Early Opioid Prescriptions for Work-Related Musculoskeletal Disorders of the Low Back: Understanding Dispensing Patterns, Their Determinants, and Their Impact on Work Disability
Year: 2017
Type: dissertation
Study design: Observational Study
Abstract: Opioids are prescribed early for low back pain (LBP), despite little evidence supporting this practice. The dissertation objective was to understand factors associated with early opioid provision after a LBP workersâ compensation claim and their relationship with work disability. A systematic review (Manuscript 1) found evidence of a positive association between early opioids and prolonged work disability for musculoskeletal disorders, but internal validity was jeopardized by exposure measurement and confounding biases. Informed by review findings, an historical cohort study was conducted of workersâ compensation claimants with LBP using dispensing data on LBP-indicated drug classes: opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), and skeletal muscle relaxants (SMRs). Opioids, NSAIDs, and SMRs were dispensed to 19.7%, 21.2%, and 6.3% of claimants, respectively, one year pre-injury, and 39.0%, 50.2%, and 28.4% one year post-injury (Manuscript 2). Dispensing was stable pre-injury, increased within eight weeks post-injury, and declined thereafter, although not to pre-injury levels. A small subgroup demonstrated prolonged dispensing, suggesting delayed recovery. Claimant factors associated with early post-injury dispensing included pre-injury days supplied with the three drug classes, prior adjuvant medication dispenses, diagnosis, prior health care, age, sex, and occupation (Manuscript 3). Prescriber sex, birth year, and specialty were associated with drug class(es) at first prescription and the prescriber accounted for 25-36% of outcome variability. Examining the relationship between these drug classes dispensed within eight weeks post- injury and wage replacement benefits after eight weeks (Manuscript 4) revealed claimants receiving opioids, particularly with NSAIDs and/or SMRs, were more likely to receive benefits compared to NSAIDs/SMRs only. Strong and weak opioid combinations and days supply for all classes were positively associated with receiving benefits. There is evidence of increased opioid, NSAID, and SMR dispensing within eight weeks of a LBP claim. Early dispensing is multifactorial and prescribers play a role in dispensing variation. Early opioids compared to NSAIDs/SMRs appear to confer a greater risk of work disability. Methodological strengths include capturing pre-injury factors and all prescriptions and partially addressing confounding by indication/severity. However, residual confounding remains concerning. Consideration of severity, prescriber, and system/workplace measures is needed to advance understanding of opioid use for LBP and work disability.
Source: TSpace (University of Toronto)
Author: Nancy Carnide
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W3035196196