Metabolic Syndrome

Aetiology / Pathophysiology

• Insulin resistance is central, leading to compensatory hyperinsulinaemia and disrupted glucose–lipid metabolism.

• Excess visceral fat contributes to pro-inflammatory cytokine release and exacerbates insulin resistance.

• Common contributory factors include obesity, poor diet (high refined sugars/fats), sedentary lifestyle, certain medications (e.g. antipsychotics), and familial/genetic influences.

Diagnostic Criteria

Most guidelines require ≥3 of the following 5 criteria. Cut-offs may vary by ethnicity:

• Waist Circumference (WC)

  • European/North American men: ≥102 cm

  • European/North American women: ≥88 cm

  • Non-white or Asian men: >90–94 cm (varies by guideline)

  • Non-white or Asian women: >80–88 cm (varies by guideline)

• Elevated Triglycerides (TG): ≥1.7 mmol/L

• Reduced HDL-C

  • Men: <1.0 mmol/L

  • Women: <1.3 mmol/L

• Elevated Blood Pressure: ≥130/85 mmHg or on treatment for hypertension

• Elevated Fasting Glucose: ≥5.5 mmol/L or previously diagnosed T2DM

Having metabolic syndrome increases the risk of CVD, T2DM, and CKD by approximately 2–3 times.

Clinical Features

• Often asymptomatic, discovered incidentally on routine health checks.

• Abdominal obesity (central adiposity).

• Hypertension (may manifest as headache or found on screening).

• Dyslipidaemia (can be asymptomatic unless severe).

• Possible mild hyperglycaemic symptoms if borderline T2DM (e.g. fatigue, increased thirst).

Differential Diagnosis

• T2DM alone: Overlaps with metabolic syndrome but focuses primarily on hyperglycaemia.

• Hypothyroidism: Can cause weight gain and dyslipidaemia, important to exclude.

• Cushing’s syndrome: Features include central obesity, hypertension, skin changes.

• PCOS: Women may exhibit insulin resistance, obesity, and dyslipidaemia.

Investigations

• Fasting Lipid Profile (total cholesterol, HDL, LDL, TG).

• Fasting Glucose / HbA1c.

• Waist Circumference (annual measurement if high risk or overweight/obese).

• Blood Pressure (regular measurement).

• Consider OGTT if borderline glucose or additional risk factors for T2DM.

• Screen for microalbuminuria in patients with elevated BP and/or hyperglycaemia.

Management

1. Lifestyle Modifications (First-Line Intervention)

Weight Loss

• Aim for 5–10% reduction in body weight over 3–6 months.

• Bariatric surgery can be considered in severe obesity or if lifestyle measures are insufficient and comorbidities are significant.

Diet

• Emphasise Mediterranean-style or similarly balanced diets rich in vegetables, whole grains, lean protein, and healthy fats (e.g. olive oil, nuts).

• Limit refined carbohydrates, sugar-sweetened beverages, and processed foods.

• Increase intake of omega-3 fatty acids (e.g. fish twice weekly).

Physical Activity

• At least 150 minutes per week of moderate-intensity aerobic exercise (e.g. brisk walking, cycling, swimming).

• Incorporate resistance training 2–3 times per week to improve insulin sensitivity and maintain lean body mass.

Behavioural Interventions

• Support for smoking cessation, stress reduction, and adequate sleep.

2. Pharmacological Review

• Identify and adjust any medications that exacerbate metabolic risks (e.g. certain antipsychotics, corticosteroids).

• Consider antihypertensives, lipid-lowering agents, or antidiabetic drugs if indicated by comorbidities or severity of each metabolic abnormality.

• Metformin not routinely indicated for metabolic syndrome alone but recommended if T2DM is present or in prediabetes with high risk of progression.

3. Monitoring and Ongoing Care

• Regular reassessment of waist circumference, blood pressure, lipids, and glycaemic parameters (fasting glucose/HbA1c) every 3–6 months, or as clinically indicated.

• Use absolute cardiovascular risk calculators to guide intensity of interventions.

• Encourage long-term adherence to lifestyle modifications and follow-up to prevent progression to T2DM and CVD.

Complications

• 2–3 times higher CVD risk compared with those without metabolic syndrome.

• Significantly increased risk of developing T2DM.

• Increased CKD likelihood due to hypertension, hyperglycaemia, and other related factors.

Prognosis

• Early and effective lifestyle interventions can substantially reduce the risk of progression to T2DM and major cardiovascular events.

• Pharmacotherapy for specific components (e.g. statins, antihypertensives, antidiabetics) further reduces morbidity and mortality if instituted early.

Notes:

• Metabolic syndrome is a useful clinical concept to identify patients at high risk who benefit most from preventive measures.

• Lifestyle modifications remain the cornerstone of treatment.

• Ethnic-specific waist circumference cut-offs are crucial for accurate diagnosis.

• Regular follow-up and a team-based approach (GP, dietitian, exercise physiologist) improve outcomes and patient adherence.