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Abstract: Mean pain intensity alone is insufficient to describe pain phenotypes in sickle cell disease (SCD). The objective of this study was to determine impact of day-to-day intraindividual pain variability on patient outcomes in SCD. We calculated metrics of pain variability and pain intensity for 139 participants with <10% missing data in the first 28 days of the Pain in Sickle Cell Epidemiology Study. We performed Spearman rank correlations between measures of intraindividual pain variability and outcomes. We then used k-means clustering to identify phenotypes of pain in SCD. We found that pain variability was inversely correlated with health-related quality of life, except in those with daily or near-daily pain. Pain variability was positively correlated with affective coping, catastrophizing, somatic symptom burden, sickle cell stress, health care utilization, and opioid use. We found 3 subgroups or clusters of pain phenotypes in SCD. Cluster 1 included individuals with the lowest mean pain, lowest temporal instability and dependency, lowest proportion of days with pain and opioid use, and highest physical function. Cluster 2 included individuals with the highest mean pain, highest temporal dependency, highest proportion of days with pain and opioid use, and lowest physical function. Cluster 3 included individuals with high levels of mean pain, highest temporal instability, but with lower temporal dependency, proportion of days with pain and opioid use, and physical function compared with cluster 2. We conclude that intraindividual pain variability is associated with patient outcomes and psychological characteristics in SCD and is useful in delineating phenotypes of pain in SCD. [ABSTRACT FROM AUTHOR]

Previous research reports suggest greater baseline variability is associated with greater pain relief in those who receive a placebo. However, studies that evidence this association do not control for confounding effects from regression to the mean and natural history. In this report, we analyzed data from two randomized clinical trials (Placebo I and Placebo II, total N = 139) while adjusting for the effects of natural history and regression to the mean via a no treatment group. Results agree between the two placebo groups in each study: both placebo groups showed negligible semi-partial correlations between baseline variability and adjusted response [rsp (CI95%) = 0.22 (0.03, 0.42) and 0 (−0.07, 0.07) for Placebo I and II, respectively]. The no treatment group in Placebo I showed a negative correlation [−0.22 (−0.43, −0.02)], but the no treatment and drug groups in Placebo II's correlations were negligible [−0.02 (−0.08, 0.02) and 0.00 (−0.10, 0.12) for the no treatment and drug groups, respectively]. When modeled as a linear covariate, baseline pain variability accounted for

Pain is an inherently negative perceptual and affective experience that acts as a warning system to protect the body from injury and illness. Pain unfolds over time and is influenced by myriad factors, making it highly dynamic. Despite this, statistical measures often treat any intraindividual variability in pain ratings as noise or error. This is consequential, especially for research on chronic pain, because pain variability is associated with greater pain severity and depression. Yet, differences in pain variability between patients with chronic pain and controls in response to acute pain has not been fully examined-and it is unknown if dispositional factors such as pain catastrophizing (negative cognitive-affective response to potential or actual pain in which attention cannot be diverted away from pain) relate to pain variability. In the current study, we recruited chronic-pain patients (N = 30) and pain-free controls (N = 22) to complete a 30-second thermal pain task where they continually rated a painful thermal stimulus. To quantify pain variability and capture potential dynamics, we used both a traditional intraindividual standard deviation (iSD) metric of variability and a novel derivatives approach. For both metrics, patients with chronic pain had higher variability in their pain ratings over time, and pain catastrophizing significantly mediated this relationship. This suggests patients with chronic pain experience pain stimuli differently over time, and pain catastrophizing may account for this differential experience. PERSPECTIVE: The present study demonstrates (using multiple variability metrics) that chronic pain patients show more variability when rating experimental pain stimuli, and that pain catastrophizing helps explain this differential experience. These results provide preliminary evidence that short-term pain variability could have utility as a clinical marker in pain assessment and treatment., (Copyright © 2024 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Abstract Background This study examines the association of both pain severity and within-person pain variability with physical activity (PA) in older adults with osteoarthritis (OA). Methods Data from the European Project on OSteoArthritis were used. At baseline, clinical classification criteria of the American College of Rheumatology were used to diagnose OA in older adults (65–85 years). At baseline and 12–18 months follow-up, frequency and duration of participation in the activities walking, cycling, gardening, light and heavy household tasks, and sports activities were assessed with the Longitudinal Aging Study Amsterdam Physical Activity Questionnaire. Physical activity was calculated in kcal/day, based on frequency, duration, body weight and the metabolic equivalent of each activity performed. At baseline and 12–18 months follow-up, pain severity was assessed using the pain subscales of the Western Ontario and McMaster Universities OA Index and the Australian/Canadian Hand OA Index. Within-person pain variability was assessed using two-week pain calendars that were completed at baseline, 6 months follow-up and 12–18 months follow-up. Results Of all 669 participants, 70.0% were women. Sex-stratified multiple linear regression analyses showed that greater pain severity at baseline was cross-sectionally associated with less PA in women (Ratio = 0.95, 95% CI = 0.90–0.99), but not in men (Ratio = 0.99, 95% CI = 0.85–1.15). The longitudinal analyses showed a statistically significant inverse association between pain severity at baseline and PA at follow-up in women (Ratio = 0.94, 95% CI = 0.89–0.99), but not in men (Ratio = 1.00, 95% CI = 0.87–1.11). Greater pain variability over 12–18 months was associated with more PA at follow-up in men (Ratio = 1.18, 95% CI = 1.01–1.38), but not in women (Ratio = 0.94, 95% CI = 0.86–1.03). Conclusions Greater pain severity and less pain variability are associated with less PA in older adults with OA. These associations are different for men and women. The observed sex differences in the various associations should be studied in more detail and need replication in future research.

Abstract: Many factors are known to affect assay sensitivity; however, limited attention has been devoted to understanding whether characteristics of patients' baseline pain impact assay sensitivity. In this study, we tested whether a combination of 3 baseline pain indices based on ecological momentary assessments (EMA) could detect patients with enhanced responses to placebo. The analysis was conducted with secondary data from 2 clinical trials in fibromyalgia patients (N = 2084). For each patient, pain intensity, pain variability (individual SD), and pain consistency (first-order autocorrelation) were computed from baseline EMA. A latent profile analysis identified 3 subgroups of patients based on these indices. Group 1 (n = 857, 41.3%) showed the lowest pain intensity levels, coupled with the highest consistency and greatest variability of pain. Group 3 (n = 110, 5.3%) showed the opposite pattern, and group 2 (n = 1109, 53.4%) showed intermediate levels on all pain indices. It was then tested whether the subgroups moderated treatment effects (changes in pain for active treatment vs placebo) using repeated-measures analysis of variance. Treatment effects varied significantly between subgroups. Patients in group 3 demonstrated greater reduction in pain in response to placebo then those in groups 1 and 2. Further analysis showed that the removal of patients in class 3 would significantly enhance the observed treatment effect by 8% to 15%. In conclusion, profiles of pain characteristics derived from baseline EMA may be useful for detecting patient subgroups with enhanced placebo responses that can diminish assay sensitivity in pain clinical trials. [ABSTRACT FROM AUTHOR]

Pain is a key symptom of osteoarthritis (OA) and has been linked to poor mental health. Pain fluctuates over time within individuals, but a paucity of studies have considered day-to-day fluctuations of joint pain in relation to affective symptoms in older persons with OA. This study investigated the relationship of pain severity as well as within-person pain variability with anxiety and depression symptoms in 832 older adults with OA who participated in the European Project on OSteoArthritis (EPOSA): a 6-country cohort study. Affective symptoms were examined with the Hospital Anxiety and Depression Scale, pain severity was assessed with the Western Ontario and McMaster Universities OA Index and the Australian/Canadian Hand Osteoarthritis Index, and intraindividual pain variability was measured using pain calendars assessed at baseline, 6, and 12 to 18 months. Age-stratified multiple linear regression analyses adjusted for relevant confounders showed that more pain was associated with more affective symptoms in older-old participants (74.1–85 years). Moreover, older-old participants experienced fewer symptoms of anxiety (ratio = .85, 95% confidence interval [CI], .77–.94), depression (ratio = .90, 95% CI, .82–.98), and total affective symptoms (ratio = .87, 95% CI, .79–.94) if their pain fluctuated more. No such association was evident in younger-old participants (65–74.0 years). These findings imply that stable pain levels are more detrimental to mental health than fluctuating pain levels in older persons. Perspective This study showed that more severe and stable joint pain levels were associated with anxiety and depressive symptoms in older persons with OA. These findings emphasize the importance of measuring pain in OA at multiple time points, because joint pain fluctuations may be an indicator for the presence of affective symptoms. [ABSTRACT FROM AUTHOR]

Background Chronic postsurgical pain ( CPSP) is a debilitating and costly condition. Risk factors for CPSP after autologous breast reconstruction have not been clearly established. Previously, we demonstrated that transversus abdominis plane ( TAP) catheters delivering intermittent local anesthetic reduced postoperative morphine consumption. This prospective follow-up study aimed to (1) compare the incidence of CPSP after autologous breast reconstruction between patients who received postoperative intermittent TAP catheters with bupivacaine or saline boluses and (2) assess the factors that contribute to the development and maintenance of CPSP in this study cohort. Methods Ninety-three patients who underwent deep inferior epigastric artery perforator or muscle-sparing transverse rectus abdominis breast reconstruction were randomized to receive TAP catheters with bupivacaine or saline postoperatively. Subsequently, patients were followed for a year to assess persistent pain, pain severity, quality of life scores, and functional disability at 6 and 12 months after surgery. Results Twenty-four percent and 23% of patients reported CPSP at 6 and 12 months, respectively. There were no significant differences between groups (bupivacaine vs. placebo) on pain-related variables, including incidence of CPSP. Patients who reported greater variability in pain scores at rest over the first 48 hours postoperatively were more likely to have CPSP 6 months, but not 12 months, later. Conclusions Acute postoperative pain variability may contribute to the development of CPSP up to 6 months after autologous breast reconstruction surgery. Neither postoperative use of bupivacaine vs. saline in the TAP catheters nor acute pain severity influenced the 6- or 12-month incidence of CPSP. [ABSTRACT FROM AUTHOR]

Clinical trials of analgesics have been plagued with poor assay sensitivity due, in part, to variability in subjects' pain reporting. Herein, we develop and evaluate the focused analgesia selection test (FAST), a method to measure patients' pain reporting skills. Subjects with osteoarthritis of the hip, knee, and/or ankle with pain intensity of ≥3/10 on a 0-10 numerical rating scale were enrolled. Subjects underwent the FAST procedure, which consists of recording subjects' pain reports in response to repeated administration of thermal noxious stimuli of various intensities applied on the arm with the Medoc® Thermal Sensory Analyzer II. Subjects also rated non-noxious stimuli consisting of visual contrast rating. After performing an exercise task, subjects also rated clinical pain and were asked to report whether their pain had increased, decreased, or stayed the same. Overall, 88 subjects were enrolled, and 83 were included in the analyses. FAST's outcomes including the R², intraclass correlation coefficient (ICC), and coefficient of variation (CoV) indicated that subjects' pain reporting skills were widely distributed. Higher FAST ICC significantly predicted greater changes in clinical pain following exercise (p=0.017), whereas the visual contrast test did not predict postexercise pain. FAST is the first method that measures subjects' pain reporting skills. Using FAST to enrich clinical trials with "good" pain reporters (with high FAST ICC) could increase assay sensitivity. Further evaluation of FAST is ongoing. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although pain is common among patients with advanced cancer, little is known about longitudinal variability in pain intensity. For this report, the authors examined variability in pain intensity over 24 months among ambulatory patients with advanced stage cancers, associations between patient characteristics and within-patient pain variability, and the relation of pain variability to overall survival. METHODS: The sample comprised 949 patients with solid tumors who received care and reported pain scores in at least 3 different months within 24 months of their initial stage IV diagnosis during the period from 2004 to 2006. Pain intensity was measured using a scale ranging from 0 (no pain) to 10 (worst pain). Pain variability was defined as the standard deviation of the maximum monthly pain scores and was dichotomized at the 50th percentile into high and low variability groups. RESULTS: Considerable between-patient differences in pain variability (range, 0-5.77) were observed. Nonwhites, patients with a stage IV cancer diagnosed within the previous 3 months, and those with moderate or severe pain at baseline were more likely to experience high pain variability. Although patients with head and neck cancer generally had the highest pain variability, the intensity of their pain typically decreased over the disease course. High pain variability with worsening pain trajectory was associated with increased risk of death. CONCLUSIONS: Longitudinally, pain intensity was highly variable among patients with stage IV cancer. Minority patients, newly diagnosed patients, patients with head and neck cancer, and patients with moderate or severe pain at baseline were at higher risk of large fluctuations in pain intensity. Cancer 2012. © 2012 American Cancer Society. [ABSTRACT FROM AUTHOR]

Background: This study examines the association of both pain severity and within-person pain variability with physical activity (PA) in older adults with osteoarthritis (OA).Methods: Data from the European Project on OSteoArthritis were used. At baseline, clinical classification criteria of the American College of Rheumatology were used to diagnose OA in older adults (65-85 years). At baseline and 12-18 months follow-up, frequency and duration of participation in the activities walking, cycling, gardening, light and heavy household tasks, and sports activities were assessed with the Longitudinal Aging Study Amsterdam Physical Activity Questionnaire. Physical activity was calculated in kcal/day, based on frequency, duration, body weight and the metabolic equivalent of each activity performed. At baseline and 12-18 months follow-up, pain severity was assessed using the pain subscales of the Western Ontario and McMaster Universities OA Index and the Australian/Canadian Hand OA Index. Within-person pain variability was assessed using two-week pain calendars that were completed at baseline, 6 months follow-up and 12-18 months follow-up.Results: Of all 669 participants, 70.0% were women. Sex-stratified multiple linear regression analyses showed that greater pain severity at baseline was cross-sectionally associated with less PA in women (Ratio = 0.95, 95% CI = 0.90-0.99), but not in men (Ratio = 0.99, 95% CI = 0.85-1.15). The longitudinal analyses showed a statistically significant inverse association between pain severity at baseline and PA at follow-up in women (Ratio = 0.94, 95% CI = 0.89-0.99), but not in men (Ratio = 1.00, 95% CI = 0.87-1.11). Greater pain variability over 12-18 months was associated with more PA at follow-up in men (Ratio = 1.18, 95% CI = 1.01-1.38), but not in women (Ratio = 0.94, 95% CI = 0.86-1.03).Conclusions: Greater pain severity and less pain variability are associated with less PA in older adults with OA. These associations are different for men and women. The observed sex differences in the various associations should be studied in more detail and need replication in future research. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this secondary data analysis is to determine whether depression, cognition, functional status, health, and pain severity are predictors of day-to-day pain variability in older adults in long-term care settings., Methods: Seventy-seven adults aged 68 years and older were included in the multiple linear regression analyses. Pain severity mean and variability were measured over 30 days of daily self-reported pain levels. The Geriatric Depression Scale (GDS), Blessed Memory-Information-Concentration test, Physical Self-Maintenance Scale (PSMS), baseline pain severity, mean of daily health, and mean of daily pain severity were used as predictors. Pain variability was measured by examining intra-individual standard deviations of daily pain scores., Results: Results show that global depression and pain severity are predictors of pain variability in that greater baseline depression and pain severity predicted higher pain variability. Daily mean pain and health were also found to be predictors of pain variability., Discussion: Pain variability is an important characteristic that is not given enough emphasis in current literature. Understanding pain variability may give insight into older adults' experiences with both pain and depression, and may essentially improve quality of care and quality of life.