michigan hypertension core curriculum - State of Michigan

ETIOLOGY
Resistant HTN in most of the cases is mutifactorial. 4 Causes can be divided as patient-related
causes (life style factors, adherence), physician-related (suboptimal therapy), medication-related
and disease-related (or secondary HTN). It is also very important to rule out psuedoresistance.
Pseudoresistance can result from poor BP technique, poor medication adherence, white-coat effect, or
pseudohypertension (Osler phenomena):
Lifestyle Factors
1- Obesity is a common feature of patients with resistant hypertension and more than 40
percent of patients with resistant hypertension are obese. 5 Accordingly, obesity is known to be
associated with resistance to pharmacological BP lowering.
2- Excessive dietary salt intake has been specifically documented as being common in patients
with resistant hypertension. 2 The frequency of salt sensitivity is increased among patients
who are at least 60 years of age, patients who are African American or obese, and patients
with renal impairment. 6 Approximately 75 – 80% of dietary sodium intake can be linked to the
consumption of high sodium foods (e.g., processed meats, canned goods).
3- Heavy alcohol intake is associated with treatment-resistant hypertension. 7 On the other
hand, alcohol reduction is associated with a significant reduction in systolic and diastolic blood
pressures of -3.31 mm Hg and -2.04 mm Hg, respectively. 8 Alcohol consumption should be kept
to 2 or fewer drinks per day in men and no more than 1 drink per day in women.
Physician Related Factors (Suboptimal therapy)
Suboptimal therapy was the single most common (and most correctable) cause of resistant
hypertension. The major causes of inadequate medical treatment were lack of administration of
enough effective drugs and failure to prevent volume expansion with adequate diuretic therapy. 9 It is
important to ensure the diuretic therapy is appropriate to the level of kidney function. For example,
hydrochlorothiazide is ineffective when the estimated glomerular filtration rate is < 45 ml/min.1.73 m 2 , at
least when dosed conventionally. Chlorthalidone, a thiazide-like diuretic, effectively lowers BP down to
estimated glomerular filtration rates in the low to mid 30’s. It is not uncommon for patients with poorly
NKFM & MDCH 227