Pain Med. 2002 (Jun); 3 (2): 102107 ~ FULL TEXT
M. Carrington Reid, PhD, MD Kimberly T. Crone, PhD John Otis, PhD Robert D. Kerns, PhD
Clinical Epidemiology Unit,
VA Connecticut Healthcare System,
West Haven, Connecticut 06516, USA.
The most disturbing comment in this article was:
Furthermore, the vast majority of respondents reported that the pain causing them the most discomfort had been present for years: Over 90% of all respondents reported a pain duration of greater than 6 months suggesting that chronic (as opposed to acute) pain conditions are more concerning to veterans receiving primary care.
OBJECTIVES: To characterize the nature of pain complaints among younger and older veterans receiving primary care, and to determine whether characteristics of pain vary as a function of age.
METHODS: Primary care patients at a Veterans Affairs medical center were screened for pain prior to a routine office visit, and those who endorsed a concern about pain were given a self-administered questionnaire that inquired about specific characteristics of their pain including site, duration, frequency, and average intensity of the pain.
RESULTS: Over a 7month period, 1,290 patients were screened; 641 (50%) reported a concern about pain, and of these, 516 (82%) completed the pain survey. Among younger (age <65 years, N = 191) and older (age > or =65 years, N = 325) respondents, the mean number of sites causing pain was similar (3.6 vs 3.3). Back pain was the most frequently reported site of pain causing the most discomfort among younger (vs older) respondents (31.9% vs 17.8%), whereas older (vs younger) respondents most often endorsed leg pain (32.3% vs 19.9%). The mean duration of pain was not significantly different between older and younger (10.7 vs 10.1 years) respondents; but older (vs younger) respondents were more likely to report constant pain (63.7% vs 46.9%). Using a 0 to 10 numeric rating scale, pain intensity scores were higher among younger (vs older) respondents (5.3 vs 4.3). Rates of prescription pain medication use were not significantly different (52.4% vs 48.0%). Compensation for pain-related disability was more common among younger (vs older) respondents (40.4% vs 19.4%).
CONCLUSION: Concerns about pain are common among veterans receiving primary care. Characteristics of pain, including site, frequency, and intensity, varied as a function of age. Future studies are needed to confirm these findings in other primary care populations and to determine reasons for these differences.
Keywords: Pain, Primary Health Care, Aging
From the FULL TEXT Article:
Prior studies have demonstrated that pain is common among younger primary care populations and associated with substantial disability.  For example, in one multicenter, crossnational study of primary care patients aged 18 to 65 years, the prevalence of persistent pain, defined as pain present most of the time for 6 or more months during the previous year, ranged from 5.5% to 33.0% across study sites.  Persistent pain was associated with significantly higher rates of depressive symptoms, anxiety disorders, and activity limitations in this study. 
The epidemiology of pain in older (i.e., 65 years of age or above) persons is a source of considerable interest, given the advancing age of the U.S. population and because of the increased likelihood that older persons will experience a greater number of chronic conditions that predispose to pain. [4, 5] Based on prior studies conducted in community settings, prevalence estimates for chronic pain in older persons range from 10% to 62%.  The wide range in prevalence rates is likely due to differences in the populations studied and the criteria used to define chronic pain. Conditions that predispose to chronic pain among older persons include degenerative and inflammatory arthropathies, myalgias, neuralgias, as well as fractures due to trauma and osteoporosis, and frequently coexist in this age group. Prior research has demonstrated strong and independent associations between the presence of pain and disability in older persons.  Nonpain factors that may adversely impact function among older persons with pain include medical factors such as obesity , as well as psychological factors such as depressive symptoms [16, 17] and low self-efficacy. [18, 19] Pain-related factors that may increase the risk for disability in this age group include pain intensity, number of locations, and duration of pain. 
Although increasing attention has been directed at better defining the prevalence and health-related consequences of pain in older populations, the epidemiology of pain among older persons in primary care settings remains inadequately characterized. Determining the prevalence and nature of pain complaints among older persons receiving primary care is important and could lead to the development of more focused assessment and treatment strategies in this clinical setting. Such information would be particularly useful to primary care providers who provide the vast majority of care for older persons in this country. In addition, determining whether characteristics of pain (e.g., site, frequency, intensity) vary between older versus younger primary care patients could also help to focus future intervention efforts.
Accordingly, the purpose of our study was to characterize the nature of pain complaints in a sample of predominantly older veterans receiving primary care, and to determine whether specific characteristics of pain vary as a function of age.
Study Population and Survey Procedure
The source population consisted of veterans enrolled in the primary care practice at VA Connecticut Healthcare System (VACHS), West Haven, Connecticut. The VACHS primary care practice (West Haven campus) provides longitudinal care to more than 14,000 veterans who are predominantly male (92%) and have a mean age of 67 years. From September 1997 through March 1998, health psychology interns approached patients in a waiting area prior to the time of the patient's scheduled appointments with a primary care provider, and asked them to complete a brief, self-administered questionnaire regarding various health behaviors (e.g., smoking, alcohol use, exercise). The survey included one question about pain, i.e., do you have a concern about pain? (yes/no).
Immediately following completion of the health behavior survey, the responses were reviewed by the health psychology interns, and respondents that endorsed a concern about pain were asked to complete a second, self-administered questionnaire. This pain questionnaire was also administered in the waiting area, and included questions about respondents' demographic and pain status.
To assess site(s) of pain, fifteen anatomic sites (e.g., head, face, hip, leg, back), including the category of other, were listed and patients were asked to circle all of the sites where they experienced pain. Respondents were subsequently asked which one site causes the most discomfort? and how long have you experienced this specific pain? To ascertain pain intensity, respondents were asked to please rate your pain right now on a scale of 0 to 10, where a 0 represents no pain and a 10 represents excruciating pain. Use of the 0 to 10 numeric rating scale has been shown previously to be a valid method for ascertaining pain intensity in younger as well as older persons.  The frequency of pain was assessed by asking would you best describe your pain as (circle one) intermittent or constant? Finally, participants were asked whether they took prescribed medications for pain (yes/no), and if they received disability income for their pain condition (yes/no).
A total of 1,290 patients completed the health behavior survey during the study period, and 641 (50%) respondents endorsed a concern about pain. Of the 232 respondents aged 64 years or less who endorsed a concern about pain, 191 (82%) completed the pain survey; and of the 409 respondents aged 65 years or older with concerns about pain, 325 (79%) completed the pain survey. The overall completion rate for the pain questionnaire was 81% (516/641).
The study protocol was approved by the Institutional Review Board at the VACHS and the Human Investigations Committee at Yale University School of Medicine. Simple verbal consent was obtained from all respondents prior to completion of both surveys.
To assess for age-related differences in characteristics of pain, the study sample (N = 516) was stratified into younger (<65 years of age) and older (=65 years of age) groups. Chi-square or Fisher exact tests were used to assess for differences in categorical variables, and t tests were used for dimensional variables. P values less than 0.05 were considered statistically significant.
Table 1 shows the demographic and pain-related characteristics of the sample stratified by age. Younger respondents (N = 191) were less likely to be married (46.0% vs 60.6%, P < 0.001) but more likely to be employed at least part time (36.6% vs 9.3%, P < 0.01) when compared with older respondents (N = 325).
The mean number of sites causing pain did not differ significantly between the two groups (3.6 vs 3.3, P = 0.35). Low back pain was cited by 31.9% of younger respondents as the site of pain causing the most discomfort, whereas 32.3% of older respondents indicated leg pain as the site of pain that caused the most discomfort. The mean duration of pain causing the most discomfort was not significantly different between the groups (10.1 vs 10.7 years, P = 0.89). Only 8.4% of younger and 7.4% of older respondents reported a pain duration (causing the most discomfort) of less than 6 months. Older (vs younger) respondents were more likely to report constant pain (63.7% vs 46.9%, P < 0.001), but younger respondents reported higher pain intensity scores (5.3 vs 4.3, P < 0.001) on a 0 to 10 scale. The two groups did not differ in prescription pain medication use (52.4% vs 48.0%, P = 0.45). Finally, compensation for pain-related disability was more commonly received by younger (40.4% vs 19.4%, P < 0.001) than older respondents.
We found that concerns about pain are highly prevalent in this study of 516 veterans receiving primary care and that characteristics of pain, including site, frequency, and intensity, varied as a function of age.
The high prevalence of pain complaints found in our investigation provides strong support for recent guidelines promulgated by the Veterans Health Administration National Pain Management Strategy (PPT)  and the Joint Commission on Accreditation of Healthcare Organizations (JCAHO)  that call for routine assessment of pain in ambulatory as well as other healthcare settings. Furthermore, the vast majority of respondents reported that the pain causing them the most discomfort had been present for years: Over 90% of all respondents reported a pain duration of greater than 6 months suggesting that chronic (as opposed to acute) pain conditions are more concerning to veterans receiving primary care.
Finally, we observed a high prevalence of compensation for pain-related disability in our sample: 40% of younger and approximately 20% of older respondents reported receiving disability income for a pain condition. Although our study did not focus on disability, these findings provide indirect evidence that painful conditions are responsible for substantial disability in our study population. These findings extend prior research on the prevalence of pain in primary care populations  and provide additional support for future studies that further characterize the epidemiology and health-related consequences of pain in primary care settings.
Differences in site of pain causing the most discomfort were present. Younger respondents were more likely to endorse low back pain, whereas older respondents were more likely to report leg pain as the site that caused the most discomfort. These findings are generally consistent with prior studies.  Although we did not ascertain the etiology of respondents' pain complaints, it is likely that possible extrinsic causes, such as work-related accidents or other trauma, may have contributed to the substantial prevalence of back pain in younger participants, whereas intrinsic causes, including degenerative joint and peripheral vascular disease, as well as diabetic neuropathy, are likely responsible for the high prevalence of leg pain in older participants. Prior studies have demonstrated that back and leg pain are strongly associated with disability. [12, 2630]
These findings, along with the results of the current study, provide support for future studies that seek to reduce or prevent disability among veterans with back or leg pain in primary care settings.
We also found that older respondents were more likely to report constant, as opposed to intermittent, pain when compared with younger respondents. This age-related difference is important, because increasing frequency of pain has been shown previously to be associated with greater disability.  A greater prevalence of chronic conditions that cause constant (e.g., spinal stenosis) as opposed to intermittent (e.g., headache) pain among older patients may be responsible for the observed difference. Alternatively, differences in unmeasured factors between the two groups, including the presence of depressive symptoms and/or types of coping strategies (e.g., catastrophizing), could also have contributed to this finding. [16, 17, 31] For example, those with poor coping strategies or depressive symptoms may be more likely to report having constant (as opposed to intermittent) pain.
Age-related differences were also present with respect to pain intensity. Older respondents reported lower average pain intensity scores on a 0 to 10 numeric rating scale, as compared with younger respondents. Although several studies have reported no differences in level of pain intensity as a function of age , at least two prior investigations found pain intensity scores decreased with advancing age. [35, 36] Although the mechanisms underlying a potential relationship between increased age and reductions in pain intensity are not presently defined, adaptation to pain may be one possible explanation.
For example, older persons may become accustomed to the presence of pain (i.e., become tolerant over time) relative to younger persons. However, duration of pain causing the most discomfort was similar between older and younger patients in our study, which does not support this possible explanation. Alternatively, older persons may participate in fewer activities that provoke pain (i.e., activity restriction), which could contribute to lower pain intensity scores. Other possible explanations include selection bias (e.g., older patients with increased pain levels may no longer be receiving care in ambulatory settings), survivor cohort bias, underreporting by older patients, and/or decreased nociception with advancing age. 
Our results add to the literature by demonstrating age-related differences in characteristics of pain in a nonreferred clinical sample. Our study was not designed to identify factors that may be responsible for these differences, and we did not seek to determine whether the differences (e.g., intensity) were associated with important endpoints, such as functional status. Future research in other primary care settings is indicated to confirm our findings, to identify potential mechanisms for these differences, and to ascertain the extent to which age-related differences in characteristics of pain are associated with greater or lesser pain-related disability. Prospective studies could best address these specific questions and could also serve to identify groups of primary care patients who may benefit most from future intervention efforts.
Our study has several limitations that warrant consideration. First, our findings are based on a convenience sample of veterans who were largely Caucasian and almost exclusively male. Therefore, our results may not be generalizable to women or minority populations. Second, it is possible that patients with concerns about pain who did not provide information about their pain status (i.e., completed the health behavior survey but not the pain questionnaire) were dissimilar from our study population. However, 81% of those who endorsed a concern about pain in the health behavior survey also completed the pain questionnaire, thereby reducing the likelihood of nonresponse bias. Third, our pain questionnaire did not inquire about other pain descriptors such as aching, burning, or throbbing sensations, which some patients endorse rather than pain. 
Our prevalence estimates may therefore have underestimated the true extent of pain symptoms in our study population. Finally, as some persons may endorse the presence of pain but not have a concern about the pain, it is possible that our results may have been different had we used a different measure to identify patients with pain symptoms. This may be particularly true for older patients who may view the presence of pain as synonymous with aging. Although our observed prevalence rates of pain may underestimate the true prevalence of pain as a clinical or subclinical symptom in our target population, it is likely that they reflect the prevalence of pain that is meaningful to patients in the context of their overall medical care.
In conclusion, our study demonstrated that concerns about pain are common among veterans receiving primary care, and that differences in characteristics of pain, including site, frequency, and intensity, are present among younger versus older veterans in this clinical setting. Future research is needed to confirm these findings in other primary care populations (e.g., women and minority groups) and to determine reasons for these differences
Dr. Reid is supported by an Advanced Career Development Award from the Department of Veterans Affairs Health Services Research and Development Service. Dr. Reid's work is also supported by a Paul Beeson Physician Faculty Scholar in Aging Research and a Robert Wood Johnson Foundation Generalist Physician Faculty Scholar Award. This research was also supported by a Merit Review grant from the Department of Veterans Affairs Medical Research Service awarded to Dr. Kerns
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