Hypoglycaemia — evaluation and management

Definition and grading. Level 1 (alert value) — glucose <70 mg/dL; Level 2 (clinically significant) — <54 mg/dL; Level 3 (severe) — any level associated with cognitive impairment requiring external assistance, with no glucose threshold. Hypoglycaemia is the critical limiting factor in achieving glycaemic targets in older adults with diabetes.

Why older people are especially vulnerable. Higher levels of polypharmacy, presence of frailty, and a high comorbid burden. Additional risk factors: cognitive impairment, renal disease, exposure to sulphonylureas — particularly long-acting agents, insulin exposure — particularly twice-daily mixed and basal-bolus regimens — a low glycated haemoglobin, and low body mass.

Symptom classification. Autonomic — palpitations, tremor, sweating, hunger, anxiety. Neuroglycopaenic — behavioural change, confusion, incoordination, seizure, coma. Autonomic symptoms are the warning system; neuroglycopaenic symptoms are the damage.

The geriatric problem — blunted warning. Hypoglycaemic symptoms become less intense with advancing age, especially the autonomic ones, and the symptom profile is modified. This reduction in autonomic symptoms is perceived by older people as hypoglycaemia unawareness. Their symptom threshold may differ from the conventional cut-off of 70 mg/dL — so a "normal-sounding" glucose may still be symptomatic.

Atypical presentation in old age. With increasing age and disease progression, presentations become atypical: falls, delirium, focal neurological deficit mimicking stroke, angina or arrhythmia, nocturnal sweating and nightmares, or simply behavioural disturbance. These are routinely misattributed to dementia, ageing or transient ischaemic attack.

Consequences. Hypoglycaemia causes hospital admission, injurious falls and fracture, myocardial ischaemia and arrhythmia (the "dead-in-bed" mechanism), accelerated cognitive decline — with a bidirectional relationship between hypoglycaemia and dementia — loss of confidence, driving cessation and treatment non-adherence.

Evaluation in a diabetic patient. Document the episode and its timing; review every drug, especially sulphonylurea type and dose and insulin regimen; assess renal and hepatic function, nutritional intake and meal pattern, alcohol, recent weight loss, cognition and the patient's ability to self-administer treatment; look for a precipitating acute illness; and check whether the HbA1c is inappropriately low.

Evaluation in a non-diabetic older adult. Establish Whipple's triad — symptoms, a documented low plasma glucose, and relief on raising the glucose. Then, during a spontaneous episode or a supervised 72-hour fast, measure insulin, C-peptide, proinsulin, β-hydroxybutyrate and a sulphonylurea screen. Causes to consider: drugs (sulphonylurea, quinolones, quinine), alcohol, sepsis, hepatic or renal failure, adrenal insufficiency, hypopituitarism, non-islet-cell tumour hypoglycaemia (IGF-2), insulinoma and severe malnutrition.

Acute treatment. Conscious and able to swallow — the "15/15 rule": 15–20 g of fast-acting carbohydrate (glucose tablets, 3–4 teaspoons of sugar, 150 mL fruit juice), recheck at 15 minutes, repeat if still <70 mg/dL, then give a complex carbohydrate snack. Unconscious or unable to swallow — 25% dextrose 50–100 mL IV followed by a 10% dextrose infusion, or glucagon 1 mg IM/SC if no venous access. Glucagon is ineffective in hepatic glycogen depletion — malnutrition, alcohol, prolonged fasting.

Prevention — the highest-scoring section. Key recommendations to minimise hypoglycaemia and its admissions are to assess hypoglycaemia risk and adjust glucose targets for frailty, functional status and life expectancy, and to regularly review diabetes medicines — sulphonylureas, insulin and its regimens — including the patient's capacity to self-administer treatment. Practically: relax HbA1c (7.0–7.5% if non-frail, up to 8.5% if frail), avoid HbA1c <6%, de-intensify therapy, prefer agents with low hypoglycaemia risk (metformin, DPP-4 inhibitors, SGLT2 inhibitors, GLP-1 receptor agonists), avoid glibenclamide (long-acting, renally cleared active metabolites — a Beers criteria drug), and educate the patient and carer.

ADA Standards of Care 2026, Section 13 "Older Adults" (endorsed by the American Geriatrics Society). Continuous glucose monitoring is now recommended for older adults with type 1 diabetes and, newly in 2026, for those with type 2 diabetes on insulin — explicitly "to improve glycaemic outcomes, reduce hypoglycaemia and reduce treatment burden". Alongside this, Recommendation 13.2 requires at least annual screening for geriatric syndromes (cognitive impairment, depression, incontinence, falls, persistent pain, frailty), for hypoglycaemia and for polypharmacy in every older adult with diabetes. There is also new guidance on assessing geriatric syndromes with validated screening questions, and on protein intake.

Sulphonylurea-induced hypoglycaemia is a prolonged, relapsing admission — not a treat-and-discharge event. Current practice is to admit and observe for at least 24–48 hours with a continuous dextrose infusion, because recurrence after apparent recovery is the rule — especially with renal impairment. Octreotide 50–100 µg subcutaneously is used for refractory or recurrent sulphonylurea hypoglycaemia because it suppresses further insulin release; it is more effective than escalating dextrose alone. Deprescribing the sulphonylurea, not merely reducing it, is the discharge action.

HbA1c 7.0–7.5 / 8.0 / 8.5% by frailty tier.