From the Guidelines
Low creatinine levels can be caused by factors such as low dietary protein intake, reduced muscle mass, old age, and female sex, as well as certain medical conditions like malnutrition and muscle-wasting conditions. These factors can lead to a decrease in creatinine generation, resulting in lower serum creatinine levels 1.
Factors Affecting Creatinine Levels
Some of the key factors that can cause low creatinine levels include:
- Low dietary protein intake, particularly a diet low in cooked meat
- Reduced muscle mass, which can be due to old age, female sex, or muscle-wasting conditions
- Malnutrition and critical illness, which can reduce creatinine generation
- Amputation, which can decrease muscle mass and subsequently lower creatinine levels
Clinical Considerations
It is essential to consider these factors when interpreting serum creatinine levels, as they can affect the accuracy of estimated glomerular filtration rate (eGFR) and the diagnosis of acute kidney injury (AKI) 1.
Management
While low creatinine levels themselves are not typically treated directly, addressing the underlying cause is crucial to prevent further complications and improve patient outcomes. If you have unexpectedly low creatinine levels, it is recommended to consult with a healthcare provider to determine the cause and appropriate management.
From the Research
Causes of Low Creatinine
- Low muscle mass: Serum creatinine levels are influenced by muscle mass, as creatinine is a byproduct of muscle metabolism 2, 3.
- Advanced age: Older adults may have lower muscle mass, leading to lower creatinine levels 2.
- Malnutrition: Inadequate nutrition can result in lower muscle mass and subsequently lower creatinine levels 2, 3.
- Liver disease: Liver disease can affect creatinine metabolism, leading to lower creatinine levels 4.
- Certain medications: Some medications, such as trimethoprim, can increase creatinine secretion and lead to lower serum creatinine levels 5.
Clinical Implications of Low Creatinine
- Sarcopenia: Low creatinine levels can be a marker of sarcopenia, which is associated with increased morbidity and mortality 3.
- Malnutrition: Low creatinine levels can indicate malnutrition, particularly in patients with chronic diseases 2, 3.
- Muscle wasting: Low creatinine levels can be a sign of muscle wasting, which can occur in various clinical settings, including cancer, HIV, and other chronic diseases 3.
Measurement and Interpretation of Creatinine
- Serum creatinine is the most widely used functional biomarker of the kidney, but it has substantial shortcomings 6.
- Understanding the pathways involved in creatinine generation and metabolism is critical for accurate interpretation of creatinine values 6.
- Alternative functional biomarkers of the kidney, such as serum cystatin C, may be useful in certain clinical settings 2, 6.