What causes hypocreatinemia (low serum creatinine levels)?

From the Guidelines

Hypocreatinemia, or low serum creatinine levels, can be caused by factors such as reduced muscle mass, severe malnutrition, or a vegetarian diet.

Factors Affecting Serum Creatinine Levels

• Reduced muscle mass, as seen in the elderly or in individuals with muscle-wasting diseases, can lead to lower creatinine generation and subsequently lower serum creatinine levels 1
• Severe malnutrition or a vegetarian diet can also result in lower serum creatinine levels due to reduced creatinine intake and generation 1
• Other factors, such as extrarenal excretion and creatinine secretion, can also affect serum creatinine levels, making it a less reliable indicator of kidney function 1

Limitations of Serum Creatinine as a Measure of Kidney Function

• Serum creatinine concentration is affected by factors other than glomerular filtration rate (GFR), such as creatinine secretion and generation, and extrarenal excretion 1
• As a result, there is a relatively wide range for serum creatinine in normal individuals, making it difficult to use serum creatinine concentration alone to estimate the level of kidney function or detect earlier stages of chronic kidney disease 1
• The use of GFR, rather than serum creatinine measurement, is recommended to characterize kidney function, as it provides a more accurate assessment of kidney function 1

From the Research

Causes of Hypocreatinemia

• Low body mass 2
• Pregnancy 2
• Insulin-dependent diabetes mellitus 2
• Total immobilization 2
• Severe hepatic disease, including fulminant hepatitis and advanced primary biliary cirrhosis 3
• Sarcopenia, which is characterized by low muscle mass and is associated with low serum creatinine levels 4
• Certain clinical settings, such as prediabetes and diabetes, although the relationship between low serum creatinine levels and these conditions is not fully understood 5

Associated Conditions

• Low serum urate (as uric acid) concentration 3
• Increased endogenous creatinine clearance 3
• Reduced inulin clearance 3
• Increased tubular secretion of creatinine related to body fluid expansion caused by large fluid infusion 3
• Decrease in predialysis body weight 6

Prognostic Value

• Low serum creatinine levels have been associated with adverse outcomes in patients undergoing maintenance hemodialysis 6
• Antecedent creatinine decrease is independently associated with an increased risk of all-cause mortality and cardiovascular death in hemodialysis patients 6