Table 5.
Effect of change of reference standard to NHANES III (Hankinson et al 1999) on the classification of severity of restrictive spirometric ‘abnormality’, using percent predicted FVC (n = 228)
| Reference equation | Percent disagreement | Weighted Kappa | Generalized McNemar’s test | Comment on comparison with NHANES III reference standard |
|---|---|---|---|---|
| Morris et al 1971 | 32.46 | 0.61 (0.54, 0.69) | p < 0.001 | Morris classifies a lower level of severity |
| Kory et al 1961 | 21.49 | 0.75 (0.69, 0.81) | p < 0.001 | Kory classifies a lower level of severity |
| Crapo et al 1981 | 12.28 | 0.87 (0.82, 0.92) | p = 1.00 | Crapo classifies a similar level of severity |
| Knudson et al 1976 | 22.37 | 0.74 (0.67, 0.80) | p < 0.001 | Knudson usually classifies a lower level of severity |
| Knudson et al 1983 | 14.49 | 0.84 (0.78, 0.89) | p = 0.06 | Knudson tends to classify a lower level of severity, although the trend is not statistically significant |
*
Numbers in parenthesis reflect 95% confidence intervals