There are several reasons why it is of utmost importance to diagnose the CPFE syndrome. First, the risk of the development of PH is elevated (between 50% and 90%2,9) and is associated with poor survival. Indeed, the 5-year survival rate was 25% for patients with PH vs 75% for patients without PH at echocardiography in our study2; the presence of severe PH at echocardiography was associated with an increased risk of death in the study by Mejia et al9 (hazard ratio, 1.88; 95% confidence interval, 1.01 to 3.48). Second, since lung volumes are relatively preserved in patients with CPFE (as opposed to patients with IPF without emphysema) and the main determinant of mortality is represented by PH, it is expected that lung volumes, which are usually evaluated in the course of IPF, may not be relevant for the follow-up of patients with CPFE. While FVC may not accurately reflect progression of disease, it may be anticipated that variations in diffusion capacity, hypoxemia, or pulmonary artery pressure, could represent better surrogates for the progression of disease and mortality. Third, the inclusion of patients with CPFE syndrome in IPF clinical trials may lead to spurious underevaluation of the effect of treatment in IPF patients, as the inclusion criteria of several international clinical trials10–12 in patients with IPF were likely compatible with the inclusion of patients with CPFE. We consider that patients with CPFE should thus be carefully excluded from future IPF trials (or at least a stratification should be anticipated to account for the presence of emphysema). Fourth, it is currently not clear whether pathologic features of CPFE reflect the sole combination of emphysema and a pattern of usual interstitial pneumonia, or whether non-usual interstitial pneumonia patterns (some of which have been reported in CPFE patients2,5) may be frequent. Last, the diagnostic criteria for IPF may not apply to all patients with CPFE, who may have normal lung volumes despite advanced disease and the need for long-term nasal oxygen therapy.