This systematic review identified 11 harm reduction strategies for patients on long-term prescription opioids presenting to an ED with complications related to their opioid therapy. A pooled analysis of outcomes for “support for patients in pain” showed a clinically important decrease in the number of ED visits and ED discharge opioid prescriptions. Other harm reduction strategies could not be analyzed in a rigorous fashion and may be considered by healthcare providers until additional evidence becomes available.
Opioid use is an important and increasing problem in the US and Canada. Multiple harm reduction strategies for acute healthcare settings have been developed and studied, but the evidence had not been collated for an assessment of their impact. Most of the harm reduction strategies identified were from small, single center studies, were too heterogeneous to be meta-analyzed, or were infrequently studied (Table 4). While most reported positive results, a number of these are single-center studies with a small number of patients. These small studies often lack the scientific rigor or external validity to allow meaningful interpretation in a larger context, and to support widespread changes in practice (33).
We identified multiple studies with enough data to perform a meta-analysis for outcomes of the “supports for patient in pain” strategy (Table 4 for definitions). These studies were chosen due to their similarity in the coordinated care models used and the target populations. There was a clinically important decrease in system-related outcomes of ED visits and ED discharge opioid prescriptions for this strategy. For both outcomes, 3 RCTs were included, with the most compelling data for ED visits due statistical significance and uniform data (I2 0%), while ED discharge opioid prescriptions were significant but showed substantial heterogeneity (I2 87%). The ED visits outcome was also supported by the meta-analysis of cohort studies that all trended in the same direction despite substantial heterogeneity (I2 87%). Across all studies, there were only four instances of patient-related outcomes being evaluated. In these cases, the decrease in system-related outcomes were associated with unfavorable patient-related outcomes. Faryar et al. and Fulton-Kehoe respectively showed an increase in heroin use and methadone poisonings as the number of opioid prescriptions and poisonings decreased (34,35). Alexandridis et al. was the only study with a favourable patient-related outcome, demonstrating lower overdose mortality related to healthcare professional education, but as a whole did not change the rate of ED visits (11). This highlights concerns by experts that harm reduction strategies that focus on decreasing opioid prescriptions might actually contributed to unanticipated increases in avoidable deaths and overdoses (36) as patients seek out non-prescribed opioids to replace the previously prescribed opioids. The outcomes meta-analyzed may thus represent a poor proxy for appropriately impactful harm reduction strategies.
The other harm reduction strategies listed in Table 4 represent a combination of frequently recurring well-defined harm reduction strategies as well as composite terms representing harm reduction strategies referred to with different names across studies. This was determined through careful review of the detailed intervention performed in each study in order to reclassify them under umbrella headings. Unfortunately, precise definitions for each harm reduction strategy identified were not present in most studies. This limits our ability to both have homogeneous interventions under each harm reduction strategy. As such, based on the analysis of the interventions performed, most studies have multiple simultaneous harm reductions strategies employed. Accordingly, this limits the rigorous analysis of each harm reduction strategy independently.
In a similar fashion, there are no comparative studies of harm reduction strategies to inform which strategies may be superior, in which specific context, and where to direct organization and resources. Alexandridis et al. was the only study to include multiple well-differentiated strategies but analyzed them as independent variables despite a simultaneous implementation (11). However, identifying a superior strategy may be of limited importance, as statistical superiority does not necessarily reflect the clinical reality in these complex patients. Indeed, the most appropriate strategy depends on multiple local factors such as individual patient’s specific needs and availability as well as access to resources. This highlights the complexity of assessing these process of care interventions for successful implementation and effectiveness of intervention. Such interventions may not lead to statistical or clinical significance in traditional outcomes (i.e., mortality) but have wider ranging benefits in care processes, workflow and resource optimization, as in the case and wide adoption of medical emergency teams (MET) (37).
Strengths and limitations
While this study had several important strengths (i.e., breadth of scope, rigorously pre-defined methodology stretching across several medical domains, presence of patient advisors), several important limitations warrant discussion. First, important terms (i.e., long-term medical opioid therapy, opioid ‘abuse’ and misuse, harm reduction strategies) were heterogeneously defined across studies and may have been a barrier to study identification. Most importantly, the harm reduction strategies were overall poorly defined across studies. Despite a careful analysis of the interventions in order to regroup or reclassify them under umbrella terms, it was difficult to clearly identify separate harm reduction strategies in some studies. Accordingly, these studies then often used multiple harm reduction strategies simultaneously, which significantly limited our ability to have a rigorous analysis. This is reflected in the meta-analysis where the most important harm reduction strategy was analyzed, acknowledging that it may not be fully separated from other minor elements of the intervention that may be classified under another umbrella term. We attempted to mitigate these factors by independent screening by two authors to ensure the inclusion of all relevant studies and appropriately classify the harm reduction strategies. Second, the rate of study inclusion was only 0.4%. This was secondary to most identified studies either studied illicit drug use or did not adequately differentiate between illicit drug use and opioid misuse, or poorly defined their population. When unclear following full-text review of the relevant publications, we erred to exclude studies from this review, hence focusing the findings of this review to those patients on prescribed opioid therapy. Third, the wide scope of some harm reduction strategies lead to difficult decisions for study inclusion. Indeed, a number of harm reductions were part of a package organized at a state level. It was difficult to separate the specific impact of each strategy, the impact on acute versus non-acute healthcare settings and to discern which studies dealt with patients on appropriate long-term opioid therapy. In these situations, we opted to include these state level studies if there was a well-described significant proportion of long-term opioid users, and if number of acute healthcare presentations was an outcome of interest. We do acknowledge that these studies reflect a very heterogeneous group in a lot of instances and limit the validity of the findings. This is not reflected well in the quality assessment of the cohort study who are technically for the most part of moderate to high methodological quality. The RCTs are for their part paradoxically at moderate to high risk of bias due to their design but represent a more homogeneous population. Fourth, most identified studies were from the US, limiting the generalizability of our findings to other jurisdictions that may have different policies and context that affect the outcomes of the identified harm reduction strategies. This is not surprising as the opioid epidemic was first recognized in the US, and many findings in the US are applicable across Canada and other high-income countries(1). Finally, while we decided to include studies from 1996, all of the studies included are from the last 15 years. This is likely explained by the delayed recognition of the public health crisis from the opioid epidemic.
Future directions
Our systematic review revealed that most of the studies have targeted patients presenting to the ED, with very little data on inpatient harm reduction strategies. This knowledge gap is reflected in the most recent Canadian guidelines for opioid use for chronic non-cancer pain, which do not address acute admissions in this population (38). These guidelines do reflect the importance of a multidisciplinary approach in the chronic non-cancer pain population, which would be similar to the “supports for patient in pain” harm reductions strategy. Studying this harm reduction strategy for non-ED acute healthcare settings would strengthen the current body of evidence. Importantly, studying these strategies using patient-related outcomes such as mortality, quality of life and pain is of paramount importance, as opioid prescriptions and ED visits appear to be poor or misleading surrogate endpoints. Future policy work informed by these results would lead to better resource utilization through a shift from reactionary processes (i.e., ED visits) to preventative strategies that prevent acute healthcare presentations.