Pulmonary arterial hypertension (PAH) is common among patients with connective tissue disease (CTD) and significantly affects their prognosis; patients with higher levels of hemoglobin (Hb) and pH are at increased risk for mortality, according to study results published in Clinical Rheumatology.
Investigators conducted a retrospective cohort study including patients aged at least 18 years with connective tissue disease-pulmonary arterial hypertension (CTD-PAH). They assessed clinical disease characteristics to aid clinicians in recognizing prognostic and survival predictors among patients with CTD-PAH.
The primary endpoints were prevalence of PAH among patients with CTD and the clinical characteristics of CTD-PAH. Secondary endpoints included prognostic factors and clinical outcomes among patients with systolic pulmonary arterial pressure (sPAP) greater than 35 mmHg and survival rates among patients with non-PAH-CTD, mild CTD-PAH, and moderate-severe CTD-PAH.
Out of 5142 patients with CTD, 144 patients (2.80%) were diagnosed with PAH and included in the analysis. The prevalence of PAH differed depending on the type of CTD, with the greatest prevalence found among patients with systemic sclerosis (15.32%), mixed connective tissue disease (14.10%), and primary biliary cholangitis (11.54%).
The median sPAP value was 52.5 (95% CI, 44.0-71.0) mmHg, 55.6% of patients received targeted drugs, and 27.5% received combination therapy.
Patients with CTD-PAH had worse cardiac function (P =.019), higher levels of N-terminal pro-B-type natriuretic peptide (NT-pro BNP; P =.022) and γ-globulin (P =.023), as well as lower levels of partial pressure of carbon dioxide (P =.045) compared against patients with non-PAH-CTD.
There was no significant difference in final follow-up sPAP greater than 35 mmHg among patients with non-PAH-CTD, mild CTD-PAH and moderate-severe CTD-PAH, though a notable difference in survival rates was observed. The investigators noted this finding demonstrates that baseline sPAP values affect survival rates.
Univariate analysis based on cut off values revealed that Hb (hazard ratio [HR], 2.48; 95% CI, 1.07-5.77; P =.035), pH (HR, 4.55; 95% CI, 1.78-11.62; P =.002), and NT-pro BNP (HR, 2.91; 95% CI, 1.2-7.05; P =.018) were found to be significantly associated with survival.
According to multivariate analysis, Hb greater than 109.0 g/L and pH greater than 7.457 were independent predictors of increased risk for mortality.
This study was limited by diagnosis of PAH via echocardiography instead of invasive right heart catheterization, which could lead to inaccuracies in PAH rates. Additionally, the small sample size analyzed may affect the strength of the results and confounding variables may be present.
The study authors noted, “Regular echocardiography monitor is recommended strongly in the CTD patients management to identify CTD-PAH as early as possible.”
References:
Huang J, An Q, Shi H, et al. Retrospective cohort study of pulmonary arterial hypertension associated with connective tissue disease effect on patients’ prognosis. Clin Rheumatol. Published online June 29, 2023. doi:10.1007/s10067-023-06667-9
