Kevin O’Connor, MD
The ATACH-2 trial compared the effect of intensive systolic blood pressure (SBP) management (110-139 mmHg) to standard reduction (140-179 mm-Hg) on the incidence of death or severe disability following intracerebral hemorrhage (ICH).1 Although the study was stopped because of futility (no significant difference in primary outcome between treatment groups), the authors have since performed several post hoc analyses. The current report assesses the rates and predictors of acute kidney injury (AKI) and renal adverse events (AEs) and their effect on death within 90 days and death or disability at 90 days in 1000 participants from ATACH-2.
AKI and renal adverse events were present in 14.9% and 6.5% of ATACH-2 participants, respectively. In a multiple regression analysis, there was no difference in the frequency of AKI between standard and intensive treatment groups (relative risk 1.0 [95% CI, 1.0-1.0] versus relative risk 1.1 [95% CI, 0.8-1.5]; p=0.4241). There was, however, a higher risk of renal adverse events in the intensive treatment group (relative risk 2.3 [95% CI, 1.3–3.8] versus standard relative risk 1.0 [95% CI, 1.0-1.0], p=0.0013). Only AKI was associated with death within 90-days (odds ratio 2.9 [95% CI, 1.6–5.5]) and death or disability at 90 days (odds ratio 2.7 [95% CI, 1.7–4.1]).
Subgroup analyses can be useful when pitfalls associated with such studies are considered.2 These exploratory results should be hypothesis-generating and interpreted cautiously as the authors’ hypothesis was not developed until after the ATACH-2 trial ended and participant randomization was not stratified based on these subgroups. Although other studies have reported similar rates of AKI in the setting of acute stroke, as well as increased mortality in patients with ICH and renal dysfunction, further study is needed to explore the effects of kidney dysfunction in ICH patients.
References:
1. Qureshi AI, Palesch YY, Barsan WG, Hanley DF, Hsu CY, Martin RL, Moy CS, Silbergleit R, Steiner T, Suarez JI, et al. ATACH-2 Trial Investigators and the Neurological Emergency Treatment Trials Network. Intensive blood-pressure lowering in patients with acute cerebral hemorrhage. N Engl J Med. 2016;375:1033–1043.
2. Sun X, Ioannidis JP, Agoritsas T, Alba AC, Guyatt G. How to use a subgroup analysis: users’ guide to the medical literature. JAMA. 2014; 311:405–411.
