What causes loss of control of hypertension?

Causes of Loss of Control of Hypertension

Poor medication adherence is the most common cause of loss of control of hypertension, affecting 10-80% of hypertensive patients and serving as a key driver of suboptimal blood pressure control. 1

Primary Causes

Patient-Related Factors

1. Poor Medication Adherence

   • 40% of patients discontinue antihypertensive medications during the first year of treatment 1
   • Less than 40% of patients persist with prescribed treatment during 5-10 years of follow-up 1
   • Contributing factors include:
     • Medication cost
     • Complex regimens
     • Side effects
     • Lack of symptoms (asymptomatic nature of hypertension)
     • Poor understanding of disease consequences

2. Lifestyle Factors

   • Salt consumption: Excessive dietary sodium directly increases BP and blunts medication effectiveness 1
   • Alcohol intake: Heavy consumption associated with treatment resistance 1
   • Obesity: Linked to more severe hypertension and need for increased medications 1
   • Physical inactivity: Lack of regular exercise 1
   • Poor diet: Low intake of fruits, vegetables, and high consumption of processed foods 1

3. Interfering Substances

   • Medications that raise BP 1:
     • NSAIDs (including aspirin)
     • COX-2 inhibitors
     • Sympathomimetics (decongestants, diet pills)
     • Stimulants (methylphenidate, amphetamines)
     • Oral contraceptives
     • Cyclosporine
     • Erythropoietin
   • Other substances:
     • Natural licorice
     • Herbal compounds (ephedra/ma huang)
     • Cocaine
     • Alcohol

Clinical Factors

1. Pseudoresistance

   • White-coat effect: Clinic BPs elevated while out-of-office measurements normal (20-30% prevalence) 1
   • Poor BP measurement technique: Not allowing patient to sit quietly, using too small a cuff 1

2. Secondary Hypertension 1

   • Obstructive sleep apnea: Particularly common in resistant hypertension (83% in one study) 1
   • Primary aldosteronism: Present in ~20% of resistant hypertension cases 1
   • Chronic kidney disease: Especially with eGFR <30 ml/min 1
   • Renal artery stenosis: More common in older patients, smokers, those with atherosclerotic disease 1
   • Less common causes: Pheochromocytoma, Cushing's syndrome, hyperparathyroidism, aortic coarctation 1

3. Treatment-Related Issues

   • Inadequate medication dosing: Suboptimal doses of medications 1
   • Inappropriate combinations: Not using complementary medication mechanisms 1
   • Insufficient diuretic therapy: Especially in volume overload states 1
   • Seasonal variation: BP tends to be higher in cold weather (average 5/3 mmHg higher in winter) 1

Evaluation Algorithm for Loss of BP Control

1. Confirm true loss of control

   • Verify proper BP measurement technique
   • Consider out-of-office BP monitoring (home or ambulatory) to exclude white-coat effect 1

2. Assess medication adherence

   • Direct questioning about missed doses
   • Pharmacy refill records
   • Consider objective evaluation (detecting drugs in blood/urine) in apparent resistant cases 1

3. Review lifestyle factors and interfering substances

   • Dietary sodium intake
   • Alcohol consumption
   • Weight changes
   • Physical activity levels
   • Complete medication review (including OTC and supplements)

4. Screen for secondary causes when appropriate:

   • Sleep apnea: Ask about snoring, daytime sleepiness, witnessed apneas 1
   • Primary aldosteronism: Check aldosterone/renin ratio 1
   • Renal disease: Check creatinine/eGFR, urinalysis 1
   • Renovascular disease: Consider in patients with atherosclerotic disease or worsening renal function 1

Management Approach

1. Address adherence issues

   • Simplify regimen when possible (once-daily dosing, combination pills)
   • Educate about importance of consistent medication use
   • Address side effects by medication adjustments

2. Optimize lifestyle modifications 1

   • Salt reduction (<1500 mg/day)
   • DASH-style diet rich in fruits, vegetables, low-fat dairy
   • Moderate alcohol consumption (≤2 drinks/day for men, ≤1.5 for women)
   • Weight reduction
   • Regular physical activity
   • Stress reduction

3. Adjust medication regimen

   • Ensure appropriate diuretic therapy
   • Consider adding mineralocorticoid receptor antagonist (spironolactone) for resistant hypertension 1, 2
   • Combine agents with different mechanisms of action 1
   • Consider chronotherapy (timing medications to match circadian BP patterns)

4. Treat secondary causes when identified

Common Pitfalls to Avoid

1. Overlooking non-adherence: This is the most common cause of apparent treatment failure 1

2. Failing to adjust for seasonal variations: Consider that BP naturally rises in colder weather 1

3. Ignoring interfering substances: Many medications and supplements can raise BP 1

4. Inadequate diuretic therapy: Volume overload is a common contributor to resistant hypertension 1

5. Missing secondary causes: Particularly sleep apnea and primary aldosteronism in resistant cases 1

6. Accepting white-coat hypertension: Out-of-office measurements are essential to confirm true loss of control 1