Connective tissue disease--associated interstitial lung disease: an underreported cause of interstitial lung disease in Sub-Saharan Africa

Interstitial lung disease (ILD) occurs in 15% of connective tissue disease (CTD) patients causing considerable morbidity and mortality. Data is scarce regarding its clinical characteristics and outcomes in Africa. We aim to study the frequency, clinico-radiological characteristics, and treatment outcomes of African CTD-ILD patients. A retrospective cross-sectional study of ILD among 318 CTD patients diagnosed using relevant ACR criteria at the rheumatology unit of Lagos State University Teaching Hospital (LASUTH), Lagos from 2012 to 2019. Socio-demographics, clinical features, radiological findings, and treatment outcomes were documented. Data was analyzed using SPSS version 21 withp< 0.05. The LASUTH ethics committee approved the study. Interstitial lung disease occurred in 31 (9.7%) of 318 CTD cases. Their mean age was 38.8 +/- 13.3 years, range 19-68 years with 28 (90.3%) females. Proportions of CTD-ILD were Sjogren's syndrome (50%), UCTD (50%), systemic sclerosis (46.7%), MCTD (33.3%), PM/DM (25%), SLE (6.5%), and RA (2.6%). Commonest presentations were cough (93.5%) and bibasal inspiratory crackles (83.9%) with a restrictive pattern in 83.9%. Antinuclear antibody occurred in 100% and anti-ENA in 67.7%. Traction bronchiectasis (89.7%) and ground glass opacities (96.6%) were frequent HRCT findings. Treatments included pulse-dose prednisolone, cyclophosphamide, mycophenolate mofetil, pirfenidone, and rituximab. Outcomes were ambulatory oxygen therapy (12.9%) and mortality (16.1%) with 9.7% lost to follow-up. CTD-ILD is a female predominant disease occurring in 9.7% of CTD patients mostly those with Sjogren's syndrome and systemic sclerosis. Due to significant morbidity and mortality, we advocate routine ILD screening for all CTD patients including those with undifferentiated disease.