The association between pain intensity and the prescription of analgesics and non-steroidal anti-inflammatory drugs

Effect of ABT-639 on Cav3.2 channel activity and its analgesic actions in mouse models of inflammatory and neuropathic pain

Cav3.2 T-type calcium channels are important targets for pain relief in rodent models of inflammatory and neuropathic pain. Even though many T-type channel blockers have been tested in mice, only one molecule, ABT-639, has been tested in phase II clinical studies and did not produce analgesic effects over placebo. Here we examined the effects of ABT-639 on Cav3.2 channel activity in tsA-201 cells and dorsal root ganglion (DRG) neurons, in comparison with another established Cav3.2 inhibitor Z944. These experiments revealed that Z944 mediated ∼100-fold more potent inhibition of Cav3.2 currents than ABT-639, with the latter blocking channel activity by less than 15 percent when applied at a concentration of 30 μM. A slight increase in ABT-639 potency was observed at more depolarized holding potentials, suggesting that this compound may act preferentially on inactivated channels. We tested the effects of both compounds in the Complete Freund's Adjuvant (CFA) model of chronic inflammatory pain, and in partial sciatic nerve injury model of neuropathic pain in mice. In the neuropathic pain model, both Z944 and ABT-639 reversed mechanical hypersensitivity to similar degrees when delivered systemically, but remarkably, when delivered intrathecally, only Z944 was effective. In the CFA model, both compounds reversed thermal hyperalgesia upon systemic delivery, but only Z944 mediated pain relief upon intrathecal delivery, indicating that ABT-639 acts primarily at peripheral sites. ABT-639 lost its analgesic effects in CFA treated Cav3.2 null mice, indicating that these channels are essential for ABT-639-mediated pain relief despite its poor inhibition of Cav3.2 currents.

Opioid coping motives and pain intensity among adults with chronic low back pain: associations with mood, pain reactivity, and opioid misuse

Chronic low back pain (CLBP) is a significant public health problem that is associated with opioid misuse and use disorder. Despite limited evidence for the efficacy of opioids in the management of chronic pain, they continue to be prescribed and people with CLBP are at increased risk for misuse. Identifying individual difference factors involved in opioid misuse, such as pain intensity as well as reasons for using opioids (also known as motives), may provide pertinent clinical information to reduce opioid misuse among this vulnerable population. Therefore, the aims of the current study were to examine the relationships between opioid motives-to cope with pain-related distress and pain intensity, in terms of anxiety, depression, pain catastrophizing, pain-related anxiety, and opioid misuse among 300 (Mage= 45.69, SD = 11.17, 69% female) adults with CLBP currently using opioids. Results from the current study suggest that both pain intensity and motives to cope with pain-related distress with opioids were associated with all criterion variables, but the magnitude of variance explained by coping motives was larger than pain intensity in terms of opioid misuse. The present findings provide initial empirical evidence for the importance of motives to cope with pain-related distress with opioids and pain intensity in efforts to better understand opioid misuse and related clinical correlates among adults with CLBP.

Factors associated with early opioid dispensing compared with NSAID and muscle relaxant dispensing after a work-related low back injury

OBJECTIVES

The objective of this historical cohort study was to determine the claimant and prescriber factors associated with receiving opioids at first postinjury dispense compared with non-steroidal anti-inflammatory drugs (NSAIDs) and skeletal muscle relaxants (SMRs) in a sample of workers' compensation claimants with low back pain (LBP) claims between 1998 and 2009 in British Columbia, Canada.

METHODS

Administrative workers' compensation, prescription and healthcare data were linked. The association between claimant factors (sociodemographics, occupation, diagnosis, comorbidities, pre-injury prescriptions and healthcare) and prescriber factors (sex, birth year, specialty) with drug class(es) at first dispense (opioids vs NSAIDs/SMRs) was examined with multilevel multinomial logistic regression.

RESULTS

Increasing days supplied with opioids in the previous year was associated with increased odds of receiving opioids only (1-14 days OR 1.62, 95% CI 1.51 to 1.75; ≥15 days OR 5.12, 95% CI 4.65 to 5.64) and opioids with NSAIDs/SMRs (1-14 days OR 1.49, 95% CI 1.39 to 1.60; ≥15 days OR 2.82, 95% CI 2.56 to 3.12). Other significant claimant factors included: pre-injury dispenses for NSAIDs, SMRs, antidepressants, anticonvulsants and sedative-hypnotics/anxiolytics; International Statistical Classification of Diseases and Related Health Problems, 9th Revision diagnosis; various pre-existing comorbidities; prior physician visits and hospitalisations; and year of injury, age, sex, health authority and occupation. Prescribers accounted for 25%-36% of the variability in the drug class(es) received, but prescriber sex, specialty and birth year did not explain observed between-prescriber variation.

CONCLUSIONS

During this period in the opioid crisis, early postinjury dispensing was multifactorial, with several claimant factors associated with receiving opioids at first prescription. Prescriber variation in drug class choice appears particularly important, but was not explained by basic prescriber characteristics.

Development and validation of a pain monitoring app for patients with musculoskeletal conditions (The Keele pain recorder feasibility study)

Background

Assessing daily change in pain and related symptoms help in diagnosis, prognosis, and monitoring response to treatment. However, such changes are infrequently assessed, and usually reviewed weeks or months after the start of treatment. We therefore developed a smartphone application (Keele Pain Recorder) to record information on the severity and impact of pain on daily life. Specifically, the study goal was to assess face, content and construct validity of data collection using the Pain Recorder in primary care patients receiving new analgesic prescriptions for musculoskeletal pain, as well as to assess its acceptability and clinical utility.

Methods

The app was developed with Keele’s Research User Group (RUG), a clinical advisory group (CAG) and software developer for use on Android devices. The app recorded pain levels, interference, sleep disturbance, analgesic use, mood and side effects. In a feasibility study, patients aged > 18 attending their general practitioner (GP) with a painful musculoskeletal condition were recruited to use the app twice per day for 28 days. Face and construct validity were assessed through baseline and post-study questionnaires (Spearman’s rank correlation coefficient). Usability and acceptability were determined through post-study questionnaires, and patient, GP, RUG and CAG interviews.

Results

An app was developed which was liked by both patients and GPs. It was felt that it offered the opportunity for GPs to discuss pain control with their patients in a new way. All participants found the app easy to use (it did not interfere with their activities) and results easy to interpret. Strong associations existed between the first 3 days (Spearman r = 0.79) and last 3 days (r = 0.60) of pain levels and intensity scores on the app with the validated questionnaires.

Conclusions

Collaborating with patient representatives and clinical stakeholders, we developed an app which can be used to help clinicians and patients monitor painful musculoskeletal conditions in response to analgesic prescribing. Recordings were accurate and valid, especially, for pain intensity ratings, and it was easy to use. Future work needs to examine how pain trajectories can help manage changes in a patient’s condition, ultimately assisting in self-management.

Electronic supplementary material

The online version of this article (10.1186/s12911-019-0741-z) contains supplementary material, which is available to authorized users.

Predictors of chronic prescription opioid use after orthopedic surgery: derivation of a clinical prediction rule

Background

Prescription opioid use at high doses or over extended periods of time is associated with adverse outcomes, including dependency and abuse. The aim of this study was to identify mediating variables that predict chronic opioid use, defined as three or more prescriptions after orthopedic surgery.

Methods

Individuals were ages between 18 and 50 years and undergoing arthroscopic hip surgery between 2004 and 2013. Two categories of chronic opioid use were calculated based on individuals (1) having three or more unique opioid prescriptions within 2 years and (2) still receiving opioid prescriptions > 1 year after surgery. Univariate elationships were identified for each predictor variable, then significant variables (P > 0.15) were entered into a multivariate logistic regression model to identify the most parsimonious group of predictor variables for each chronic opioid use classification. Likelihood ratios were derived from the most robust groups of variables.

Results

There were 1642 participants (mean age 32.5 years, SD 8.2, 54.1% male). Nine predictor variables met the criteria after bivariate analysis for potential inclusion in each multivariate model. Eight variables: socioeconomic status (from enlisted rank family), prior use of opioid medication, prior use of non-opioid pain medication, high health-seeking behavior before surgery, a preoperative diagnosis of insomnia, mental health disorder, or substance abuse were all predictive of chronic opioid use in the final model (seven variables for three or more opioid prescriptions; four variables for opioid use still at 1 year; all< 0.05). Post-test probability of having three or more opioid prescriptions was 93.7% if five of seven variables were present, and the probability of still using opioids after 1 year was 69.6% if three of four variables were present.

Conclusion

A combination of variables significantly predicted chronic opioid use in this cohort. Most of these variables were mediators, indicating that modifying them may be feasible, and the potential focus of interventions to decrease the risk of chronic opioid use, or at minimum better inform opioid prescribing decisions. This clinical prediction rule needs further validation.

Trends in long-term opioid prescribing in primary care patients with musculoskeletal conditions: an observational database study

Supplemental Digital Content is Available in the Text.

Long-term opioid use decreased from 2011, but the proportion of more potent opioids prescribed increased. Ongoing review of effectiveness and need for discontinuation is important.

Long-term opioids may benefit patients with chronic pain but have also been linked to harmful outcomes. In the United Kingdom, the predominant source of opioids is primary care prescription. The objective was to examine changes in the incidence, length, and opioid potency of long-term prescribing episodes for musculoskeletal conditions in UK primary care (2002-2013). This was an observational database study (Clinical Practice Research Datalink, 190 practices). Participants (≥18 years) were prescribed an opioid for a musculoskeletal condition (no opioid prescribed in previous 6 months), and issued ≥2 opioid prescriptions within 90 days (long-term episode). Opioids were divided into short- and long-acting noncontrolled and controlled drugs. Annual incidence of long-term opioid episodes was determined, and for those still in a long-term episode, the percentage of patients prescribed each type 1 to 2 years, and >2 years after initiation. Annual denominator population varied from 1.25 to 1.38 m. A total of 76,416 patients started 1 long-term episode. Annual long-term episode incidence increased (2002-2009) by 38% (42.4-58.3 per 10,000 person-years), remaining stable to 2011, then decreasing slightly to 55.8/10,000 (2013). Patients prescribed long-acting controlled opioids within the first 90 days of long-term use increased from 2002 to 2013 (2.3%-9.9%). In those still in a long-term opioid episode (>2 years), long-acting controlled opioid prescribing increased from 3.5% to 22.6%. This study has uniquely shown an increase in prescribing long-term opioids to 2009, gradually decreasing from 2011 in the United Kingdom. The trend was towards increased prescribing of controlled long-acting opioids and earlier use. Further research into the risks and benefits of opioids is required.

Pain medication management of musculoskeletal conditions at first presentation in primary care: analysis of routinely collected medical record data

BACKGROUND

Primary care pharmacological management of new musculoskeletal conditions is not consistent, despite guidelines which recommend prescribing basic analgesics before higher potency medications such as opioids or non-steroidal inflammatory drugs (NSAIDs).The objective was to describe pharmacological management of new musculoskeletal conditions and determine patient characteristics associated with type of medication prescribed.

METHODS

The study was set within a UK general practice database, the Consultations in Primary Care Archive (CiPCA). Patients aged 15 plus who had consulted for a musculoskeletal condition in 2006 but without a musculoskeletal consultation or analgesic prescription in the previous 12 months were identified from 12 general practices. Analgesic prescriptions within two weeks of first consultation were identified. The association of socio-demographic and clinical factors with receiving any analgesic prescription, and with strength of analgesic, were evaluated.

RESULTS

3236 patients consulted for a new musculoskeletal problem. 42% received a prescribed pain medication at that time. Of these, 47% were prescribed an NSAID, 24% basic analgesics, 18% moderate strength analgesics, and 11% strong analgesics. Increasing age was associated with an analgesic prescription but reduced likelihood of a prescription of NSAIDs or strong analgesics. Those in less deprived areas were less likely than those in the most deprived areas to be prescribed analgesics (odds ratio 0.69; 95% CI 0.55, 0.86). Those without comorbidity were more likely to be prescribed NSAIDs (relative risk ratios (RRR) compared to basic analgesics 1.89; 95% CI 0.96, 3.73). Prescribing of stronger analgesics was related to prior history of analgesic medication (for example, moderate analgesics RRR 1.88; 95% CI 1.11, 3.10).

CONCLUSION

Over half of patients were not prescribed analgesia for a new episode of a musculoskeletal condition, but those that were often received NSAIDs. Analgesic choice appears multifactorial, but associations with age, comorbidity, and prior medication history suggest partial use of guidelines.

Inadequate pain relief and large functional loss among patients with knee osteoarthritis: evidence from a prospective multinational longitudinal study of osteoarthritis real-world therapies

Objective. To estimate the prevalence of inadequate pain relief (IPR) among patients with symptomatic knee OA prescribed analgesic therapy and to characterize patients with IPR.

Methods. Patients ≥50 years old with physician-diagnosed knee OA who had taken topical or oral pain medication for at least 14 days were recruited for this prospective non-interventional study in six European countries. Pain and function were assessed using the Brief Pain Inventory (BPI) and the WOMAC; quality of life (QoL) was assessed using the 12-item short form. IPR was defined as an average pain score of >4 out of 10 on BPI question 5.

Results. Of 1187 patients enrolled, 68% were female and the mean age was 68 years (s.d. 9); 639 (54%) met the definition of IPR. Patient responses for the BPI average pain question were well correlated with responses on the WOMAC pain subscale (Spearman r = 0.64, P < 0.001). In multivariate logistic regression, patients with IPR had greater odds of being female [adjusted odds ratio (adjOR) 1.90 (95% CI 1.46, 2.48)] and having OA in both knees [adjOR 1.48 (95% CI 1.15, 1.90)], higher BMI, longer OA duration, depression or diabetes. Patients with IPR (vs non-IPR) were more likely to have worse QoL, greater function loss and greater pain interference.

Conclusion. IPR is common among patients with knee OA requiring analgesics and is associated with large functional loss and impaired QoL. Patients at particular risk of IPR, as characterized in this study, may require greater attention towards their analgesic treatment options.

Trial registration:https://clinicaltrials.gov/ (NCT01294696).

The psychometric properties of the PABS-PT in neck pain patients: a validation study

OBJECTIVE

This study aims to assess the reliability and validity of the Pain Attitudes and Beliefs Scale for Physiotherapists (PABS-PT) in neck pain patients. Three research goals were formulated. (1): to reexamine the factor structure of the PABS-PT, (2) to assess the test-retest reliability of the PABS-PT and (3) to determine the construct validity of the biomedical factor of the PABS-PT.

METHODS

Manual therapists (n = 272) included in this study participated in an educational upgrade program for a professional masters' degree in the Netherlands and completed the Health Care Providers' Pain and Impairment Relationship Scale and the PABS-PT. Principal Axis Factor analysis was performed and correlation coefficients were calculated. In addition, Bland and Altman plots and the smallest real difference were determined.

RESULTS

We performed factor analysis on 182 questionnaires and test-rest calculations on 73 questionnaires. The principal factor analysis confirmed the existing interpretable 2-factor model of a 'biomedical treatment orientation' and a 'behavioral treatment orientation'. Test-retest reliability was 'moderate' to 'good' and construct validity for the biomedical factor was 'moderate' to 'substantial'.

CONCLUSION

The PABS-PT shows a consistent factor structure and good test-retest reliability and construct validity. More research is needed to gain further insight in the interplay between implicit and explicit attitudes and the dynamics of the PABS-PT score across different body parts.