Pulmonary hypertension in systemic sclerosis and systemic lupus erythematosus.

Pulmonary arterial hypertension (PAH) is a severe manifestation of systemic sclerosis (SSc) and systemic lupus erythematosus (SLE). Due to improvements in the understanding of the pathogenesis of these diseases, improved methodological rigour in the conduct of epidemiological studies and the advent of successful therapies, our understanding of SSc-PAH and SLE-PAH has evolved considerably. In this review we will review the current evidence regarding the prevalence, prognostic factors and survival estimates for SSc-PAH and SLE-PAH. In doing so, we will compare and contrast these two diseases, highlight clinically useful features, discuss methodological limitations of existing data, and draw attention to areas where research is needed.