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Study finds diagnostic add-on tests are effective for patients with inflammatory arthritis at risk of RA
Researchers of this study found diagnostic tests were more cost-effective when used for patients with early inflammatory arthritis at immediate risk for rheumatoid arthritis.
“Applying a new diagnostic test as an add-on in the evaluation of patients at risk of [rheumatoid arthritis] RA is probably cost-effective, with the largest diagnostic benefit arising in intermediate risk patients,” Jolanda J. Luime, PhD, from the Erasmus Medical Center and Erasmus University Rotterdam in Rotterdam, The Netherlands, and colleagues wrote in their study.
Luime and colleagues evaluated four diagnostic add-ons tests for 552 patients who underwent tests for rheumatoid arthritis RA 1 year after diagnosis and were a part of the Rotterdam Early Arthritis Cohort. The add-on tests included assessing sensitivity, specificity and costs of hand and foot MRI (sensitivity = 0.90; specificity = 0.60; cost = €756), B cell–related gene expression (sensitivity = 0.60; specificity = 0.90; cost = €150), gene assay for RA (sensitivity = 0.40; specificity = 0.85; cost = €750) and interleukin-6 (IL-6) serum level tests (sensitivity = 0.70; specificity = 0.53; cost = €50). Overall, there were 329 seronegative patients and 263 immediate-risk patients included in the study, and researchers calculated the unweighted diagnostic net benefit (UDNB) and incremental cost-effectiveness ratio (ICER) of each test for the patients.
Investigators found the highest UDNB was achieved for immediate-risk patients who underwent the B cell assay (43%; ICER = €5,314) and the lowest UDNB was achieved for seronegative patients who underwent the IL-6 add-on test (−11.4%; ICER = €7,650), according to the abstract. Luime and colleagues noted that if the B cell assay test was applied with a threshold of €20,000, there would be a 78% cost-effectiveness for immediate-risk patients; 73% cost-effectiveness for seronegative patients; and 57% cost-effectiveness for all patients.
“Test developers should balance sensitivity and specificity in favor of specificity and take into account that under the current utility assumptions the headroom is between €151 and €369 per test,” Luime and colleagues wrote in their study. – by Jeff Craven
Disclosure: The researchers report no relevant financial disclosures.