# Hypertension Management in the Outpatient Setting

## Introduction

Hypertension affects nearly half of all US adults and remains the single largest modifiable risk factor for cardiovascular disease, stroke, and chronic kidney disease. The 2017 ACC/AHA guidelines redefined hypertension as blood pressure at or above 130/80 mmHg, substantially expanding the population requiring intervention. Internal medicine residents must master accurate measurement, risk stratification, and individualized pharmacotherapy.

## Blood Pressure Measurement

### Proper Technique

- **Seated** with back supported, feet flat on the floor, arm supported at heart level
- **Appropriate cuff size**: bladder encircling at least 80% of the upper arm circumference
- No caffeine, exercise, or smoking for 30 minutes prior
- Allow **5 minutes of quiet rest** before measurement
- Average of **2-3 readings** taken 1-2 minutes apart

### Out-of-Office Measurement

- **Ambulatory blood pressure monitoring (ABPM)**: gold standard for confirming hypertension and detecting white-coat or masked hypertension
- **Home blood pressure monitoring (HBPM)**: morning and evening readings over 7 days; discard first day, average remaining values
- **White-coat hypertension** (elevated office BP, normal out-of-office): prevalence 15-30%; associated with intermediate cardiovascular risk
- **Masked hypertension** (normal office BP, elevated out-of-office): prevalence 10-15%; carries risk similar to sustained hypertension

![Proper blood pressure measurement technique](images/bp-measurement-technique.png)

## Classification (2017 ACC/AHA)

| Category | Systolic (mmHg) | Diastolic (mmHg) |
|----------|-----------------|-------------------|
| Normal | < 120 | < 80 |
| Elevated | 120-129 | < 80 |
| Stage 1 HTN | 130-139 | 80-89 |
| Stage 2 HTN | >= 140 | >= 90 |

## Secondary Hypertension Screening

- Consider when onset is before age 30, resistant hypertension, abrupt worsening, or suggestive clinical features
- **Primary aldosteronism**: aldosterone-to-renin ratio (most common secondary cause)
- **Renovascular disease**: renal artery duplex ultrasound or CT angiography
- **Pheochromocytoma**: plasma free metanephrines
- **Obstructive sleep apnea**: STOP-BANG questionnaire, polysomnography
- **Cushing syndrome**: overnight dexamethasone suppression test or 24-hour urine cortisol
- **Thyroid disease**: TSH

## Nonpharmacologic Interventions

- **DASH diet**: rich in fruits, vegetables, whole grains, low-fat dairy; reduces SBP by 8-14 mmHg
- **Sodium restriction**: target < 1500 mg/day; reduces SBP by 5-6 mmHg
- **Aerobic exercise**: 150 minutes/week moderate intensity; reduces SBP by 5-8 mmHg
- **Weight loss**: 1 mmHg reduction per kg lost
- **Alcohol moderation**: limit to 1 drink/day (women), 2 drinks/day (men)
- **Potassium supplementation**: 3500-5000 mg/day from dietary sources

## Pharmacotherapy

### First-Line Agents

- **ACE inhibitors / ARBs**: preferred in diabetes, CKD with proteinuria, heart failure with reduced ejection fraction
- **Calcium channel blockers** (amlodipine, nifedipine): effective across demographics; preferred in Black patients as monotherapy
- **Thiazide/thiazide-like diuretics** (chlorthalidone, indapamide): chlorthalidone preferred over HCTZ (longer half-life, stronger evidence)

### Special Populations

- **Black patients**: initiate with CCB or thiazide; dual therapy often needed early
- **CKD with proteinuria**: ACEi or ARB mandatory; switch to loop diuretic if eGFR < 30
- **Heart failure (HFrEF)**: ACEi/ARB (or ARNI), beta-blocker, MRA, and diuretic
- **Pregnancy**: labetalol, nifedipine, or methyldopa; avoid ACEi/ARB (teratogenic)
- **Post-stroke**: ACEi + thiazide combination (PROGRESS trial)

### Resistant Hypertension

- Defined as BP above goal despite 3 optimally dosed agents including a diuretic
- Confirm adherence (pill counts, liquid chromatography-mass spectrometry)
- Add **spironolactone** 25-50 mg daily (PATHWAY-2 trial): most effective fourth-line agent
- Rule out secondary causes and optimize diuretic therapy

![Algorithm for stepwise antihypertensive therapy](images/hypertension-treatment-algorithm.png)

## Blood Pressure Targets

- **General population**: < 130/80 mmHg (ACC/AHA 2017)
- **SPRINT trial**: intensive target (SBP < 120) reduced major cardiovascular events by 25% and all-cause mortality by 27%
- **Elderly (>= 65 years)**: individualize; SPRINT included ambulatory patients >= 75 and showed benefit
- **Diabetes**: < 130/80 mmHg; evidence strongest for SBP < 130 (ACCORD BP showed stroke benefit)

![Blood pressure targets by population](images/bp-targets-summary.png)

## Follow-Up and Monitoring

- Recheck BP at **1-month intervals** after initiating or adjusting therapy
- Monitor **electrolytes and creatinine** within 2-4 weeks of starting ACEi/ARB or diuretic
- Once at goal, follow-up every **3-6 months**
- Assess for **medication side effects**, adherence barriers, and lifestyle modifications at each visit

## Key Clinical Pearls

- Always confirm the diagnosis with out-of-office measurements before initiating lifelong pharmacotherapy
- Chlorthalidone is preferred over HCTZ based on superior 24-hour BP lowering and cardiovascular outcome data
- Spironolactone is the most effective add-on agent for resistant hypertension
- Single-pill combinations improve adherence and should be considered early, especially in Stage 2 hypertension

## References

1. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA Guideline for Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. *Hypertension*. 2018;71(6):e13-e115.
2. SPRINT Research Group. A Randomized Trial of Intensive versus Standard Blood-Pressure Control. *N Engl J Med*. 2015;373(22):2103-2116.
3. Williams B, MacDonald TM, Morant S, et al. Spironolactone versus Placebo, Bisoprolol, and Doxazosin to Determine the Optimal Treatment for Drug-Resistant Hypertension (PATHWAY-2). *Lancet*. 2015;386(10008):2059-2068.
4. Muntner P, Shimbo D, Carey RM, et al. Measurement of Blood Pressure in Humans: A Scientific Statement from the AHA. *Hypertension*. 2019;73(5):e35-e66.