Daniel M. Doleys

Ethnic Differences in Pain Tolerance: Clinical Implications in a Chronic Pain Population

Objective Although numerous studies have independently examined ethnic differences in clinical and experimental pain, few have investigated differences in both sensitivity to controlled noxious stimuli and clinical pain reports in the same sample. The present experiment examined the effects of ethnicity (African American vs. white) on experimental pain tolerance and adjustment to chronic pain. Methods Three hundred thirty-seven (68 African American and 269 white) patients with chronic pain referred to a multidisciplinary treatment center participated in the study. In addition to completing a number of standardized questionnaires assessing adjustment to chronic pain, participants underwent a submaximal effort tourniquet procedure. This experimental pain procedure yields a measure of tolerance for a controlled noxious stimulus (ie, arm ischemia). Results African American subjects reported higher levels of clinical pain as well as greater pain-related disability than white participants. In addition, substantial group differences were observed for ischemic pain tolerance, with African Americans demonstrating less tolerance than whites. Correlational analyses revealed a small but significant inverse relationship between ischemic pain tolerance and the reported severity of chronic pain. Conclusions Collectively these findings support previous research revealing ethnic differences in responses to both clinical and experimental pain. Moreover, the present results suggest that enhanced sensitivity to noxious stimuli on the part of African Americans may be associated with ethnic differences in reported clinical pain, although the magnitude of ethnic differences was much greater for ischemic pain tolerance than for clinical pain measures.

Exercise quotas, anticipatory concern and self-efficacy expectancies in chronic pain: A preliminary report.

&NA; Reduced activity levels are a frequently encountered problem among chronic pain patients which has been shown to be responsive to exercise quota systems. This study extends the knowledge of exercise quota systems by examining their effects on beliefs relevant to exercise avoidance. Results indicate that exercise quota systems produce systematic increases in both exercise levels and expectancies of capability while reducing worry and concern about exercising. These data highlight the importance of avoidance learning in chronic pain and suggest that the effectiveness of exercise quota systems is related to a deconditioning process based on exposure rather than the process of applying reinforcement to quota achievement.

Clinical characteristics of chronic back pain as a function of gender and oral opioid use.

Study Design. A cross-sectional analysis of data derived from patients with chronic spinal pain undergoing evaluation at a multidisciplinary pain treatment center was conducted. Objective. To determine whether pain severity, psychological status, and physical disability differed as a function of gender and opioid use, and whether the clinical correlates of opioid use differed in women and men with chronic back pain. Summary of Background Data. Gender differences in the experience of pain have been widely reported. For example, in the general population, several chronic pain conditions are more prevalent among women than among men, and many experimental studies demonstrate lower pain thresholds and tolerances among women. In addition, recent evidence from studies of experimental and acute clinical pain suggests that responses to analgesic medications may differ in women and men. Methods. The sample consisted of 240 patients (35% women) with low back, upper back, or neck pain undergoing evaluation for treatment at a multidisciplinary pain center. The patients were classified as opioid or nonopioid users on the basis of self-report and medical record review. All the patients completed a battery of clinical assessments, including measures of pain severity, psychological adjustment, self-reported disability, functional tasks, and pain tolerance. Analyses were conducted to examine clinical variables as a function of gender and opioid use. Results. The results indicated that opioid use was associated with greater self-reported disability and poorer function in both women and men. However, the association of opioid use with affective distress differed between women and men. The women using opioids showed lower affective distress, whereas the opioid-using men reported greater affective distress. Opioid use was not associated with pain severity, although the women reported greater pain than men. Conclusions. These findings indicate that both opioid use and gender are significant predictors of clinical status of patients with chronic spinal pain. More interesting, these two variables interact because opioid use was associated with increased affective distress among the men, but the reverse was true for the women. In addition, the women reported greater pain severity, which is consistent with some previous findings. Potential explanations for these findings are presented, and the practical implications are discussed.

Prediction of outcome among chronic pain patients

Abstract This study examined the role of self-efficacy expectancies as outcome predictors for chronic pain patients. Post-treatment self-efficacy and concern ratings were observed to significantly correlate with medication use, exercise levels and work status at follow-up. Efficacy and concern ratings, however, failed to consistently account for a significant amount of the variance at follow-up when regression analysis was employed. Follow-up work status was predicted by concern ratings, pre-treatment pain levels and Scale 3 of the MMPI. Follow-up medication use was predicted by scores on the Beck Depression Inventory.

Pain tolerance as a predictor of outcome following multidisciplinary treatment for chronic pain: differential effects as a function of sex.

&NA; Sex‐related differences in the experience of clinical and experimental pain have been widely reported. Females are at elevated risk for developing several chronic pain conditions and women demonstrate greater sensitivity to noxious stimulation in the laboratory. However, relationships between responses to experimental noxious stimuli and the experience of clinical pain have not been well characterized. One previous study of healthy adults indicated that pain threshold and tolerance were associated with clinical pain among women but not men (i.e. females with lower pain threshold and tolerance reported more clinical pain). In the present investigation, relationships between pain tolerance and outcomes of treatment for chronic pain were evaluated in a sex‐dependent manner. Ischemic pain tolerance was assessed prior to treatment in 171 chronic pain patients completing a pain management program. Outcomes were measured as changes in pain severity, affect, and pain‐related disability. Over the course of treatment, women demonstrated greater improvement in pain‐related disability while men showed more reduction in pain. Ischemic pain tolerance was related to outcome in a sex‐specific fashion. Women with higher pain tolerances showed greater improvement in pain, more reduction in pain‐related interference, and more increases in activity level than women with lower pain tolerances. In contrast, pain tolerance was not associated with positive treatment outcomes among men. These results indicate that experimental pain responses may be most clinically relevant for women, and that sex differences may exist in the determinants of pain‐treatment outcomes.

The role of self-efficacy expectancies in the prediction of pain tolerance

&NA; The association of self‐efficacy expectancies with pain tolerance on the cold pressor test was examined during treatment conditions of setting quotas alone and in conjunction with monetary reinforcement and placebos in 64 college volunteers. It was found that quota setting was an effective means of increasing cold presser pain tolerance. The addition of monetary reinforcement of quota achievement did not enhance performance, while the addition of a placebo decreased the effectiveness of quota setting. Self‐efficacy expectancies were significantly correlated with pain tolerance times and were better predictors of tolerance than pain ratings. Self‐efficacy expectancies and pain tolerance times at treatment were both found to predict 1 week follow‐up performance.

Dry-bed training and retention control training: A comparison

This study examined the efficacy of Dry-Bed Training (DBT) in the treatment of nocturnal enuresis and provided a direct comparison with Retention Control Training (RCT). Changes in bladder capacity as well as wets per night were recorded. The results revealed (a) DBT to be effective in reducing enuresis, (b) DBT to be clearly superior to RCT, and (c) no apparent relationship between bladder capacity and changes in wetting frequency. The differences between these data and those obtained from previous studies using DBT and RCT were discussed, as were the accuracy and reliability of the estimates of bladder capacity.

Depressive symptoms and pain evaluations among persons with chronic pain: catastrophizing, but not pain acceptance, shows significant effects.

ABSTRACT Cognitive factors such as catastrophic thoughts regarding pain, and conversely, one’s acceptance of that pain, may affect emotional functioning among persons with chronic pain conditions. The aims of the present study were to examine the effects of both catastrophizing and acceptance on affective ratings of experimentally induced ischemic pain and also self‐reports of depressive symptoms. Sixty‐seven individuals with chronic back pain completed self‐report measures of catastrophizing, acceptance, and depressive symptoms. In addition, participants underwent an ischemic pain induction procedure and were asked to rate the induced pain. Catastrophizing showed significant effects on sensory and intensity but not affective ratings of the induced pain. Acceptance did not show any significant associations, when catastrophizing was also in the model, with any form of ratings of the induced pain. Catastrophizing, but not acceptance, was also significantly associated with self‐reported depressive symptoms when these two variables were both included in a regression model. Overall, results indicate negative thought patterns such as catastrophizing appear to be more closely related to outcomes of perceived pain severity and affect in persons with chronic pain exposed to an experimental laboratory pain stimulus than does more positive patterns as reflected in measures of acceptance.

Dietary management of obesity: evaluation of the time-energy displacement diet in terms of its efficacy and nutritional adequacy for long-term weight control

1. An unsupplemented 4200 kJ (1000 kcal) diet emphasizing large quantities of relatively unrefined complex carbohydrates was evaluated among sixty obese adults for its effectiveness and nutritional adequacy in a long-term weight-control programme. Patients were followed individually as outpatients by a physician and dietician-an average of thirteen visits over 26 weeks. Assessment of health indices included anthropometric measurements, blood pressure, lipid levels and assays for seven vitamins, beta-carotene and iron. 2. Weight loss averaged 8.2 kg or 24% of excess weight during the 6 months of active treatment. Over an average of 17 months of post-treatment follow-up, 44% of patients continued to lose weight and 92% remained below pretreatment levels. 3. Average skinfold thickness fell 7 mm (P less than 0.001) whereas muscle mass was maintained (arm muscle circumference + 10 mm, not significant; creatinine-height index + 3% of standard (Bistrian et al. 1975; not significant). Systolic and diastolic blood pressure fell 7 and 5 mmHg respectively (P less than 0.01). Total serum cholesterol and triglycerides fell 200 and 660 mg/1 respectively (P less than 0.01), while high-density-lipoprotein-cholesterol remained statistically unchanged. Mean serum levels of retinol, beta-carotene, folate, vitamin B12, ascorbic acid, Fe and transferrin saturation, and activity coefficients for thiamin, riboflavin and pyridoxine were within normal limits after periods of treatment ranging from 5 to 84 weeks. 4. An earlier age of onset of obesity tended to be associated with greater weight loss during treatment and lesser weight rebound during follow-up. 5. The results indicate that the experimental diet, without supplementation, was nutritionally adequate as well as effective for long-term weight control.

Disease-specific and Generic Health Outcomes: A Model for the Evaluation of Long-term Intrathecal Opioid Therapy in Noncancer Low Back Pain Patients

OBJECTIVE The present study provided comprehensive characterization of the long-term outcomes of intrathecal opioid administration via a drug administration system (DAS) in chronic pain patients with predominantly low back pain. A conceptual framework based on multidimensional outcomes is proposed using both disease-specific and generic measures. DESIGN Pre-post longitudinal data were collected in a retrospective fashion on 38 patients receiving intraspinal opioid therapy for a minimum of 36 months (average = 50 months). MAIN OUTCOME MEASURES Disease-specific measures included magnitude of infused opioid, side effects/complications, pain ratings, McGill Pain Questionnaire, Beck Depression Inventory, Oswestry Disability Questionnaire, and patient estimated improvement in pain (0-100%). Generic measures of health included the Quality of Well-Being Scale, Medical Outcomes Study (MOS) Short Form 36 (SF-36), return to work, patient estimated improvement in functioning, overall patient satisfaction, and family opinion of patient improvement. RESULTS Disease-specific outcomes. Patients receiving long-term intrathecal opioid administration showed a sixfold increase in morphine equivalents infusion rates across time. DAS patients showed a small but significant decrease in pain ratings from pre-treatment levels. Following 3 years or more of intrathecal opioid infusion, patients endorsed high pain levels on the McGill Pain Questionnaire, severe levels of disability via the Oswestry Disability Questionnaire, mild levels of depression based on the Beck Depression Inventory, and multiple side effects associated with the intrathecal opioids and complications related to the infusion system. On retrospective questioning, patients receiving long-term intrathecal opioid administration reported an average of 64% improvement in their pain and 48% improvement in functioning. Family members of patients reported that they observed on average a 61% improvement in patients pain. Generic outcome measures. On the Quality of Well-Being Scale, patients reported significantly lower health-related quality of life than health maintenance organization enrollees with no known chronic condition and patients with rheumatoid arthritis (p < 0.001). On the MOS SF-36, patients reported significantly lower physical functioning than the U.S. general population, patients with uncomplicated medical conditions, diabetes-type II patients, and congestive heart failure patients. Mental functioning was comparable to the U.S. general population (p > 0.001). Fourteen percent of patients were working following implantation. Eighty-nine percent of patients reported good to excellent satisfaction with the long-term intrathecal opioid therapy. CONCLUSIONS Results from this study revealed differences in findings across the outcome measures, highlighting the complexity of intrathecal opioid therapy. Generally, patients after 3 years or more of intrathecal opioid therapy can be characterized as hav ing substantially impaired physical functioning with a high prevalence of side effects. Despite poor physical functioning, patients endorsed relatively good mental health status with only mild depressive symptoms. Longitudinal pain ratings showed a modest decrease from pretreatment levels. On retrospective evaluation, patients and their family endorsed high levels of pain relief secondary to intrathecal therapy. Overall, findings support that intrathecal opioid therapy provides some therapeutic benefit although substantial physical impairment continues to cause debilitation in the patient population.