CKM Syndrome: When to Apply the Label and Comprehensive Work-Up
Apply the CKM (Cardiovascular-Kidney-Metabolic) syndrome label to any adult with excess or dysfunctional adiposity (particularly visceral obesity) who has metabolic risk factors (dysglycemia, dyslipidemia, hypertension), chronic kidney disease, or existing cardiovascular disease—recognizing this represents a progressive continuum from Stage 0 (no risk factors) through Stage 4 (established CVD with persistent metabolic dysfunction). 1
Understanding the CKM Framework
The American Heart Association's 2023 CKM construct fundamentally reframes how we view the clustering of metabolic syndrome, kidney disease, and cardiovascular disease. CKM syndrome includes both individuals at risk for CVD due to metabolic risk factors and/or CKD, and those with existing CVD that is related to or complicated by metabolic dysfunction and/or CKD. 1 This affects approximately 90% of US adults to varying degrees, with metabolic syndrome alone present in 47% of the population 1, 2.
The syndrome captures the vicious cycle where excess adiposity (especially visceral and ectopic fat) drives insulin resistance, inflammation, oxidative stress, and vascular dysfunction, which in turn damage the kidneys and heart, creating self-reinforcing cycles of multi-organ injury 3, 4.
Five-Stage Classification System
Stage 0: No Risk Factors
- No excess adiposity
- No metabolic risk factors
- Normal kidney function
- No cardiovascular disease
Stage 1: Excess Adiposity or Other Metabolic Risk Factors
- Abdominal obesity (waist circumference >102 cm men, >88 cm women for Europid populations)
- Prediabetes or impaired fasting glucose
- Dyslipidemia (triglycerides ≥1.7 mmol/L, low HDL)
- Hypertension (≥130/85 mmHg)
- No kidney damage or CVD yet present
Stage 2: Metabolic Risk Factors PLUS Early Kidney Disease
- This is the most prevalent stage, affecting nearly half of adults 2
- Metabolic syndrome (≥3 of the Stage 1 criteria)
- Type 2 diabetes
- CKD defined by:
- eGFR 60-89 mL/min/1.73 m² with albuminuria (UACR ≥30 mg/g)
- eGFR 45-59 mL/min/1.73 m² with or without albuminuria
- Albuminuria is a key biomarker for CKM syndrome 4
Stage 3: Early Cardiovascular Disease or Advanced Kidney Disease
- CKD with eGFR 30-44 mL/min/1.73 m² (Stage G3b)
- CKD with eGFR 15-29 mL/min/1.73 m² (Stage G4)
- Moderate-to-severe albuminuria (UACR ≥300 mg/g)
- Subclinical CVD (coronary calcium, LV hypertrophy, arterial stiffness)
Stage 4: Established Cardiovascular Disease
- Heart failure (HFrEF or HFpEF)
- Coronary artery disease/prior MI
- Stroke or TIA
- Peripheral arterial disease
- Atrial fibrillation
- All occurring in the context of persistent metabolic dysfunction and/or CKD
Comprehensive Work-Up Algorithm
Initial Screening (All Adults ≥30 Years)
Anthropometric Measurements:
- Waist circumference (ethnic-specific cutoffs)
- BMI calculation
- Blood pressure (office and consider ambulatory/home monitoring) 5
Laboratory Assessment:
- Fasting glucose or HbA1c (diagnose diabetes/prediabetes)
- Lipid panel (total cholesterol, LDL, HDL, triglycerides)
- Serum creatinine with eGFR calculation (CKD-EPI equation preferred)
- Urine albumin-to-creatinine ratio (UACR) on random spot urine
- Electrolytes (potassium, sodium)
- Liver function tests (screen for MASLD/MASH)
- Uric acid (if symptomatic hyperuricemia) 8
Cardiovascular Risk Stratification:
- Calculate 10-year CV risk using validated tools (SCORE2 for age <70, SCORE2-OP for age ≥70) 9
- Consider incorporating kidney measures (eGFR, albuminuria) into risk calculation 10
Stage-Specific Additional Work-Up
For Stage 2-3 (Metabolic Risk + Kidney Disease):
- Annual monitoring minimum of eGFR and UACR 7, 11
- More frequent monitoring (every 3-6 months) if:
- eGFR <45 mL/min/1.73 m²
- UACR >300 mg/g
- Rapid eGFR decline (>5 mL/min/1.73 m²/year)
- Recent medication changes affecting kidney function
- Assess for CKD complications when eGFR <60 mL/min/1.73 m²:
For Stage 3-4 (CVD or Advanced CKD):
- ECG (assess for LVH, atrial fibrillation, ischemia)
- Echocardiography (evaluate LV function, wall motion abnormalities, valvular disease)
- Consider coronary calcium scoring or stress testing based on symptoms
- Ankle-brachial index if peripheral arterial disease suspected
- Retinal examination (microvascular damage assessment)
- Hepatic ultrasound or elastography if MASLD/MASH suspected 12
Identify Reversible or Accelerating Factors
Critical to assess:
- NSAID use (discontinue if possible) 6, 13
- Volume depletion status
- Acute kidney injury episodes
- Uncontrolled hypertension (target <130/80 mmHg, lower if proteinuria) 1
- Medication adherence
- Dietary sodium and protein intake
- Smoking status
- Sleep quality and obstructive sleep apnea screening
Nephrology Referral Criteria
Refer when: 13
- eGFR <30 mL/min/1.73 m² (Stage G4-G5)
- UACR persistently >60 mg/mmol (approximately >530 mg/g) despite treatment
- Progressive rise in UACR despite appropriate therapy
- Rapid eGFR decline (>5 mL/min/1.73 m²/year or >30% decline within 3 months)
- Inability to achieve BP targets
- Hyperkalemia preventing use of RAAS inhibitors
- Unexplained hematuria or signs of glomerulonephritis
- Inability to continue kidney-protective therapies due to adverse effects
Management Priorities by Stage
Stage 0-1: Prevention Focus
- Intensive lifestyle intervention (7-10% weight loss over 6-12 months, 500-1000 calorie/day reduction) 5
- Mediterranean-style diet 8
- Minimum 30 minutes daily moderate physical activity 5
- Sleep optimization and stress management 4
- No pharmacotherapy unless hypertension requires treatment
Stage 2: Early Intervention
Lifestyle remains cornerstone PLUS:
For diabetes + CKD (eGFR ≥20 mL/min/1.73 m²):
For albuminuria (UACR ≥30 mg/g):
Lipid management:
Weight management pharmacotherapy:
Stage 3-4: Comprehensive Multi-Drug Approach
"Triple therapy" foundation:
- SGLT2 inhibitor (if eGFR ≥20 mL/min/1.73 m²) 7, 13
- ACE inhibitor or ARB (if albuminuria present) 7
- Statin or statin/ezetimibe 8
Additional considerations:
Non-steroidal MRA (finerenone) if eGFR ≥25 mL/min/1.73 m² with albuminuria 7
- Reduces CV events and CKD progression
- Monitor potassium closely
GLP-1 receptor agonist for additional CV risk reduction if not already prescribed 7, 13
Aspirin 75-100 mg daily for secondary prevention if established CVD 8
Diuretics as needed for volume management (loop diuretics if eGFR <30 mL/min/1.73 m²)
Dietary protein restriction to 0.8 g/kg/day for Stage G3 or higher CKD 7
Common Pitfalls to Avoid
Do NOT:
- Use ACE inhibitor or ARB for "primary prevention" in patients with normal BP, normal UACR, and normal eGFR 7
- Discontinue RAAS blockade for mild creatinine increases (<30%) without evidence of volume depletion 7
- Delay SGLT2 inhibitor initiation until "diabetes is uncontrolled"—benefits are independent of glycemic control 13
- Restrict dietary protein excessively in early CKD (only indicated at Stage G3+) 7
- Overlook sex-specific risk factors (gestational diabetes, hypertensive disorders of pregnancy) 1
- Treat asymptomatic hyperuricemia with uric acid-lowering therapy (no proven CKD benefit) 8
Monitoring Disease Progression
- Sustained eGFR decline >5 mL/min/1.73 m²/year
- Drop in GFR category (e.g., G2→G3a) with ≥25% eGFR decline from baseline
- Progression in albuminuria category (A1→A2→A3)
Each stage transition increases cardiovascular mortality risk incrementally, with 34% of Stage 1 individuals progressing over time. 2 The goal is to interrupt these trajectories through early, aggressive, multidisciplinary intervention targeting all components of the syndrome simultaneously.