 |
|
|
 |
Mortality Trends in Rheumatoid Arthritis: The Role of Rheumatoid Factor ANGEL GONZALEZ, MURAT ICEN, HILAL MARADIT KREMERS, CYNTHIA S. CROWSON, JOHN M. DAVIS III, TERRY M. THERNEAU, VERONIQUE L. ROGER, and SHERINE E. GABRIEL
ABSTRACT. Methods. A population-based RA incidence cohort (1955-1995, and aged >= 18 yrs) was followed longitudinally until death or January 1, 2006. The underlying cause of death as coded from national mortality statistics and grouped according to ICD-9/10 chapters was used to define cause-specific mortality. Expected cause-specific mortality rates were estimated by applying the age-, sex-, and calendar-year-specific mortality rates from the general population to the RA cohort. Poisson regression was used to model the observed overall and cause-specific mortality rates according to RF status, accounting for age, sex, disease duration, and calendar year. Results. A cohort of 603 subjects (73% female; mean age 58 yrs) with RA was followed for a mean of 16 years, during which 398 died. Estimated survival at 30 years after RA incidence was 26.0% in RF+ RA subjects compared to 36.0% expected (p < 0.001), while in RF- RA subjects, estimated survival was 29.1% compared to 28.3% expected (p = 0.9). The difference between the observed and the expected mortality in the RF+ RA subjects increased over time, resulting in a widening of the mortality gap, while among RF- RA subjects, observed mortality was very similar to the expected mortality over the entire time period. Among RF+ RA subjects, cause-specific mortality was higher than expected for cardiovascular [relative risk (RR) 1.50; 95% confidence interval (CI) 1.22, 1.83] and respiratory diseases [RR 3.49; 95% CI 2.51, 4.72]. Among RF- RA subjects, no significant differences were found between observed and expected cause-specific mortality. Conclusion. The widening in the mortality gap between RA subjects and the general population is confined to RF+ RA subjects and largely driven by cardiovascular and respiratory deaths. (J Rheumatol First Release April 15 2008) Key Indexing Terms:
SURVIVAL From the Department of Internal Medicine, Caritas St. Elizabeth's Medical Center, Boston, Massachusetts; Division of Epidemiology and Biostatistics, Department of Health Sciences Research; Division of Rheumatology, and Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA. Supported in part by a grant from the US National Institutes of Health, NIAMS (R01 AR46849), and the National Institutes of Health (AR-30582) US Public Health Service. A. Gonzalez, MD, Department of Internal Medicine, Caritas St. Elizabeth's Medical Center; M. Icen, MD; H. Maradit Kremers, MD, MSc, Division of Epidemiology, Department of Health Sciences Research; C.S. Crowson, MS, Division of Biostatistics, Department of Health Sciences Research; J.M. Davis III, MD, Division of Rheumatology, Department of Medicine; T.M. Therneau, PhD, Division Biostatistics, Department of Health Sciences Research; V.L. Roger, MD, MPH, Division of Epidemiology, Department of Health Sciences Research, and Division of Cardiovascular Diseases, Department of Medicine; S.E. Gabriel, MD, MSc, Professor, Division of Epidemiology, Chair, Department of Health Sciences Research, and Division of Rheumatology, Department of Medicine, Mayo Clinic. Address reprint requests to Dr. S.E. Gabriel, Mayo Foundation, 200 First St. SW, Rochester, MN 55905. E-mail: gabriel.sherine@mayo.edu Accepted for publication January 4, 2008. |
