What is the difference between a healthcare proxy, living will, advanced directive (AD), and Physician Orders for Life-Sustaining Treatment (POLST) for an adult patient, particularly the elderly or those with significant medical conditions?

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Last updated: January 27, 2026View editorial policy

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Understanding the Four Key Documents in Advance Care Planning

These are four distinct but complementary documents: an advance directive is the umbrella term that includes both a living will (your written treatment preferences) and a healthcare proxy/durable power of attorney (your designated decision-maker), while POLST is a separate medical order form that converts your goals into actionable orders for patients with life-limiting illness.

Advance Directive: The Umbrella Document

An advance directive is the comprehensive legal document that all adults aged 18 and older should complete, regardless of current health status, because anyone can face sudden life-limiting illness or injury 1. This document should include two essential components 1, 2:

  • A living will that specifies your treatment preferences
  • A durable power of attorney for health care (also called healthcare proxy) that appoints your surrogate decision-maker

Written advance directives are more legally trustworthy than verbal conversations and must be properly documented in the medical record, with copies given to family, loved ones, and physicians 1, 2.

Living Will: Your Written Treatment Preferences

A living will provides written direction to healthcare providers about approved care if you become terminally ill and unable to make decisions 2. Essential elements to document include 1:

  • Preferences regarding cardiopulmonary resuscitation (CPR)
  • Mechanical ventilation decisions
  • Intensive care unit admission preferences
  • Artificial nutrition and hydration wishes
  • Antibiotic use preferences

This document constitutes legally enforceable evidence of your wishes in most jurisdictions 2.

Healthcare Proxy (Durable Power of Attorney for Health Care): Your Decision-Maker

This component appoints an authorized person to make healthcare decisions on your behalf, accounting for unforeseen circumstances 2. The critical distinction is that your healthcare proxy can make decisions that may even conflict with your living will when circumstances arise that you didn't anticipate 2.

Your proxy should participate in goals-of-care conversations with you beforehand so they can make "just in time" decisions that align with your values, which reduces burden and stress on friends and family 3.

POLST: Actionable Medical Orders for Advanced Illness

POLST is fundamentally different from traditional advance directives—it is a medical order form, not a planning document 4. POLST should only be completed for patients with 1:

  • Life expectancy less than one year
  • Advanced metastatic cancer
  • End-stage cardiac disease
  • End-stage pulmonary disease
  • Advanced dementia
  • Advanced chronic progressive illness

Why POLST Exists: The Limitation of Traditional Advance Directives

Traditional advance directives are rarely sufficiently precise to dictate patient preferences in specific situations as disease progresses 4. For patients approaching end of life, converting patient-centered treatment goals into actionable medical orders while the patient maintains capacity is more effective than advance directives alone 4.

Key Features of POLST

POLST provides explicit direction about 4:

  • Resuscitation status if the patient is pulseless and apneic
  • Transport decisions
  • ICU care preferences
  • Antibiotic use
  • Artificial nutrition

The form accompanies the patient and is transferable across all care settings (long-term care, emergency medical services, hospital), and emergency personnel must honor these orders 4, 5. Research from Oregon demonstrates that POLST more accurately conveys end-of-life preferences that are more likely to be followed by medical professionals than traditional advance directives alone 4.

Critical Implementation Pitfalls to Avoid

The Timing Error

Advance directives must be completed while patients retain decision-making capacity, not when capacity is already compromised 1. More than a quarter of elderly patients require surrogate decision-making at the end of life, making early completion essential 1.

The Health Literacy Problem

Patients have significant functional health illiteracy about life-sustaining treatments 4, 1. You must avoid medical jargon and ensure patients understand realistic outcomes—for example, average CPR survival rate is only 15%, with 44% of survivors experiencing significant functional decline 1. For patients with multiple comorbidities, survival rates can be less than 5% or even less than 1% 5.

The Physician Initiative Gap

Only 19% of patients report discussing advance directives with their clinician, and lack of physician initiative is among the most frequently cited barriers 1. Healthcare institutions are mandated by the Patient Self-Determination Act of 1990 to facilitate completion of advance directives if patients desire them 1, 2.

The Documentation Access Problem

Healthcare facilities must have mechanisms ensuring providers can access advance directives across care settings 2. The documents must be transferable to ensure continuity 1.

When to Use Each Document

All adults need an advance directive (living will + healthcare proxy) 1. This is universal, regardless of age or health status.

Add POLST only when the patient has advanced illness with potential life expectancy less than one year 1. At this point, you need both the traditional advance directive AND the POLST form—they serve complementary functions 4.

Regular Reassessment Required

Advance directives should be revisited regularly as medical conditions and treatment preferences change over time 1. For patients with incurable illness, conversations should be initiated within one month of diagnosis and readdressed periodically based on clinical events 1.

References

Guideline

Advance Care Planning for Adults

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Guideline

Advance Directives Under the Patient Self-Determination Act

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Approach to POLST Discussion in Patients with Advanced Cardiopulmonary Disease

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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