What's the actual evidence for contrast induced nephropathy?

[Zebra Hunter]

I figured this question would be relevant for this forum considering the amount of studies that are ordered in the ED w/o contrast due to concern for worsening kidney function of at risk patients.

I recently came across this study in Radiology, http://pubs.rsna.org/doi/full/10.1148/radiol.12121823, which shows that contrast induced nephropathy (CIN) might not actually be a thing. While only a retrospective study, it has a very large number of patients (53,439) and appears to do a decent job of correcting for selection bias.

What's your opinion of the study? And again, I was unable to find it, but what is the evidence behind CIN?

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[shookwell]

here's a recent paper from the EM literature that also questions the existence of contrast-induced nephropathy

http://www.ncbi.nlm.nih.gov/pubmed/23167857

 

[Apollyon]

Just to be clear, recall that these data are being applied to ED populations, and so, it is 100mL of Optiray or Visipaque (or whatever is the protocol amount). I don't know if it would pass an IRB to study cardiac cath patients who already have CKI, and they get a big slug of contrast during angiography, and then go on dialysis. Although it is only anecdote, when I was a resident, I saw more than 5 patients, who needed urgent to emergent cath, who had a Cr >2, who had their "last hurrah", and became anuric and went into ESRD and needed permanent dialysis. Although it was not studied, it sounds rather incredible that multiple sequential patients all went into ESRD temporally directly after a presumed nephrotoxic contrast dose, without that being the causative agent (ie, coincidentally). What I do not recall if there were any of those patients that did NOT need dialysis, or recovered their kidney function. But, as I say, I am not sure if any IRB would OK such a study.

Just sayin' (before @Dr.McNinja lambastes me again).

 

[diphenyl]

The contrast is amazing stuff. If you've ever had it in your hand it's amazing how thick and sticky it is. Imagine what it's doing injected into someone's circulatory system. That being said, in emergent patients, once again efficacy trumps side effects.

 

[deleted109597]

I don't have to think as much, because smarter people than me already have. However, I still have to read critically. That being said, Joel Topf thinks it exists http://www.pbfluids.com/2013/10/news-flash-iv-contrast-still-toxic-that.html.

 

[Zebra Hunter]

post hoc, ergo propter hoc seems to be the general argument when I have brought this up to attendings, and appears to be the argument made by Dr. Topf, as well. From reading up on a few more studies, it seems there is some decent evidence for the increased incidence of AKI with intra-arterial contrast administration (although even this is questionable due to obviously being unable to establish a control group); however, when looking specifically at IV administration, the waters get a little murkier. I think it's fair to say that the issue of contrast induced nephropathy, at least for IV administration, is overblown. Nevertheless, I will not deny that my appraisal of scientific literature is not as refined as most of y'all, so if one of you finds fault in my conclusion, I would love for you to lead me in the right direction with some accompanied literature.

 

[Kahreek]

I cant think of anything arterial infused that is not nephrotoxic.

 

[deleted109597]

The argument is that it's such a moving target that it's hard to pin down. And for all of those little old ladies at Cr 1.9 (or 1.6, or whatever your local cutoff is) that you don't give it because you're worried about the beans that are counted in the analysis.
Sadly, we aren't going to get an RCT on this (nor should we).
Why? Because the radiology literature is pretty clear that most contrast isn't needed anyway. Maybe we could just get them to do the studies without?

 

[deuist]

http://www.ncbi.nlm.nih.gov/pubmed/?term=23895627 : page S257, similar conclusions to the Radiology article. Contrast appears to become renal protective as the years go on.

 

[DocEspana]

CIN is totally a real thing. Rather than picking one study or two studies out of the blue... why not use every single study:

http://www.smartem.org/podcasts/ct-consent

Guy goes through and analyzes every single study on a subject and covers in depth the take away points of the ones with the most merit and impact. Its a fantastic unbiased review of all the literature worth knowing.

Kidney damage is one of the few things that is a real risk with IV contrast (allergy is overstated and almost unavoidable when it does happen, and unless your nuking a young woman, the cancer risk of a CT is measurable but tiny). Though perhaps the incidence of CIN is less common that thought too. but its definitely quite real.

 

[Zebra Hunter]

CIN is totally a real thing. Rather than picking one study or two studies out of the blue... why not use every single study:

http://www.smartem.org/podcasts/ct-consent

Guy goes through and analyzes every single study on a subject and covers in depth the take away points of the ones with the most merit and impact. Its a fantastic unbiased review of all the literature worth knowing.

Kidney damage is one of the few things that is a real risk with IV contrast (allergy is overstated and almost unavoidable when it does happen, and unless your nuking a young woman, the cancer risk of a CT is measurable but tiny). Though perhaps the incidence of CIN is less common that thought too. but its definitely quite real.

Man, I think you and I listened to 2 very different podcasts.

1. They didn't address "every single study" they just brought up 2 of Dr. Kline's studies on CIN that had severe flaws (like not actually having a control group).

2. I would hardly consider a CIN review that is already operating under the belief that it is a real entity is unbiased.

The only worthwhile positive study for CIN that I have found was a 1989 NEJM article which is the only positive study I saw that establishes a control group. The study showed that individuals with diabetic nephropathy were significantly more likely to have AKI after contrast administration. Nevertheless, even that study shows that the incidence of AKI was not significantly different between those who received contrast and had diabetes or renal insufficiency alone and those who received no contrast.

 

[DocEspana]

Man, I think you and I listened to 2 very different podcasts.

1. They didn't address "every single study" they just brought up 2 of Dr. Kline's studies on CIN that had severe flaws (like not actually having a control group).

2. I would hardly consider a CIN review that is already operating under the belief that it is a real entity is unbiased.

The only worthwhile positive study for CIN that I have found was a 1989 NEJM article which is the only positive study I saw that establishes a control group. The study showed that individuals with diabetic nephropathy were significantly more likely to have AKI after contrast administration. Nevertheless, even that study shows that the incidence of AKI was not significantly different between those who received contrast and had diabetes or renal insufficiency alone and those who received no contrast.

you have to listen to them regularly. The CT contrast one is relatively new for them (Even though it might be 2 years old by now) and they literally do a search of all the literature out there and evaluate all of it and then discuss only the ones that actually have relevance to the discussion. Earlier podcasts theyd cover tens and tens of studies and most of them would be "this study is so insanely flawed that we only mention it to be thorough and say we read it". Now they work under the assumption theyve read it all and if its not referenced its because its either better addressed by a different study or the study was basically disqualified by them for having too many flaws to be analyze-able.

Also I do think we listened to a different podcast because I just recently used this podcast to get a paper published on the risks of contrast induced nephropathy and I pulled multiple quality research studies demonstrating it from this podcast alone. Admittedly, I went straight to the reference list nad just mined the reference list for sources to use on my paper and havent listened to the podcast itself in the 2 years since it was released, so I cant promise you all of them were "deep dived" on.