title: Prediction equations for single-breath diffusing capacity in subjects aged 65 to 85 years.
abstract: BACKGROUND
  In senior subjects, diffusing capacity of the lung for carbon monoxide (Dlco) is interpreted using prediction equations derived from primarily younger adult populations. Our objectives were to provide reference equations for single-breath Dlco for a cohort of healthy, never-smoking, white, European adults between 65 and 85 years of age and to compare the predicted values of this sample with those from other studies involving middle-aged adults.
  
  
  METHODS
  Reference equations were derived from a randomly selected sample from the general population of 431 healthy never smoker subjects aged 65 to 85 years (262 women and 169 men). Spirometry, lung volume determinations by plethysmography, and single-breath Dlco (corrected for hemoglobin) were performed following the American Thoracic Society/European Respiratory Society guidelines. Reference values and lower and upper limits of normal were derived using a piecewise polynomial model.
  
  
  RESULTS
  In addition to age, our reference equations confirmed the height and body size dependence of Dlco and diffusing capacity for alveolar volume (Dlco/Va) in older subjects. Practically all of the reference values obtained by extrapolating reference equations of middle-aged adults underestimated the true diffusing capacity of the healthy elderly volunteers. Middle-aged reference equations underestimated Dlco by 2.1% to 22.3% in women and 2.8% to 37.8% in men. In addition, Dlco/Va was overestimated up to 18% and 39.8% in women and men, respectively, whereas other equations underestimated Dlco/Va up to 22.2% and 11.9% in women and men, respectively.
  
  
  CONCLUSIONS
  These results underscore the importance of using prediction equations appropriate to the origin and age characteristics of the subjects being studied.
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain; CIBER de Enfermedades Respiratorias-CIBERES, Madrid, Spain. Electronic address: fgr01m@gmail.com.
authors.forename: Francisco
authors.initials: F
authors.lastname: Garcia-Rio
authors.affiliation: Carburos Medica, Madrid, Spain.
authors.forename: Ali
authors.initials: A
authors.lastname: Dorgham
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
authors.forename: Raul
authors.initials: R
authors.lastname: Galera
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Casitas
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
authors.forename: Elizabet
authors.initials: E
authors.lastname: Martinez
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Alvarez-Sala
authors.affiliation: Servicio de Neumología, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Pino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D010991:Plethysmography; D011237:Predictive Value of Tests; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D012016:Reference Values; D012727:Sex Characteristics; D013147:Spirometry