Endoscopic score vs blood cell indices for determining timing of immunomodulator withdrawal in quiescent ulcerative colitis

While immunomodulators (IMs) are used as key drugs in remission maintenance treatment for ulcerative colitis (UC), there has been no evidence to date for determining monitoring methods and drug withdrawal. Therefore, we examined if a decrease in white blood cell count (WBC) and an elevation in mean cell volume (MCV) could be used as optimization indices and if mucosal healing (MH) could be a rationale for determining the time of IM withdrawal. Subjects were 89 UC patients who were using IMs and for whom clinical remission had been maintained. Those with a Rachmilewitz Clinical Activity Index score of 4 or lower and those with a Mayo endoscopic subscore (MES) of 0 or 1 were defined as MH. The remission maintenance rates of the following comparative groups were examined: an IM continuation group and an IM withdrawal group; an IM continuation group with a WBC of less than 3000 or a MCV of 100 or greater and an IM continuation group with a WBC of 3000 or greater and a MCV of 99 or lower; an IM continuation group of patients for whom MH had been achieved and an IM continuation group of patients for whom MH had not been achieved; and an IM withdrawal group with a MES of 0 and an IM withdrawal group with a MES of 1. A significantly higher remission maintenance rate was observed in the IM continuation group compared to the withdrawal group (p < 0.01). No significant difference was observed between the IM continuation group with a WBC of less than 3000 or a MCV of 100 or greater and the IM continuation group with a WBC of 3000 or greater and a MCV of 99 or lower (p = 0.08). Higher remission maintenance rates were observed in the IM continuation group of patients for whom MH had been achieved compared to the IM continuation group of patients for whom MH had not been achieved (p = 0.03). No significant difference was observed between the IM withdrawal group with MES 0 and the IM withdrawal group with MES 1. (p = 0.48). This retrospective study showed that remission maintenance could be firmly obtained by continuing IM administration in case of endoscopic MH; however, MH was not an indicator of IM withdrawal.