Bronchodilator response per the ERS/ATS 2022 criterion

Classifies bronchodilator response (BDR) by the percent change in the measured value relative to the patient's predicted value, as recommended by Stanojevic et al. ERJ 2022. Significant BDR is defined as a post-bronchodilator increase of more than 10% of the predicted value in either FEV1 or FVC. This replaces the 2005 standard, which used a >=12% AND >=200 mL change from baseline.

Usage

pft_bdr(pre, post, predicted, threshold = BDR_THRESHOLD_PCT_PRED)

Arguments

pre, post: Numeric vectors of pre- and post-bronchodilator measurements (same units, same length).
predicted: Numeric vector of predicted (median) values for the same measure, typically the <measure>_pred column from a previous call to pft_spirometry().
threshold: Percent-of-predicted change considered significant. Defaults to 10 (the Stanojevic 2022 criterion).

Value

A data frame with one row per input observation and columns:

pct_pred_change: (post - pre) / predicted * 100.
is_significant: logical, TRUE when pct_pred_change > threshold. NA is propagated wherever any of pre, post, predicted is NA.

Column naming

This function's pct_pred_change column is percent-of-predicted change (the 2022 criterion). The predecessor pft_bdr_2005() emits a similarly-named but different column, pct_change, which is percent-of-baseline change ((post - pre) / pre * 100, the 2005 criterion). The two functions deliberately use distinct column names so a result frame can carry both without ambiguity.

References

Stanojevic S, Kaminsky DA, Miller MR, et al. ERS/ATS technical standard on interpretive strategies for routine lung function tests. Eur Respir J. 2022;60(1):2101499. doi:10.1183/13993003.01499-2021 . See the "Bronchodilator responsiveness testing" section.

Examples

pft_bdr(pre = 2.5, post = 3.0, predicted = 4.0)
#> # A tibble: 1 × 2
#>   pct_pred_change is_significant
#>             <dbl> <lgl>         
#> 1            12.5 TRUE          
# -> 12.5% of predicted change, is_significant = TRUE