W Alastair Chambers

The epidemiology of chronic pain in the community

BACKGROUND Chronic pain is recognised as an important problem in the community but our understanding of the epidemiology of chronic pain remains limited. We undertook a study designed to quantify and describe the prevalence and distribution of chronic pain in the community. METHODS A random sample of 5036 patients, aged 25 and over, was drawn from 29 general practices in the Grampian region of the UK and surveyed by a postal self-completion questionnaire. The questionnaire included case-screening questions, a question on the cause of the pain, the chronic pain grade questionnaire, the level of expressed needs questionnaire, and sociodemographic questions. FINDINGS 3605 questionnaires were returned completed. 1817 (50.4%) of patients self reported chronic pain, equivalent to 46.5% of the general population. 576 reported back pain and 570 reported arthritis; these were the most common complaints and accounted for a third of all complaints. Backward stepwise logistic-regression modelling identified age, sex, housing tenure, and employment status as significant predictors of the presence of chronic pain in the community. 703 (48.7%) individuals with chronic pain had the least severe grade of pain, and 228 (15.8%) the most severe grade. Of those who reported chronic pain, 312 (17.2%) reported no expressed need, and 509 (28.0%) reported the highest expressed need. INTERPRETATION Chronic pain is a major problem in the community and certain groups within the population are more likely to have chronic pain. A detailed understanding of the epidemiology of chronic pain is essential for efficient management of chronic pain in primary care.

A review of chronic pain after inguinal herniorrhaphy.

BackgroundChronic pain was believed to be a recognized but infrequent complication after inguinal hernia repair. Evidence suggests that patients with chronic pain place a considerable burden on health services. However, few scientific data on chronic pain after this common elective operation are available. ObjectivesTo review the frequency of chronic pain and to discuss etiological theories and current treatment options for patients with chronic post herniorrhaphy pain. Materials and MethodsAll studies of postoperative pain after inguinal hernia repair with a minimum follow-up period of 3 months, published between 1987 and 2000, were critically reviewed. Results and DiscussionThe frequency of chronic pain after inguinal hernia repair was found to be as high as 54%, much more than previously reported. Quality of life of these patients is affected. Chronic pain is reported less often after laparoscopic and mesh repairs. Recurrent hernia repair, preoperative pain, day case surgery, delayed onset of symptoms, and high pain scores in the first week after surgery, however, were identified to be risk factors for the development of chronic pain. Definition of chronic pain was not explicit in the majority of the reviewed studies. Accurate evaluation of the frequency of chronic pain will require standardization of definition and methods of assessment. Prospective studies are required to define the role of risk factors identified in this review.

A retrospective cohort study of post mastectomy pain syndrome

Post mastectomy pain syndrome is a condition which can occur following breast surgery and has until recently been regarded as uncommon. Recent reports have suggested that it may affect 20% or more of women following mastectomy. The symptoms are distressing and may be difficult to treat however treatment for neuropathic pain can be successful. This paper reports a retrospective cohort of consecutive mastectomy cases over a six year period in one region of whom 511 survivors were traced and eligible for survey. A total of 408 completed a questionnaire survey which revealed that 175 (43%) had ever suffered from postmastectomy pain syndrome and 119 (29%) reported current symptoms although the majority were decreasing in intensity. A striking finding was the very high cumulative prevalence in younger women (65%) decreasing to 26% in the over 70 year group. The details of the onset, frequency and intensity of symptoms are described along with their natural history. The age effect on the frequency of the syndrome influences the marital status, employment status, housing, and educational status of those who report typical symptoms. Body weight and height are also associated with the frequency of post mastectomy pain syndrome. Relationship between the frequency of post mastectomy pain syndrome and radiotherapy, chemotherapy and the use of tamoxifen are difficult to unravel because of the combinations of pre and post operative treatments received confounded by age. The implications of a much higher frequency of post mastectomy pain are discussed with regard to management and counselling. The high frequency of the syndrome in the younger women is important and possible explanations are explored.

Changes in chronic pain severity over time: the Chronic Pain Grade as a valid measure.

&NA; Our understanding of the natural history of chronic pain in the community is limited. This is partly due to the lack of a validated measure of chronic pain severity known to be responsive to change over time. The Chronic Pain Grade questionnaire has been shown to be valid and reliable for use in a general population as a self‐completion questionnaire. However, its reliability and validity for use in longitudinal studies and its responsiveness to change over time has not yet been assessed. We undertook a postal survey designed to test the responsiveness and the validity of the Chronic Pain Grade questionnaire over time. A random sample of 560 chronic pain patients, aged 25 years and over was drawn from an existing cohort and stratified for age, gender and chronic pain severity. Subjects were re‐surveyed by a postal self‐completion questionnaire consisting of the Chronic Pain Grade and the SF‐36 general health questionnaire, which is known to be responsive to change in health over time. To test whether changes in CPG scores correlated with changes in SF‐36 scores, Spearmans rank correlation coefficients were calculated. A response rate of 86% was achieved for the follow‐up study. The majority of SF‐36 scores changed in the hypothesized directions. Changes in CPG scores were significantly correlated with changes in most of the SF‐36 domains. We concluded that the CPG is a useful and valid objective instrument for measuring change in severity of chronic pain over time and could be used in longitudinal studies of chronic pain severity.

Psychological, surgical, and sociodemographic predictors of pain outcomes after breast cancer surgery: A population-based cohort study

Summary Risk factors for chronic pain up to 9 months after breast cancer surgery include younger age, psychological vulnerability, axillary clearance surgery, and severe acute postoperative pain. ABSTRACT Chronic postsurgical pain (CPSP) is a common postoperative adverse event affecting up to half of women undergoing breast cancer surgery, yet few epidemiological studies have prospectively investigated the role of preoperative, intraoperative, and postoperative risk factors for pain onset and chronicity. We prospectively investigated preoperative sociodemographic and psychological factors, intraoperative clinical factors, and acute postoperative pain in a prospective cohort of 362 women undergoing surgery for primary breast cancer. Intraoperative nerve handling (division or preservation) of the intercostobrachial nerve was recorded. At 4 and 9 months after surgery, incidence of chronic painful symptoms not present preoperatively was 68% and 63%, respectively. Univariate analysis revealed that multiple psychological factors and nerve division was associated with chronic pain at 4 and 9 months. In a multivariate model, independent predictors of CPSP at 4 months included younger age and acute postoperative pain (odds ratio [OR] 1.34, 95% confidence interval [CI] 1.12 to 1.60), whereas preoperative psychological robustness (OR 0.70, 95% CI 0.49 to 0.99), a composite variable comprising high dispositional optimism, high positive affect, and low emotional distress, was protective. At 9 months, younger age, axillary node clearance (OR 2.97, 95% CI 1.09 to 8.06), and severity of acute postoperative pain (OR 1.17, 95% CI 1.00 to 1.37) were predictive of pain persistence. Of those with CPSP, 25% experienced moderate to severe pain and 40% were positive on Douleur Neuropathique 4 and Self‐Complete Leeds Assessment of Neuropathic Symptoms and Signs pain scales. Overall, a high proportion of women report painful symptoms, altered sensations, and numbness in the upper body within the first 9 months after resectional breast surgery and cancer treatment.

Factors related to the onset and persistence of chronic back pain in the community: results from a general population follow-up study

Introduction. We compared the prevalence of chronic back pain (CBP) at two points 4 years apart and examined socio-demographic, health, and pain-related factors associated with its onset and persistence. Method. A random population sample of 2,184 adults was surveyed in 1996 and resurveyed in 2000. The questionnaire included chronic pain case definition questions (pain for 3 months or longer); the cause (1996) or site (2000) of any chronic pain; the Chronic Pain Grade questionnaire; the Level of Expressed Need (LEN) questionnaire; the SF-36 general health questionnaire; and demographic questions. Those with CBP in 1996 and 2000 had “persistent” CBP; those with CBP in 1996 but not 2000 had “recovered” CBP; those with CBP in 2000 but not 1996 had “new” CBP. Results. Corrected response rates were 82.3% (1996) and 83.0% (2000). The sample prevalence of CBP was 16% (1996) and 27% (2000). Factors in 1996 independently associated with “persistent” compared with “recovered” CBP were preexisting arthritis, high LEN, poor mental health, and not living alone. Factors independently predicting “new” CBP compared with no previous CBP were previous chronic pain elsewhere and poor physical health. “Persistent” CBP was associated with more severe pain, higher LEN, and poorer general health than “new” CBP. Discussion. CBP is a common and lasting problem, whose persistence and onset are predicted by clinical (especially pain) and help-seeking behavior factors, rather than socio-demographic. Prevention should focus on these factors.

Quantitative assessment of chronic postsurgical pain using the McGill Pain Questionnaire

ObjectivesThe McGill Pain Questionnaire (MPQ) provides a quantitative profile of 3 major psychologic dimensions of pain: sensory-discriminative, motivational-affective, and cognitive-evaluative. Although the MPQ is frequently used as a pain measurement tool, no studies to date have compared the characteristics of chronic post-surgical pain after different surgical procedures using a quantitative scoring method. MethodsThree separate questionnaire surveys were administered to patients who had undergone surgery at different time points between 1990 and 2000. Surgical procedures selected were mastectomy (n = 511 patients), inguinal hernia repair (n = 351 patients), and cardiac surgery via a central chest wound with or without saphenous vein harvesting (n = 1348 patients). A standard questionnaire format with the MPQ was used for each survey. The IASP definition of chronic pain, continuously or intermittently for longer than 3 months, was used with other criteria for pain location. The type of chronic pain was compared between the surgical populations using 3 different analytical methods: the Pain Rating Intensity score using scale values, (PRI-S); the Pain Rating Intensity using weighted rank values multiplied by scale value (PRI-R); and number of words chosen (NWC). ResultsThe prevalence of chronic pain after mastectomy, inguinal herniorrhaphy, and median sternotomy with or without saphenectomy was 43%, 30%, and 39% respectively. Chronic pain most frequently reported was sensory-discriminative in quality with similar proportions across different surgical sites. Average PRI-S values after mastectomy, hernia repair, sternotomy (without postoperative anginal symptoms), and saphenectomy were 14.06, 13.00, 12.03, and 8.06 respectively. Analysis was conducted on cardiac patients who reported anginal symptoms with chronic post-surgical pain (PRI-S value 14.28). Patients with moderate and severe pain were more likely to choose more than 10 pain descriptors, regardless of the operative site (P < 0.05). DiscussionThe prevalence and characteristics of chronic pain was remarkably similar across different operative groups. This study is the first to quantitatively compare chronic post-surgical pain using similar methodologies in heterogeneous post-surgical populations.

The Level of Expressed Need--a measure of help-seeking behaviour for chronic pain in the community.

Chronic pain is a common and disabling condition, with a high impact on health and the health services in the community. The extent of help‐seeking behaviour and factors that influence this are complex, but poorly understood. A simple, valid measure of help‐seeking behaviour would be useful for community‐based research, with a view to developing and evaluating interventions.

Bilateral hand oedema related to acupuncture

We report the case of bilateral hand swelling following acupuncture therapy for chronic low back pain. Despite thorough history, examination and laboratory testing no systemic cause for the swelling could be elicited. This case highlights the incomplete knowledge of acupuncture mechanisms and that limited acupuncture therapy can have significant adverse effects.

Rehabilitation following surgery: Clinical and psychological predictors of activity limitations

PURPOSE/OBJECTIVE Activity limitations following surgery are common, and patients may have an extended period of pain and rehabilitation. Inguinal hernia surgery is a common elective procedure. This study incorporated fear-avoidance models in investigating cognitive and emotional variables as potential risk factors for activity limitations 4 months after inguinal hernia surgery. METHOD This was a prospective cohort study, predicting activity limitations 4 months postoperatively (Time 3 [T3]) from measures taken before surgery (Time 1, [T1]) and 1 week after surgery (Time 2 [T2]). The sample size at T1 was 135; response rates were 89% and 84% at T2 and T3 respectively. Questionnaires included measures of catastrophizing, fear of movement, depression, anxiety, optimism, perceived control over pain, pain, and activity limitations. Biomedical and surgical variables were recorded. Predictors of T3 activity limitations from T1 and T2 were examined in hierarchical multiple regression equations. RESULTS Over half of participants (57.7%) reported activity limitations due to their hernia at 4 months post-surgery. Higher activity limitation levels were significantly predicted by older age, higher preoperative activity limitations, higher preoperative anxiety, and more severe postoperative pain and depression scores. CONCLUSIONS/IMPLICATIONS Interventions to reduce preoperative anxiety and postoperative depression may lead to reduced 4-month activity limitations. However, the additional variance explained by psychological variables was low (ΔR² = 0.05). Our models, which included biomedical and surgical variables, accounted for less than 50% of the variance in activity limitations overall. Therefore, further investigation of psychological variables, particularly cognitions related specifically to activity behavior, would be merited.