Per Sjøgren

Pain epidemiology and health related quality of life in chronic non-malignant pain patients referred to a Danish multidisciplinary pain center

&NA; This paper presents the results of a detailed study of the pain epidemiology and health related quality of life (HRQL) in 150 chronic non‐malignant pain patients consecutively referred to a Danish multidisciplinary pain center. Mean pain severity was 71.6 (SD=18.5) on the VAS scale. Forty‐two percent reported poor quality of sleep. HRQL was evaluated with the Medical Outcome Study‐Short Form (SF‐36), the Hospital Anxiety and Depression scale (HAD) and the Psychological General Well‐Being Scale (PGWB). Compared with the normal population (NP) both SF‐36 scores and PGWB scores were significantly reduced (P<0.001) indicating that physical, psychological and social well‐being were severely reduced. On the HAD scale 58% were found to have a depressive or anxiety disorder. Statistically significant but modest correlations were found between pain severity and HRQL. Psychological and social well‐being was closely correlated. Sixty‐three percent of the referred patients had neurogenic pain conditions. Of these, only 25% were treated with antidepressants or anticonvulsants at referral. Seventy‐three percent were treated with opioids at referral. Mean opioid consumption was 64 mg of morphine per day (range 1–280 mg). Compared with the NP the chronic pain patients had used the health care system five times more often in the years prior to referral (P<0.001). The study confirms the severe multidimensional impact of chronic pain and demonstrates that HRQL of chronic non‐malignant pain patients is among the lowest observed for any medical condition.

Critical issues on opioids in chronic non-cancer pain: An epidemiological study

&NA; The aim of the study was epidemiologically to evaluate the long‐term effects of opioids on pain relief, quality of life and functional capacity in long‐term/chronic non‐cancer pain. The study was based on data from the 2000 Danish Health and Morbidity Survey. As part of a representative National random sample of 16,684 individuals (>16 years of age), 10,066 took part in an interview and completed a self‐administered questionnaire. Cancer patients were excluded. The interview and the self‐administered questionnaire included questions on chronic/long‐lasting pain (>6 months), health‐related quality of life (SF‐36), use of the health care system, functional capabilities, satisfaction with medical pain treatment and regular or continuous use of medications. Participants reporting pain were divided into opioid and non‐opioid users. The analyses were adjusted for age, gender, concomitant use of anxiolytics and antidepressants and pain intensity. Pain relief, quality of life and functional capacity among opioid users were compared with non‐opioid users. Opioid usage was significantly associated with reporting of moderate/severe or very severe pain, poor self‐rated health, not being engaged in employment, higher use of the health care system, and a negative influence on quality of life as registered in all items in SF‐36. Because of the cross‐sectional nature causative relationships cannot be ascertained. However, it is remarkable that opioid treatment of long‐term/chronic non‐cancer pain does not seem to fulfil any of the key outcome opioid treatment goals: pain relief, improved quality of life and improved functional capacity.

Epidemiology of chronic non-malignant pain in Denmark.

&NA; A series of health surveys are conducted every sixth to seventh year in Denmark. In the most recent survey of 2000, a national random sample (>16 years) was drawn from the Danish Central Personal Register. Out of the original sample 12,333 (74%) were interviewed and of these 10,066 returned a completed questionnaire (SF‐36). The present study includes only those who both took part in the interview and the postal questionnaire. Cancer patients were excluded. Persons suffering from chronic pain (PG) were identified through the question ‘Do you have chronic/long lasting pain lasting 6 months or more’? An overall chronic pain prevalence of 19% was found −16% for men and 21% for women. Prevalence of chronic pain increased with increasing age. Persons ≥67 years had 3.9 higher odds of suffering from chronic pain than persons in the age group 16–24 years. Compared with married persons, divorced or separated persons had 1.5 higher odds of chronic pain. Odds for chronic pain were 1.9 higher among those with an education of less than 10 years compared with individuals with an education of 13 years or more. During a 14‐day period reporters of chronic pain had an average of 0.8 days (range 0–10) lost due to illness compared with an average of 0.4 days (range 0–10) for the control group (CG) (Odds Ratio (OR)) 2.0). Persons with a job which required high physical strain were more likely to report chronic pain compared with those with a sedentary job (OR 2.2). The odds of quitting ones job because of ill health were seven times higher among people belonging to the PG. A strong association between chronic pain and poor self‐rated health was also demonstrated. The PG had twice as many contacts with various health professionals compared with the CG, and the health care system was, on average, utilised 25% more (overall contacts) by the PG than by the general population. Among the persons in the PG, 33% were not satisfied with the examinations carried out in connection with their pain condition and 40% were not satisfied with the treatment offered. Nearly 130,000 adults, corresponding to 3% of the Danish population, use opioids on a regular basis. Opioids are used by 12% of the PG.

Addiction to opioids in chronic pain patients: A literature review

Opioids have proven very useful for treatment of acute pain and cancer pain, and in the developed countries opioids are increasingly used for treatment of chronic non‐malignant pain patients as well. This literature review aims at giving an overview of definitions, mechanisms, diagnostic criteria, incidence and prevalence of addiction in opioid treated pain patients, screening tools for assessing opioid addiction in chronic pain patients and recommendations regarding addiction problems in national and international guidelines for opioid treatment in cancer patients and chronic non‐malignant pain patients.

Treatment outcome of chronic non-malignant pain patients managed in a Danish multidisciplinary pain centre compared to general practice: a randomised controlled trial

Abstract This randomised controlled study investigated the effect of outpatient multidisciplinary pain centre treatment (MPT) compared with treatment by a general practitioner after initial supervision by a pain specialist (GP‐group) and with a group of patients waiting for 6 months before treatment was initiated (WL‐group). One‐hundred‐and‐eighty‐nine chronic non‐malignant pain patients were studied. At referral, and after 3 and 6 months patients filled in questionnaires evaluating pain intensity, health related quality of life (HRQL) and use of analgesics. HRQL was evaluated using the Medical Outcome Study‐Short Form (SF‐36), the Hospital Anxiety and Depression scale (HAD) and the Psychological General Well‐being Scale (PGWB). After 6 months patients allocated to MPT (n=63) reported statistically significant reduction in pain intensity (VAS‐score, P<0.001), improvement in psychological well‐being (PGWB, P<0.001), quality of sleep (P<0.05) and physical functioning (SF‐36‐Phycical Functioning, P<0.05). No improvements were seen in the GP‐group (n=63). In the WL‐group (n=63) a statistically significant deterioration was observed in PGWB‐scores, HAD‐scores and in 6 of 8 SF‐36‐subscores (P ≤ 0.05). A reduction in use of opioids administered on demand was obtained in the group receiving MPT (P<0.001). In the MPT‐ and GP‐groups a decrease in the use of short acting opioids was observed (P<0.01). No change in use of analgesics was seen in the WL‐group. The study showed that (i) in the MPT‐group there was a significant reduction in pain intensity and improvement of HRQL compared to the WL‐group, and (ii) the mere establishment of a pain diagnosis and a pain management plan by a pain specialist was not sufficient to enable the referring GP to manage severely chronic pain patients.

Breakthrough pain in malignant and non-malignant diseases: a review of prevalence, characteristics and mechanisms.

Breakthrough pain or transient worsening of pain in patients with an ongoing steady pain is a well known feature in cancer pain patients, but it is also seen in non‐malignant pain conditions with involvement of nerves, muscles, bones or viscera. Continuous and intermittent pain seems to be a general feature of these different pain conditions, and this raises the possibility of one or several common mechanisms underlying breakthrough pain in malignant and non‐malignant disorders. Although the mechanisms of spontaneous ongoing pain and intermittent flares of pain (BTP) may be difficult to separate, we suggest that peripheral and/or central sensitization (hyperexcitability) may play a major role in many causes of BTP. Mechanical stimuli (e.g. micro‐fractures) changes in chemical environments and release of tumour growth factors may initiate sensitization both peripherally and centrally. It is suggested that sensitization could be the common denominator of BTP in malignant and non‐malignant pain.

Disappearance of morphine-induced hyperalgesia after discontinuing or substituting morphine with other opioid agonists.

Hyperalgesia and allodynia in 4 cancer patients treated with morphine disappeared after discontinuing or substituting morphine with other opioid agonists. The first case describes a young female who developed hyperalgesia and myoclonus during intravenous morphine infusion. The hyperalgesia and myoclonus disappeared when the morphine administration was discontinued and she felt comfortable on small and sporadic oral doses of methadone. The second case describes hyperalgesia occurring after a small dose of sustained-release morphine which disappeared after alternative use of oral ketobemidone. The third case describes hyperalgesia following high doses of intramuscular morphine which disappeared after alternative use of continuous subcutaneous infusion of sufentanil. The fourth case describes a boy developing hyperalgesia after high doses of oral and intramuscular morphine. The hyperalgesia disappeared after discontinuing morphine administration but withdrawal symptoms developed due to too small doses of methadone. Possible mechanisms of morphine-induced hyperalgesia are discussed.

Epidemiology of chronic pain in Denmark: An update

The most recent Danish health survey of 2005 is based on a region‐stratified random sample of 10.916 individuals. Data were collected via personal interviews and self‐administrated questionnaires. Respondents suffering from chronic pain were identified through the question ‘Do you have chronic/long‐lasting pain lasting 6 months or more?’ The prevalence of chronic pain among individuals with a present or earlier cancer diagnosis was also assessed. In all, 7275 individuals (66.6%) completed a personal interview and 5552 individuals (50.9% of the original sample) completed and returned the self‐administrated questionnaire. The same questions were included in the survey in 2000 and, hence, it was possible to evaluate the trends in the past five years. In all, 20.2% of the adult Danish population has chronic pain. From year 2000–2005 the prevalence of chronic pain has remained stable. Generally, chronic pain was associated with female gender and increasing age. Higher prevalence of chronic pain were associated with being divorced, separated or widowed, having less than 10 years of education and high BMI. Musculoskeletal diseases (66.8%) were the most common cause for chronic pain and most persons with chronic pain rated their health and quality of life as poor. Persons with earlier or present cancer diagnosis were more likely to report chronic pain. A substantial part of persons with chronic pain were not satisfied with the examinations and treatments offered. In conclusion, over a five‐year period the prevalence of chronic pain in Denmark has remained stable, but high.

Impaired Neuropsychological Performance in Chronic Nonmalignant Pain Patients Receiving Long-Term Oral Opioid Therapy

The study investigated neuropsychological performance in chronic nonmalignant pain patients receiving long-term oral opioid therapy. Forty patients treated solely with regular and stable doses of an oral opioid were compared with 40 healthy volunteers. The patients received daily opioid doses of 15-300 mg of oral morphine (median: 60 mg) or equianalgesic doses of other opioids. The neuropsychological tests consisted of continuous reaction time (CRT), which measured vigilance/attention; finger tapping test (FTT), which measured psychomotor speed; and paced auditory serial addition task (PASAT), which measured working memory. Three months after the study had been carried out, 14 of the controls were retested in order to determine the reliability of the three tests. The patients performed statistically significantly poorer than the controls in all the tests. Significantly positive correlations were found between the PASAT and pain visual analogue scales (VAS). In the retesting of 14 controls, it was found that the tests showed high reliability. Vigilance/attention, psychomotor speed, and working memory were significantly impaired in chronic nonmalignant pain patients. The present study cannot determine which factors influenced the test results, but pain itself seemed to have an arousal effect on working memory.

Chronic pain and other sequelae in long‐term breast cancer survivors: Nationwide survey in Denmark

Objectives: To investigate self‐reported chronic pain and other sequelae in a nationally representative sample of long‐term breast cancer survivors (BCS).