Pain is highly prevalent in palliative care populations and pain management is one of the hallmarks of good palliative medicine. This article summarizes and discusses new concepts in a number of areas important to both clinicians and researchers.
The fact that patients with advanced cancer often experience pain is well known. The Study to Understand Patient Prognoses and Preferences for Outcomes and Risks of Treatment (SUPPORT) study found that in 316 patients with metastatic colon cancer, the prevalence of pain increased from 30 percent at 6 months prior to death to 45 percent in the last 3 days; the prevalence of confusion was 20 percent starting 1 month prior to death. Similar findings were obtained for 747 patients with advanced non-small-cell lung cancer . In a survey of 240 medical hematology oncology patients, 94 (67%) of 140 inpatients had pain, and 47 (47%) of 100 outpatients had pain. Nonmalignant pain accounted for 34 percent of inpatient pain diagnoses and 74 percent of outpatient pain diagnoses (p < 0.001). Arthritis was the major nonmalignant cause of pain for the outpatients . This finding highlights that patients with advanced cancer can experience pain from other chronic medical conditions (e.g., arthritis, low-back pain), complications of pain medications (e.g., constipation), and painful side effects of cancer treatments.
What surprised the SUPPORT investigators was the prevalence of pain in other terminal conditions. Of 539 patients with congestive heart failure who died within 1 year of hospitalization, the prevalence of pain and dyspnea increased over time, with pain increasing from 20 to 40 percent of patients, and dyspnea from 30 to 60 percent of patients . In 416 patients with advanced chronic obstructive pulmonary disease (COPD), during the last 6 months of life, moderate to severe pain was reported by 20 to 30 percent of patients and dyspnea by 70 to 80 percent of patients . A higher prevalence of pain was reported by Elkington et al., who performed a retrospective study of companions of 399 patients who died from COPD. The 209 respondents' answers regarding symptoms yielded figures of 98 percent breathlessness, 96 percent weakness, 77 percent low mood, and 70 percent pain .
Of 166 SUPPORT study patients with end-stage liver disease who died during the study, 30 to 40 percent experienced moderate to severe pain in the 6 months before death. Other symptoms included confusion and dyspnea, with a similar prevalence in the 1 month before death. The median age was 52 years .
Of 417 patients greater than 80 years old who died during the Hospitalized Elderly Longitudinal Project study, moderate to severe pain was reported by 25 to 30 percent of inpatients in the last 6 months of life and increased from 18 to 35 percent in outpatients. Pain was associated with orthopedic and infectious conditions, falls, cardiac and gastrointestinal disease, depressed mood, level of activity, and site of hospitalization .
Pain is also highly prevalent in two other disease categories associated with palliative care: chronic renal failure and human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). In a survey of a cohort of 205 Canadian hemodialysis patients, Davison found that 103 patients (50%) had pain. They described their worst pain as severe, and causes included musculoskeletal disease (63%), dialysis procedures (13.6%), neuropathic pain (12.6%), and peripheral vascular disease (9.7%). Worst pain was greater than 7 out of 10 for half the patients with pain, and strong opioids were used in 10 percent of all pain patients . In a multicenter study of deaths of 131 dialysis patients, Cohen et al. found that 42 percent of 79 patients available for follow-up were in pain in the last 24 hours of life and 5 percent were in severe pain. Other symptoms included agitation (30%), dyspnea and myoclonus (28%), and dyspnea (25%) . …