Download special considerations in patients with renal disease

Nephrol Dial Transplant (1999) 14: Editorial Comments
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Nephrol Dial Transplant (1999) 14: 2291–2292
Hypertension and the risk of intracerebral haemorrhage:
special considerations in patients with renal disease
Amanda G. Thrift1,3, Roger G. Evans2, and Geoffrey A. Donnan3
1Department Epidemiology and Preventive Medicine, Monash Medical School, Alfred Hospital, Prahran, 2Department of
Physiology, Monash University, Clayton, and 3National Stroke Research Institute, Austin and Repatriation Medical Centre,
Heidelberg West, Victoria, Australia
Intracerebral haemorrhage (ICH ) comprises about
10–15% of strokes and is associated with a high
mortality rate and a high level of persistent disability
in survivors [1,2]. Because there is little potential to
ameliorate the damage after ICH has occurred, prevention is of particular importance.
There is now quite clear evidence that hypertension
is the most powerful risk factor for ICH. In a recent
case-control study that involved 331 cases of primary
ICH and the same number of matched controls, the
adjusted odds ratio (OR) for ICH among hypertensives
was 2.45 (95% confidence interval (CI ) 1.61–3.73) [3].
A similar OR was obtained when patients who had
ever used antihypertensive medication were considered
(OR 2.44, 95% CI 1.56–3.82). Although these ORs are
generally less than those reported in most previous
studies of the condition [4–9] they are similar to the
only other major Australian study [10]. The relatively
low ORs might partly be explained by the high level
of detection and management of hypertension in
Australia, as well as other population differences,
including the prevalence of smoking and other risk
factors for ICH [11].
Ceasing antihypertensive medication use increases
the risk of ICH
A major finding of the study was that the stroke risk
among hypertensives varied according to their current
or past use of antihypertensive medication [3]. When
compared to never users of antihypertensive medications (i.e. normotensives and undetected hypertensives)
the OR for current users was 1.95 (95% CI 1.20–3.16).
The level of risk was significantly greater (P=0.002)
among those who had received antihypertensive medications in the past but had subsequently ceased this
use (OR 4.98, 95% CI 2.25–11.02). This observation
supports the notion that antihypertensive therapy
reduces the risk of ICH among hypertensive patients.
It is unlikely that patients ceased their antihypertensive
therapy because their blood pressure had normalized;
Correspondence and offprint requests to: Dr A. Thrift, National
Stroke Research Institute, Boronia Centre, Austin and Repatriation
Medical Centre, Banksia Street, West Heidelberg, Victoria 3081,
Australia.
more likely the all too common problem of a failure
to comply with medical advice. Although it was not
possible to directly attribute this increased risk of ICH
among people ceasing antihypertensive therapy to the
absolute increases in levels of blood pressure (blood
pressure was not measured in these people prior to
their ICH ), this seems a reasonable explanation. The
higher risk of ICH in such patients, therefore,
emphasises the importance of continuing (and indeed
improving) therapy and adequate blood pressure monitoring, as well as encouraging compliance, in patients
with established hypertension. Because of the prevalence and severity of hypertension among patients with
renal diseases, these findings are of particular importance among this group of patients.
Implications for patients with renal disease
Although many factors probably contribute to the
dramatically increased risk of ICH in chronic haemodialysis patients, there is clear evidence for a major
role of hypertension [12,13]. Furthermore, the prevalence and severity of hypertension in this group of
patients might also suggest that they are at increased
risk of ICH [14]. Aggressive treatment of hypertension,
with lower than normal target blood pressure, has
been recommended for patients with renal failure,
particularly those on haemodialysis [12,13].
To maximize the value of antihypertensive therapy
to these patients, consideration must be given to the
issues of compliance, antihypertensive efficacy, and the
renoprotective value of the various therapeutic alternatives. At least in lower socio-economic groups,
decreased satisfaction with patient care and with interpersonal relationships with physicians, correlate with
decreased antihypertensive compliance [15]. The type
of antihypertensive agent used appears to influence
compliance, it being greater for angiotensin converting
enzyme inhibitors and calcium antagonists than for
beta-blockers and diuretics, possibly because of a
reduced incidence of side-effects, particularly with combination therapies [16 ]. The former agents also probably have additional benefits in protecting the kidney
from progressive damage [17], particularly in diabetic
hypertensives [18]. Recent epidemiological evidence
clearly shows that antihypertensive monotherapy has
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very limited success in reaching target blood pressures,
and that combined therapies are significantly more
effective [19]. Thus, combination antihypertensive therapies, based on the use of angiotensin converting
enzyme inhibitors and calcium antagonists, have particular merit in patients with renal disease. There may
also be a place for long, slow haemodialysis for better
control of blood pressure in patients [20].
Greater risk of ICH among younger hypertensives
There is also evidence that the impact of hypertension
on stroke risk is greatest among younger individuals.
In our recent case-control study hypertensives less than
55 years of age were at greater risk of ICH than those
above this age (OR=7.68, 95% CI 2.65–22.5) [3]. The
OR declined for each increasing age category: 2.96
(95% CI 1.39–6.30) for ages 55–64, 1.33 (0.71–2.49)
for ages 65–74, and 1.94 (0.84–4.52) for those aged
75 years and over. A similar gradient has been observed
in the Honolulu Heart Programme [21]. The impact
of age on risk of ICH is probably exacerbated in endstage renal failure, since haemodialysis patients suffer
ICH on average 10 years earlier than the general
population [12].
Conclusions
There is potential to reduce the likelihood of ICH
among patients with renal disease by improving blood
pressure control, and blunting the progression of renal
disease. Strategies to achieve this should include consideration of the need to (i) educate both patients and
physicians about the hazards of poor compliance,
(ii) improve both the access to and quality of health
care, particularly among lower socio-economic groups,
and (iii) the increased use of angiotensin converting
enzyme inhibitors, alone or in combination with calcium antagonists (increased compliance and renoprotection). In young hypertensive patients, who also have
increased risk of ICH, there is considerable scope for
reducing risk by enhanced detection and more aggressive treatment of hypertension.
Acknowledgements. The authors’ work was made possible with
financial support from the Victorian Health Promotion Foundation,
the National Health and Medical Research Council, the Alfred
Hospital Research Trust and the National Stroke Foundation. We
would also like to acknowledge the assistance of Dr Göran Bergström
in providing critical comment on the manuscript.
Nephrol Dial Transplant (1999) 14: Editorial Comments
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