Records of rheumatoid arthritis (RA) patients from the national Veterans Health Administration (VHA) system to determine the prevalence of rheumatoid vasculitis (RV) in this population were examined by researchers at the University of Wisconsin School of Medicine and Public Health.
The study found a downward trend in the number of RA patients who go on to develop RV, with a significant drop of 53% among inpatients and 31% among outpatients between 2000 and 2001. Full details of the study are published in the September issue of Arthritis & Rheumatism, a journal of the American College of Rheumatology.
Rheumatoid Vasculitis is a complication of severe RA, an autoimmune disease that causes painful inflammation of the joints. Approximately 2%-5% of RA patients develop RV, an extraarticular (occurring outside the joint) manifestation of rheumatoid arthritis, affecting small and medium-size arteries in the body. RV can involve many body organs including the skin, eyes, heart, lungs, nerves to the hands and feet, as well as blood vessels in the fingers and toes.
A past study of data from California hospitals also showed hospitalizations for RV declined between 1980 and 2001. But analysis of only inpatient data raises questions of whether RV cases escaped detection due to changing outpatient management of the disease. "Our study is the first to examine a national U.S. population for RV prevalence among both inpatients and outpatients," stated Dr. Bartels. "We found the frequency of RV fell from 41 to 28 cases per 1,000 RA outpatients and from 32 to only 15 cases per 1000 RA inpatients."
Researchers believe the decline in RV reported in the current study may be attributed to: a decrease in the number of RV incidences, a disease cure in some patients, patients discontinuing VHA services or dying, or error. Treatment for rheumatoid arthritis improved throughout the 1990s and researchers speculate that the use of biologic agents and more aggressive combinations of anti-rheumatic drugs targeting severe RA may have diminished extraarticular disease, such as RV.
Additionally the authors noted that the VHA made system-wide efforts to decrease tobacco use among patients that may have impacted the rates of rheumatoid vasculitis prevalence. "Future studies should examine trends in smoking and pharmacotherapy in relation to RV, and ongoing monitoring is merited," concluded the authors.
This study included a greater number of men who were older than average RA patients and whose use of tobacco was likely higher than most RA cohorts. These demographics may limit the ability to apply the results to the general RA population. "Previous reports have described increased rates of extraarticular manifestations among men, smokers, and persons who were older at the time of RA onset, so perhaps the characteristics of our study sample facilitated detection of changes among the most at-risk population," Dr. Bartels surmised. "As RA treatment evolves, it will be important to continue following trends in rheumatoid vasculitis prevalence using samples with a sex ratio that more closely reflects the general population," she added.