Predictors of pulmonary hypertension in patients with hypersensitivity pneumonitis

Introduction. Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) that occurs in susceptible individuals in response to various inhaled antigens. Pulmonary hypertension (PH) is a common and unfavourable prognostic complication of HP, particularly in patients with the progressive fibrotic phenotype. Early detection of PH is significantly more difficult due to the non-specific nature of clinical symptoms and the complexity of diagnosis.

Аim. To estimate the prevalence of PH and to identify predictors of PH in patients with chronic HP.

Materials and methods. We conducted an observational longitudinal study that included 85 patients with an established diagnosis of HP. Clinical examination, high-resolution computed tomography (HRCT) of the chest, arterial blood gases analyses, six-minute walking test (6MWT), pulmonary function tests, and echocardiography were performed.

Results. Patients were divided into groups with fibrotic (71.8%) and nonfibrotic phenotype (28.2%) of HP (fHP and nfHP). PH was diagnosed in 42 patients (49.4%): 35 (57.4%) in the fHP subgroup and 7 (29.2%) in the nfHP subgroup. The most significant predictors of PH development in patients with HP were the presence of pulmonary fibrosis on HRCT (OR 6.35 (95% CI 1.63–24.70), p = 0.008) and a history of cardiovascular diseases (OR 3.72 (95% CI 1.0–13.6), p = 0.050). Furthermore, the likelihood of developing PH rises with age over 60 years, SpO₂ levels at the end of the 6MWT below 85%, the distance covered in the 6MWT less than 390 metres, and a FVC/DLco ratio greater than 1.5.

Conclusions. PH is a common condition in patients with chronic HP, especially with the fibrotic phenotype. Early detection of the PH predictors is necessary for the timely diagnosis of this complication of HP.

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