Persistent pain is a common health issue for older adults, with a prevalence ranging between 45% and 80% among seniors in the community [26,31,49,54] and within institutionalized settings [16,41,48,55,58]. Improved recognition coupled with effective assessment and management of persistent pain could lead to substantial improvements in the quality of life of older adults as well as reductions in the socioeconomic burden of pain-related conditions and disabilities. The presence of pain has been associated with depression, sleep disturbance, functional impairment, decreased socialization, and increased health care utilization and costs [1,14,39,40,42,43,49]. Yet, the assessment and appropriate management of pain in older adults may be complicated by several factors including the co-existence of cognitive impairment [17,25,61]; the high prevalence of multi-morbidity and polypharmacy; and, an increased vulnerability to potentially harmful side effects from analgesics and adverse drug interactions [18,19,22].
Pharmacotherapy is the most common pain management strategy utilized for older patients . The World Health Organization analgesic ladder  has been shown both to be effective and to have a low rate of complication when used in the management of pain among patients with advanced cancer . In this three-step hierarchy, acetaminophen and/or non-steroidal anti-inflammatory drugs (NSAIDs) including aspirin (unless contraindicated) are used for mild to moderate pain. When pain persists or increases, a weak opioid (e.g., codeine) is added. Strong opioids (e.g., morphine) are reserved for the management of moderate to severe pain or for patients who fail to achieve adequate relief from the therapeutic agents described in step two. Though developed for the management of malignant pain, this stepped approach has informed the management of persistent non-malignant pain  and, with some modifications, has been found to be effective in alleviating pain in other patient populations [5,32].
Despite the high prevalence of pain among seniors, the presence of treatment options, and the availability of clinical management guidelines [1,2,60], undertreatment remains an important problem. Approximately 25% or more of those experiencing daily pain do not receive any analgesic medication. Lower treatment rates have been observed among the most vulnerable sub-groups of older adults  including the oldest old and those with cognitive or communication impairments [7,31,47,54].
Prior research has focused on the pain management of cancer patients [7,11] and nursing home residents [46,52,55,58]. Fewer investigations have addressed the prevalence, clinical and sociodemographic correlates of pain and its pharmacotherapy in older persons residing in the community [31,44,54,65]. Further, this past research has largely investigated the prevalence and correlates of any analgesic use, without the consideration of medication type or potential contraindications.
Using a large, well-defined older home care population, we examined the extent of pharmacological treatment of daily pain and the client characteristics associated with the receipt of opioid analgesics and, separately, with the receipt of non-opioid analgesics (NSAIDs and acetaminophen only). When there was apparent undertreatment of pain, we attempted to distinguish between possible treatment bias (i.e., the absence of analgesic use among those apparently eligible for treatment) and rational prescribing practices (i.e., the absence of analgesic use among those with potential contraindications for select medications).
A total of 2779 home care clients aged 65 years and older (and with complete drug data) were assessed as part of a pilot implementation of the Resident Assessment Instrument-Home Care (RAI-HC) in 14 Community Care Access Centres (CCACs) in the province of Ontario, Canada. CCACs are local agencies established to coordinate public access to government-funded home and community services and long-term care facilities. Participating CCACs included a variety of geographic settings ranging from rural areas to larger metropolitan centres. During the study period, there were 43 CCACs active in the province. Compared to this larger provincial population of home care clients, our study sample was significantly older (given our age restriction) and included a larger proportion of females and more clinically complex clients (e.g., with greater comorbidity and marginally higher resource intensity).
Clients were assessed at intake (or as scheduled) with the RAI-HC by trained case managers (typically nurses) between 1999 and 2001. At the time of data collection, the RAI-HC was implemented on a voluntary basis, but in 2002 the instrument became mandated for all long-stay home care clients (i.e., those with an expected length of stay of 60 days or more) in Ontario. Research using this database was possible through a data sharing agreement between the Ontario Ministry of Health and Long Term Care and interRAI (represented by Hirdes). Ethics approval for the secondary analyses of these anonymized data was provided by the Office of Research Ethics, University of Waterloo.
The RAI-HC is a comprehensive assessment and care planning instrument currently used in eight Canadian provinces and territories and 15 US states. The tool provides a standardized assessment of clients’ sociodemographic, physical and cognitive status, psychological and health conditions, receipt of formal services and informal (e.g., family, friends) care, and use of prescription and over-the-counter drugs. Evidence in support of the reliability and validity of the tool has been reported elsewhere [27,30,37].
The RAI-HC includes several items on pain, including the frequency and intensity of pain symptoms reported by clients and/or signs observed during the past 3 days. Assessors are trained to ask clients directly about their experience with pain and to carefully observe clients for behavioural signs of pain (e.g., wincing or other facial expressions of pain, guarding/protecting an area of the body). For clients with cognitive or communication impairments, assessors are further directed to contact family members and/or formal care providers working with the client in order to assess pain symptoms and behavioural signs. Current daily pain was defined as any type of pain or discomfort reported or observed in each of the preceding 3 days. InterRAI data have been used to investigate pain in older nursing home, palliative and home care populations from several countries [7,31,49,54,58,65].
As part of the RAI-HC assessment, information on drugs (including name, dose, amount, frequency and route of administration) is directly transcribed from medication containers in the client’s residence and includes all prescribed and over-the-counter (OTC) therapeutic products used by the client in the past 7 days. Medications were coded based on a modified version of the American Hospital Formulary System (AHFS) . Analgesics were classified into three groups: (i) non-opioid medications (including acetaminophen and NSAIDs); (ii) weak opioids (including codeine and propoxyphene) and (iii) strong opioids (including anileridine, fentanyl, meperidine, morphine, oxycodone, pentazocine and hydrocodone). Low-dose acetylsalicylic acid (≤81mg/day) was excluded from group (i) as use at this dose would primarily reflect stroke prevention rather than pain management. A complete list of the analgesics assessed in the sample is provided in Appendix A. Of note, the drug tramadol is not included in this Appendix because it was not available in Ontario during the study period nor was it listed in any of the in-home drug reviews completed for our study subjects.
The RAI-HC sociodemographic and health variables assessed as potential correlates of treatment included age, sex, marital status, chronic disease diagnoses (i.e., cerebrovascular disease, congestive heart failure, coronary artery disease, hypertension, peripheral vascular disease, dementia, parkinsonism, arthritis, fractures, osteoporosis, any psychiatric diagnosis, cancer, diabetes, chronic obstructive pulmonary disease, renal failure, thyroid disease), health conditions (e.g., vomiting in past 3 days), number of prescribed medications, functional and cognitive status, depressive symptoms, communication disorders and need for interpreter (as assessed during RAI-HC assessment). Our analyses included three health index measures validated for use with the RAI-HC tool: (i) the Activities of Daily Living (ADL) self-performance hierarchy scale (range 0–6) ; (ii) the Cognitive Performance Scale (CPS) score (range 0–6) ; and (iii) the Depression Rating Scale (DRS) (range 0–14) . Higher scores on all three indicate a more severe impairment. For the ADL and CPS scales, a cut point of 2 was used (i.e., at least mild impairment) and a cut point of 3 was used for the DRS (indicating at least mild/moderate depressive symptoms) . Clients were coded as having a possible communication disorder if they were assessed as having hearing difficulties, problems in making self-understood and/or problems understanding others.
The disease diagnoses section of the RAI-HC includes a list of conditions to be checked by the assessor as present where: (i) indicated by a physician and/or the medical record (and noted to affect the client’s status); and/or (ii) treatment or monitoring by a home care professional is required; or (iii) the disease was the reason for hospitalization in the past 90 days. This section also includes an open-text field for the assessors to document other current or more specific diagnoses not included in the disease checklist. The listed diagnoses specifically explored as possible disease-related contraindications to analgesic use among older clients in our sample included congestive heart failure and renal failure for non-opioid analgesics because of the potential for NSAIDs to aggravate pre-existing states of fluid retention and renal impairment. Chronic obstructive pulmonary disease (COPD) and any psychiatric diagnosis were examined in relation to opioid use due to the risk of respiratory depression and the potential for abuse. Additionally, based on the information included in the open-text field, a variable was created for other disease-related contraindications to analgesic use including any mention of the following: cardiomyopathy (fluid retention with NSAIDs), cirrhosis or other liver disease (acetaminophen, NSAIDs and opioids all contraindicated with severe hepatic dysfunction), Crohn’s disease (gastrointestinal tract irritation with NSAIDs), systemic lupus erythematosus (aseptic meningitis with NSAIDs), gastrointestinal ulceration or bleeding (NSAIDs), other internal bleeding and iron deficient anemia (bleeding risk with NSAIDs). Since these other conditions were relatively rare in the sample, any mention of them was used to create a single binary variable rather than coding them separately as non-opioid vs. opioid condition-related contraindications.
Descriptive statistics were calculated and prevalence estimates of current daily pain and pharmacotherapy were reported. Associations between select client characteristics and analgesic treatment among those with current daily pain were examined using multivariable multinomial logistic regression. Based on the World Health Organization analgesic ladder , a three level dependent variable was created as follows: no prescription or OTC analgesic use (the reference group); use of prescription or OTC non-opioid analgesics (acetaminophen or NSAIDs only); and, use of opioids alone or in combination with non-opioid analgesics. Variables significant at the bivariate level (p≤0.10) or identified as potentially relevant correlates of pain treatment in previous research were included in the multivariable analysis. Data were complete for most variables examined with the exception of need for interpreter (87 clients from the total sample and 45 of those in daily pain had missing data for this variable). Consequently, missing values were coded as a separate category for this variable. All analyses were performed using SAS version 9.1.
Among this predominantly older female home care sample, nearly a half (n=1329, 47.8%) were assessed as having current daily pain (Table 1). Clients with daily pain were significantly more likely to be female; have three or more comorbid conditions; use nine or more prescription and OTC drugs; experience vomiting in the past 3 days; have arthritis, osteoporosis and/or cancer; have other disease-related contraindications to analgesic use; and, exhibit mild to moderate depressive symptoms. However, those in daily pain were significantly less likely to have cognitive impairment or a communication disorder (Table 1). Among clients in daily pain, the most common diagnoses were arthritis (62.4%), diabetes (18.8%), osteoporosis and chronic obstructive pulmonary disease (COPD) (both at about 16%).
Of clients assessed with current daily pain, 287 (21.6%) were not receiving any analgesic (Fig. 1). Among those receiving at least one prescription or OTC analgesic, NSAIDs were the most commonly used medications (56.4%), followed by acetaminophen (39.1%), weak opioids (27.7%), and strong opioids (14.6%). The distribution of our dependent variable was as follows: (i) no prescription or OTC analgesic use (n=287; 21.6%); (ii) non-opioid use only (n=614; 46.2%); and, (iii) opioid use, alone or in combination with non-opioids (n=428; 32.2%). Of this latter group, 49% (n=211) were receiving an opioid only. There were 24 clients (1.8% of those in daily pain) using only low dose (≤81mg) acetylsalicylic acid who were classified as not receiving any analgesic.
Table 2 presents the percent distribution and estimated adjusted odds ratios for receiving opioids (alone or in combination with non-opioids) and non-opioids (NSAIDs and/or acetaminophen only) compared with no analgesic (reference group) among clients assessed with current daily pain. After adjusting for various sociodemographic and health characteristics, clients aged 75+years and those with congestive heart failure, diabetes, other disease-related contraindications, cognitive impairment and/or requiring an interpreter were significantly less likely to receive an opioid alone or in combination with a non-opioid. Conversely, clients using nine or more prescription and/or OTC medications and those with a diagnosis of cancer or arthritis were significantly more likely to be receiving an opioid. Clients with congestive heart failure and without a diagnosis of arthritis were significantly less likely to receive a non-opioid. There was also a decreased likelihood for non-opioid use among those with renal failure and other potential disease contraindications. There was a positive association between increasing age and non-opioid analgesic use.
Almost 50% of our home care sample was assessed as having current daily pain, most commonly associated with arthritis. This is consistent with other community-based prevalence estimates in older adults [31,44,54,65]. This accumulating evidence underscores the need for improved recognition and management of pain among seniors living at home. The majority of clients with daily pain received some form of pharmacotherapy, but approximately one-fifth received no analgesic. Potential undertreatment was lower among those with a diagnosis of cancer or arthritis (13.4% and 16.4%, respectively). Our estimates of potential undertreatment are comparable to findings from a larger cross-sectional study of Ontario home care clients , but lower than previous reports [7,11,31,54,58]. This may point to recent improvements in pharmacotherapy for pain among vulnerable older adults.
The most commonly used analgesics were non-opioids. Fewer clients with current daily pain (particularly those over 75) used either a weak or strong opioid. It has been suggested that opioids are under-utilized in older populations [9,50]. Since the present analyses did not consider pain severity, it was not possible to determine the extent of potential undertreatment with opioids for those who are arguably in most need (i.e., in moderate to severe pain).
Clients with current daily pain were significantly more likely to exhibit depressive symptoms, but significantly less likely to present with any cognitive or communication impairments relative to those not in daily pain. The relationship between pain and depression is widely recognized [39,48,57], but the direction of this association remains unclear. Depression may be both a determinant and a consequence of persistent pain . There is also increasing awareness of the common physiological pathways underlying chronic pain and depression and supportive evidence of the efficacy of selected depression treatments (e.g., antidepressants, psychotherapy) in both conditions [28,33].
The finding of a lower prevalence of cognitive and communication impairment among older clients in pain is consistent with previous research [34,41,46,54]. Studies of long-term care residents have shown an inverse association between pain and severity of cognitive impairment or the inability to communicate [12,61]. This likely reflects the challenges encountered in detecting pain among older adults with cognitive and/or communication impairments rather than a lower prevalence of pain in these populations [25,51]. Although there have been reports of altered pain perception and experience in people with Alzheimer’s disease , the clinical relevance of such differences remains unclear [20,35].
The present study also provided some evidence of rational prescribing practices given the observed associations between certain chronic conditions (e.g., congestive heart failure, renal failure and ‘other’ disease-related contraindications) and a reduced likelihood for receiving non-opioids (largely NSAIDs). Similarly, caution with regard to the use of opioids among clients with cognitive impairment may be warranted [1,9]. The finding that clients with congestive heart failure and with diabetes were significantly less likely to use opioids should be interpreted with the understanding that approximately half of those classified as using opioids were also using non-opioids. While this finding may reflect a reservation among prescribing physicians about the use of non-opioids in patients with congestive heart failure  and diabetes–where there might be renal insufficiency , it does not explain the reluctance to use an opioid alone for pain control.
There was also notable evidence of potential treatment bias, including a lower use of analgesics among those with cognitive impairment and a significantly lower use of opioids among older aged clients and those requiring an interpreter. Others have reported a greater risk for suboptimal pain treatment among persons aged 75 years and older and with cognitive impairment [7,13,31,57]. Because clients with cognitive impairment often present with behavioural manifestations of their pain, they may also be at an increased risk for inappropriate antipsychotic use in addition to undertreatment of pain .
The finding of significantly lower opioid use among clients with current daily pain requiring an interpreter may reflect the importance of language barriers and/or cultural factors in the detection and appropriate management of pain in older persons [15,24,56]. Disparities in the recognition and treatment of persistent pain among minorities may arise due to patient or provider characteristics as well as health system barriers . Most clients who required an interpreter (91%) spoke a language other than English or French as their primary language. It was not possible to draw more precise conclusions related to this observed association because data on clients’ ethnic and cultural background, beliefs and preferences and provider characteristics were not available. Priorities for further research in this area include the development of culturally and linguistically sensitive pain assessment tools and investigations of variation in clinical decision-making and health system barriers across ethnic sub-groups .
Consistent with past research was the significant positive association between the use of multiple medications and receipt of analgesics [7,57]. This association may reflect greater access to health (including physician) care and financial resources, physician prescribing practices and/or clients’ beliefs about medications. However, this finding also highlights a potential concern given the risks associated with multiple medications and complex drug regimens, including an increased likelihood of adverse drug effects and interactions, medication nonadherence and adverse health outcomes . The appropriate use of analgesics, especially in combination with other medications, remains an important challenge for physicians caring for vulnerable older patients in pain .
Limitations of the present study include the possibility that the RAI-HC pain items may be insensitive in detecting pain among clients with cognitive and/or communication impairment. This could result in an underestimate of both the prevalence of pain  and the strength of the association between cognitive/communication impairment and non-use of analgesics. However, relative to pain assessment instruments based solely on self-report, the RAI-HC tool may provide a more comprehensive assessment of pain as it encourages assessors to consider multiple data sources (e.g., self-report, proxy reports and observed behavioural signs). Although an explicit element of RAI-HC training, it is unknown what proportion of assessors used other data sources (e.g., interviews with family and care providers) in their pain assessment of cognitively impaired clients. Our findings and those from others [31,39,49,54,65] showing strong associations between assessed pain and pain-causing conditions in cognitively intact and impaired older adults support the clinical utility of the RAI-HC pain items. However, the tool is limited in that it does not provide information on the type of pain experienced or its location and cause.
The study sample was limited to CCACs that participated voluntarily and, as such, the findings may not be generalizable to all Ontario home care clients. Also, there are likely to have been changes in the availability and use of prescription analgesics since the study period. However, our estimate of undertreatment of daily pain is identical to that reported by a recent Ontario home care study conducted during 2003–04 . As many jurisdictions across Canada are now adopting the RAI-HC as their mandatory clinical assessment instrument, it will soon be possible to conduct large-scale longitudinal investigations to explore changes in pain and its pharmacotherapy among home care clients. This future research should also address the validity of RAI-HC pain items across vulnerable sub-groups of clients.
It is unclear as to what proportion of clients with current daily pain may have been undertreated because of poor recognition by their health care providers [29,64]. Poor detection of pain may also arise because of reluctance by the older client to disclose this information to their physician or other care provider . Seniors, even those living with multiple chronic illnesses, may hesitate to discuss their pain because of increased stoicism and a tendency to attribute pain to the aging process  – this may be particularly so for seniors from minority sub-groups . Finally, lower treatment rates among clients in daily pain may reflect poorer adherence (for both intentional and non-intentional reasons) and/or a decision to opt for non-pharmacological approaches to pain management. There were no data on the relative use or effectiveness of non-pharmacological strategies for pain control in our study sample and the study did not consider use of adjuvant medications (e.g., anticonvulsants, antidepressants) for pain control. This may explain the lower use of opioids (with or without non-opioids) among clients with diabetes who may be suffering from neuropathic pain. Classification of these medications would have been problematic given the absence of data on indications for drug use.
Daily pain is prevalent among community-based seniors and apparent undertreatment of pain in this population remains a significant issue. While a portion of this undertreatment may reflect rational prescribing practices, certain sub-groups such as the oldest old and those with cognitive or language difficulties seem to be at increased risk for receiving inadequate pain treatment. Since many of these clients are likely to be eligible for various effective pain therapies , further exploration of the factors underlying suboptimal management of pain (including both pharmacological and non-pharmacological therapies) in older frail populations is warranted . Longitudinal data are required to clarify the direction of associations observed between clinical characteristics and persistent pain and to better understand the outcomes of alternate pain control strategies in older adults.
Dr. Maxwell is funded by a New Investigator Award from the Canadian Institutes of Health Research (CIHR) – Institute on Aging and a Health Scholar Award from the Alberta Heritage Foundation for Medical Research (AHFMR). Drs. Patten and Eliasziw are also supported with Health Scholar Awards from AHFMR. Dr. Hogan holds the Brenda Strafford Foundation Chair in Geriatric Medicine and the Chair provides financial support to both Drs. Hogan and Maxwell. Dr. Hirdes’ participation was supported by a CIHR Investigator Award. Dr. Dalby was partially funded by the Grace Anderson Research Fellowship provided by Wilfrid Laurier University. The authors wish to acknowledge the Health Transition Fund – Health Canada (ON 421) and the Homewood Foundation for financial support of this research.
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