ARTICLE: Prevention Strategies for Contrast-Induced Nephropathy
AUTHORS: Eric B. Bass and Rathan M. Subramaniam
JOURNAL: Ann Intern Med. 2016 Oct 18;165(8):601. doi: 10.7326/L16-0278.
IN RESPONSE to http://annals.org/aim/article/2569399/prevention-strategies-contrast-induced-nephropathy
We appreciate Dr. Cain and Ms. Goldstone's concern about the possibility of falsely low serum creatinine measurements in the presence of NAC when the Trinder and Trinder-like reaction assays are used. When we reviewed Genzen and associates' study (1), we found that low doses of NAC did not substantially affect the serum creatinine level. Thus, we see no reason to change our conclusion that low strength of evidence indicates that low-dose NAC plus intravenous saline compared with intravenous saline had a clinically important benefit.
The concern then mainly applies to studies using high doses of NAC. Many of the studies included in our review used high doses of this agent, which we defined as more than 1200 mg/d. Several may have used doses high enough to cause a small effect on the creatinine level if measured by the Trinder assay. Unfortunately, few studies reported which assay was used to measure the serum creatinine levels. None reported using the Trinder assay.
We cannot exclude the possibility that use of the Trinder assay contributed to a small overestimation of the effect of high-dose NAC, but that would not explain why we did not find a clinically important benefit for high-dose NAC with intravenous saline compared with intravenous saline alone. Although we stand by our conclusions about the effects of NAC on contrast-induced nephropathy, we agree that studies of this agent to prevent nephrotoxicity should be more consistent in reporting the assay used to measure serum creatinine levels.
For a link to the full article, click here: http://annals.org/aim/article/2569398/prevention-strategies-contrast-induced-nephropathy
