Interstitial lung disease in South Africans with systemic sclerosis

Abstract

To investigate the frequency, severity and predictors of interstitial lung disease (ILD) in a cohort of South Africans with systemic sclerosis (SSc). Retrospective record review of SSc patients attending a tertiary Connective Tissue Diseases Clinic. Patients with ILD, defined by a combination of clinical findings, imaging, and lung function tests were compared to patients without ILD in terms of demographics, clinical features and autoantibodies. The majority (86.8%) of the 151 patients included were of Black ethnicity, 40% had ILD, of whom 39% had moderate-severe lung disease. Univariate predictors of ILD included: disease duration (OR 1.08, 95% CI 1.01-1.15); cough (OR 2.93, 95% CI 1.37-6.29); dyspnoea (OR 2.44, 95% CI 1.23-4.87); bibasal crackles (OR 7.58, 95% CI 3.31-17.37); diffuse cutaneous SSc (dcSSc) (OR 4.55, 95% CI 2.10-9.86) and a speckled anti-nuclear antibody (ANA) pattern (OR 2.47, 95% CI 1.25-4.90). Conversely, limited cutaneous disease (OR 0.22, 95% CI 0.09-0.50) and anti-centromere antibody (ACA) (OR 0.12, 95% CI 0.02-0.97) were protective. Independent predictors of ILD on multivariate analysis were bibasal crackles (OR 9.43, 95% CI 3.25-27.39), disease duration (OR 1.19, 95% CI 1.09-1.30) and speckled ANA (OR 2.95, 95% CI 1.22-7.15). Almost all (86.4%) patients received immunosuppressive treatment and the leading cause of death was related to ILD itself (44.4%). In this cohort of predominantly Black South Africans, SSc ILD was common and carried a poor prognosis. ILD occurred mainly, but not exclusively, in patients with dcSSc, especially those with a speckled ANA pattern. Conversely, the presence of ACA was protective against ILD.

Keywords: Interstitial lung disease; Sub-Saharan Africa; Systemic sclerosis.