PAH survival unaffected by rheumatoid arthritis origin

Feb 13 2015

By Lucy Piper, Senior medwireNews Reporter

Patients with rheumatoid arthritis-associated pulmonary arterial hypertension (RA-PAH) have comparable survival to those with idiopathic pulmonary arterial hypertension (IPAH), researchers report.

Sindhu Johnson (Toronto Western Hospital, Ontario, Canada) and study co-authors say that their findings provide “interesting information” about the survival of patients with RA-PAH, a condition that is currently poorly understood.

The team screened 1385 patients and identified 18 RA-PAH patients and 155 IPAH patients who met the inclusion criteria of a mean pulmonary arterial pressure (mPAP) of 25 mmHg or above, pulmonary capillary wedge pressure of 15 mmHg or below and pulmonary vascular resistance of more than 3 Wood units by cardiac catheterisation.

Significant differences between the two groups included older age at PAH onset in patients with RA-PAH, at a median 64.0 years versus 53.7 years for IPAH patients, and a lower mPAP at baseline of 41 mmHg versus 50 mmHg.

Also, there was a higher proportion of women among patients with RA-PAH compared with IPAH (83 vs 70%) and fewer RA-PAH patients had a baseline World Health Organization functional class of III/IV (39 vs 52%). Neither of these differences was significant, however.

In total, 35 of the study participants died; two (11%) of the RA-PAH patients and 33 (21%) of those with IPAH.

The unadjusted 1-year survival for RA-PAH patients was 93% and 94% for IPAH patients. There was a separation of Kaplan–Meier curves over time, but otherwise there was no significant difference in survival between the two groups, the researchers comment in Respirology.

They acknowledge that a small sample size of RA-PAH patients and low death rate may have limited the power of their study and its ability to show a significant survival difference.

The team advises testing survival in larger cohorts of RA or pulmonary hypertension patients, as well as evaluating the effect of RA disease activity and response of PAH to immunosuppressive therapy.

Many of the RA-PAH patients in the current study were treated with immunosuppressives, the researchers note, but none were treated with biological agents. This suggests that RA-PAH patients had milder RA disease or that aggressive biological agents protected RA patients against PAH, they say.

“Although our data do not address this issue, this hypothesis would be supported by the data that suggest that PAH in RA is related to inflammatory vasculopathy and immunoglobulin formation from activated B cells”, the researchers explain.

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