The journal of pain : official journal of the American Pain Society
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Multicenter Study
Predictors of postherpetic neuralgia among patients with herpes zoster: a prospective study.
Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ). The main objectives of this study were to: 1) estimate the severity and duration of PHN; and 2) identify the predictors of PHN. From October, 2005 to July, 2006, 261 outpatients with HZ, aged ≥ 50, were recruited within 14 days of rash onset during the routine clinical practice of 83 physicians across Canada. Physicians documented HZ characteristics, treatments, general health, functional, and immune status. HZ pain was measured at recruitment and on days 7, 14, 21, 30, 60, 90, 120, 150, and 180 following recruitment. PHN was defined as a worst pain ≥ 3 persisting or appearing more than 90 days after rash onset. Predictors of PHN were obtained by hierarchical log-binomial regression. Twenty-two percent of 249 immunocompetent subjects with HZ developed PHN. Median duration of PHN was 77 days. Independent predictors of PHN included: older age, limitation in performing usual activities prior to HZ, and pain severity at recruitment. This study confirms that older age and greater acute pain severity are predictors of PHN, while functional status emerges as a novel independent predictor of PHN that deserves further exploration. These findings will contribute to optimal use of the HZ vaccine and testing of new therapies that might prevent PHN. ⋯ This study confirmed that older age and greater acute pain severity are robust predictors of PHN, whereas functional status emerged as a novel predictor. Despite the high proportion of subjects treated with antivirals, the burden of PHN remains considerable, suggesting that prevention and additional early interventions are needed to reduce the burden of HZ.
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Randomized Controlled Trial Comparative Study
Preference, expectation, and satisfaction in a clinical trial of behavioral interventions for acute and sub-acute low back pain.
The equivalency of behavioral interventions has led to the consideration of whether patient-related factors influence clinical trial outcomes. The primary purpose of this secondary analysis was to determine if treatment preference and patient expectation were predictors of trial outcomes and if selected patient-satisfaction items were appropriate as outcome measures. Perceived effectiveness, treatment preference, and patient expectation were assessed before random assignment, and patient satisfaction was assessed 6 months later. Patient preference was associated with perceived effectiveness for those with no treatment preference and those preferring graded exposure. Higher patient expectation was associated with higher perceived effectiveness ratings for all treatments in the clinical trial. Patients with no strong treatment preferences had larger 6-month improvements in pain intensity and disability, while patients with higher expectations had lower disability at baseline, 4 weeks, and 6 months. Patient satisfaction rates did not differ based on treatment received. Patient satisfaction was highest with treatment delivery and much lower with treatment effect. Patient satisfaction was uniformly associated with expectations being met, but only satisfaction with treatment effect was associated with lower pain and disability scores. These data support assessment of treatment preference and patient expectation as predictors and patient satisfaction as an outcome measure in low back pain (LBP) clinical trials. ⋯ These data indicate treatment preference potentially impacts rate of improvement for patients with low back pain. Patient expectation did not impact rate of improvement, but those with higher expectations had lower pain and disability scores throughout the trial. Optimal assessment of patient satisfaction should include items that separately consider treatment delivery and effect.
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A cross-sectional, Internet-based survey was conducted in a nationally representative sample of United States (US) adults to estimate the point prevalence of chronic pain and to describe sociodemographic correlates and characteristics of chronic pain. The survey was distributed to 35,718 members (aged 18 years and older) of a Web-enabled panel that is representative of the US population, and 27,035 individuals responded. Crude and weighted prevalence estimates were calculated and stratified by age, sex, and type of chronic pain. The weighted point-prevalence of chronic pain (defined as chronic, recurrent, or long-lasting pain lasting for at least 6 months) was 30.7% (95% CI, 29.8-31.7). Prevalence was higher for females (34.3%) than males (26.7%) and increased with age. The weighted prevalence of primary chronic lower back pain was 8.1% and primary osteoarthritis pain was 3.9%. Half of respondents with chronic pain experienced daily pain, and average (past 3 months) pain intensity was severe (≥ 7 on a scale ranging from 0 to 10) for 32%. Multiple logistic regression analysis identified low household income and unemployment as significant socioeconomic correlates of chronic pain. Chronic pain is prevalent among US adults and is related to indicators of poorer socioeconomic status. ⋯ The results of this cross-sectional Internet-based survey suggest a considerable burden of chronic pain in US adults. Chronic pain, experienced by about a third of the population, was correlated with indicators of poorer socioeconomic status. Primary chronic pain was most commonly attributed to lower back pain, followed by osteoarthritis pain.
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Comparative Study
Salivary cortisol release and hypothalamic pituitary adrenal axis feedback sensitivity in fibromyalgia is associated with depression but not with pain.
Results on hypothalamicpituitary-adrenal (HPA) axis function in fibromyalgia are heterogeneous and studies that integrate psychological and biological mechanisms in the search for pathways to fibromyalgia are rare. The goal of the study was to evaluate cortisol release and HPA axis feedback regulation in fibromyalgia and its association with psychopathology and pain. Beneath assessment of pain thresholds and self-report of pain, salivary free cortisol release over the day before and after intake of 0.5 mg of dexamethasone was measured in 21 female patients with fibromyalgia and 26 control women. Depression was assessed by questionnaires and clinical interview. We found reduced feedback sensitivity and slightly enhanced cortisol release in patients with fibromyalgia compared with healthy control subjects. Post hoc analyses showed that these effects are exclusively found in those patients, who also had major depressive disorder. Patients with fibromyalgia had lower pain pressure threshold, whereas heat pain thresholds were comparable with control subjects. Pain pressure and heat pain thresholds were not associated with cortisol release. On the other hand measurements of affective pain experience and depression were positively correlated with salivary cortisol over the day. Our results support the hypotheses that HPA axis related alterations are associated with affective disturbances, for example, depression, in patients with fibromyalgia. ⋯ The presented data suggest depression to be an important factor in HPA axis-related dysfunction in fibromyalgia. This might be one explanation for equivocal findings in the literature.
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This study examined characteristics associated with prescription drug use disorder (PDUD) in primary-care patients with chronic pain from a cross-sectional survey conducted at an urban academically affiliated safety-net hospital. Participants were 18 to 60 years old, had pain for ≥ 3 months, took prescription or nonprescription analgesics, and spoke English. Measurements included the Composite International Diagnostic Interview (PDUD, other substance use disorders (SUD), Posttraumatic Stress Disorder [PTSD]); Graded Chronic Pain Scale, smoking status; family history of SUD; and time spent in jail. Of 597 patients (41% male, 61% black, mean age 46 years), 110 (18.4%) had PDUD of whom 99 (90%) had another SUD. In adjusted analyses, those with PDUD were more likely than those without any current or past SUD to report jail time (OR 5.1, 95% CI 2.8-9.3), family history of SUD (OR 3.4, 1.9-6), greater pain-related limitations (OR 3.8, 1.2-11.7), cigarette smoking (OR 3.6, 2-6.2), or to be white (OR 3.2, 1.7-6), male (OR 1.9, 1.1-3.5) or have PTSD (OR 1.9, 1.1-3.4). PDUD appears increased among those with easily identifiable characteristics. The challenge is to determine who, among those with risk factors, can avoid, with proper management, developing the increasingly common diagnosis of PDUD. ⋯ This article examines risk factors for prescription drug use disorder (PDUD) among a sample of primary-care patients with chronic pain at an urban, academic, safety-net hospital. The findings may help clinicians identify those most at risk for developing PDUD when developing appropriate treatment plans.