Frequency of Disease Subsets and Spectrum of Organ Involvement and Interstitial Lung Disease Patterns in Patients of Systemic Sclerosis in Pakistani Population.

Objective: To assess the frequency of disease subsets and the spectrum of organ involvement, particularly focusing on interstitial lung disease (ILD) patterns among patients with systemic sclerosis (SSc).

Study design: Observational study. Place and Duration of the Study: Institute of Rheumatic Diseases, Central Park Teaching Hospital, and its affiliated Arthritis Care Centre, Lahore, Pakistan, from July 2022 to December 2023.

Methodology: Data were extracted from electronic records and gathered using a questionnaire. Patients were classified into limited cutaneous systemic sclerosis (lcSSc) and diffuse cutaneous systemic sclerosis (dcSSc) subsets based on clinical criteria. Gender, age, duration of disease, clinical features, and ILD patterns were compared between the groups.

Results: The mean age of the 68 (88.3%) female patients was 37.9 ± 11.2 years. Younger patients presented with diffuse scleroderma (36 ± 11.3 years) compared to those with limited scleroderma (40.2 ± 10.7 years). The most common clinical feature was Raynaud's phenomenon (90.9%), followed by digital ulcers (41.6%). ILD was present in 68.8%, with non-specific interstitial pneumonia (NSIP) identified in 31.2%, usual interstitial pneumonia (UIP) in 19.5%, and fibrosing NSIP in 3.9%.

Conclusion: Systemic sclerosis predominantly affects younger females, with a higher diffuse cutaneous subtype. Raynaud's phenomenon is the most common manifestation. ILD is a significant complication, with NSIP being the most common pattern observed.

Key words: Systemic sclerosis, Rheumatic diseases, Limited cutaneous systematic sclerosis, Diffuse cutaneous systematic sclerosis.