alive groups for year of birth left prognostic utility unchanged. Only current zFEV(1) could significantly predict zFEV(1) 1 year hence (56% variability explained, P < 0.00001); no other lung function, gender, age or nutrition factor was significant.


CONCLUSIONS
The value of routine plethysmography and gas transfer measurements in CF is questionable in CF management. Detecting abnormal spirometry even at age 8 years may be too late to affect long-term outcome.
Rosenthal
Mark
M
The Royal Brompton Hospital, London, UK. m.rosenthal@rbht.nhs.uk
D002648:Child; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000401:mortality* / Q000601:surgery*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016040:Lung Transplantation; D008297:Male; D010991:Plethysmography; D011237:Predictive Value of Tests; D011659:Pulmonary Gas Exchange; D013147:Spirometry