Potential of CKD misclassification due to increases in serum creatinine levels….
The number one cause of end stage renal disease (ESRD) in the world is diabetic nephropathy. Because of this, chronic kidney disease screening is essential to provide adequate diabetes management. The current method for measuring kidney function is by measuring its glomerular filtration rate, (GFR). However, the gold standard techniques for measuring GFR are impractical. Therefore, estimating the GFR by measuring other variables like serum creatinine, age, and body size is recommended and more realistic. However, variations in serum creatinine levels can potentially lead to a misclassification of chronic kidney disease. Ideally, blood samples used to determine serum creatinine are taken after a patient fasts overnight but in practice this is not usually observed.
There have been studies done that show the relationship between protein creatinine in the body. One study shows that even an acute ingestion of cooked meat causes a marked postprandial transient increase in serum and urinary creatinine. Other studies have shown that the ingestion of raw meat had no effect on serum creatinine in healthy human subjects. However there have been no studies on the effects of cooked meat on creatinine levels in a well-defined patient population with different stages of diabetes-related chronic kidney disease.
A prospective experimental study was done with diabetic patients in various stages of chronic kidney disease. A total of 80 subjects were split into 5 subgroups which consisted of chronic kidney disease stages 1, 2, 3a, 3b, and 4. All subjects were Caucasian with an average age of 67 years, and had either type 1 or 2 diabetes. A control group of 16 subjects also participated in the study. Each subject was given a meat and nonmeat meal which consisted of 2 quarter pound Angus beef burgers and 2 vegetarian burgers respectively that were grilled from a frozen state for 25 minutes. Both meals also included two buns, a vegetable salad, and water. Blood samples were obtained after a 12 hour overnight fast, pre-prandial, and 1, 2, and 4 hours after the meat meal was consumed. For the non-meat meal, blood samples were obtained after a 12 hour overnight fast, and 1, 2, and 4 hours after the non-meat meal was consumed. Serum creatinine was the variable that was tested and measured in these blood samples. The results showed significant (higher) differences in serum creatinine levels after the meat meals were consumed in both the health group and the chronic kidney disease groups, and no significant differences after consuming the non-meat meal. The different serum creatinine levels were not significantly different 12 hours after meat consumption.
In conclusion, there are statistically significant increases in serum creatinine levels after a cooked meat meal in diabetic patients with stage 1-4 chronic kidney disease, which is due to the creatinine present in the cooked meat. This could lead to a misclassification of chronic kidney disease among diabetic patients. This misclassification can lead to wrongly starting or withdrawing certain medications for these patients. Because there is no significant difference in serum creatinine after an overnight fast, it is suggested that kidney function should be measured via GFR after a sufficient fasting, and not at an arbitrary time.
- Cooked meat can artificially raise serum creatinine levels and can potentially cause a misclassification of chronic kidney disease.
- Kidney function should be assessed with blood samples after a 12 hour overnight fast.
Nair, S. et al. "Effect of a Cooked Meat meal on Serum Creatinine and Estimated Glomerular Filtration Rate in Diabetes-Related Kidney Disease" Diabetes Care. 2014;37(2): 483-487