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RANDOM NON-FASTING C-PEPTIDE CAN BE USED AS A RISK ASSESSMENT TOOL FOR HYPOGLYCAEMIA IN ELDERLY NSULIN-TREATED PATIENTS WITH TYPE 2 DIABETES

Introduction

Hypoglycaemia can prove a challenge in elderly people with diabetes. HbA1c guidelines pragmatically advocate relaxation of targets in those with more functional dependence, dementia and frailty, although the evidence base is limited. Severe endogenous insulin deficiency (C-peptide <200 pmol/L) correlates with increased hypoglycaemia in Type 1 diabetes, but data is limited in Type 2. We assessed if hypoglycaemia was correlated with C-peptide levels in Type 2 diabetes.

Methods:

• Objective hypoglycaemia assessed using continuous glucose monitoring (CGM), comparing HbA1c and gender-matched participants with insulin-treated Type 2 diabetes: 17 with random non-fasting C-peptide (rCP) <200 pmol/L and 17 with rCP > 600 pmol/L. Mean 4.1 days’ CGM assessed, and CGM-recorded hypoglycaemia defined as >20 mins <4 mmol/L.

• Subjective/self-reported hypoglycaemia on a larger scale was assessed by 256 community-based insulin-treated participants with a GP-diagnosis of Type 2 diabetes who completed Clarke's hypoglycaemia questionnaire, and rCP measured.

Results:

• Median HbA1c was 72 mmol/mol in the severe insulin deficiency CGM group, and 72 mmol/mol in the comparison group (p = 0.97). Average glucose levels on CGM were also similar (10.2vs9.9 mmol/L, p = 0.50). Groups were also matched for age (72.7vs71.8, p = 0.69), diabetes duration (24.5vs19.8 years, p = 0.12), and BMI (26.6vs27.9 kg/m2, p = 0.28).

  Despite similar HbA1c, more hypoglycaemia occurred in the <200 pmol/L group (median 5.3 (interquartile range 1.7–7.7) vs 0(0–2.3)episodes/person/week, p = 0.003), and total hypoglycaemia duration higher (407(196–988) vs 0(0–305)minutes/person/week, p = 0.0027).

• 35/256 (13.7%) participants had rCP < 200 pmol/L. They self-reported a median of 4 (2–4) episodes/month with blood glucose <3.5 mmol/mol, vs 2(0–2) in those with rCP > 200 pmol/L, p = 0.0006. HbA1c levels were 68vs64 mmol/mol respectively, p = 0.07.

Conclusions

13.7% community-based insulin-treated participants with Type 2 diabetes had severe insulin deficiency, and despite matched HbA1c levels, both objective and self-reported hypoglycaemia occurred more in participants with severe insulin deficiency. C-peptide may prove a useful biomarker in helping identify insulin-treated patients with Type 2 diabetes at higher risk of hypoglycaemia, and hence assist in choosing appropriate glycaemic targets.