[The plethysmographic reference equations established for adult natives of Eastern Algeria are not applicable to natives of Northern Algeria].

Introduction: The validity of the published plethysmographic reference equations specific to adults living in Eastern Algeria (RE-EA) in the interpretation of spirometric results in adult natives of Northern Algeria has not been assessed.

Aim: To test the application of the RE-EA (Constantine, mean altitude=694m) to a population of healthy adults living in Algiers (mean altitude=153m).

Methods: The plethysmographic parameters of 453 healthy adults living in Algiers (234 women; age: 45±15 years, height: 1.66±0.10m, weight: 73±14kg) were determined and were compared with those predicted from the RE-EA. In addition, the percentages of adults with an obstructive ventilatory defect (OVD), a restrictive ventilatory defect (RVD) and/or lung hyperinflation were noted. The RE-EA are considered inapplicable to healthy adults living in Algiers if, firstly, the differences between the determined and predicted plethysmographic parameters are statistically significant and, secondly, more than 5% of healthy adults have OVD and/or RVD and/or lung hyperinflation.

Results: The RE-EA significantly overestimated the following parameters: FEV1 by 0.27±0.39L, MMEF by 0.52±0.75L/s, FEF25% by 0.75±0.56L/s, FEF50% by 0.85±1.02L/s, FEF75% by 0.28±1.25L/s, VC by 0.21±0.50L, TLC by 0.31±0.62L, ERV by 0.06±0.48L, IC by 0.27±0.48L, FEV1/VC by 0.03±0.05, and FEV1/FVC by 0.03±0.05. They significantly underestimated the RV/TLC by 0.01±0.05. Moreover, 14.35 %, 8.83 % and 5.74 % of healthy adults had OVD, RVD and lung hyperinflation, respectively.

Conclusion: The RE-EA are not applicable in adult natives of Northern Algeria.