Prevalence of pulmonary hypertension in an unselected, mixed connective tissue disease cohort: results of a nationwide, Norwegian cross-sectional multicentre study and review of current literature.

Objectives: The aim of this study was to assess the overall prevalence of pulmonary hypertension (PH) in an unselected MCTD cohort and review the current knowledge with a systematic database search.
Methods: A nationwide multicentre cohort of 147 adult MCTD patients were initially screened for PH by echocardiography, high-resolution computed tomography (HRCT), pulmonary function tests and N-terminal pro-brain natriuretic peptide (NT-proBNP) and then followed up for a mean of 5.6 years. Right-sided heart catheterization was performed when estimated pulmonary artery systolic pressure was >40 mmHg on echocardiography. PH was diagnosed according to the 2009 European Society of Cardiology and European Respiratory Society guidelines.
Results: At inclusion, 2.0% (3/147) had established PH. Two additional PH patients were identified during follow-up, giving a total PH frequency in the cohort of 3.4% (5/147). All five had elevated serum NT-proBNP. Two had isolated pulmonary arterial hypertension (PAH) and three PH associated with interstitial lung disease (PH-ILD). Three PH patients died during follow-up. Nine other patients in the cohort also died, but none of them had echocardiographic signs of PH prior to death.
Conclusion: The data from the current unselected MCTD cohort suggest that the prevalence of PH is much lower than expected from previous studies but confirm the seriousness of the disease complication.