Anti-synthetase syndrome: consider pulmonary hypertension screening (death HR 2.52)

Design

International multicentre physician-reported registry, 103 centres

Population

1,868 patients with anti-synthetase syndrome and 2,043 autoimmune disease controls

Primary outcome

Prevalence of pulmonary hypertension and all-cause mortality

Effect

Prevalence 8.9%; 5-year survival 88.3% vs 94%; mortality HR 2.52 (95% CI 1.41 to 4.53)

An international physician-reported registry in Rheumatology (published 29 September) analysed 1,868 patients with anti-synthetase syndrome and 2,043 controls with other autoimmune diseases from 103 centres.

Pulmonary hypertension was present in 8.9% of anti-synthetase syndrome, compared with 3% in other myositis, 4% in rheumatoid arthritis and 3% in interstitial pneumonia with autoimmune features, and not significantly different from systemic sclerosis (13%) or lupus (11%). After adjustment for age, sex, smoking and interstitial lung disease, odds were about twice those of other myositis. Five-year survival was 94% overall but 88.3% with pulmonary hypertension, which was independently associated with death (HR 2.52, 95% CI 1.41 to 4.53).

Systematic screening for pulmonary hypertension is established in systemic sclerosis but not in anti-synthetase syndrome, where attention focuses on the lung parenchyma. These data suggest pulmonary hypertension is common enough, and important enough, to look for, particularly when breathlessness is out of proportion to lung disease or the diffusion capacity falls disproportionately. The study does not define the best screening tool or interval.

• Consider echocardiography to look for pulmonary hypertension in patients with anti-synthetase syndrome, especially with interstitial lung disease.
• Suspect pulmonary hypertension when breathlessness or a falling DLCO is out of proportion to lung imaging.
• Check NT-proBNP as part of the assessment where available.
• Refer suspected cases for right heart catheterisation and specialist pulmonary hypertension assessment.
• Record pulmonary hypertension status at diagnosis and during follow-up.

Why it matters

It extends to anti-synthetase syndrome a screening habit currently reserved for systemic sclerosis.

Don't overread it

This physician-reported registry did not use uniform diagnostic criteria for pulmonary hypertension, and it does not show that screening improves survival.

The statistics, in plain English

A hazard ratio of 2.52 means patients with pulmonary hypertension died at about two and a half times the rate of those without, after allowing for lung disease. Prevalence may be over- or under-estimated because diagnosis depended on each centre's practice.

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