Clinical characteristics and survival of Japanese patients with connective tissue disease and pulmonary arterial hypertension: a single-centre cohort.

OBJECTIVE: To clarify the characteristics, survival and predictors of mortality in Japanese patients with pulmonary arterial hypertension (PAH) associated with CTD.
METHODS: This single-centre cohort study enrolled 70 consecutive patients with PAH-CTD who visited a tertiary referral centre in Japan between 1970 and 1990 (n=30, historical group) and between 2000 and 2009 (n=40, recent group). Baseline clinical features, haemodynamic parameters and ANA profiles were recorded. The Cox proportional hazards regression model was used to determine independent factors associated with an increased risk of mortality.
RESULTS: MCTD and SLE were the major underlying CTDs, comprising 43% and 29% of PAH patients respectively, whereas SSc was less common (19%). Anti-U1RNP antibody was the most prevalent ANA (61%). The cumulative survival rate was significantly better in the recent group in comparison with the historical group (76% vs 26% at 3 years; P<0.001). When both groups were combined, World Health Organization functional class III or IV at diagnosis was identified as an independent predictor of mortality, whereas modern PAH drug use was associated with a favourable outcome.
CONCLUSION: The major PAH-CTD population in Japan suffers from MCTD or SLE with anti-U1RNP antibody, in contrast to PAH-CTD patients in the USA and Europe. Modern PAH treatment has improved survival rates, but long-term outcomes are still unsatisfactory. Independent predictors of mortality indicate that early diagnosis and the prompt use of PAH drugs should improve survival.