Endocrine Abstracts

Introduction: Obstructive sleep apnoea (OSA) is common and frequently found in patients with obesity and type 2 diabetes mellitus. This case report shows the infrequently documented link between OSA and type 1 diabetes and highlights the need to confirm the type of diabetes especially in complex and atypical cases.

Case report: A 44-year-old gentleman, with a BMI of 34, was diagnosed with type 2 diabetes and was treated with metformin and given lifestyle advice. One year later, he became unwell with 2.5 stone weight loss, polyuria, and polydipsia. The history pointed towards a diagnosis of type 1 diabetes and he was commenced on basal bolus insulin regimen. During one of his clinic consultations, he described symptoms of OSA and both Epworth Sleepiness Scale and formal sleep studies performed subsequently confirmed the diagnosis of OSA. Anti-GAD antibody was positive, confirming the diagnosis of latent autoimmune diabetes of adult (LADA), a subset of type 1 diabetes. Metformin was re-initiated and within 6 months, his insulin requirement was reduced by about 50%. He only had minimal weight loss during this period.

Conclusion: There are now studies showing an unexpectedly high prevalence of OSA in type 1 diabetes patients independent of weight and this case serves as a reminder the importance of screening for OSA in this patient group due to its serious implications. Secondly, this patient showed a remarkable reduction in insulin requirement after metformin initiation although he had type 1 diabetes. Most studies showed only an average of 20% insulin sparing effect.