Prevalence, Severity, and Pattern of Pulmonary Arterial Hypertension and Interstitial Lung Disease in Patients with Connective Tissue Disease.

INTRODUCTION: Interstitial lung disease and pulmonary arterial hypertension are two major causes of morbidity and mortality in connective tissue diseases. This observational study was conducted to determine the prevalence, type, and severity of pulmonary arterial hypertension and interstitial lung disease in patients with various connective tissue diseases. The objective is to determine the prevalence, severity, and pattern of pulmonary arterial hypertension and interstitial lung disease in patients with connective tissue disease.

METHODS: This prospective observational cross-sectional study enrolled adult patients with confirmed diagnoses of connective tissue diseases. Both inpatients and outpatients were included. Pulmonary pressure was assessed via echocardiogram as right ventricular systolic pressure by a dedicated cardiologist. Interstitial lung disease was suspected based on chest X-ray and pulmonary function tests and later confirmed with high-resolution computed tomography.

RESULTS: During the study period of two years, 220 patients who fulfilled the inclusion criteria were enrolled. The majority of the patients were female, with a male-to-female ratio of 1:7.5. The most common connective tissue disease was rheumatoid arthritis (53%), and the least common was overlap syndrome (2.3%). Pulmonary arterial hypertension was observed in 26.3% of the studied patients, with the highest prevalence in mixed connective tissue disease (60%). Interstitial lung disease was seen in 24.5% of the patients, with the highest prevalence in systemic sclerosis (60.7%).

DISCUSSION: Pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD) emerged as major complications of connective tissue diseases (CTDs) in our cohort. The prevalence of PAH was notably high in systemic sclerosis (50%) and mixed connective tissue disease (60%), whereas ILD was most frequent in rheumatoid arthritis (14.7%) and scleroderma (50%), with a predominance of the NSIP pattern of ILD. Compared to Western cohorts, PAH and ILD were more frequent, suggesting possible contributions from delayed diagnosis and treatment or ethnic differences. Interestingly, moderate-to-severe PAH in rheumatoid arthritis often coexists with ILD, consistent with type 3 PAH, although isolated PAH has also been observed. These findings underscore the need for early screening and aggressive management strategies, particularly for systemic sclerosis, rheumatoid arthritis, and mixed connective tissue disease, to reduce morbidity and mortality.

CONCLUSION: Interstitial lung disease and pulmonary arterial hypertension are present in a significant number of patients with connective tissue diseases. Proactive examination and early identification of these complications could help in addressing and managing these life-threatening conditions.