Severity grading per the Pellegrino 2005 standard
Source:R/interpretation_2005.R
pft_severity_2005.RdAssigns a five-band severity grade from FEV1 percent predicted, per
the Pellegrino et al. ERJ 2005 standard (the predecessor to the
2022 z-score-based grading implemented by pft_severity()).
Boundary conventions (matching the function's implementation):
| Grade | FEV1 % predicted |
| mild | >= 70% |
| moderate | 60% - 69% |
| moderately severe | 50% - 59% |
| severe | 35% - 49% |
| very severe | < 35% |
Note that unlike pft_severity(), the 2005 grading has no
"normal" tier – the grades describe the severity of an impairment
that has already been identified, and "normal" lung function is
indicated by the pattern classifier returning "Normal" rather than
by the severity grade itself. Pass only percent-predicted values
from patients with an identified impairment.
Arguments
- pctpred
Numeric vector of FEV1 percent predicted values (e.g. the
fev1_pctpredcolumn frompft_spirometry()times nothing – it is already a percent).
Value
Character vector the same length as pctpred with values
"mild", "moderate", "moderately severe", "severe",
"very severe", or NA.
References
Pellegrino R, Viegi G, Brusasco V, et al. Interpretative strategies for lung function tests. Eur Respir J. 2005;26(5):948-968. doi:10.1183/09031936.05.00035205 . Severity bands taken from Table 4.
See also
pft_severity() for the current Stanojevic 2022
z-score-based grading. pft_classify() with standard = "2005"
for the matching 2005-era pattern classifier.
Examples
pft_severity_2005(c(85, 65, 55, 40, 30))
#> [1] "mild" "moderate" "moderately severe"
#> [4] "severe" "very severe"
# -> "mild" "moderate" "moderately severe" "severe" "very severe"