Response to “Fine-Tuning Dry Weight: a Key Component in Managing Blood Pressure for Dialysis Patients”

Replies: We appreciate the thoughtful letter from Dr. Tuncay Sahutoglu regarding our recent article analyzing the relationship between intradialytic hypotension and the use of calcium channel blockers, utilizing data from the Hemodialysis Study. 1 Dr. Sahutoglu rightly emphasizes the importance of managing volume status with respect to controlling blood pressure in patients receiving hemodialysis. 2However, though there is a plethora of observational evidence showing associations of extremes of blood pressure with adverse outcomes, 3 we note that there is a paucity of trial-level evidence to guide the optimal blood pressure (or even blood pressure parameter we should be targeting) among these patients. 4 In our analysis, we already accounted for ultrafiltration rate, which was defined as the ultrafiltration volume/time in hours/post-hemodialysis weight in kg.Given that this variable is highly collinear with estimated dry weight, additionally adjusting for estimated dry weight would likely overfit the model.Unfortunately, there were no objective measures of volume status in the Hemodialysis Study.However, to address the question raised, we examined if the association of calcium channel blockers with intradialytic hypotension differed according to the ultrafiltration rate, which did not show evidence for differential associations (P-interaction 0.80).Although our study provides valuable insights, ultimately, trials with adequate statistical power are needed to test objective assessments of volume status, blood pressure metrics and targets, and appropriate antihypertensive agents for these high-risk patients.