OBJECTIVES:

Rheumatoid arthritis (RA) diagnosis requires a combination of clinical, laboratory and imaging investigations. It is known that the detection of antibodies to cyclic citrullinated peptides (CCP) may occur long before the onset of RA symptoms. The diagnostic accuracy of CCP testing is important. However, the clinical and economic consequences of CCP-misclassifications have not been investigated. In RA, the consequences of misclassification are particularly costly: subjects with a CCP False Positive (FP) results are managed as RA patients, bringing about extra costs until correct diagnosis is made. CCP False Negatives (FNs), but affected by RA, see the initiation of further investigations and treatment delayed in time, allowing for disease progression.

The aim of the present study is to simulate the clinical and economic burden of wrong CCP test results in Spain, comparing the misclassification results obtained with five anti-CCP tests from different manufacturers for RA diagnosis.

METHODS:

A 12-months Markov model simulated, from the hospital perspective, 1.000 RA-suspected individuals tested in secondary care with five CCP tests (Thermo Fisher Scientific; InovaDiagnostics; Eurodiagnostics; Axis-Shield; Roche), whose sensitivities and specificities derive from a systematic literature review and meta-analysis, and included resources utilization and clinical procedures.

Uncertainty was addressed with sensitivity analysis.

RESULTS:

Depending on the CCP test used, FPs ranged between 1.7% (Thermo Fisher Scientific) and 4.3% (Roche), and FNs between 11.7% (Roche) and 24.2% (Inova Diagnostics). FPs total costs were lowest when using Thermo Fisher Scientific (10724€-25406€), and highest when using Roche (26798€-63515€).

CONCLUSIONS:

Results show that the Thermo Fisher Scientific CCP test correctly classifies more RA patients / healthy subjects compared to comparator CCP tests. As a consequence, the Thermo Fisher Scientific CCP test demonstrates superior value from patient, health care provider, and payer perspective.