The prevalence of undiagnosed pulmonary arterial hypertension in subjects with connective tissue disease at the secondary health care level of community-based rheumatologists (the UNCOVER study)

Abstract

Objective: Most of the data about the prevalence of pulmonary arterial hypertension (PAH) are from tertiary centers that are biased toward seeing more severe cases; therefore, the true prevalence of PAH among patients with connective tissue disease is unknown. We sought to determine the point prevalence of undiagnosed PAH in community-based rheumatology practices.

Methods: The study design was a multicenter, prospective and retrospective survey and analysis of clinical cases in 50 community rheumatology practices. We evaluated a total of 909 patients with either scleroderma (systemic sclerosis [SSc]) or mixed connective tissue disease (MCTD). If a subject had not been diagnosed as having PAH, then a new Doppler echocardiogram was obtained to measure cardiac parameters, including estimated right ventricular systolic pressure (ERVSP), and a full review of medical records was done.

Results: Of 909 screened patients, 791 were evaluable and completed the study; 669 had not previously been studied for PAH. Of these 669 patients, 89 (13.3%) were found by Doppler echocardiography to have an ERVSP of > or = 40 mm Hg. Of these 89 patients, 82 (92.1%) had SSc and 7 (7.9%) had MCTD. The total prevalence of PAH in the survey was 26.7% (211 of 791 patients, including 122 with known PAH and 89 newly diagnosed as having PAH). Doppler echocardiographic data showed 20 of 89 patients (22.5%) with ERVSP of > or = 50 mm Hg, 20 of 89 patients (22.5%) with increased RV dimension, and 25 of 89 patients (28.1%) with right atrial enlargement. Patients with ERVSP > or = 40 mm Hg had decreased exercise tolerance compared with those with ERVSP <40 mm Hg (27% compared with 9.5%, respectively, were severely symptomatic).

Conclusion: A significant number of patients with SSc or MCTD (13.3%) followed up in a community rheumatology practice setting have undiagnosed elevated ERVSP consistent with PAH.