A randomized, double-blind, placebo-controlled, clinical trial of curcuminoids in oral lichen planus

Introduction. This dissertation describes the anti-inflammatory activity and safety of curcuminoids based on the published literature, a clinical trial of the efficacy and safety of curcuminoids in the treatment of oral lichen planus (OLP), and the validation of instruments used to measure signs and symptoms of OLP used in this trial.;Methods. (1) A systematic review of the published literature (1966-Jan 2002) on safety and anti-inflammatory properties of curcumin was conducted. (2) A randomized, double-blind, placebo-controlled trial (RCT) with a sample size of 100 was designed. Instruments used were the Visual Analogue Scale (VAS), the Numeric Rating Scale (NRS) and Change in Symptoms Scale (CSS) to measure symptoms and the Modified Oral Mucositis Index (MOMI) to measure clinical signs of OLP. (3) Analyses of criterion validity, construct validity and internal consistency of these instruments were conducted.;Results and conclusions. (1) Curcumin has been demonstrated to be safe and have anti-inflammatory activity. (2) The first interim analysis was conducted using data from 33 subjects enrolled February 2003 to August 2004. This analysis did not show a significant difference between the placebo and control group. Conditional power calculations suggested a less than 2% chance that the curcuminoids group would have a significantly better outcome compared with the placebo group if the trial was to continue to completion. Therefore, the study was ended early for futility. As a result, reaching a conclusion regarding the efficacy of curcuminoids based on the results of this study is not possible. However, curcuminoids at this dose were well-tolerated and the results suggest that for future studies a larger sample size and possibly a higher dose and/or longer duration of curcuminoids should be considered. (3) NRS, VAS, CSS and MOMI are valid scales for measurement of symptoms and signs of OLP. VAS, NRS and CSS show good concurrent validity. NRS has a higher construct validity than VAS, based on higher correlations with clinical signs. For clinical signs, erythema plus ulceration is a better measure than ulceration alone. Sensitivity to change is good for VAS, NRS and MOMI. The internal consistency of the MOMI scale is good.