Endocrine Abstracts

Background: Low glucose is a relatively common primary care referral to specialist endocrine services. However the prevalence of endocrine disease causing endogenous hypoglycaemia is extremely rare.

Methods: We obtained all plasma glucose results <4 mM originating from primary care within NHS Lothian, in non-diabetic individuals (20 145 people (77.6% female)) aged 18–40 years, between 2002 and 2017. These data were linked to national admission, mortality, cancer and diabetes registers to assess associations with mortality and morbidity.

Results: Median follow-up was 4.8 years (IQR 2.6–7.8). Glucose was marginally higher in women 3.6 mM vs 3.5 mM, P<0.0001. Glucose concentration was <2.2 mM in 0.63% (A), 2.2–<3.0 mM in 8.7% (B), 3.0–<3.5 mM in 28.0% (C) and ≥3.5 mM in 62.6% (D). A history of eating disorder was present in 2.4% (A), 1.1% (B), 0.4% (C) and 0.3% (D), P<0.0001. Increasing age (HR 1.03, P<0.001) and male gender (HR 4.20, P<0.001), but not glucose <3 mM (HR 0.89, P=0.79), were associated with mortality. The risk of a subsequent new diagnosis of cancer or hospital admission with incident cardiovascular, renal, liver or infectious disease was not related to glucose category. Incident diabetes was observed in 0.2% of those with glucose <3 mM and in 0.6% of those with glucose ≥3 mM (OR 3.0, P=0.009). No cases of insulinoma were detected based on the results of these tests.

Conclusion: Low plasma glucose results from primary care are almost never indicative of an endogenous hyperinsulinaemic disorder and are not associated with adverse outcomes in adults up to 40 years of age. Underlying eating disorder should be considered in this context. Assessment by an endocrinologist should be limited to cases where Whipple’s triad is present.