Exercise Oxygen Desaturation, Pulmonary Function Predict Outcomes in SSc-PH

Risk factors predictive of poor outcomes in patients with systemic sclerosis (SSc) who are at risk for pulmonary hypertension (PH) include male sex, exercise oxygen desaturation, diffusing capacity of the lungs for carbon monoxide (DLCO) <50%, and pericardial effusions, according to study results published in the Journal of Rheumatology.

Patients with a natural history of definite SSc pulmonary arterial hypertension and SSc-PH were enrolled (n=236). All patients had an echocardiogram systolic pulmonary arterial pressure of >40 mm Hg, a predicted DLCO of <55%, or a ratio of percentage of forced vital capacity/%DLCO >1.6. In analyses adjusted for age, sex, race, and disease duration, researchers evaluated the association between various baseline clinical measures with predictors of hospitalization and death.

During a median of 4 years (range, 0.4-8.5 years), a total of 35 patients developed PH after study enrollment. Factors associated with a higher risk for mortality included male sex (adjusted hazard ratio [aHR], 4.72; 95% CI, 1.79-12.45), low oxygen desaturation during 6-minute walk test (aHR per 15% decrease, 5.39; 95% CI, 1.66-17.50), low pulmonary function test readings (low %DLCO aHR per 15% decrease, 2.07; 95% CI, 1.43-3.01), pericardial effusion (aHR, 5.32; 95% CI, 1.85-16.00), and anemia (hemoglobin <11.2 g/dL vs ≥11.2 g/dL: aHR, 3.76; 95% CI, 1.33-10.63).

Study limitations included the small number of patients with PH as well as the lack of a clinically important biomarker for PH.

According to the researchers, patients with SSc with these risk factors for poor outcomes “should undergo right heart catheterization and receive appropriate intervention if PH is confirmed.”

Reference

Hsu VM, Chung L, Hummers LK, et al. Risk factors for mortality and cardiopulmonary hospitalization in systemic sclerosis patients at risk for pulmonary hypertension, in the PHAROS Registry [published online October 1, 2018]. J Rheumatol. doi:10.3899/jrheum.180018