1/ This is the second #tweetorial #MedThread on contrast nephropathy from my grand rounds. For more information take a look here: pbfluids.com/2019/11/contra…
2/ The first #Tweetorial dealt with the lack of evidence tying contrast to AKI. This one is shorter and examines one of the major arguments regarding CIN: that the clinical outcomes of people who develop CIN is dismal.
3/ In most studies of contrast nephropathy the authors will not only report on the incidence of CIN but on the clinical outcomes of patients with and with CIN.
4/ The implication of those studies is that a disease causes the need for contrast which causes AKI which causes death. But alternatively the disease causes the need for contrast and the disease causes the AKI and the disease causes mortality. 
5/ The way to distinguish between these two scenarios is find an intervention which lowers the rate of AKI, and then see if that decreases the mortality rate.
6/ Sinai’s @scoca1 did a meta analysis of 14 interventions, 7 that increased AKI and 7 that decreased AKI. Look at the forest plots, the diamond for AKI is clearly to the left (or right) of the line of identity while the diamonds for CKD and mortality, are centered on the line.
7/ So regardless of whether the intervention increased or decreased AKI, in prospective randomized controlled trials, there is no difference in mortality.
8/ So when we see patients develop AKI after contrast we should be worried about them because they are at increased risk of mortality but preventing that contrast induced AKI will probably not eliminate or reduce that risk. /fin
