Intradialytic hypotension (IDH) is less likely to occur during hemodialysis (HD) as HD start times advance throughout the day, whereas intradialytic hypertension (HTN) is more likely to occur over time, study data presented at the American Society of Nephrology’s Kidney Week 2020 Reimagined virtual conference suggest.

In a study that included 5346 adults on thrice-weekly maintenance HD, Murad Alostaz, BSc, of Brigham and Women’s Hospital in Boston, Massachusetts, and colleagues examined the effect of HD start time on IDH and intradialytic HTN. Of these patients, 1938 were from the Hemodialysis Study (HEMO), a multicenter, randomized clinical trial, and 3408 received HD at a large dialysis organization (LDO). The HEMO patients had a mean age of 58 years, and 56% were female. The patients from the LDO had a mean age of 63 years, and 42% were female.

The investigators established 3 HD start time categories: before 9 AM (category 1), 9 AM to 12 PM (category 2), and after 12 PM (category 3). Compared with time category 1 (reference), time categories 2 and 3 were associated with 9% and 17% decreased odds of IDH, respectively, and 14% and 40% increased risk of intradialytic HTN, respectively, after adjusting for demographics, cardiovascular comorbidities, HD dose, session length, and other potential confounders, Dr Alostaz’s team reported.

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The investigators defined IHD as nadir intra-HD systolic blood pressure (SBP) less than 90 mm Hg if pre-HD SBP was less than 160 mm Hg, or less than 100 mm Hg if pre-HD SBP was 160 mm Hg or higher. They defined intradialytic HTN as any increase in post-HD SBP compared with pre-HD SBP.

“Whether HD treatment allocation to certain times of the day in hypotensive-prone or hypertensive-prone patients improves outcomes deserves further investigation,” the authors concluded in a study abstract.


Alostaz M, Correa S, Waikar SS, McCausland FR. Time of hemodialysis and risk of intradialytic hypotension and intradialytic hypertension. Presented at: Kidney Week 2020 Reimagined virtual conference, October 19-25. Poster PO1056.