FEV1 as percentage of predicted, does not appear to be the best predictor of mortality in elderly patients with asthma, according to the results of a study by researchers in Italy. When longer-term prognostic stratification is required, FEV1 as a multiple of the sex-specific first percentile should be considered, though the authors noted that no spirometric index can predict 5-year mortality in this population.
For the stiudy, researchers analyzed data on 200 patients with asthma who were at least 65 years of age. Participants had a mean FEV1 of 1.5 L, a mean FEV1 % predicted of 65.6, a mean FEV1 divided by height-cubed of 0.4 L/m3 and a mean FEV1 expressed as a multiple of the gender-specific first percentile (FEV1Q) of 3.4.
At 5-year follow-up, no expression of FEV1 effectively predicted mortality. By contrast, at 10 years, FEV1Q was the only spirometric parameter independently associated with mortality; each standard deviation increase resulted in a 65% lower risk for death. This was confirmed at 15 years, when it was associated with a 62% lower risk for death.
“The association of FEV1Q with long-term mortality suggests that respiratory function also is related to survival in elderly patients with asthma and multiple morbidities and thus encourages further research on the best way of quantifying lung dysfunction in this population,” the authors concluded.
Researchers noted that this finding is in contrast to the prognostic role FEV1 has in patients with COPD.