Salem MM
Hypertension in the hemodialysis population: A survey of
649 patients
Am J Kidney Dis
(Sep) 26:461-468 1995
This is a descriptive study of blood pressures in 649 mostly (89%) black
patients in dialysis units in Mississippi. Patients were classified as
hypertensive if they were taking anti-hypertensive meds or if mean
predialysis
MAP was greater than 114 mm Hg. Isolated systolic hypertension was defined
as
presystolic greater than 160 with a prediastolic BP less than 90. Patients
were
judged to be volume responsive if MAP decreased by more than 5% during
dialysis.
About 72% of the total population was hypertensive according to this
definition.
Of the hypertensives, about 80% were being treated, and 20% were not. BP
was
lower in patients more than 65 years of age. Hypertension was "volume
responsive" in
65% of cases, BP increased during dialysis in 9%, and BP was largely
unchanged
in the remainder of patients. MAP fell by 10% in untreated hypertensives,
but
only by 7% in patients receiving one or more drugs. Predialysis BP was
similar
in patients whose etiology of ESRD was hypertension, glomerulonephritis,
diabetes, and PCKD. Of the 40% hypertensives receiving monotherapy, 22% were
on
CCBs, 10% on vasodilators, 10% on sympatholytics, and 5% on ACE-inhibitors.
Pre-MAP was similar in these groups, and the ACE-group had similar
interdialytic
weight gains to the others (other data have suggested that ACE inhibitor
administration to thirsty patients with high renin levels mitigates thirst).
Comment: In the analyses, treated hypertensive patients were mixed
in
with untreated patients, thus, a chicken vs. egg question comes up with a
number
of the findings. In the abstract, the author implies that anti-
hypertensives
may not be effective, as BP was only 3 mm less in treated hypertensives than
in
untreated hypertensives. This is a flawed argument, as patient selection
may
play an important role (i.e., if the treated patients had not been treated,
their BP may have been much higher, with the presently untreated cohort
representing a mildly affected subgroup). A further point made is, that
since
the BP fell by only 7% in treated hypertensives vs. 10% in treated
hypertensives, volume is not an important component to the hypertension.
The
author also found, in agreement with Luik et al (Contrib Nephrol 106:90-93,
1994), that BP gain did not correlate with interdialytic weight gain. Yet,
65%
of patients were volume responsive by the author's own definition, and the
adequacy of ultrafiltration is difficult to assess in dialysis patients.
Futhermore, volume overload per se may predispose to LVH independently of
the
level of blood pressure. This study does serve to focus attention on the
gravity of the problem of high BP in dialysis patients.
(Daugirdas)
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CRF by organ system :
Cardiovascular/Hypertension
H: Special problems :
Dialysis patients