Prescription Dispensing Patterns Before and After a Workers' Compensation Claim: An Historical Cohort Study of Workers With Low Back Pain Injuries in British Columbia

Association Between Pre-Injury Opioid Use and Opioid Use Patterns After a Work Injury

BACKGROUND

Few studies have assessed long-term opioid prescribing after a work-related injury. There is limited information about opioid prescriptions before an injury and how receipt of opioids before a work injury is associated with long-term opioid prescribing. We present patterns of long-term opioid prescription among workers after an injury, overall, and by pre-injury opioid use.

METHODS

We used linked workers' compensation and prescription drug monitoring program (PDMP) data to identify workers injured between July 2019 and June 2020 with an opioid prescription dispensed within 6 weeks after injury. Opioid prescribing was assessed for the 3 months before injury and for 1 year after injury or claim closure, whichever came first.

RESULTS

Among injured workers with an opioid in the first 6 weeks, 23% had opioids 6-12 weeks after injury, 19% had opioids 3-6 months, 14% had opioids 6-9 months, and 12% had opioids 9-12 months after injury; 19% had opioids in the 3 months before injury. For workers with opioid prescription prior to injury, the percentage with opioids 9-12 months after injury was 34%, versus 7% among workers with no opioids in the 3 months before injury (p < 0.001). Receipt of chronic opioids (for at least 60 days) 9-12 months after injury was substantially higher among those with prior opioid prescription (20%) than in those with no prior opioids (0.4%) (p < 0.001).

CONCLUSIONS

We found a strong relationship between opioid prescription in the 3 months before a work injury and opioid prescribing after an injury. Healthcare providers should be vigilant to the important relationship between prior opioid use and longer-term opioid use after work-related injuries.

Secular trends in gabapentinoid dispensing by compensated workers with low back pain: a retrospective cohort study

OBJECTIVES

The increase in gabapentinoid prescribing is paralleling the increase in serious harms. To describe the low back pain workers compensation population whose management included a gabapentinoid between 2010 and 2017, and determine secular trends in, and factors associated with gabapentinoid use.

METHODS

We analysed claim-level and service-level data from the Victorian workers' compensation programme between 1 January 2010 and 31 December 2017 for workers with an accepted claim for a low back pain injury and who had programme-funded gabapentinoid dispensing. Secular trends were calculated as a proportion of gabapentinoid dispensings per year. Poisson, negative binomial and Cox hazards models were used to examine changes over time in incidence and time to first dispensing.

RESULTS

Of the 17 689 low back pain claimants, one in seven (14.7%) were dispensed at least one gabapentinoid during the first 2 years (n=2608). The proportion of workers who were dispensed a gabapentinoid significantly increased over time (7.9% in 2010 to 18.7% in 2017), despite a reduction in the number of claimants dispensed pain-related medicines. Gabapentinoid dispensing was significantly associated with an opioid analgesic or anti-depressant dispensing claim, but not claimant-level characteristics. The time to first gabapentinoid dispensing significantly decreased over time from 311.9 days (SD 200.7) in 2010 to 148.2 days (SD 183.1) in 2017.

CONCLUSIONS

The proportion of claimants dispensed a gabapentinoid more than doubled in the period 2010-2017; and the time to first dispensing halved during this period.

Impact of reported NSAID "allergies" on opioid use disorder in back pain

BACKGROUND

It is crucial to identify patients at highest risk for opioid use disorder (OUD) and to address challenges in reducing opioid use. Reported nonsteroidal anti-inflammatory drug (NSAID) allergies may predispose to use of stronger pain medications and potentially to OUD.

OBJECTIVE

We sought to investigate the clinical impact of reported NSAID allergy on OUD in patients with chronic back pain.

METHODS

We conducted a retrospective study of adults receiving care at a tertiary health care system from January 1, 2013, to December 31, 2018. Back pain and OUD were identified using administrative data algorithms. We used propensity score matching and logistic regression to estimate the impact of self-reported NSAID adverse drug reactions (ADRs) on risk of OUD, adjusting for other relevant clinical information.

RESULTS

Of 47,114 patients with chronic back pain, 3,620 (7.7%) had a reported NSAID ADR. In an adjusted propensity score-matched analysis, patients with NSAID ADRs had higher odds (odds ratio, 1.34; 95% CI, 1.07-1.67) of developing OUD as compared with those without NSAID ADRs. Additional risk factors for OUD included younger age, male sex, Medicaid insurance, Medicare insurance, higher number of inpatient and outpatient visits in the previous year, and comorbid anxiety and depression. Patients with listed NSAID ADRs also had higher odds of a documented opioid prescription during the study period (odds ratio, 1.22; 95% CI, 1.11-1.34).

CONCLUSIONS

Adults with chronic back pain and reported NSAID ADRs are at a higher risk of developing OUD and receiving opioid analgesics, even after accounting for comorbidities and health care utilization. Allergy evaluation is critical for potential delabeling of patients with reported NSAID allergies and chronic pain.

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.

The impact of income support systems on healthcare quality and functional capacity in workers with low back pain: a realist review

Low back pain (LBP) is a leading cause of work disability. While absent from work, workers with LBP may receive income support from a system such as workers' compensation or social security. This study examines how and in what contexts income support systems impact the healthcare quality for people with work disability and LBP and their functional capacity. We performed a realist review. Five initial theories about the relationship between income support systems and outcomes were developed, tested, and refined by acquiring and synthesising academic literature from purposive and iterative electronic database searching. This process was supplemented with gray literature searches for policy documents and semistructured interviews with experts in income support, health care, and LBP. Income support systems influence healthcare quality through funding restrictions, healthcare provider administrative burden, and allowing employers to select providers. They also influence worker functional capacity through the level of participation and financial incentives for employers, measures to prove the validity of the worker's LBP, and certain administrative procedures. These mechanisms are often exclusively context-dependent, and generate differing and unintended outcomes depending on features of the healthcare and income support system, as well as other contextual factors such as socioeconomic status and labour force composition. Research and policy design should consider how income support systems may indirectly influence workers with LBP through the workplace.

Relationship between early prescription dispensing patterns and work disability in a cohort of low back pain workers' compensation claimants: a historical cohort study

Objectives

To examine and compare whether dispensing of prescription opioids, non-steroidal anti-inflammatory drugs (NSAIDs) and skeletal muscle relaxants (SMRs) within 8 weeks after a work-related low back pain (LBP) injury is associated with work disability.

Methods

A historical cohort study of 55 571 workers’ compensation claimants with LBP claims in British Columbia from 1998 to 2009 was conducted using linked compensation, dispensing and healthcare data. Four exposures were constructed to estimate the effect on receipt of benefits and days on benefits 1 year after injury: drug class(es) dispensed, days' supply, strength of opioids dispensed and average daily morphine-equivalent dose.

Results

Compared with claimants receiving NSAIDs and/or SMRs, the incidence rate ratio (IRR) of days on benefits was 1.09 (95% CI 1.04 to 1.14) for claimants dispensed opioids only and 1.26 (95% CI 1.22 to 1.30) for claimants dispensed opioids with NSAIDs and/or SMRs. Compared with weak opioids only, the IRR for claimants dispensed strong opioids only or strong and weak opioids combined was 1.21 (95% CI 1.12 to 1.30) and 1.29 (95% CI 1.20 to 1.39), respectively. The incident rate of days on benefits associated with each 7-day increase in days supplied of opioids, NSAIDs and SMRs was 10%, 4% and 3%, respectively. Similar results were seen for receipt of benefits, though effect sizes were larger.

Conclusions

Findings suggest provision of early opioids leads to prolonged work disability compared with NSAIDs and SMRs, though longer supplies of all drug classes are also associated with work disability. Residual confounding likely partially explains the findings. Research is needed that accounts for prescriber, system and workplace factors.