Poster Presentation The Joint Annual Scientific Meetings of the Endocrine Society of Australia and the Society for Reproductive Biology 2017

Predictors of long term remission, relapse and non-resolution with anti-thyroid medication in Graves' disease in a Tasmanian population (#198)

James P Robinson 1 , Venkat Parameswaran 2 3 , Roland W McCallum 2 3
  1. School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
  2. Menzies Institute, Hobart, Tasmania, Australia
  3. Royal Hobart Hospital, Hobart, Tasmania, Australia

Introduction

Tasmania is an iodine deficient island and response to anti-thyroid medication in Graves’ disease has not been reported in the Tasmanian population. Predictors of anti-thyroid medication efficacy would be valuable for guiding clinical decisions. Our previous study of 52 patients highlighted the importance of following patients >4 years after ceasing treatment to detect long-term remission. In this study we included 143 patients and investigated long-term remission, relapse and non-resolution from medical treatment over 5 years and explored potential predictors of response to anti-thyroid medication.

Methods

We retrospectively analysed Royal Hobart Hospital endocrine clinic patients with positive TSH receptor antibodies (TRAb >1.75) diagnosed with Graves’ prior to 2012 and treated with a dose titration schedule of carbimazole or propylthiouracil.

Results

40 patients remitted, 60 relapsed and 43 had no resolution. Average treatment duration for remission was 22.8 +/-3.8 months and relapse was 17.9 +/-1.7 months. Presenting FT4 was lower in remission (32.6 +/-3.0, p<0.001) and relapse (38.8 +/-2.8, p<0.01) compared to non-resolution (51.7 +/-3.9). Presenting TRAb was higher in non-resolution (20.4 +/-2.5) compared to relapse (11.2 +/-1.5, p<0.01) and remission (8.9 +/-1.5, p<0.001). Final TRAb was lower in remission (1.3 +/-0.2) than relapse (3.6 +/-1.0, p=0.03). Final TSH was higher in remission (1.8 +/-0.3) compared to relapse (1.3 +/-0.1, p=0.09) and non-resolution (0.6 +/-0.2, p<0.01)

Discussion

In this study, 28% achieved long-term remission, 42% relapsed within 5 years and 30% had no resolution. The only significant predictor of long-term remission was decreased final TRAb. Raised TRAb and FT4 at diagnosis were also significant predictors of non-resolution from medication. We recommend at least 18m of treatment to increase potential for long-term remission and aiming for TRAb <1.0, TSH >1.0 before ceasing treatment. Early discussion with patients regarding long-term outcomes based on their individual profile should be used to guide treatment decisions.