Purpose: There are sporadic reports illustrating more severe TED and complications in those with diabetes mellitus (DM) and from local experience these patients have poorer outcomes as seen in other diseases, such as cardiovascular disease. However, the relationship between glycaemia and clinical activity/severity and disease course are not well described.
Methods: A multi-centre retrospective patient-cohort study of 236 patients referred to three TED multidisciplinary (MDT) clinics in London between 2012 and 2019. Patient characteristics were analysed to investigate group-wise differences and correlations between variables collected at baseline to help predict subsequent disease activity, with particular focus being placed on glycaemic control factors.
Results: Median age was 49.0 years (interquartile range: 3657), 19.5% Asian, 77.5% female. Out of 236 patients, 14.0% had diabetes. The proportion with diabetes also increased with disease activity and severity, culminating in 23.5% in those with dysthyroid optic neuropathy (DON). The median HbA1c in the 131/236 patients who had a baseline HbA1c was 39 mmol/mol (IQR 3643, NR <42 mmol/mol). For the whole group, there was a trend towards a positive correlation between HbA1c and CAS (r = 0.1684, P = 0.05). HbA1c was significantly higher in patients who had moderate-to-severe disease or DON compared to those with milder disease (P= 0.0114).
Conclusions: Our results show a higher prevalence of DM compared to the rest of the UK (6.0%) in our cohort with TED. However ethnicity variation, could influence our reported high prevalence. The relationship between HbA1c and disease severity requires further exploration but potentially is a modifiable risk factor that could influence outcome. It is important as therapies for TED e.g. orbital radiotherapy and high-dose corticosteroids are relatively contraindicated in DM. Underlying mechanisms could include aberrant signaling of insulin-like growth factor-I receptor (IGFR-1), as well as low-grade systemic inflammation seen in both disease states.