Bordson SJ, Atayee RS, Ma JD, Best BM. Tricyclic antidepressants: is your patient taking them? Observations on adherence and unreported use using prescriber-reported medication lists and urine drug testing. Pain Med. doi:10.1111/pme.12300 (2013) (Epub ahead of print).
Tricyclic antidepressants (TCAs) are first-line treatment drugs for neuropathic pain and also used for other chronic pain conditions. This study used urinary excretion data to assess adherence rates to TCAs prescribed for pain in a large population of pain patients. The adherence rate was 66%, suggesting that 34% had self-discontinued their TCA. Adherence was lower among younger and male patients, but number of other medications did not affect adherence to TCA treatment. The study also found that 3% of all patients at a pain practice took TCAs without the knowledge of their pain practitioner and roughly half of those taking TCAs did so without the drug being on the pain practitioner‘s medication list. Drug–drug interactions were identified in both groups of TCA users, which may be particularly concerning if they are not being monitored or if they are being misunderstood, due to the treating physician being unaware of the TCA use. This study emphasizes the importance of accurate medication records.
– Written by Nanna Finnerup
van Hecke O, Austin SK, Khan RA, Smith BH, Torrance N. Neuropathic pain in the general population: a systematic review of epidemiological studies. Pain doi:10.1016/j.pain.2013.11.013 (2013) (Epub ahead of print).
This is a comprehensive systematic review of epidemiological studies of neuropathic pain in the general population. The review showed that studies using questionnaires found that the prevalence of pain, which was described with predominantly neuropathic pain descriptors, ranged from 7 to 18%, while studies based on diagnostic codes found rates of neuropathic pain of 1–2%. The study also reported on prevalence of neuropathic pain associated with specific conditions and estimated prevalence of, for example, painful diabetic polyneuropathy ranged from 15 to 72/100,000 person-years. The wide differences highlight the difficulty in identifying neuropathic pain in population-based studies.
– Written by Nanna Finnerup
Dorleijn D, Burdorf A, Rozendaal R, Verhaar J, Bos P, Bierma-Zeinstra S. Associations between weather conditions and clinical symptoms in patients with hip osteoarthritis: a two-year cohort study. Pain doi:10.1016/j.pain.2014.01.018 (2014) (Epub ahead of print).
Researchers from the Erasmus MC University (Rotterdam, The Netherlands) have published a study that aimed to assess whether there is an association between ambient weather conditions and patients‘ clinical symptoms in patients with hip osteoarthritis (OA).
The team designed a cohort study with a 2-year follow-up and 3-monthly measurements and prospectively collected data of weather variables. Study participants were 222 primary care patients with hip OA. Weather variables included temperature, wind speed, total amount of sun hours, precipitation, barometric pressure and relative humidity. The primary outcomes of the study included severity of hip pain and hip disability measured with the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) pain and function subscales. Associations between hip pain and hip disability and the weather variables were assessed using crude and multivariate adjusted linear mixed-model analysis for repeated measurements.
On the day of questionnaire completion, mean relative humidity was associated with WOMAC pain (estimate: 0.1; 95% CI: 0.0–0.2; p = 0.02). Relative humidity contributed ≤1% to the explained within-patient variance and between-patient variance of the WOMAC pain score. Mean barometric pressure was associated with WOMAC function (estimate 0.1; 95% CI: 0.0–0.1; p = 0.02). Barometric pressure contributed ≤1% to the explained within-patient variance and between-patient variance of the WOMAC function score.
No other weather variables were associated with the WOMAC pain or function score.
The results support a general opinion held by OA patients that barometric pressure and relative humidity influences perceived OA symptoms. However, the authors pointed out that the contribution of these weather variables (≤1%) to the severity of OA symptoms is not considered to be clinically relevant.
– Written by Dominic Chamberlain
Keogh E, Cavill R, Moore D, Eccleston C. The effects of menstrual-related pain on attentional interference. Pain doi:10.1016/j.pain.2014.01.021 (2014) (Epub ahead of print).
The purpose of the current study was, to examine the effects of menstrual pain on attentional interference. Pain-related attentional interference has been found in both chronic pain and laboratory-inducted pain settings. However, to date, few studies have examined interference effects during common everyday painful episodes. The study consisted of 52 healthy adult females tested during two different phases of their menstrual cycles: once during a nonpain phase (mid follicular), and once whilst experiencing menstrual pain (late luteal/early follicular).
On each testing session participants received a battery of four attentional interference tasks: selective attention (flanker task), attention span (n-back task), attentional switching (switching task), and divided attention (dual task). The authors report that greater attentional interference effects were observed during the menstrual pain phase compared with the nonpain phase. The nature of this effect was a general worsening in performance (e.g., slowing, less accurate), rather than a specific attentional deficit. The results reported in the current study add to a growing literature that indicates that attentional interference occurs across a range of different types of pain, including common painful episodes. However, additionally the results, highlight that the specific nature of this interference effect may depend on the type pain under consideration.
– Written by Dominic Chamberlain
Dansie E, Turk D, Martin K, Van Domelen D, Patel KV. Association of Chronic Widespread Pain with objectively measured physical activity in adults: findings from the National Health and Nutrition Examination Survey. J. Pain doi:10.1016/j.jpain.2014.01.489 (2014) (Epub ahead of print).
Chronic widespread pain (CWP) is a common and often debilitating disorder. Patterns of physical activity (PA) in adults with CWP have primarily been investigated using subjective, self-report measures.
The current study sought to characterize PA among community-dwelling individuals with CWP, chronic regional pain, or no chronic pain (NCP) using objective measurements obtained via accelerometry in the 2003–2004 National Health and Nutrition Examination Survey. The researchers examined data from 3952 participants ages 20 years and older to assess relationships between pain status and objective measurements of PA. Prevalence of CWP was 3.3 and 5.4% for men and women, respectively. In men and women, the average activity counts per minute) and time spent in moderate-to-vigorous PA were significantly lower for the CWP group than for the NCP group. One finding of some interest, was that time spent in sedentary, light, and lifestyle activities was not associated with pain status. Statistical interaction tests indicated that the effects of chronic pain on counts per minute were stronger in men than in women. Despite recommendations for increased moderate-to-vigorous PA as a pain management strategy for CWP, results from this nationally representative study indicate that adults with CWP participate in less moderate-to-vigorous PA than individuals without chronic pain.
The study demonstrates that adults with CWP participate in reduced daily and moderate-to-vigorous physical activity in comparison to people with NCP. Thus, the results would appear to further promote the idea that clinicians need to take greater steps to emphasize the importance of increasing PA in patients with CWP.
– Written by Dominic Chamberlain
Financial & competing interests disclosure
D Chamberlain is an employee of Future Science Group. N Finnerup receives research funding from the EUROPAIN Investigational Medicines Initiative, which is a public–private partnership between the European Federation of Pharmaceutical Industries and Associations (EFPIA) and EU. N Finnerup has also received honoraria from Pfizer and Grünenthal. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.