Background Pulmonary arterial hypertension (PAH) is the leading cause of mortality in patients with scleroderma (SSc).
Objectives To determine the incidence, prevalence and risk factors for PAH development in a large Australian SSc cohort.
Methods PAH was diagnosed on right heart catheterization (mPAP >25 and PAWP <15 mmHg at rest). Patients with PH secondary to interstitial lung disease (ILD; defined as abnormal HRCT scan and FVC<60%) were excluded. Summary statistics, chi-square tests, univariate and multivariable logistic regression along with post-estimation diagnostics were used to determine the associations of different combinations of risk factors with PAH.
Results Among 1579 SSc patients, 8.4% (132 patients) were diagnosed with PAH over a mean (±SD) follow-up of 3.2 (±2.5) years. The incidence of PAH in this cohort was 0.7% per annum. Of these, 68.9% had limited disease subtype (lcSSc). In multivariable regression analysis, the presence of anti-centromere antibody (ACA) (OR 1.6, 95%CI 1.1–2.5, p=0.03), oesphageal stricture (OR 2.0, 95%CI 1.2–3.3, p=0.006), calcinosis (OR 1.9, 95%CI 1.2–2.9, p=0.003), sicca symptoms (OR 1.6, 95%CI 1.1–2.5, p=0.03), mild ILD (OR 2.3, 95%CI 1.5–3.7, p<0.001) and digital ulcers (OR 1.6, 95%CI 1.0–2.4, p=0.03) were predictive of PAH. This model had an area under the curve of 0.7 and concordance of 91.8%. Risk factors for PAH were were analyzed by disease subtype and are presented in Table 1 and 2.
Conclusions The incidence and prevalence of PAH in this cohort are 0.7% per annum and 8.4%, respectively. The clinical-serologic risk factors for PAH differ based on disease subtype. In both subtypes, mild ILD is associated with PAH, suggesting the possibility of a common pathogenic mechanisms underlying both of these disease manifestations. This model identifies a subset of patients at an appreciably higher risk of developing PAH, who should be screened and would in future, benefit from preventative therapies.
Acknowledgement This work was supported by Scleroderma Australia, Arthritis Australia, Actelion Australia, Bayer, CSL Biotherapies, GlaxoSmithKline Australia, Pfizer and BMS. Dr Morrisroe is a recipient of an NHMRC and RACP Shields Fellowship. Dr Nikpour holds a University of Melbourne Faculty of Medicine Dentistry and Health Science David Bickart Clinician Researcher Fellowship and is a recipient of an NHMRC Fellowship (APP1071735).
Disclosure of Interest None declared