Dietary creatine supplements raise serum creatinine mimicking acute kidney injury

[stef]

by Jordan Feigenbaum, Kristopher Hunt, and Robert Hoffman

Both creatine monohydrate and creatine ethyl ester have the ability to substantially increase serum creatinine levels during initial stages of supplementation, which may potentially alter or inappropriately influence diagnosis and management of a patient presenting to the emergency department with and isolated elevated serum creatinine.

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[irongeek]

I wish I had this article a few months ago when my doc flipped out about my serum creatinine level. He demanded that I quit creatine supplementation and have my serum creatinine checked a month later where (of course), it went down. He probably felt like a hero for reducing his patient's "dangerous" creatinine levels. A few weeks later after studying serum creatinine as related to supplementing creatine mono, I started using creatine again. For some reason, I think I'll live...

[Jordan Feigenbaum]

We're all gonna make it.

[pgoreham]

Hey Jordan,

I'm a fan of your work and read as much of it as I can.

I have recently begun trying to read studies on health/fitness/etc. and I have questions about the following creatine related study and how it relates to the study you published in this article. Please note, I am not linking this to argue what you presented in your study, rather I would like to understand your more educated/experienced take on the linked study's importance in creatine research. https://www.ncbi.nlm.nih.gov/pubmed/25984094 (full text: The effects of the recommended dose of creatine monohydrate on kidney function)

Now, I recognize that the study I linked is an accounting of a single individual and I understand the fallacy of small numbers. Therefore, I understand upfront that it is not statistically significant and at best it indicates a need for more research.

The linked study says a "renal biopsy" was taken. I do not know what this entails. Is it possible that a miss diagnosis occurred because of, from your conclusion, "...possible confounders when evaluating renal function in a patient supplementing with creatine."?
What level of importance should I put into the linked study when talking about creatine with people (read as uneducated about health/fitness)? Should I even bring up this study?


Thanks,
Peter

[pgoreham]

Hey Jordan,

I'm a fan of your work and read as much of it as I can.

I have recently begun trying to read studies on health/fitness/etc. and I have questions about the following creatine related study and how it relates to the study you published in this article. Please note, I am not linking this to argue what you presented in your study, rather I would like to understand your more educated/experienced take on the linked study's importance in creatine research. The effects of the recommended dose of creatine monohydrate on kidney function. - PubMed - NCBI (full text: The effects of the recommended dose of creatine monohydrate on kidney function)

Now, I recognize that the study I linked is an accounting of a single individual and I understand the fallacy of small numbers. Therefore, I understand upfront that it is not statistically significant and at best it indicates a need for more research.

The linked study says a "renal biopsy" was taken. I do not know what this entails. Is it possible that a miss diagnosis occurred because of, from your conclusion, "...possible confounders when evaluating renal function in a patient supplementing with creatine."?
What level of importance should I put into the linked study when talking about creatine with people (read as uneducated about health/fitness)? Should I even bring up this study?


Thanks,
Peter

[Jordan Feigenbaum]

Hey Jordan,

I'm a fan of your work and read as much of it as I can.

I have recently begun trying to read studies on health/fitness/etc. and I have questions about the following creatine related study and how it relates to the study you published in this article. Please note, I am not linking this to argue what you presented in your study, rather I would like to understand your more educated/experienced take on the linked study's importance in creatine research. The effects of the recommended dose of creatine monohydrate on kidney function. - PubMed - NCBI (full text: The effects of the recommended dose of creatine monohydrate on kidney function)

Now, I recognize that the study I linked is an accounting of a single individual and I understand the fallacy of small numbers. Therefore, I understand upfront that it is not statistically significant and at best it indicates a need for more research.

The linked study says a "renal biopsy" was taken. I do not know what this entails. Is it possible that a miss diagnosis occurred because of, from your conclusion, "...possible confounders when evaluating renal function in a patient supplementing with creatine."?
What level of importance should I put into the linked study when talking about creatine with people (read as uneducated about health/fitness)? Should I even bring up this study?


Thanks,
Peter

Yea this is an interesting case report on a single individual and ultimately, it does not comport with our data and the long term work done by Poortman et al. A biopsy is basically when they go take a piece of tissue to look at it under a microscope and in this case, they did that with a piece of the kidney and found some findings consistent with acute tubular necrosis (ATN) per the authors report.

ATN typically is an ischemic (not enough blood flow) or result of a toxic insult (drugs or contrast material) causing issues with cells in particular areas of the kidney. How creatine supplementation did this seems, well, odd and I would look at this case report with skepticism without knowing more history of the patient, e.g. other toxic exposures, urinary creatinine levels, and how they arrived at "creatine induced ATN"

[Marenghi]

Great study, badly needed for athletes, coaches and medical professions.

Have you submitted it to peer-review yet? Which journal are you gonna target, more the Strength and Cond. type or medical?

[Robnet]

A few unsolicited comments:

1) You flipped the colors and legend order of the monohydrate and ester in Figures 1 and 2. It would be easier to follow if these were consistent; using different symbols would also be helpful.
2) Always show your error bars.
3) Are differences between the two groups' urinary creatinine at 1.5 hours statistically significant? In fact, are there any statistically significant differences in serum and urine creatinine between the two groups? It looks like the serum level comparisons are mostly significant, but some of the error ranges overlap in the urine comparisons (the urine creatinine measurements are variable, which isn't surprising, since you didn't lock your subjects in a cell for 24 hours with no access to food and water).
4) It is a good thing you limited participants to humans.
5) What is the rationale for a 10g creatine dose, as opposed to a body weight specified dose?
6) Minor typo page 2 paragraph 3 sentence 1 "Currently, creatine use is legal does not appear " possibly missing "and".
7) In Main Results you write "creatine monohydrate group baseline mean urine ... and paradoxically decreased to trough mean urine"; can you expand and possibly speculate on this decrease?
8) To nitpick with study design, to eliminate any arguments that the experimental order (monohydate, washout, ester) could have affected the results, the subjects could have been split into two groups, with the second group taking ester then monohydrate.

[m_sporkboy]

Jordan - thanks for this paper. I brought a printout with me to my annual physical, and it greatly shortened my doc's freakout when he skimmed the results section. He took the printout for later study.

[stef]

Have you submitted it to peer-review yet? Which journal are you gonna target, more the Strength and Cond. type or medical?

More that once. It was read over and accepted. But $1200 for page charges that leave it behind a paywall? So it was reviewed again here and published.