Introduction

The population is aging, with demographic shifts resulting in a significant increase in the proportion of adults 65 years and older. The rising prevalence of many long-term conditions, of which pain is a frequent symptom, is strongly associated with advancing age. Persistent pain, which exists beyond the expected healing time, often has no identifiable physical cause and is reported by around 50% of community-dwelling older adults and up to 80% of nursing home residents. In addition to increasing age, factors associated with the development of persistent pain include sex, with women being more likely than men to report persistent pain ; low income ; and mental health conditions such as depression and anxiety. Obesity is a leading risk factor for development of the painful condition osteoarthritis, which affects as many as half of all older adults. Cancer-related pain is also prevalent in older adults, with cancer being the second leading cause of death in this population. Research indicates that advancing age is a strong risk factor for undertreatment of cancer-related pain. In contrast, acute pain, a sign of injury or disease, is often treatable or even curable.

Unrelieved persistent pain in later life has many debilitating consequences, including psychological distress, social isolation, impaired sleep quality, physical disability, and increased risk for falls, as well as loss of independence. Optimizing pain management is important, but in older adults this process can be complex. Consideration of an older patient’s functional capacity is essential when formulating a management plan. Cognitive deficits are common in later life and must be considered, especially in relation to the patient’s ability to reliably report pain. The presence of obstacles to the identification, assessment, and management of pain in older adults underscores the importance of paying extra attention when providing pain care to older patients. This chapter provides the reader with an overview of current thinking regarding the assessment and management of persistent pain in older adults and describes challenges that health care providers may encounter when delivering pain care to older patients.

Physiologic Function and Aging

Anatomic and physiologic changes are considered a normal part of the aging process. Such changes are progressive, but concomitant injury or disease can rapidly worsen the health status of older individuals. Age-related changes in both pharmacokinetics (alteration of absorption, distribution, metabolism, and excretion of drugs) and pharmacodynamics (drug-related adverse side effects) necessitate a modified approach to pain management in older patients. Renal impairment is quite common and leads to increased half-lives of medications that are excreted by the kidneys. In addition, hepatic function can decline and thereby reduce arterial hepatic blood flow and increase the elimination time for hepatically metabolized drugs. Reductions in dose strength and the frequency of analgesic dosing are necessary to decrease the risk for toxicity. Older age is also associated with a change in the volume of distribution. Total body fat increases and total body water decreases, which translates into higher peak plasma concentrations for water-soluble drugs and prolonged half-lives for lipid-soluble drugs.

Both the peripheral and central nervous systems are affected by aging. There is a reduction in β-endorphin content and γ-aminobutyric acid (GABA) synthesis in the lateral thalamus and a reduced concentration of GABA and serotonin receptors. Speed of processing nociceptive stimuli and both C- and Aδ-fiber function also decrease with age, which can lead to corresponding reductions in older adults’ ability to sense and respond to “first or initial pain.” As a result, older adults may have greater susceptibility to burns and other injuries such as lacerations because they are not as likely to sense the initial pain and do not respond (e.g., removing the hand) as quickly as younger adults.

Physiologic Function and Aging

Anatomic and physiologic changes are considered a normal part of the aging process. Such changes are progressive, but concomitant injury or disease can rapidly worsen the health status of older individuals. Age-related changes in both pharmacokinetics (alteration of absorption, distribution, metabolism, and excretion of drugs) and pharmacodynamics (drug-related adverse side effects) necessitate a modified approach to pain management in older patients. Renal impairment is quite common and leads to increased half-lives of medications that are excreted by the kidneys. In addition, hepatic function can decline and thereby reduce arterial hepatic blood flow and increase the elimination time for hepatically metabolized drugs. Reductions in dose strength and the frequency of analgesic dosing are necessary to decrease the risk for toxicity. Older age is also associated with a change in the volume of distribution. Total body fat increases and total body water decreases, which translates into higher peak plasma concentrations for water-soluble drugs and prolonged half-lives for lipid-soluble drugs.

Both the peripheral and central nervous systems are affected by aging. There is a reduction in β-endorphin content and γ-aminobutyric acid (GABA) synthesis in the lateral thalamus and a reduced concentration of GABA and serotonin receptors. Speed of processing nociceptive stimuli and both C- and Aδ-fiber function also decrease with age, which can lead to corresponding reductions in older adults’ ability to sense and respond to “first or initial pain.” As a result, older adults may have greater susceptibility to burns and other injuries such as lacerations because they are not as likely to sense the initial pain and do not respond (e.g., removing the hand) as quickly as younger adults.

Assessing Pain in Older Adults

Although accurate assessment of pain is the critical first step in the pain management process, this step can challenge even seasoned clinicians. The presence of sensory and cognitive deficits, older patients’ beliefs that pain is a natural part of the aging process, patient (or caregiver) misconceptions about the meaning of pain, and language and cultural issues can all operate as barriers to effective assessment. Barriers to assessment also occur at the provider level. For example, the belief that pain is an expected part of the aging process can lead to underassessment of pain. Inadequate provider training is likewise a commonly endorsed barrier to effective pain assessment. Furthermore, older adults typically have multiple symptoms and medical conditions, which leave health care providers little time to address pain in the context of a busy office visit. The implications of these barriers are described in subsequent sections of this chapter. Recognizing these challenges and addressing them are important first steps in the assessment and management of pain in older adults.

Older patients should be asked routinely about pain at each visit, but because many older adults will not admit to experiencing “pain,” they should also be queried about the presence of ache, discomfort, or burning sensations. The following section outlines age-appropriate assessment tools for use with both cognitively intact and cognitively impaired older adults.

Pharmacologic Management of Persistent Pain in Older Patients

Analgesic medications constitute the primary treatment used by physicians when managing older adults with persistent pain, and it is the most commonly reported method used by older persons with a persistent pain condition. For example, in one study of older black and non-Hispanic white adults with osteoarthritis, more than 80% of both groups reported regular use of prescription and over-the-counter (OTC) pain medications.

Barriers to effective pharmacologic management of pain in older adults are diverse and include age-related physiologic changes (described earlier), which often dictates altering the dose and frequency of analgesic administration. Most older adults with a persistent pain disorder have multiple chronic conditions such as diabetes, hypertension, and osteoporosis, and they must be taken into account when formulating a treatment plan. Many older adults experience polypharmacy (defined as the use of multiple medications, with five or more being a typical threshold criterion), which frequently complicates the pharmacologic management of pain. Various patient sociodemographic factors can also operate as barriers. Although adequate social support enhances adherence to medication, many older adults live alone with limited social support. In addition, many older adults cannot afford the high cost of certain pain medications. Furthermore, substantial numbers of older adults lack the necessary skills to read and process basic health care information, including understanding instructions on pill bottles, information present on patient handouts, and clinicians’ instructions about the side effects of medications. Low health literacy can lead to problems with medication adherence, such as taking too much or too little pain medication.

In older adults with persistent pain, commonly prescribed analgesic agents include nonopioids, opioids, and adjuvant therapies ( Box 34.2 ). Issues related to the safety and efficacy of these three analgesic classes are summarized briefly in the following sections.

Nonpharmacologic and Self-Management Approaches to Managing Persistent Pain

A range of nonpharmacologic pain management (NPM) modalities are available and should be considered when managing pain in older patients. Strategies popular among older adults include exercise, the application of heat or cold, and nutritional supplements. The American Geriatrics Society guideline recommends NPM as an adjunctive treatment to pharmacologic management. The guideline specifically advises practitioners to consider recommending exercise, cognitive-behavioral therapy (CBT), and patient education for long-term pain management. Complementary and alternative approaches such as massage, transcutaneous electrical nerve stimulation, or acupuncture may be initiated on a trial basis to find strategies that offer short-term relief in the event of pain flare-ups. Fear of pain can result in avoidance of movement and consequentially reduced physical function, which exacerbates the pain experience. With regular moderate exercise, older adults can increase physical function, slow physical deterioration, and improve joint range of motion. Prescribed exercise should be individualized, be supervised for those with either severe pain or significant physical disability, and include flexibility, strength, and endurance exercises. Poor coping skills and negative beliefs about pain and its management make managing persistent pain difficult regardless of patient age. CBT is a psychological therapy that aims to promote and reinforce self-management and positive health behavior and pain beliefs. CBT is recommended for older adults with persistent pain disorders and can be provided as a structured, professionally led program that can be delivered on an individual or group basis, face to face or online. However, the limited number of providers skilled in delivering CBT may restrict the availability of this particular therapy.

Most older adults express a willingness to try new strategies and voice preference for self-delivered strategies that promote independence and control. An increasing number of papers on the management of persistent pain in older adults have been published, and there is increasing awareness that self-management of persistent pain is a viable strategy for older populations. The American Geriatrics Society guideline recommends encouraging older patients to locate information about self-help strategies and participate in pain education to increase awareness of pain treatments and skills important in pain management, such as goal setting. Pain self-management is a patient-centered process that involves the acquisition, practice, and execution of skills needed to respond to and control pain and its associated symptoms. Successful and optimized pain management requires that older patients be confident and able to manage the everyday symptoms and consequences of pain. To achieve this, older patients must adopt responsibility for managing their pain, along with support from others. Identifying older patients who are already effective self-managers and those who would benefit from additional support remains a difficult area, however. Self-efficacy, or confidence in one’s ability to self-manage pain, is an important psychological predictor of an individual’s capability for effective self-management and can be assessed in the clinical setting. Other factors, such as pain beliefs, attitudes, and motivation, also influence participation in self-management. For older patients who require additional support, a variety of materials and interventions are available, including professional or lay-led group courses (delivered in person or online), educational resources (i.e., workbooks, leaflets, and CDs), and self-help groups. The efficacy of self-management programs for older adults that specifically focus on generalized management of persistent pain remains controversial, with some reviews suggesting little patient benefit. Conversely, disease-specific programs, such as those developed for arthritis, have demonstrated more consistent benefit, including moderate reductions in pain and enhanced psychological well-being. Decisions on how best to support older patients’ self-management will largely be determined by what is available and accessible to the patient locally, but to the extent possible, older patients should be encouraged to choose between available formats and select individual strategies that best meet their needs.

Older patients’ use of NPM and self-management strategies varies extensively, and barriers include a lack of advice and support from their primary care providers, affordability of and access to certain strategies, and the pain management attitudes of professionals, older patients, and their caregivers. It is important that clinicians discuss NPM and self-help strategies with older patients. These strategies can improve quality of life and reduce pain and the associated impact of pain on daily life through the adoption of positive pain behavior and coping responses. Although many strategies may appear harmless, unknown risks may exist. For example, some dietary supplements or herbal remedies may pose a risk to older patients when taken with particular pharmacologic agents. It is therefore imperative that clinicians ascertain the full extent of their older patients’ pain and pain management experiences and consider cultural, lifestyle, and socioeconomic factors that may influence these experiences. This must be done in a manner that identifies the use of risky NPM strategies that have the potential to cause harm but still encourages patients to play an active role in the management of their pain.