CDC Guideline for Prescribing Opioids for Chronic Pain — United States, 2016

This document is a clinical practice guideline, not a primary research study. It systematically reviewed existing scientific evidence to develop recommendations for primary care clinicians regarding the prescribing of opioid pain medications for adult patients experiencing chronic pain (lasting >3 months or past normal tissue healing) outside of active cancer treatment, palliative care, and end-of-life care.

The guideline focused on three main areas:

1. **When to initiate or continue opioids for chronic pain:** This involved evaluating the benefits and harms of starting or continuing opioid therapy versus non-opioid treatments or no treatment.

2. **Opioid selection, dosage, duration, follow-up, and discontinuation:** This covered practical aspects of managing opioid therapy, including choosing the right opioid, determining appropriate doses, setting treatment durations, planning for ongoing monitoring, and strategies for tapering or discontinuing opioids.

3. **Assessing risk and addressing harms of opioid use:** This included recommendations for identifying patients at higher risk of opioid-related harms (e.g., opioid use disorder, overdose) and strategies to mitigate these risks.

The primary outcome measures considered in the underlying evidence reviews would have included:

**Pain intensity:** Reduction in self-reported pain scores.

**Function:** Improvement in daily activities, work productivity, and quality of life.

**Opioid-related harms:** Incidence of opioid use disorder, overdose, respiratory depression, falls, fractures, and death.

**Side effects:** Common adverse events associated with opioid use (e.g., nausea, constipation, sedation).

The guideline's ultimate goal was to improve communication between clinicians and patients about the risks and benefits of opioid therapy, enhance the safety and effectiveness of pain treatment, and reduce the risks associated with long-term opioid therapy, including opioid use disorder, overdose, and death.

As a guideline, there was no single "study population." Instead, the recommendations were developed for **primary care clinicians** in the United States who treat **adult patients with chronic pain** (defined as pain lasting >3 months or past the time of normal tissue healing). Importantly, the guideline specifically **excluded** patients receiving opioids for active cancer treatment, palliative care, or end-of-life care.

The evidence reviewed to inform the guideline would have encompassed studies involving diverse populations of adults with various types of chronic non-cancer pain, such as musculoskeletal pain (e.g., arthritis, back/neck problems), neuropathic pain, and frequent severe headaches. The guideline notes that estimates of chronic pain prevalence vary, with 14.6% of adults reporting widespread or localized pain lasting at least 3 months (1999–2002 National Health and Nutrition Examination Survey) and 11.2% of adults reporting daily pain (2012 National Health Interview Study).

The CDC guideline was developed using the **Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework**. This is a systematic and transparent approach for developing clinical practice guidelines by assessing the quality of evidence and the strength of recommendations.

The GRADE framework involves:

**Systematic reviews of evidence:** Comprehensive searches and evaluations of existing scientific literature related to the guideline questions. This included both clinical evidence (e.g., randomized controlled trials, observational studies on opioid efficacy and harms) and contextual evidence (e.g., patient values and preferences, resource allocation, feasibility).

**Assessment of evidence quality:** For each outcome, the quality of the evidence was rated as high, moderate, low, or very low, based on factors such as study design, risk of bias, consistency of results, directness of evidence, and precision. For example, randomized controlled trials generally start as high-quality evidence but can be downgraded for limitations, while observational studies start as low-quality but can be upgraded for strong effects or dose-response gradients.

**Formulation of recommendations:** Recommendations were developed by considering the balance between desirable and undesirable effects (benefits vs. harms), the quality of the evidence, patient values and preferences, and resource implications.

**Strength of recommendations:** Recommendations were categorized as "strong" or "weak" (conditional). A strong recommendation means that most individuals would want the recommended course of action, and clinicians should follow it in most circumstances. A weak recommendation means that the best action may differ depending on individual circumstances or patient values, and clinicians need to help patients make decisions consistent with their values.

The guideline development process also involved extensive input from:

**Core Expert Group (CEG):** A multidisciplinary group of experts who helped define the scope, key questions, and methodology.

**Opioid Guideline Workgroup (OGW):** A broader group of experts and stakeholders who reviewed the evidence and drafted recommendations.

**Public and Stakeholder Input:** Opportunities for public comment and feedback from various organizations and individuals.

**Peer Reviewers:** Independent experts who critically evaluated the draft guideline.

**Federally Chartered Advisory Committee:** The National Center for Injury Prevention and Control (NCIPC) Board of Scientific Counselors (BSC) provided final review and approval.

This rigorous process aimed to ensure that the recommendations were evidence-based, transparent, and considered a broad range of perspectives.

This CDC Guideline is a **systematic review and guideline development process**, not a primary research study. Its methodology is focused on synthesizing existing evidence to create actionable recommendations for clinicians.

**How they ran the study (Guideline Development):**

1. **Scope and Key Questions Definition:** The process began by defining the scope of the guideline (chronic non-cancer pain, primary care setting) and formulating specific clinical questions about opioid prescribing.

2. **Evidence Review:**

* **Clinical Evidence Review:** A systematic review of the scientific literature was conducted to identify studies on the benefits and harms of opioid therapy for chronic pain. This involved comprehensive searches of electronic databases (e.g., PubMed, Embase, Cochrane Library). The guideline specifically mentions that evidence supports short-term efficacy (primarily ≤12 weeks) of opioids for reducing pain and improving function in noncancer nociceptive and neuropathic pain, but few studies rigorously assessed long-term benefits (≥1 year).

* **Contextual Evidence Review:** This involved gathering information on patient values and preferences, resource allocation, feasibility, and acceptability of potential recommendations.

3. **GRADE Framework Application:** The collected evidence was then assessed using the GRADE framework. This involved:

* **Rating the quality of evidence:** For each outcome, the quality was rated (high, moderate, low, very low) based on factors like study design, risk of bias, consistency, directness, and precision. For example, evidence from randomized controlled trials (RCTs) is generally considered higher quality for efficacy, while observational studies might be the primary source for rare harms.

* **Balancing benefits and harms:** The guideline development group carefully weighed the potential benefits (e.g., pain reduction, improved function) against the potential harms (e.g., opioid use disorder, overdose, side effects) for each recommendation.

* **Considering values and preferences:** The preferences of patients regarding pain management and the risks associated with opioids were considered.

* **Assessing resource implications:** The feasibility and cost-effectiveness of implementing recommendations were also taken into account.

4. **Recommendation Formulation:** Based on the evidence assessment and the balance of factors, specific recommendations were drafted. These recommendations were categorized by strength (strong or weak/conditional).

5. **Stakeholder Engagement and Review:** Throughout the process, input was gathered from a Core Expert Group, an Opioid Guideline Workgroup, public comments, peer reviewers, and a federally chartered advisory committee (NCIPC Board of Scientific Counselors). This iterative process ensured broad input and critical review.

6. **Funding and Conflict of Interest:** The CDC provided 100% of the funding for the supplemental evidence review tasks and meeting support. No foundation or industry support was accepted. Disclosures of relationships for all expert group members were provided, noting any past activities related to opioid prescribing or pain management, and recusal from discussions where conflicts might arise (e.g., a member whose husband worked for a drug testing company was recused from urine drug testing discussions).

**Why that design matters:**

**Systematic Review:** This approach ensures that recommendations are based on a comprehensive and unbiased synthesis of the best available scientific evidence, rather than individual opinions or isolated studies. It minimizes selection bias by defining clear search strategies and inclusion criteria for studies.

**GRADE Framework:** This structured approach provides transparency in how evidence quality is assessed and how recommendations are formulated. It explicitly considers not just the evidence, but also the balance of benefits and harms, patient values, and resource implications, leading to more robust and applicable guidelines.

**Multidisciplinary Expert and Stakeholder Input:** Involving a diverse group of clinicians, researchers, public health experts, and patient advocates helps ensure that the guideline is clinically relevant, addresses real-world challenges, and considers various perspectives.

**Transparency in Funding and Conflicts:** Explicitly stating funding sources and disclosing potential conflicts of interest enhances the credibility and trustworthiness of the guideline.

**What this design can and cannot prove:**

**Can prove:** This design can identify the current state of scientific evidence regarding the efficacy and harms of opioid therapy for chronic pain. It can highlight areas where evidence is strong (e.g., short-term efficacy) and areas where it is weak or lacking (e.g., long-term efficacy, comparative effectiveness of different non-opioid treatments). It can establish consensus recommendations based on the best available evidence at the