Drs. Clarke and Joseph are National Research Scholars of the Fonds de Recherche en Sante du Quebec.
Systemic Lupus Erythematosus
Association of the Charlson comorbidity index with mortality in systemic lupus erythematosus
Article first published online: 29 AUG 2011
Copyright © 2011 by the American College of Rheumatology
Arthritis Care & Research
Volume 63, Issue 9, pages 1233–1237, September 2011
How to Cite
Jönsen, A., Clarke, A. E., Joseph, L., Belisle, P., Bernatsky, S., Nived, O., Bengtsson, A. A., Sturfelt, G. and Pineau, C. A. (2011), Association of the Charlson comorbidity index with mortality in systemic lupus erythematosus. Arthritis Care Res, 63: 1233–1237. doi: 10.1002/acr.20506
- Issue published online: 29 AUG 2011
- Article first published online: 29 AUG 2011
- Accepted manuscript online: 25 MAY 2011 11:09AM EST
- Manuscript Accepted: 17 MAY 2011
- Manuscript Received: 6 SEP 2010
- Singer Family Fund for Lupus Research
- Swedish National Association Against Rheumatism
- Swedish Research Council. Grant Numbers: 15092, 70297601
- Medical Faculty of the University of Lund
- Alfred Österlund Foundation
- The Crafoord Foundation
- Greta och Johan Kock Foundation
- King Gustaf V's 80th birthday fund
- Lund University Hospital
- Prof. Nanna Svartz Foundation
- Junior Investigator Award from the Canadian Institutes for Health Research
To investigate whether comorbidity as assessed by the Charlson Comorbidity Index (CCI) is associated with mortality in a long-term followup of systemic lupus erythematosus (SLE) patients.
Data were collected from 499 SLE patients attending the Lupus Clinic at the McGill University Health Center, Montreal, Quebec, Canada, and 170 SLE patients from the Department of Rheumatology at Lund University Hospital, Lund, Sweden. This included data on comorbidity, demographics, disease activity, the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI), and antiphospholipid antibody syndrome (APS). Variables were entered into a Cox proportional hazards survival model.
Mortality risk in the Montreal cohort was associated with the CCI (hazard ratio [HR] 1.57 per unit increase in the CCI, 95% confidence interval [95% CI] 1.18–2.09) and age (HR 1.04 per year increase in age, 95% CI 1.00–1.09). The CCI and age at diagnosis were also associated with mortality in the Lund cohort (CCI: HR 1.35, 95% CI 1.13–1.60; age: HR 1.09, 95% CI 1.05–1.12). Furthermore, the SDI was associated with mortality in the Lund cohort (HR 1.40, 95% CI 1.19–1.64), while a wide CI for the estimate in the Montreal cohort prevented a definitive conclusion (HR 1.20, 95% CI 0.97–1.48). We did not find a strong association between mortality and sex, race/ethnicity, disease activity, or APS in either cohort.
In this study, comorbidity as measured by the CCI was associated with decreased survival independent of age, lupus disease activity, and damage. This suggests that the CCI may be useful in capturing comorbidity for clinical research in SLE.