What does a creatinine level of 1.37 mg/dL indicate and how is it managed?

Interpreting a Creatinine Level of 1.37 mg/dL

A creatinine level of 1.37 mg/dL indicates mild renal dysfunction that requires monitoring but does not meet criteria for acute kidney injury. This level should prompt evaluation for underlying causes and risk factors, with appropriate management based on the clinical context.

Clinical Significance

• A creatinine level of 1.37 mg/dL falls within Grade 1 renal dysfunction according to clinical guidelines (creatinine 1.5-2.0× above baseline) 1
• This level may represent early chronic kidney disease (CKD), as it approaches the threshold of 1.5 mg/dL in men or 1.3 mg/dL in women that corresponds to an estimated GFR <60 mL/min/1.73m² 1
• Even mild elevations in serum creatinine are associated with increased cardiovascular and all-cause mortality 2, 3

Evaluation Approach

• Assess for potential alternative causes of elevated creatinine:

  • Medications (especially nephrotoxic agents like NSAIDs, ACE inhibitors, contrast media) 1, 4
  • Volume status (dehydration or fluid overload) 5
  • Recent contrast exposure 1, 6
  • Urinary tract infection or obstruction 1
  • Underlying comorbidities (hypertension, diabetes, heart failure) 1, 5

• Calculate estimated GFR using prediction equations (MDRD or Cockcroft-Gault) rather than relying on serum creatinine alone 1

• Consider checking for albuminuria/proteinuria as it provides additional prognostic information 1, 5

Management Recommendations

• For patients without risk factors and normal baseline renal function:

  • Monitor creatinine regularly (every 3-6 months) 5
  • Avoid nephrotoxic medications when possible 1

• For patients on ACE inhibitors or ARBs:

  • If this represents a minor increase (<30% from baseline), continue current medication with regular monitoring 4
  • If increase is >30% from baseline, consider temporary dose reduction or medication hold 4

• For patients with hypertension:

  • Ensure adequate blood pressure control (target <140/90 mmHg) 1, 7
  • For those with proteinuria or diabetes, aim for stricter BP control (<130/80 mmHg) 1

• For patients with heart failure:

  • Monitor renal function closely, especially if on diuretics 1
  • Adjust diuretic dosing if needed to prevent worsening renal function 1, 4

Special Considerations

• In patients with cirrhosis, a creatinine of 1.37 mg/dL may suggest developing hepatorenal syndrome, especially if accompanied by other clinical signs 1, 5

• In patients receiving immune checkpoint inhibitors, this level may warrant closer monitoring for immune-related nephritis 1, 5

• In elderly patients, serum creatinine may underestimate the degree of renal dysfunction due to decreased muscle mass 1, 8

• Biological and analytical variability in creatinine measurements can be 14-17% even in stable patients, so trends are more important than single values 5, 6

Follow-up Recommendations

• Repeat creatinine measurement within 1-2 weeks to establish trend 1, 5

• If creatinine continues to rise or exceeds 2.0 mg/dL, consider nephrology consultation 1

• Address modifiable risk factors: optimize blood pressure control, manage diabetes, avoid nephrotoxic medications 1, 5, 7

• For patients on medications affecting renal function (ACE inhibitors, ARBs, diuretics), monitor creatinine and electrolytes regularly 4