Association between disease duration and comorbidity burden in systemic lupus erythematosus: a multicentre study from Pakistan.

OBJECTIVE

This study aimed to evaluate the prevalence and predictors of cardiovascular disease (CVD), chronic kidney disease (CKD) and osteoporosis among patients with systemic lupus erythematosus (SLE) in Punjab, Pakistan.

METHODS

A cross-sectional analysis of a prospective registry was conducted using data from the Punjab Lupus Registry between January 2020 and December 2024. Adults (≥18 years) fulfilling the 2019 European League Against Rheumatism/American College of Rheumatology SLE classification criteria were included. Of 536 registered patients, 482 with complete data were analysed. Comorbidities were physician-confirmed, and disease activity was assessed using Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). Associations between disease duration and comorbidities were examined using χ² tests for trend, while predictors of comorbidity burden were identified using multivariable Poisson regression with robust error variance.

RESULTS

Among 482 patients (mean age 39.6±12.4 years; 67.2% female), 43.6% had at least one comorbidity and 15.1% had multimorbidity. The prevalence of CVD, CKD and osteoporosis increased with disease duration: 12.3%, 10.6% and 8.2% in <5 years versus 39.6%, 28.9% and 25.4% in >10 years (p<0.001). Older age (adjusted prevalence ratios (aPR) 1.31 per 10 years), longer disease duration (aPR 1.22 per 5 years), corticosteroid use (aPR 1.33), smoking (aPR 1.26) and low socioeconomic status (aPR 1.38) were independent predictors, while hydroxychloroquine use was protective (aPR 0.78). Patients with comorbidities had higher disease activity (SLEDAI-2K 6.9 vs 5.6, p=0.009) and greater organ damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index 2.4 vs 1.3, p<0.001).

CONCLUSION

Comorbidities are common in SLE and increase with age and disease duration, underscoring the need for early, integrated management to improve outcomes.