Emphysema elevates the DETECT scores: impact on pulmonary hypertension screening and diagnosis in systemic sclerosis

Combined pulmonary fibrosis and emphysema (CPFE) predicts unfavourable outcomes in systemic sclerosis (SSc). CPFE and emphysema are associated with pulmonary function tests (PFTs) abnormalities. As screening algorithms for pulmonary hypertension include PFTs, we aimed to assess whether CPFE and emphysema affect the performance of the DETECT algorithm to select patients for right-heart catheterization (RHC).

SSc patients from our referral centre, with available chest tomography images to identify emphysema or interstitial lung disease (ILD) and data to calculate the DETECT score were included. Baseline visit was set as the first visit with available information. Patients with any form of pulmonary hypertension at baseline were excluded. We tested the association of CPFE (and ILD and emphysema separately) with the DETECT score, DETECT score positivity and false positivity, using regression models adjusted for selected covariates.

Among 550 eligible cases, ILD was detected in 232 (42%) and emphysema in 59 (11%) patients, resulting in a 7% prevalence of CPFE. The DETECT score was higher and on average above the threshold for referral to RHC in emphysema and CPFE patients. After adjustment, both emphysema and CPFE predicted positive DETECT scores, while ILD did not. Nevertheless, we found no association between CPFE nor emphysema with false-positive DETECT scores.

In SSc, CPFE and emphysema are associated with a higher and more frequently positive DETECT score. As neither CPFE nor emphysema were associated with false-positive DETECT results, our data also support the validity of the DETECT algorithm in these SSc subgroups.