Health risk appraisal in older people 3: prevalence, impact, and context of pain and their implications for GPs

INTRODUCTION

Pain is a universal, enigmatic, and highly subjective phenomenon1 with complex organic, psychological, and social dimensions.2

Chronic pain appears to be a common experience among people aged 65 years and older,3 but it is unclear how common this is. Prevalence estimates range from 20–50%4 to 58–70% of community-dwelling older adults.5 A similar variation in chronic pain experience is encountered with advancing age. In some studies the prevalence of pain increases with age,6^–8 while other studies report a decrease in the prevalence of pain as people age.9^,10 The reasons for these conflicting findings are unclear.11

A number of factors appear to influence the experience of chronic pain. Depression is associated with more pain complaints, greater pain intensity, longer duration of pain, and greater likelihood of non-recovery.12 Although women are more likely to report chronic pain, depression associated with pain may be more common in men.13 Social relationships also seem to matter. A study into health behaviours, social networks, and healthy aging in a large cohort of American women aged 55–72 years showed that the absence of a confidant and having few close friends and relatives was associated with higher levels of persistent or recurrent bodily pain.14

Chronic pain has a wide-ranging impact on daily life and activities,15 and significantly reduces physical and mental aspects of quality of life,16 including functional limitations, fatigue, sleeping problems, and depressed mood.8 Musculoskeletal pain, particularly widespread pain, is a substantial risk factor for falls in older women with disabilities.17 Chronic pain is a common reason for seeking medical care, with one study reporting 40% of attendances in primary care being due to pain.18

Given the potential impact of pain, clinicians need to be able to assess accurately and understand the nature of pain in everyday life.1 Daily pain is perceived as prevalent among older patients living in the community and is thought to be often untreated.19

Dowrick et al, in discussing the relationship between pain and depression,20 showed that family doctors are faced with the dilemma of treating a symptom or seeking its cause, and allude to both diagnostic confusion and clinical neglect in primary care. Gloth, reviewing the 1998 American Geriatrics Society's guidelines on The Management of Chronic Pain in Older Persons, argues that ‘educating clinicians about available assessment tools, techniques and interventions, may be the biggest challenge to comforting the older adult in pain’.21

It is not clear how GPs should respond when attributed responsibility for under-treatment of older people experiencing chronic pain. This paper explores these questions by describing the experiences of pain reported by a large cohort of older people recruited through general practice, and measuring the associations between pain and psychological health, functional ability, and social relationships in those reporting pain in the previous 4 weeks. The specific questions asked were:

• How prevalent is chronic pain in non-disabled, community-dwelling older people?

• What impact does pain have on everyday life?

• What psychological and social factors are associated with the experience of pain?

METHOD

Three large group practices in suburban London were recruited to participate in a multicentre, multinational, randomised controlled trial investigating the effect of the Health Risk Appraisal in Older People on health behaviours and status.22 Practices were selected for their interest in primary care for older people, location in London, and routine use of electronic medical recording systems in clinical encounters. A full account of the methodology of the study is available elsewhere,23 as are specific descriptions of how the data have been used for epidemiological analyses.24^,25

To identify eligible patients aged 65 years and over, practice lists were examined by GPs. Eligibility criteria were: those living at home, without evidence of need for human assistance in basic activities of daily living; high dependency due to major physical or psychiatric illness, or cognitive impairment; or a terminal illness. Patients also had to have a sufficient understanding of English to complete the questionnaires. This patient population was further evaluated using the Probability of Recurrent Admissions questionnaire,26 and asked to complete a consent form by post. The Probability of Recurrent Admissions questionnaire measures risk of hospital admission, and stratifies the population by level of risk for future in-patient care. This questionnaire was used in the main study as the basis for risk-stratified outcome analyses.

Eligible and consenting patients were posted the health risk appraisal questionnaire. The findings reported in this paper are from the baseline completion of the questionnaire. The Health Risk Appraisal in Older People tool is a multidimensional, self-completion questionnaire that collects information on health, functional status, health behaviours, preventive care, and psychosocial factors in older people. The development of the health risk appraisal22 questionnaire and the feasibility of its use in UK primary care have been reported elsewhere.27 Those who gave positive answers to a screening question about the experience of pain in the previous 4 weeks completed the Geriatric Pain Measure, a 24-item multidimensional pain questionnaire that captures information on pain experience (measured on 10-point modified Likert scale) and impact of pain on everyday living.28 To identify depressed mood the 5-item Mental Health Inventory29 was used, which is a tool validated for use in older community-dwelling populations. Psychological distress other than depression was assessed by asking the question: ‘Has a doctor ever told you that you have an emotional or mental illness other than depression?’. Social networks were measured using the 6-item version30 of the Lubben Social Network Scale,31 developed specifically for use among older adult populations and used widely in both research and clinical settings.32^–35 On the Lubben scale, a range of 0–30 captures the extent of social contact with family and friends; being at risk of social isolation is defined as having a score >12. Functional ability was assessed using a modified version of the Lawton and Brody activities of daily living scale.36 Responders were asked to report other diagnosed medical problems from the checklist shown in Box 1.

Data were analysed using SPSS (version 12) to carry out χ² and stepwise-backward multiple logistic regression as appropriate. The following analyses were carried out:

• associations between the presence of pain in the last 4 weeks and age, sex, physical illnesses, depression symptoms, social network, and self-perceived health status in all those in the study population who answered a screening question on pain experience in the previous 4 weeks;

• logistic regression analysis using all those characteristics with significant associations with reported pain (with significance set at the P<0.05 level) as independent variables, and the presence of pain in the last 4 weeks as a dependent variable;

• description of the self-reported impact of pain on performance of activities of daily living and social activities in those reporting pain in the previous 4 weeks.

RESULTS

A total of 4466 patients aged 65 years and over were identified across the three practices, of which 391 were excluded based on a priori criteria. A total of 4075 older people were sent an invitation letter, a consent form, and the Probability of Recurrent Admissions questionnaire.26 Overall, 2620 patients completed the questionnaire and consent forms (64%) were returned. Based on the questionnaire, 117 patients were excluded because of self-reported need for human assistance in basic activities of daily living, leaving a study sample of 2503.

After randomisation, 1240 older people were posted the Health Risk Appraisal questionnaire at baseline, of which 1090 completed and returned the questionnaire (response rate 88%). Findings from this group are reported here. Responders were less likely to have fair or poor health (rather than excellent, very good, or good health) than non-responders (23.1 versus 34.7%; P = 0.002).

The screening question on pain experience in the previous 4 weeks was completed by 1017 (82%) responders. Four hundred and six responders (39.9%) had experienced pain in the past 4 weeks compared with 611 (60.1%) who had not. The experience of pain in the previous 4 weeks was significantly associated with female sex and advancing age up to 84 years. The 85 years and older group reported far less pain than all other age groups.

Other factors significantly associated with pain being present over the past 4 weeks were self-reported fair or poor health, depressed mood (as measured by the Mental Health Inventory as well as from a checklist of diagnoses), other emotional problems, and a number of medical conditions including arthritis/rheumatism, osteoporosis, cardiac disorders, and respiratory diseases (Table 1). Two-thirds of those reporting pain in the previous 4 weeks described their general health as good or excellent. Only seventy-six participants (19.7%) also reported feeling sad or depressed, and 18.8% of those reporting pain over the past 4 weeks had a mental mood score suggesting depression. There was no significant association between reports of pain in the last 4 weeks and the frequency or type of social contact or support received by responders.

Stepwise-backward binary logistic regression using the significant associations shown in Table 1 as independent variables, demonstrated that the experience of pain in the previous 4 weeks is not associated in a linear way with advancing age, but is associated with self-reported health. Pain is also directly associated with depressed mood, arthritis or rheumatism, and osteoporosis (Table 2).

Of those who reported pain over the previous 4 weeks, 201 (53.2%) experienced pain every day, 240 (73.6%) experienced pain several times a week, 146 (40.4%) had pain that ‘never goes away’, and 165 (44%) took medication for pain at least three times a week.

The experience of pain in the previous 4 weeks was associated with considerable changes in self-reported behaviour and function (Table 3).

DISCUSSION