National Study of Cause-Specific Mortality in Rheumatoid Arthritis, Juvenile Chronic Arthritis, and Other Rheumatic Conditions: A 20 Year Followup Study

ELAINE THOMAS, DEBORAH P.M. SYMMONS, DAVID H. BREWSTER, ROGER J. BLACK, and GARY J. MACFARLANE

ABSTRACT.

Objective. To quantify risks for cause-specific mortality among hospitalized patients with rheumatoid arthritis (RA), juvenile chronic arthritis (JCA), and 4 other rheumatic conditions in a nationwide, population based cohort over a 20 year period.

Methods. All subjects were identified from Scottish hospital inpatient records from 1981 to 2000 and were followed up by computer linkage to the national registry of deaths. Expected mortality was calculated from national mortality rates and was related to the observed incidence by the standardized mortality ratio (SMR) and the corresponding 95% confidence interval (95% CI).

Results. Overall mortality was elevated in each of the 6 rheumatic conditions examined, most notably in JCA (males: SMR 3.4, 95% CI 2.0,5.5; females: SMR 5.1, 95% CI 3.2,7.8). Among patients with RA, there was an increased risk for death in all International Classification of Disease chapters other than those relating to mental disorders. Specific causes of death with an increased risk for subjects with RA included lung cancer [males: 1.4 (1.2,1.5); females: 1.6 (1.5,1.8)], hematopoietic malignancies [M: 1.8 (1.4,2.3); F: 2.0 (1.7,2.3)], coronary artery disease (CAD) [M: 1.6 (1.5,1.7); F: 1.95 (1.9,2.0)], respiratory infections [M: 1.9 (1.7,2.2); F: 2.4 (2.3,2.6)], chronic obstructive pulmonary disease [M: 1.8 (1.6,2.0); F: 2.1 (1.9,2.3)], and renal failure [M: 3.1 (2.5,3.9); F: 3.5 (3.0,4.0)]. Conversely, RA subjects were less likely to die from gastrointestinal tract malignancies [M: 0.82 (0.7,1.0); F: 0.8 (0.7,0.9)].

Conclusion. Population studies for primary data collection are required to extend our knowledge about the underlying mechanisms of early mortality in patients with rheumatic conditions. (J Rheumatol 2003;30:958-65)

Key Indexing Terms:

MORTALITY
RHEUMATOID ARTHRITIS
JUVENILE CHRONIC ARTHRITIS
HOSPITAL COHORT

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From the Primary Care Sciences Research Centre, Keele University, Keele; the Arthritis Research Campaign Epidemiology Unit, School of Epidemiology and Health Sciences, University of Manchester, Manchester, England; the Scottish Cancer Intelligence Unit, NHS Scotland Information and Statistics Division, Edinburgh, Scotland; and the Unit of Chronic Disease Epidemiology, School of Epidemiology and Health Sciences, Medical School, University of Manchester, Manchester, England.

E. Thomas, MSc, PhD, Research Fellow in Biostatistics, Primary Care Sciences Research Centre, Keele University; D.P.M. Symmons, MD, MFPHM, FRCP, Professor of Rheumatology and Musculoskeletal Epidemiology, Arthritis Research Campaign Epidemiology Unit, University of Manchester; D.H. Brewster, FFPHM, Director of Cancer Registration; R.J. Black, MA (Hons), Head, Scottish Cancer Intelligence Unit; G.J. Macfarlane, PhD, MD, CStat, Professor of Epidemiology, Head, Unit of Chronic Disease Epidemiology, University of Manchester.

Address reprint requests to Dr. E. Thomas, Primary Care Sciences Research Centre, Keele University, Keele, North Staffordshire, ST5 5BG, UK.

Submitted June 13, 2002; revision accepted October 18, 2002.

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