Vasopressin was no better than norepinephrine in preventing kidney failure when used as a first-line treatment for septic shock, according to a report published online Aug. 2 in JAMA.
In a multicenter, double-blind, randomized trial comparing the two approaches in 408 ICU patients with septic shock, the early use of vasopressin didn’t reduce the number of days free of kidney failure, compared with standard norepinephrine.
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However, “the 95% confidence intervals of the difference between [study] groups has an upper limit of 5 days in favor of vasopressin, which could be clinically important,” said Anthony C. Gordon, MD, of Charing Cross Hospital and Imperial College London, and his associates. “Therefore, these results are still consistent with a potentially clinically important benefit for vasopressin; but a larger trial would be needed to confirm or refute this.”
Norepinephrine is the recommended first-line vasopressor for septic shock, but “there has been a growing interest in the use of vasopressin” ever since researchers described a relative deficiency of vasopressin in the disorder, Dr. Gordon and his associates noted.
“Preclinical and small clinical studies have suggested that vasopressin may be better able to maintain glomerular filtration rate and improve creatinine clearance, compared with norepinephrine,” the investigators said, and other studies have suggested that combining vasopressin with corticosteroids may prevent deterioration in organ function and reduce the duration of shock, thereby improving survival.
To examine those possibilities, they performed the VANISH (Vasopressin vs. Norepinephrine as Initial Therapy in Septic Shock) trial, assessing patients age 16 years and older at 18 general adult ICUs in the United Kingdom during a 2-year period. The study participants were randomly assigned to receive vasopressin plus hydrocortisone (100 patients), vasopressin plus matching placebo (104 patients), norepinephrine plus hydrocortisone (101 patients), or norepinephrine plus matching placebo (103 patients).
The primary outcome measure was the number of days alive and free of kidney failure during the 28 days following randomization. There was no significant difference among the four study groups in the number or the distribution of kidney-failure–free days, the investigators said (JAMA. 2016 Aug 2. doi: 10.1001/jama.2016.10485).
In addition, the percentage of survivors who never developed kidney failure was not significantly different between the two groups who received vasopressin (57.0%) and the two who received norepinephrine (59.2%). And the median number of days free of kidney failure in the subgroup of patients who died or developed kidney failure was not significantly different between those receiving vasopressin (9 days) and those receiving norepinephrine (13 days).
The quantities of IV fluids administered, the total fluid balance, serum lactate levels, and heart rate were all similar across the four study groups. There also was no significant difference in 28-day mortality between patients who received vasopressin (30.9%) and those who received norepinephrine (27.5%). Adverse event profiles also were comparable.
However, the rate of renal replacement therapy was 25.4% with vasopressin, significantly lower than the 35.3% rate in the norepinephrine group. The use of such therapy was not controlled in the trial and was initiated according to the treating physicians’ preference. “It is therefore not possible to know why renal replacement therapy was or was not started,” Dr. Gordon and his associates noted.
The use of renal replacement therapy wasn’t a primary outcome of the trial. Nevertheless, it is an important patient-centered outcome and may be a factor to consider when treating adults who have septic shock, the researchers added.
The study was supported by the U.K. National Institute for Health Research and the U.K. Intensive Care Foundation. Dr. Gordon reported ties to Ferring, HCA International, Orion, and Tenax Therapeutics; his associates reported having no relevant financial disclosures.