Validity and reliability problems with patient global as a component of the ACR/EULAR remission criteria as used in clinical practice

Abstract

Objective. To investigate what factors influence patient global health assessment (PtGlobal), and how those factors and the reliability of PtGlobal affect the rate, reliability, and validity of recently published American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) rheumatoid arthritis (RA) remission criteria when used in clinical practice. Methods. We examined consecutive patients with RA in clinical practice and identified 77 who met ACR/EULAR joint criteria for remission (<= 1 swollen joint and <= 1 tender joint). We evaluated factors associated with a PtGlobal > 1, because a PtGlobal <= 1 defined ACR/EULAR remission in this group of patients who had already met ACR/EULAR joint criteria. Results. Of the 77 patients examined, only 17 (22.1%) had PtGlobal <= 1 and thus fully satisfied ACR/EULAR criteria. A large proportion of patients not in remission by ACR/EULAR criteria had high PtGlobal related to noninflammatory issues, including low back pain, fatigue, and functional limitations, and a number of patients clustered in the range of PtGlobal > 1 and <= 2. However, the minimal detectable difference for PtGlobal was 2.3. In addition, compared with a PtGlobal severity score, a PtGlobal activity score was 3.3% less likely to be abnormal (> 1). Conclusion. Noninflammatory factors contribute to the level of PtGlobal and result in the exclusion of many patients who would otherwise be in "true" remission according to the ACR/EULAR definition. Reliability problems associated with PtGlobal can also result in misclassification, and may explain the observation of low longterm remission rates in RA. As currently constituted, the use of the ACR/EULAR remission criteria in clinical practice appears to be problematic.