What are the typical demographics and pertinent history associated with hyperosmolar hyperglycemic non‑ketotic syndrome (HHS)?

Demographics and Pertinent History of Hyperosmolar Hyperglycemic Syndrome

HHS predominantly affects elderly patients with type 2 diabetes, typically presenting in individuals over 60-70 years of age, often with poor diabetes management or undiagnosed diabetes, and is most commonly triggered by infection. 1

Key Demographics

Age Distribution

• Median age: 63-75 years, with the condition particularly affecting the elderly population 2, 3
• Extremes of age are associated with substantially worse prognosis and higher mortality 1
• In pediatric cases (rare), age ranges from 6-16 years, with 67% younger than 13 years 4

Diabetes Type

• Primarily occurs in type 2 diabetes patients 1
• However, incidence rates show 16.5 per 10,000 person-years in type 1 diabetes versus 3.9 per 10,000 person-years in type 2 diabetes 5
• 32% of HHS patients have no prior diabetes diagnosis - HHS can be the presenting manifestation of diabetes 5
• In pediatric cases, subsequent diagnosis includes both type 1 and type 2 diabetes 4

Body Habitus

• Variable BMI presentation - not limited to obese patients 4
• In elderly Japanese cohort, mean BMI was notably low at 17.8 kg/m² 6

Race/Ethnicity

• In pediatric cases, 83% were African-American 4

Pertinent Historical Features

Temporal Evolution

HHS evolves over several days to weeks (unlike DKA which develops within 24 hours) 1

Classic Symptom Constellation

• Polyuria, polydipsia, polyphagia
• Weight loss
• Progressive dehydration and weakness
• Altered mental status progressing to stupor/coma (more frequent in HHS than DKA) 1
• Notably ABSENT: abdominal pain and vomiting (these occur in DKA, not typically in pure HHS) 1

Precipitating Factors (in order of frequency)

Most Common Triggers:

1. Infection (44-51%) - particularly urinary tract infections and pneumonia 1, 2, 3
2. Non-infectious acute illness (49.5%) 2
3. New diabetes diagnosis (31.7%) 2

Other Important Precipitants:

• Cerebrovascular accident
• Myocardial infarction
• Pancreatitis
• Trauma
• Medication-related:
  • Corticosteroids
  • Thiazide diuretics
  • Sympathomimetic agents (dobutamine, terbutaline) 1

Medication History

Critical finding: Approximately 70% of HHS patients were not receiving diabetes medications 3

Social and Functional History (Particularly in Elderly)

High-risk social situations:

• Elderly individuals in chronic care facilities 1
• Living alone or only with spouse (>50% of cases) 6
• Patients unable to access fluids independently 1
• Marked ADL deterioration 6
• History of dementia (most HHS patients) 6

Past Medical History Red Flags

• History of cerebral infarction or hip fracture (50% of elderly cases) 6
• Comorbidities significantly increase risk (AHR: 3.01) 7
• Mean diabetes duration: 14 years in those with known diabetes 6

Geographic and Seasonal Patterns

• Seasonal peak in winter months 6
• Rural residents have twice the risk (AHR: 1.99) 7

Healthcare Access Issues

• Lack of community health insurance doubles risk (AHR: 2.04) 7
• Medication non-adherence more than doubles risk (AHR: 2.14) 7

Clinical Pitfalls

Common diagnostic delays occur because:

• 60% of outpatient cases are initially misdiagnosed, with some patients seen twice before accurate diagnosis 4
• Patients may be normothermic or even hypothermic despite infection (hypothermia is a poor prognostic sign) 1
• The insidious onset over days to weeks can mask the severity

Mortality considerations:

• Overall mortality: 15-21% 1, 2
• Pure HHS has 17% in-hospital mortality versus 9% for mixed HHS-DKA 5
• Isolated HHS with metabolic acidosis: 54.6% 30-day mortality 3
• Mortality varies dramatically by region: 40% in Africa, 18.2% in Asia, 4.8% in North America 2