Clinical Implications of Mildly Elevated Creatinine

Interpretation and Evaluation

A creatinine level of 1.37 mg/dL in an older adult is slightly above the normal range for adults, indicating a potential mild reduction in renal function, according to the European Society of Cardiology 3
This value does not meet the KDIGO criteria for Acute Kidney Injury (AKI) Stage 1, which requires an increase of ≥0.3 mg/dL in 48 hours or a 50% increase in 7 days, as stated by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 1, 4
In older adults, this level may represent a physiological decline in glomerular filtration rate (GFR) related to age rather than acute kidney pathology, as suggested by the European Society of Cardiology 5

Calculating the estimated glomerular filtration rate (eGFR) using formulas like MDRD or Cockcroft-Gault, which consider age, gender, race, and weight, is recommended by the European Society of Cardiology 6, 5
An eGFR <60 ml/min/1.73 m² indicates chronic kidney disease (CKD) stage 3, which is common in older adults, according to the American Heart Association 3
Evaluating the presence of albuminuria through the albumin-to-creatinine ratio in a urine sample is important, as it is a significant marker of kidney damage and cardiovascular risk, as stated by the European Society of Cardiology 5, 3

Uncontrolled hypertension is a common cause of renal deterioration in older adults, according to the European Society of Cardiology 5, 3
Dehydration or volume depletion can cause transient elevations in creatinine, as noted by the American College of Cardiology 2
The use of nephrotoxic medications (NSAIDs, certain antibiotics, radiologic contrasts) can contribute to elevated creatinine levels, as warned by the American College of Cardiology 2
Comorbidities such as diabetes, heart failure, or vascular disease can also impact kidney function, according to the European Society of Cardiology 6, 5

Repeating creatinine measurement to confirm if the elevation is persistent is recommended by the American Thoracic Society 7, 2
If the elevation is persistent, a comprehensive evaluation of renal function, including eGFR and urine analysis, should be performed, as advised by the European Society of Cardiology 6, 3
Optimizing blood pressure control, maintaining appropriate targets for age (generally <140/90 mmHg), is crucial, according to the European Society of Cardiology 5, 3
Reviewing and adjusting potentially nephrotoxic medications is necessary, as recommended by the American College of Cardiology 2

Significant albuminuria (>300 mg/g creatinine) is a criterion for referral, as stated by the European Society of Cardiology 5, 3
An eGFR <45 ml/min/1.73 m² (CKD stage 3B or higher) indicates the need for nephrology referral, according to the American Heart Association 3

Age-related sarcopenia can result in falsely "normal" creatinine levels despite reduced GFR, as noted by the American Society of Nephrology 8
Fluctuations in creatinine levels are more prominent in individuals with diminished renal reserve or overt CKD, according to the American Society of Nephrology 8
The duration of creatinine elevation may be more important than the magnitude of change for predicting adverse outcomes, as suggested by the American Society of Nephrology 8