Validity and risk of adopting PGA ≤ 2 as a remission criteria of Boolean in clinical practice in patient with rheumatoid arthritis

Validity and risk of setting patient’s global assessment (PGA) ≤ 2 as a Boolean remission criteria substituting PGA ≤ 1 in treating rheumatoid arthritis (RA) was investigated. Patients were recruited from an area cohort, of whom attained Boolean remission (Boolean-1) or near remission with PGA ≤ 2 and the rest components were ≤ 1 (Boolean-2). Simplified disease activity index (SDAI) score was compared according to the criteria variations. A total of 517 patients were studied. Mean SDAI score of patients with Boolean-1 was significantly lower than that of patients with Boolean-2 at acquisition. The trend was evident in the patients who attained Boolean-1 remission. Mean SDAI score at acquisition, 6 months after, and 1 year after of patients who attained Boolean-2 first and then Boolean-1, was significantly inferior to that of patients who attained the remissions at the same time. The mean SDAI score at month 6 in the Boolean-2 was not SDAI remission at all. We concluded that setting PGA ≤ 2 as a remission criteria may not have statistical difference in disease activity from PGA ≤ 1, however, there was an determinant risk to misread that includes patient who losses clinical remission after acquisition.