Spirometric “Lung Age” estimation for North African population

BackgroundPublished reference equations predicting Estimated-Lung-Age (ELA) did not reliably predict Chronological-Lung-Age (CLA) data in North African population.AimsTo develop and to validate novel reference equations for ELA from varied anthropometric data and FEV1.MethodsApplying multiple regression analysis, equations predicting ELA were invented using data from 540 never-smokers with normal spirometry (group I). Validation was made based on data from 41 never-smokers with normal spirometry (group II). Equations were further applied for 91 subjects with confirmed COPD.ResultsNovel regression equations allowing prediction of reference value of ELA and normal limits of difference between ELA and CLA were elaborated in both sexes. In males, ELA (yrs) = 42.85 − 20.74 × FEV1 (L) + 47.41 × Body Surface Area (m2) − 0.62 × Body-Mass-Index (BMI, kg/m2). In females, ELA (yrs) = 64.64 − 8.00 × FEV1 (L) − 0.17 × BMI (kg/m2) + 8.82 × Height (m). Normal limits of difference between ELA and CLA were ±16.9 yrs in males and ±14.8 yrs in females. Established equations predicted ELA of group II with no significant difference between CLA and ELA in either sex (respectively, 42.9 ± 16.6 vs. 40.3 ± 13.7 yrs in males, 42.0 ± 13.5 vs. 45.6 ± 7.7 yrs in females) ELA was significantly older than CLA age only in COPD with grades III and IV ((ELA minus CLA) (yrs) averaged, respectively, +21.7, +26.4).ConclusionNorth African reference equations enrich the World Bank of reference equations from which the physician should choose according to the patient’s ethnic background.