Tongue coating, severity of Ama, and disease activity in patients with Rheumatoid Arthritis: A pilot study

Tongue examination has been documented in Ayurveda and other medical systems. The severity of tongue coating (TC), an indicator of Ama in Ayurveda, can be clinically assessed by the Winkel tongue coating index (WTCI) through the analysis of smartphone images. This pilot study examines the relationship between TC and disease severity, as well as TC and Ama severity, in patients with Rheumatoid Arthritis (RA), a prototype of Amavata.

Consecutive outpatients suffering from RA (diagnosed as per ACR/EULAR criteria, 2010) were divided into two groups- Group A: Treatment naïve patients with active disease, and Group B: patients on treatment in remission as determined by Clinical Disease Activity Index (CDAI). The Ama-severity in these subjects was assessed by a validated Ama-instrument. A photograph of the tongue obtained by a smartphone was selected, edited, and marked into sextants for WTCI assessment. These photographs were randomized and submitted for TC analysis to five expert clinicians. Eleven images in each group could be analysed by all assessors. The clinical records of the respective patients were used for statistical analysis (GraphPad InStat Version 3.6 software).

Twenty-two cases, 11 with active, untreated RA (Group A), and 11 in remission (Group B), were studied. All patients were females except one. Patients in Group A were older, less educated, and had a lower BMI than those in Group B. There was moderate inter-rater agreement (0.76 in Group A and 0.73 in Group B). There was no significant correlation between CDAI and WTCI (Spearman r = -0.08356, P = 0.7116, 95 % CI = -0.4981 - 0.3621) as well as between Ama Score and WTCI (Spearman r = - 0.1608, P = 0.4748, 95 % CI = -0.5548 - 0.2921). However, the Bonferroni correction indicated a statistically significant association between WTCI and the Ama-score. Moreover, the Friedman test revealed maximum coating in the posterior-middle area (area B, Fr = 57.728; P = < 0.0001, 95 % CI 1.645 to 1.937). Also, a moderately positive correlation between the TC score in area B and Ama-score (Spearman r = 0.4790, P = 0.0241, 95 % CI = 0.05858-0.7551) as well as between TC Score in area B and CDAI (r = 0.4393, P = 0.0408, 95 % CI = 0.008332 to 0.7327) was observed.

This pilot study indicates that there is a positive association between WTCI and Ama-score in Amavata (RA). A moderately positive correlation between the severity of TC in the posterior-middle area and the severity of Ama in Amavata (RA) implies a careful examination of the posterior tongue in these patients. The inter-observer reliability was moderate during this study. Studies with a larger sample size are recommended based on observations of this study.