Resistant Hypertension in Chronic Kidney Disease

60

cause of aTRH [ 12 ]. Table 5.2 summarizes contemporary clinical outcome data for
aTRH with and without CKD, and we will describe these studies below.

Clinical Outcomes in Observational Studies of Non-CKD

Populations

A prospective observational study of [ 14 ] evaluated the prognostic importance of
office versus ambulatory BP monitoring (ABPM) in 556 mainly Caucasian patients
with aTRH using the previously stated definition. Patients with a mean age of
66 years were enrolled between 1999 and 2004 with a median follow-up of 4.9 years.
Drug adherence was assessed as moderate by a standard questionnaire. Patients
were also divided into “true” RH or white coat hypertension based on ABPM. One
hundred and nine patients (19.6%) reached a composite primary outcome of all-
cause mortality, major cardiovascular events, and major renal events (all-cause
death, stroke, acute myocardial infarction, myocardial revascularization, new-onset
heart failure, sudden death, limb amputation, or initiation of dialysis). When com-
pared to the 447 patients who did not reach the primary outcome, this group had a
higher mean serum creatinine of 1.3  ±  0.8  mg/dl (P  <  0.001), higher ABPM and
greater prevalence of true RH (77% vs 57%). Unadjusted survival analysis showed
significantly greater cardiovascular events and cardiovascular mortality for true RH
compared to white coat hypertension. Multivariable-adjusted survival models
showed no prognostic value for any office BP, while higher mean ambulatory BPs
were independent predictors of the composite outcome. Ambulatory systolic and
diastolic BP were equivalent predictors, and both were better than pulse pressure.
Nocturnal BP was superior to daytime BP. The only independent predictor of all-
cause mortality was an ABPM diagnosis of true RH. The only significant interac-
tion found was that the prognostic value of true RH was stronger in those with
diabetes (hazard ratio [HR], 5.5; 95% confidence interval [CI], 2.3–13.2) compared
to those without diabetes (HR, 1.5; 95% CI, 0.8–2.5). In total, the study demon-
strated the value of performing ABPM in patients with aTRH to identify the

Apparent

tRH

Cuff artefact adherenceNon- Sub-optimaldosage White-coateffect ‘True’ RH

Renovascular

disease

Pseudoresistance

Endocrine

causes

Sleep

Apnoea

Hypervolaemic

states (CKD,

HFNEF)

Drug-induced

HT (NSAIDs,

Liquorice)

Refractory

HT

Fig. 5.1 Classification and causes of resistant hypertension. Abbreviations: CKD chronic kidney
disease, HT hypertension, HFNEF heart failure with normal ejection fraction, NSAIDs nonsteroi-
dal anti-inflammatory drugs, RH resistant hypertension, tRH treatment-resistant hypertension

A. Odudu et al.