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. Author manuscript; available in PMC: 2012 Sep 1.
Published in final edited form as: Pediatr Pulmonol. 2011 Apr 1;46(9):857–869. doi: 10.1002/ppul.21456

Table 1.

Generic Framework on Which the FEV1-Based Phenotype was Created.

  1. Calculate age-specific FEV1 percentile score (X) for each patient, using either residuals from a sample based regression (as was done for NoRMA) or published disease specific reference equations (as in KNoRMA).

  2. Estimate cohort survival percentile for each age in 0.01 year intervals (S).

  3. Calculate age-specific mortality percentile (1-S), to adjust FEV1 percentile.

  4. Calculate age-specific, survival adjusted FEV1 percentile: X*S+(1-S).

  5. Transform the age-specific survival adjusted FEV1 percentile to a normal score for the final phenotype.