Page 32 - THE EVOLUTION OF EARLY ARTHRITIS AND CARDIOVASCULAR RISK Samina A. Turk

CHAPTER 2
with proven efficacy in the at-risk situation.(175,176) All efforts to predict RA and treat persons with an increased risk for RA are therefore currently regarded as investigational. The test for RA will eventually be a validated, cost-effective, and accurate prediction rule that is easy to apply. For comparison, consider the screening programs for colonic cancer, which have recently been established in several countries. All persons more than a certain age are offered screening, which leads to huge numbers of colonoscopies. The high cost of this procedure and the possibility of serious side effects need to be weighed against the benefit of removing polyps that would cause a high morbidity and mortality if left unnoticed.
Regarding item 1, careful consideration is needed to decide which population(s) should be screened or tested. The choices from general to specific are general population, relatives of patients with RA, persons with musculoskeletal symptoms, or persons with RA-specific autoimmunity. Because RA is not highly prevalent in most populations, with the possible exception of North American native peoples,(177,178) at this time it is not practical to test the general population for RA. Two recognizable target groups then remain: relatives of patients with RA and persons with musculoskeletal symptoms. The latter are found both in general practice and in rheumatology clinics. After history taking and physical examination, it must be decided which patients should proceed to further testing for RA risk, and which test to use. At present most clinicians use the RF and/or ACPA test, which are widely available and easy to perform. Except for patients with only RF positivity just above the reference range, the results give useful information. The question of who to test in general practice cannot accurately be answered at this time. This question requires structured longitudinal follow-up of patients in general practice, or the following of cohorts with clinically suspect arthralgia in rheumatology clinics.
Table 2. Prediction models of RA
First author (ref) and year
Cohort; Variables
Numbers
Results
Van de Stadt et al,(145) 2013
Seropositive patients with arthralgia Prediction rule vari- ables: alcohol consump- tion, family history, symptoms <12 mo, in- termittent, in upper and lower extremities, VAS 50, morning stiffness
1 h, swollen joints re- ported by patient, auto- antibody status
Arthralgia: 374 (131 developed arthritis)
Prediction rule: AUC 0.82 (CI 0.75– 0.89)
Intermediate-risk vs low-risk group: HR 4.52 (CI 2.42–8.77)
High-risk vs low-risk group: HR 14.86 (CI 8.40–28)
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