Measurement, and Pain Assessment in Clinical Trials recommendations for outcome measurements of chronic pain trials are also useful for routine assessment. Cancer pain assessment is complicated by a number of other bodily and mental symptoms such as fatigue and depression, all affecting quality of life. It is noteworthy that quality of life reported by chronic pain patients can be as much affected as that of terminal cancer patients. Any assessment of pain must take into account other factors, such as cognitive impairment or dementia, and assessment tools validated in the specific patient groups being studied.

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A gender difference in the incidence of acute pain may be a confounder in analgesic trials. We have tested the hypothesis that the incidence of acute pain after knee arthroscopic procedures is greater in women than men. We performed three RCTs on intra-articular analgesics in which no postoperative analgesia was given until the need for such treatment was documented by scoring moderate-to-severe pain on a verbal rating scale (VRS 0-4; n=219), and a 0-100 mm visual analogue pain scale (VAS) within 2 h postoperatively. All trials were performed with an intra-articular catheter technique. The design allowed us to study the natural course of pain after arthroscopic surgery until analgesia was required. Women reported more pain of at least moderate intensity than men (84 vs 57%; P<0.0001), indicating that being female is a risk factor for early postoperative pain (RR 1.47, 95% confidence interval from 1.23 to 1.74). The VAS score corresponding to moderate and severe pain is similar in men and women. Only short acting anaesthetics were given in order to minimise carry-over effects. Since previous trials on arthroscopic analgesics neither measured baseline pain nor stratified for gender, a difference between treatment groups could result from an uneven distribution regarding these factors. Our findings have major implications for the interpretation of previously published trials on intra-articular analgesia.

BP measured repeatedly by two different noninvasive devices during pregnancy and postpartum showed a statistically significant drop in mid-pregnancy, followed by a progressive increase until term.

QL block with ropivacaine reduces the postoperative ketobemidone consumption and pain intensity as a part of a multimodal analgesic regimen that excludes neuraxial morphine.

Resting blood pressure (BP) is inversely related to pain sensitivity in individuals free of chronic pain, reflecting homeostatic interactions between cardiovascular and pain modulatory systems. Several laboratory studies indicate that BP-related hypoalgesia is diminished in chronic pain patients, suggesting dysfunction in these interacting systems. Separate epidemiological findings reveal elevated hypertension prevalence in the chronic pain population. This study for the first time simultaneously evaluated both hypertension prevalence and BP-related hypoalgesia as they relate to chronic pain in the same sample. Resting BP and pain sensitivity were evaluated in a large general population sample (n=10,135, aged 30-87years). Subjects participated in a standardized 106s cold pressor test, providing pain ratings at 9s intervals. Self-reported presence of chronic pain and history of hypertension and use of antihypertensive medication were assessed. Significant interactions between chronic pain status and resting systolic (P<.001) and diastolic BP (P<.001) on mean pain ratings were observed. These interactions were due to significant (P<.001) BP-related hypoalgesia in individuals free of chronic pain that was twice the magnitude of the hypoalgesia observed in the group reporting chronic pain. Presence of chronic pain was associated with significantly increased odds of comorbid hypertension (P<.001). Within the chronic pain group, higher chronic pain intensity was a significant predictor of positive hypertension status beyond the effects of traditional demographic risk factors (P<.05). Results are consistent with the hypothesis that increased hypertension risk in the chronic pain population might be linked in part to chronic pain-related dysfunction in interacting cardiovascular-pain modulatory systems.

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Background and purpose — Functional limitations after total knee arthroplasty (TKA) are common. In this longitudinal study, we wanted to identify subgroups of patients with distinct trajectories of pain-related interference with walking during the first year after TKA and to determine which demographic, clinical, symptom-related, and psychological characteristics were associated with being part of this subgroup.Patients and methods — Patients scheduled for primary TKA for osteoarthritis (n = 202) completed questionnaires that evaluated perception of pain, fatigue, anxiety, depression, and illness on the day before surgery. Clinical characteristics were obtained from the medical records. Interference of pain with walking was assessed preoperatively, on postoperative day 4, and at 6 weeks, 3 months, and 12 months after TKA.Results — Using growth mixture modeling, 2 subgroups of patients were identified with distinct trajectories of pain-related interference with walking over time. Patients in the Continuous Improvement class (n = 157, 78%) had lower preoperative interference scores and reported a gradual decline in pain-related interference with walking over the first 12 months after TKA. Patients in the Recurrent Interference class (n = 45, 22%) reported a high degree of preoperative pain-related interference with walking, initial improvement during the first 3 months after TKA, and then a gradual increase—returning to preoperative levels at 12 months. Patients in the Recurrent Interference class had higher preoperative pain, fatigue, and depression scores, and poorer perception of illness than the Continuous Improvement class.Interpretation — 1 in 5 patients did not improve in pain-related interference with walking at 12 months after TKA. Future studies should test the efficacy of interventions designed to modify preoperative characteristics.