Trends in chronic opioid use and association with five-year survival in South Korea: a population-based cohort study

Long-term use of prescription opioids for non-cancer pain and mortality: a population-based, propensity-weighted cohort study

OBJECTIVE

The objective of this study was to identify factors associated with long-term opioid use and to assess the association between long-term use and death.

STUDY DESIGN

Retrospective cohort study combining several population-wide databases and covering a population of five million inhabitants, including all adults who were initiated on opioid treatment from 2014 to 2018 for non-cancer pain.

METHODS

We used logistic regression models to identify factors associated with chronic opioid use and carried out survival analyses using multivariable Cox regression modelling for all-cause mortality during follow-up using inverse probability of treatment weighting (IPTW) and propensity scores based on the probability of using opioids chronically.

RESULTS

Among 760,006 patients, 82,423 (10.85%) used opioids for 90 days or more after initiation. Initial therapy characteristics associated with higher risk for long-term use were initiating with long- and short-acting opioids (when compared to tramadol, odds ratio [OR]: 2.63, 95% confidence interval [CI]: 2.57, 2.69 and OR: 1.60, 95%CI: 1.46, 1.76, respectively), using higher daily doses (when compared to 50 morphine milligramme equivalent [MME] or less, prescribing 50 to 89 daily MME, OR: 1.76, 95%CI: 1.65, 1.87; 90 to 119 daily MME, OR: 2.44, 95%CI: 1.99, 3.01; and more than 120 daily MME, OR: 1.77, 95%CI: 1.64, 1.91), and overlapping with gabapentinoids (OR: 2.26, 95%CI: 2.20, 2.32), benzodiazepines (OR: 1.32, 95%CI: 1.30, 1.35), and antipsychotics (OR: 1.21, 95%CI: 1.16, 1.26). After IPTW, chronic opioid use was associated with higher risk of all-cause mortality when compared to short-term use (Hazard Ratio (HR): 1.37, 95%CI: 1.32, 1.42). Sensitivity analyses provided similar results.

CONCLUSION

These findings may help healthcare managers to identify and address patients at higher risk of long-term use and riskier prescription patterns.

Opioid Prescription and Long-Term Survival Outcomes in Adults: A Nationwide Cohort Study in Korea

BACKGROUND

We aimed to investigate the association between short- and long-term opioid use and long-term mortality in Korea.

METHODS

In this population-based retrospective cohort study, data were obtained from the National Health Insurance Service of South Korea. The study included all adult individuals who were prescribed opioids in 2016. The control group comprised adults not prescribed opioids in 2016 selected using a 1:1 stratified random sampling technique. Participants were categorized into three groups: non-user, opioid 1-89 days user (short-term), and opioid ≥ 90 days user (long-term) groups. The primary endpoint in this study was 5-year all-cause mortality, evaluated from January 1, 2017 to December 31, 2021.

RESULTS

In total, 4,556,606 adults were included in this study. Of these, 2,070,039 were prescribed opioids at least once. Specifically, 1,592,883 adult individuals were prescribed opioids for 1-89 days, while 477,156 adults were prescribed opioid for ≥ 90 days. In the multivariable Cox regression modelling, the opioid user group had a 28% (hazard ratio [HR], 1.28; 95% confidence interval [95% CI], 1.26-1.29; P < 0.001) higher risk of 5-year all-cause mortality than had the non-user group. Moreover, the opioid 1-89 days and opioid ≥ 90 days user groups had 15% (HR, 1.15; 95% CI, 1.14-1.17; P < 0.001) and 49% (HR, 1.49; 95% CI, 1.47-1.51; P < 0.001) higher risks of 5-year all-cause mortality than had the non-user group, respectively.

CONCLUSION

Both short and long-term opioid prescriptions were associated with increased long-term mortality among the Korean adult population.

Efficacy of high-voltage, long-duration pulsed radiofrequency for the treatment of acute herpes zoster-related trigeminal neuralgia in a patient with permanent pacemaker

Background

Recognizing the seriousness of the misuse and abuse of medical narcotics, the South Korean government introduced the world's first narcotic management system, the Narcotics Information Management System (NIMS). This study aimed to explore the recent one-year opioid prescribing patterns in South Korea using the NIMS database.

Methods

This study analyzed opioid prescription records in South Korea for the year 2022, utilizing the dispensing/administration dataset provided by NIMS. Public data from the Korean Statistical Information Service were also utilized to explore prescription trends over the past four years. The examination covered 16 different opioid analgesics, assessed by the total number of units prescribed based on routes of administration, type of institutions, and patients’ sex and age group. Additionally, the disposal rate for each ingredient was computed.

Results

In total, 206,941 records of 87,792,968 opioid analgesic units were analyzed. Recently, the overall quantity of prescribed opioid analgesic units has remained relatively stable. The most prescribed ingredient was oral oxycodone, followed by tapentadol and sublingual fentanyl. Tertiary hospitals had the highest number of dispensed units (49.4%), followed by community pharmacies (40.2%). The highest number of prescribed units was attributed to male patients in their 60s. The disposal rates of the oral and transdermal formulations were less than 0.1%.

Conclusions

Opioid prescription in South Korea features a high proportion of oral formulations, tertiary hospital administration, pharmacy dispensing, and elderly patients. Sustained education and surveillance of patients and healthcare providers is required.

Development and validation of a predictive model for persistent opioid use in new opioid analgesic users via a nationwide claims database

BACKGROUND

Chronic opioid use is associated with problematic opioid use, such as opioid abuse. It is important to develop a prediction model for safe opioid use. In this study, we aimed to develop and validate a risk score model for chronic opioid use in opioid-naïve, noncancer patients, using data from a nationwide database.

METHODS

Data from the National Health Insurance Claims Database in the Republic of Korea from 2016 to 2018 were used, and adult, noncancer patients who were started on non-injectable opioid analgesics (NIOAs) were included. The risk score model was developed using the β coefficient of each variable in the multivariable logistic regression analysis.

RESULTS

Overall, 676,676 noncancer patients were started on NIOAs, of which 65,877 (9.7%) were prescribed NIOAs chronically. Age, baseline healthcare utilization, comorbidities, co-medications, and pattern of first NIOA prescription were identified as risk factors for chronic opioid use. The c-static for the performance of our risk score model was 0.754 (95% confidence interval, 0.750-0.758).

CONCLUSION

To our knowledge, this is the first tool that can predict chronic opioid use in the Korean population. The model can help physicians examine the risk of chronic opioid use by patients who are started on NIOA.

Impact of the Narcotics Information Management System on Opioid Use Among Outpatients With Musculoskeletal and Connective Tissue Disorders: Quasi-Experimental Study Using Interrupted Time Series

BACKGROUND

Opioids have traditionally been used to manage acute or terminal pain. However, their prolonged use has the potential for abuse, misuse, and addiction. South Korea introduced a new health care IT system named the Narcotics Information Management System (NIMS) with the objective of managing all aspects of opioid use, including manufacturing, distribution, sales, disposal, etc.

OBJECTIVE

This study aimed to assess the impact of NIMS on opioid use.

METHODS

We conducted an analysis using national claims data from 45,582 patients diagnosed with musculoskeletal and connective tissue disorders between 2016 and 2020. Our approach included using an interrupted time-series analysis and constructing segmented regression models. Within these models, we considered the primary intervention to be the implementation of NIMS, while we treated the COVID-19 outbreak as the secondary event. To comprehensively assess inappropriate opioid use, we examined 4 key indicators, as established in previous studies: (1) the proportion of patients on high-dose opioid treatment, (2) the proportion of patients receiving opioid prescriptions from multiple providers, (3) the overlap rate of opioid prescriptions per patient, and (4) the naloxone use rate among opioid users.

RESULTS

During the study period, there was a general trend of increasing opioid use. After the implementation of NIMS, significant increases were observed in the trend of the proportion of patients on high-dose opioid treatment (coefficient=0.0271; P=.01) and in the level of the proportion of patients receiving opioid prescriptions from multiple providers (coefficient=0.6252; P=.004). An abrupt decline was seen in the level of the naloxone use rate among opioid users (coefficient=-0.2968; P=.04). While these changes were statistically significant, their clinical significance appears to be minor. No significant changes were observed after both the implementation of NIMS and the COVID-19 outbreak.

CONCLUSIONS

This study suggests that, in its current form, the NIMS may not have brought significant improvements to the identified indicators of opioid overuse and misuse. Additionally, the COVID-19 outbreak exhibited no significant influence on opioid use patterns. The absence of real-time monitoring feature within the NIMS could be a key contributing factor. Further exploration and enhancements are needed to maximize the NIMS' impact on curbing inappropriate opioid use.

Trends in Healthy Life Expectancy (HALE) and Disparities by Income and Region in Korea (2008-2020): Analysis of a Nationwide Claims Database

BACKGROUND

Healthy life expectancy is a well-recognized indicator for establishing health policy goals used in Korea's Health Plan. This study aimed to explore Koreans' healthy life expectancy and its gender, income, and regional disparities from 2008 to 2020.

METHODS

This study was conducted on the entire population covered by health insurance and medical aid program in Korea. The incidence-based "years lived with disability" for 260 disease groups by gender, income level, and region was calculated employing the methodology developed in the Korean National Burden of Disease Study, and it was used as the number of healthy years lost to calculate health-adjusted life expectancy (HALE).

RESULTS

Koreans' HALE increased from 68.89 years in 2008 to 71.82 years in 2020. Although the gender disparity in HALE had been decreasing, it increased to 4.55 years in 2020. As of 2020, 5.90 years out of 8.67 years of the income disparity (Q5-Q1) in HALE were due to the disparity between Q1 and Q2, the low-income groups. Income and regional disparities in HALE exhibited an increasing trend, and these disparities were higher in men than in women.

CONCLUSION

A subgroup with a low health level was identified through the HALE results, and it was confirmed that improving the health level of this population can reduce health inequalities and improve health at the national level. Further exploration of the HALE calculation methodology may help in the development of effective policies such as prioritizing interventions for health risk factors.

Impact of prescribed opioid use on development of dementia among patients with chronic non-cancer pain

We aimed to examine the association between opioid use and the development of dementia in patients with chronic non-cancer pain in South Korea. Data were extracted from the National Health Insurance Service database in South Korea. Adult patients diagnosed with musculoskeletal diseases with chronic non-cancer pain between 2010 and 2015 were included in the analysis. Patients who were prescribed opioids regularly and continuously for ≥ 90 days were classified as opioid users. In total, 1,261,682 patients with chronic non-cancer pain were included in the final analysis, of whom 21,800 (1.7%) were opioid users. From January 1, 2016 to December 31, 2020, 35,239 (2.8%) patients with chronic non-cancer pain were newly diagnosed with dementia. In the multivariable model, opioid users showed a 15% higher risk of developing dementia than the control group. Additionally, opioid users showed a 15% and 16% higher risk of developing Alzheimer's disease and unspecified dementia, respectively, than the control group, but did not show any significant differences for vascular dementia. Among adult patients with chronic non-cancer pain, opioid users were at a higher risk of developing dementia than the control group; the risk was significantly higher for Alzheimer's disease but not for vascular dementia in this study. Our results suggest that in patients with CNCP, public health strategies should target opioid users for early dementia detection and intervention.

Bibliometric Analysis of Research Articles on Virtual Reality in the Field of Pain Medicine Published from 1993 to 2022

Purpose

This study aims to analyze global and regional (China, Japan, and South Korea) research on virtual reality (VR) in the field of pain medicine over the past 30 years. Specifically, we quantify VR-related publications, examine the distribution of research topics on chronic and acute pain, and identify trends and future directions.

Methods

The Web of Science Core Collection (WoSCC) database was used for bibliometric analysis. This study included articles written in English between 1993 and 2022. The search strategy used predefined terms related to VR and pain. Based on the articles' titles and abstracts, two pain physicians independently reviewed and classified them as acute or chronic pain. Quantitative data on countries, institutions, journals, and research categories were analyzed. VOSviewer software was used for keyword mapping and clustering.

Results

We analyzed 808 VR-related articles on pain medicine. Over the past three decades, the number of publications in this field has increased steadily. The United States of America (n = 259) had the highest number of publications. Moreover, China (n = 42), Japan (n = 18), and South Korea (n = 24) also contributed continuously. Acute and chronic pain research accounted for 44.2% and 37.9% of the articles, respectively. The most common acute pain topic was procedure-related (n = 129, 16.0%), whereas the most common chronic pain topic was neuropathic (n = 104, 12.9%). Keywords clustered around neuroscience, pediatric pain management, and chronic pain management.

Conclusion

Our study revealed academic achievements and growing interest in VR-related research in pain medicine. Researchers worldwide have shown balanced interest in applying VR technology to acute and chronic pain, with specific contributions from China, Japan, and South Korea. Harnessing VR technology is promising for improving pain management and enhancing patients' quality of life in the field of pain medicine.

The Effects of Intraoperative Remifentanil Infusion on Postoperative Opioid Consumption in Patients Who Underwent Total Knee Arthroplasty with Femoral Nerve Block

(1) Background: Remifentanil is used for intraoperative pain control; however, it has several side effects, such as hypotension and opioid-induced hyperalgesia. We aimed to determine whether an intraoperative remifentanil infusion may increase postoperative opioid consumption in patients undergoing total knee arthroscopy (TKA) under femoral nerve block (FNB) in addition to general anesthesia. (2) Methods: We randomly assigned 66 patients who underwent total knee arthroplasty to the remifentanil (R) and control (C) groups. All patients underwent FNB and popliteal artery and posterior capsule of the knee (iPACK) block in addition to sevoflurane-based general anesthesia. Postoperative pain control was achieved using intravenous patient-controlled analgesia (IV-PCA) fentanyl. We recorded IV-PCA fentanyl consumption at various postoperative timepoints, numerical rating scale (NRS) scores, intraoperative changes in vital signs and index of nociception (qNOX), ephedrine consumption, postoperative side effects, satisfaction, and sleep quality. (3) Results: The primary outcome (the cumulative IV-PCA fentanyl usage within 48 h postoperatively) was significantly lower in the C group (541.1 ± 294.5 µg) than in the R group (717.5 ± 224.0 µg) (p < 0.001). The secondary outcome (the cumulative IV-PCA fentanyl usage within 12, 24, and 72 h) was lower in the C group than in the R group and the mean arterial pressure was lower in the R group than in the C group from immediately after tourniquet on to immediately after tourniquet off. The heart rate was lower in the R group from immediately after incision to immediately after irrigation. There was no significant between-group difference in the perioperative qNOX and NRS scores at rest and activity except for NRS scores at 72 h postoperatively. Ephedrine use was higher in the R group than in the C group (p = 0.003). There was no significant between-group difference in the incidence of postoperative nausea and vomiting, nor in the postoperative satisfaction and sleep quality. (4) Conclusions: Avoiding intraoperative remifentanil infusion may reduce total opioid consumption in patients undergoing FNB before TKA.

Risk Factors for Emergency Department Presentations after the Initiation of Opioid Analgesics in Non-Cancer Patients in Korea: A Nationwide Study

Background and Objectives: Opioid use in Korea is lower than in other developed countries. However, recent studies have reported an increase in opioid prescriptions and the number of chronic opioid users. The current status of adverse events (AEs) associated with opioid analgesics in Korea is unclear. This nested case–control study aimed to evaluate the influence of opioid analgesic use patterns on all emergency department (ED) visits and opioid-related ED visits after opioid analgesic initiation using the national claims database. Materials and Methods: Adult non-cancer patients who initiated non-injectable opioid analgesics (NIOA) between January 2017 and June 2018 were included. We defined the case group as patients who visited the ED within six months of opioid initiation, and the control group was selected in a 1:1 ratio using an exact matching method. Results: A total of 97,735 patients (13.58%) visited the ED within six months of NIOA initiation. Nearly 32% of cases were linked to opioid-related AEs. The most frequent AEs were falls and fractures (61.27%). After adjusting for covariates, opioid initiation at the ED was associated with all-cause or opioid-related ED visits (adjusted odds ratio (aOR) = 3.19, 95% confidence interval (CI) = 3.09–3.29; aOR = 3.82, 95% CI = 3.62–4.04, respectively). Chronic NIOA use was associated with all-cause and opioid-related ED visits (aOR = 1.32, 95% CI = 1.23–1.40; aOR = 1.56, 95% CI = 1.39–1.76, respectively). Conclusion: This study found that 13% of non-cancer patients visited the ED within six months of NIOA initiation. In addition, the NIOA use pattern was significantly associated with all-cause and opioid-related ED visits.

A population-based study on the risk of prescription opioid abuse in patients with chronic opioid use and cost-effectiveness of prescription drug monitoring program using a patient simulation model in South Korea

BACKGROUND

Concerns regarding the burden of inappropriate opioid use are growing. We examined the association between prescription opioid abuse and patient characteristics and estimated the cost-effectiveness of the prescription drug monitoring program (PDMP) implemented in South Korea, considering patient-level information.

METHODS

A retrospective cohort study was conducted to explore the association between opioid abuse and patient characteristics using the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database. We selected non-cancer patients with chronic opioid use and investigated the incidence of opioid abuse between 2010 and 2015. The association between opioid abuse and patient characteristics was assessed using the Cox proportional hazards model. The cost-effectiveness of the PDMP was assessed using discrete event simulation (DES) with a time horizon of 30 years from a societal perspective. Time-to-event data and event costs were obtained from the NHIS-NSC database. The abuse rate was adjusted for each patient based on the baseline characteristics and history of abuse experienced in the model. Program effectiveness, program costs, and health-state utilities were obtained from the published literature. The incremental cost-utility ratio (ICUR) was estimated at a discount rate of 5% for both costs and quality-adjusted life-years (QALYs).

RESULTS

We identified 22,524 patients with chronic opioid use in the NHIS-NSC database. Every one-year increase in age (hazard ratio: 1.002 [95% CI: 1.000-1.003]), medical aid program (1.130 [95% CI: 1.072-1.191]), high Charlson Comorbidity Index (1.054 [95% CI: 1.044-1.065]), and history of opioid abuse (1.501 [95% CI: 1.391-1.620] and 3.005 [95% CI: 2.387-3.783] for 1-2 and ≥3 abuse events, respectively) significantly increased the risk of opioid abuse. In the DES, the PDMP was cost-effective, with an estimated ICUR of $2,227/QALY, which was most affected by the program's effectiveness.

CONCLUSION

Patient characteristics and history of opioid abuse affected the risk of opioid abuse. Considering patient-level information, the PDMP implemented in South Korea is likely to be cost-effective.

Actual situation and prescribing patterns of opioids by pain physicians in South Korea

Background

Use of opioids for chronic intractable pain is increasing globally, and their proper use can improve patients’ quality of life. In contrast, opioid use disorders, such as abuse or addiction, caused by prescribing opioids, are a worldwide issue. This study aimed to understand current opioid prescribing patterns and pain physicians’ experiences with opioid use in South Korea.

Methods

Pain physicians in 42 university hospitals in South Korea were asked to complete anonymous questionnaires regarding opioid prescriptions.

Results

A total of 69 surveys were completed. Most pain physicians started prescribing opioids at a pain score of 7/10 and aimed to reduce pain by 50%. Most physicians (73.1%) actively explained the prescribed medications and possible side effects, and 61.2% of physicians preferred the prescription interval of 4 weeks. Immediate-release opioids were the most popular treatment for breakthrough pain (92.6%). The most common side effect encountered by physicians was constipation (43.3%), followed by nausea/vomiting (34.3%). Of the physicians, 56.5% replied that addiction and misuse prevalences were less than 5%. However, the most concerning side effect was addiction (33.0%).

Conclusions

The survey results showed that the prescribing patterns of pain physicians generally followed Korean guidelines. Physicians were most interested in the safety and effectiveness of opioid prescriptions. They were most concerned about respiratory depression and abuse or addiction. A significant number of physicians agreed that the NHIS regulations needed improvement for patient convenience and safe and effective treatment, though there were pros and cons of the NHIS restrictions on prescription conditions.

Prevention, diagnosis, and treatment of opioid use disorder under the supervision of opioid stewardship programs: it's time to act now

The third opium war may have already started, not only due to illicit opioid trafficking from the Golden Crescent and Golden Triangle on the international front but also through indiscriminate opioid prescription and opioid diversion at home. Opioid use disorder (OUD), among unintentional injuries, has become one of the top 4 causes of death in the United States (U.S.). An OUD is defined as a problematic pattern of opioid use resulting in clinically significant impairment or distress, consisting of 2 or more of 11 problems within 1 year, as described by the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition. Observation of aberrant behaviors of OUD is also helpful for overworked clinicians. For the prevention of OUD, the Opioid Risk Tool and the Current Opioid Misuse Measure are appropriate screening tests before and during opioid administration, respectively. Treatment of OUD consists of 3 opioid-based U.S. Food and Drug Administration-approved medications, including methadone, buprenorphine, and naltrexone, and non-opioid-based symptomatic medications for reducing opioid withdrawal syndromes, such as α2 agonists, β-blockers, antidiarrheals, antiemetics, non-steroidal anti-inflammatory drugs, and benzodiazepines. There are at least 6 recommendable guidelines and essential terms related to OUD. Opioid stewardship programs are now critical to promoting appropriate use of opioid medications, improving patient outcomes, and reducing misuse of opioids, influenced by the successful implementation of antimicrobial stewardship programs. Despite the lack of previous motivation, now is the critical time for trying to reduce the risk of OUD.

Reductions in All-Cause Mortality Associated with the Use of Methylnaltrexone for Opioid-Induced Bowel Disorders: A Pooled Analysis

OBJECTIVE

Preclinical and clinical studies suggest that activation of the µ-opioid receptor may reduce overall survival and increase the risk for all-cause mortality in patients with cancer and noncancer pain. Methylnaltrexone, a selective, peripherally acting µ-opioid receptor antagonist, has demonstrated efficacy for the treatment of opioid-induced constipation. This retrospective analysis of 12 randomized, double-blind, placebo-controlled studies of methylnaltrexone evaluated the treatment of opioid-induced bowel disorders in patients with advanced illness or noncancer pain.

METHODS

The risk of all-cause mortality within 30 days after the last dose of study medication during the double-blind phase was compared between methylnaltrexone and placebo groups. The data were further stratified by cancer vs noncancer, age, gender, and acute vs chronic diagnoses.

RESULTS

Pooled data included 2,526 methylnaltrexone-treated patients of which 33 died, and 1,192 placebo-treated patients of which 35 died. The mortality rate was 17.8 deaths/100 person-years of exposure in the methylnaltrexone group and 49.5 deaths/100 person-years of exposure for the placebo group. The all-cause mortality risk was significantly lower among patients receiving methylnaltrexone compared with placebo (hazard ratio: 0.399, 95% confidence interval: 0.25, 0.64; P = .0002), corresponding to a 60% risk reduction. Significant risk reductions were observed for those receiving methylnaltrexone who had cancer or chronic diagnoses. Methylnaltrexone-treated patients had a significantly reduced mortality risk compared with placebo regardless of age or gender.

CONCLUSIONS

Methylnaltrexone reduced all-cause mortality vs placebo treatment across multiple trials, suggesting methylnaltrexone may confer survival benefits in patients with opioid-induced bowel disorders taking opioids for cancer-related or chronic noncancer pain.

Long-term opioid use and mortality in patients with chronic non-cancer pain: Ten-year follow-up study in South Korea from 2010 through 2019

BACKGROUND

We aimed to investigate the prevalence and factors associated with long-term opioid use among patients with chronic non-cancer pain (CNCP).

METHODS

We extracted data from the National Health Insurance Service (NHIS) database in South Korea. As a nationwide database, the NHIS database contains information regarding all disease diagnoses and prescriptions for any drug and/or procedures. A total of 2.5% of adult patients (≥20 years of age) who were diagnosed with musculoskeletal diseases and CNCP from 2010 to 2019 were selected using a stratified random sampling technique and included in the analysis. Patients who were prescribed opioids continuously for ≥90 days were classified as long-term opioid users.

FINDINGS

A total of 19,645,161 patients with CNCP were included in the final analysis. The prevalence of long-term opioid use was 0.47% (95% confidence interval [CI]: 0.46%, 0.48%; 8421/1,808,043) in 2010, which gradually increased to 2.63% (95% CI: 2.61%, 2.66%; 49,846/1,892,913) in 2019. Among the 2010 cohort (n = 1,804,019), in multivariable logistic regression: old age, underlying disability, increased Charlson comorbidity index, use of benzodiazepine or Z-drug, rheumatoid arthritis, osteoarthritis, and low back pain were associated with an increased prevalence of long-term opioid use among patients with CNCP. In a multivariable Cox regression, the 10-year all-cause mortality in long-term opioid users was found to be 1·21-fold (hazard ratio: 1.21, 95% CI: 1.13, 1.31; P<0·001) higher than that in opioid-naive patients with CNCP.

INTERPRETATION

Long-term opioid use increased in patients with CNCP in South Korea from 2010 to 2019. Certain factors were potential risk factors for long-term opioid use. Moreover, long-term opioid use was associated with increased 10-year all-cause mortality among patients with CNCP.

FUNDING

None.

Survey of Opioid Risk Tool Among Cancer Patients Receiving Opioid Analgesics

BACKGROUND

The risk of opioid-related aberrant behavior (OAB) in Korean cancer patients has not been previously evaluated. The purpose of this study is to investigate the Opioid Risk Tool (ORT) in Korean cancer patients receiving opioid treatment.

METHODS

Data were obtained from a multicenter, cross-sectional, nationwide observational study regarding breakthrough cancer pain. The study was conducted in 33 South Korean institutions from March 2016 to December 2017. Patients were eligible if they had cancer-related pain within the past 7 days, which was treated with strong opioids in the previous 7 days.

RESULTS

We analyzed ORT results of 946 patients. Only one patient in each sex (0.2%) was classified as high risk for OAB. Moderate risk was observed in 18 males (3.3%) and in three females (0.7%). Scores above 0 were primarily derived from positive responses for personal or familial history of alcohol abuse (in men), or depression (in women). In patients with an ORT score of 1 or higher (n = 132, 14%), the score primarily represented positive responses for personal history of depression (in females), personal or family history of alcohol abuse (in males), or 16-45 years age range. These patients had more severe worst and average pain intensity (proportion of numeric rating scale ≥ 4: 20.5% vs. 11.4%, P < 0.001) and used rescue analgesics more frequently than patients with ORT scores of 0. The proportion of moderate- or high-risk patients according to ORT was lower in patients receiving low doses of long-acting opioids than in those receiving high doses (2.0% vs. 6.6%, P = 0.031). Moderate or high risk was more frequent when ORT was completed in an isolated room than in an open, busy place (2.7% vs. 0.6%, P = 0.089).

CONCLUSIONS

The score of ORT was very low in cancer patients receiving strong opioids for analgesia. Higher pain intensity may associate with positive response to one or more ORT item.

Ultrasound-Guided Adductor Canal Block Versus Intraoperative Transarticular Saphenous Nerve Block: A Retrospective Analysis

BACKGROUND

The ultrasound-guided adductor canal block (High-ACB) is an effective option for pain control in total knee arthroplasty (TKA), but its use can add substantial cost and preparatory time to a TKA procedure. An intraoperative adductor canal block (Low-ACB) performed by the operative surgeon has been described as an alternative. The hypothesis of this study is that the Low-ACB would achieve noninferior pain control and opioid utilization postoperatively when compared to the High-ACB.

METHODS

This is a retrospective study of a prospectively maintained database comparing the High-ACB vs the Low-ACB. The primary outcome measure was morphine milligram equivalents consumed. Secondary outcome measures included Visual Analog Scale pain scores, postoperative outcomes (Patient-Reported Outcome Measurement Information System, Knee Injury and Osteoarthritis Outcome Score, knee range of motion), length of stay, postoperative speed of mobilization, and complications related to the type of block.

RESULTS

There were 139 patients in the study. There was lower opioid use in the first 24 hours in the Low-ACB compared to the High-ACB group respectively (26.3 vs 30, P = .29) but this did not reach statistical significance. There was a statistically significant difference in Visual Analog Scale score on postoperative day 1 in the Low-ACB vs High-ACB groups respectively (4.6 vs 3.7, P = .02) but this did not reach the level of clinical significance. There was no statistical difference in the Patient-Reported Outcome Measurement Information System, Knee Injury and Osteoarthritis Outcome Score, or postoperative range of motion. There were no block-related complications in either group.

CONCLUSION

The Low-ACB is a safe, effective, and cost-saving alternative to the traditional High-ACB for pain control in TKA.

Association between long-term opioid use and cancer risk in patients with chronic pain: a propensity score-matched cohort study

BACKGROUND

Whether long-term opioid use is an independent risk factor for cancer progression remains unclear. Therefore, we conducted a propensity score-matched population-based cohort study to compare cancer incidence between patients with chronic pain with and without opioid use.

METHODS

Data from January 2008 to December 2019 were obtained from the Taiwan National Health Insurance Research Database. Patients were categorised into two groups according to the presence or absence of opioid use, and matched at a 4:1 ratio. The incidence rate ratios for specific cancers were determined.

RESULTS

Propensity score-matching yielded 63 610 patients: 50 888 with opioid use (the opioid group) and 12 722 without (the non-opioid group). In a multivariate Cox regression analysis, the adjusted hazard ratio (95% confidence interval) for cancers in the opioid group compared with the non-opioid group was 2.66 (1.44-2.94; P<0.001). The incidence rate ratios (95% confidence interval) for lung, hepatocellular, colorectal, breast, prostate, head and neck, pancreatic, gastric, oesophageal, and ovarian cancers for the opioid group were 1.87 (1.41-2.43), 1.97 (1.56-2.50), 2.39 (1.87-3.03), 2.43 (1.75-3.33), 2.00 (1.35-3.03), 1.79 (1.14-2.86), 1.87 (1.13-2.12), 2.43 (1.52-3.85), 1.82 (0.92-3.70), and 2.33 (1.01-5.55), respectively.

CONCLUSION

There was an association between long-term opioid use and development of cancer in patients with chronic pain, which should be confirmed in future studies.

Trends in potentially inappropriate opioid prescribing and associated risk factors among Korean noncancer patients prescribed non-injectable opioid analgesics

Introduction

The aim of this study was to investigate trends in the prevalence of potentially inappropriate opioid prescribing (PIOP) and identify potential risk factors among Korean noncancer patients.

Methods

We conducted a cross-sectional study of annual national patient sample data from the Korean Health Insurance Review and Assessment Service (HIRA-NPS) for the period 2012-2018. Noncancer patients who were prescribed non-injectable opioid analgesics (NIOAs) at least once were included. The proportion of patients with at least one PIOP in terms of concurrent use of benzodiazepines or gabapentinoids, substance use disorder, treatment duration, and dosage was evaluated. Multivariable logistic regression was performed to identify the risk factors associated with PIOP.

Results

Of the 9,772,503 noncancer patients, 1,583,444 (16.2%) were prescribed NIOAs at least once. Among them, 15.7% were exposed to PIOP, and the prevalence was much higher (31.6%) in the elderly group (age: ⩾65 years). The prevalence of PIOP increased 1.1-fold over 7 years (14.8-16.8%) among the total NIOA users and was more pronounced in non-tramadol NIOA users (a 1.5-fold increase, from 13.2% to 19.4%). Multivariable logistic regression indicated that older age, beneficiaries of medical aid or national meritorious service, exposure to polypharmacy, psychological disorder, chronic pain indication, and concomitant sedative use were independently associated with higher odds of PIOP.

Discussion and Conclusion

We found that the prevalence of PIOP was 15.7% among Korean noncancer patients, and it increased over the 7-year study period. This increasing trend is alarming because it was more drastic with non-tramadol NIOAs compared with that with tramadol. Several patient-level risk factors associated with PIOP would be useful in targeted management strategies for the safe use of opioids.

Plain Language Summary

Potentially inappropriate opioid prescribing and related risk factors among noncancer patients prescribed non-injectable opioids in Korea In Korea, the prevalence of non-injectable opioid analgesic (NIOA) use in noncancer patients steadily increased from 15.3% in 2012 to 17.1% in 2018.Also, the prevalence of potentially inappropriate opioid prescribing (PIOP) increased from 14.8% in 2012 to 16.8% in 2018.The following factors were associated with a markedly increased risk of PIOP: age, beneficiaries of medical aid or national meritorious service, polypharmacy, psychological disorder, chronic pain, and concomitant medications.

Development and validation of a risk-score model for opioid overdose using a national claims database

Opioid overdose can be serious adverse effects of opioid analgesics. Thus, several strategies to mitigate risk and reduce the harm of opioid overdose have been developed. However, despite a marked increase in opioid analgesic consumption in Korea, there have been no tools predicting the risk of opioid overdose in the Korean population. Using the national claims database of the Korean population, we identified patients who were incidentally prescribed non-injectable opioid analgesic (NIOA) at least once from 2017 to 2018 (N = 1,752,380). Among them, 866 cases of opioid overdose occurred, and per case, four controls were selected. Patients were randomly allocated to the development (80%) and validation (20%) cohort. Thirteen predictive variables were selected via logistic regression modelling, and a risk-score was assigned for each predictor. Our model showed good performance with c-statistics of 0.84 in the validation cohort. The developed risk score model is the first tool to identify high-risk patients for opioid overdose in Korea. It is expected to be applicable in the clinical setting and useful as a national level surveillance tool due to the easily calculable and identifiable predictors available from the claims database.

Recent trends in opioid consumption in Korea from 2002 to 2015, based on the Korean NHIS-NSC cohort

Objectives

Opioids are prescribed to treat moderate-to-severe pain. We aimed to investigate the recent trends in opioid (morphine, oxycodone, fentanyl, and hydromorphone) consumption using data from the Korean National Health Insurance Service-National Sample Cohort between 2002 and 2015.

Methods

Morphine milligram equivalent (MME) was calculated to standardize the relative potency of the opioids. The number (cases) or amount (MME) of annual opioid prescription per 10,000 registrants was computed to analyze trends of consumption of opioids after age standardization. Joinpoint regression analysis was conducted to calculate the annual percentage change and average annual percentage change (AAPC).

Results

The number (cases) of prescriptions per 10,000 registrants increased from 0.07 in 2002 to 41.23 in 2015 (AAPC [95% CIs], 76.0% [61.6-91.7%]). The MME per 10,000 registrants increased from 15.06 in 2002 to 40,727.80 in 2015 (AAPC [95% CIs], 103.0% [78.2-131.3%]). The highest AAPC of prescriptions and MME per 10,000 registrants were observed in the elderly (60-69 years) and at general hospitals. Fentanyl prescription increased most rapidly among four opioids.

Conclusion

Consumption of opioids greatly increased in South Korea over 14 years.

An overview of the use and misuse/abuse of opioid analgesics in different world regions and future perspectives

Opioids are an important therapeutic option for severe resistant chronic pain but, in the absence of proper oversight, their use has risks. The level of prescription opioid misuse/abuse differs among countries, due to differences in healthcare systems and pain management approaches. However, evaluating the true dimension of prescription opioid misuse/abuse is complicated by statistical reporting which often does not differentiate between prescription and illicit opioid use, or between prescription opioid use by patients and nonpatients, highlighting a need for greater uniformity. Parallel efforts to educate patients and the general public about opioid risks, facilitate appropriate analgesic prescribing and identify alternative formulations or options to use instead of or with opioids, may contribute to optimizing prescription opioid use for pain management.

Risk factors of chronic opioid use after surgical procedures in noncancer patients: A nationwide case-control study

BACKGROUND

Surgery is an indication for opioid prescription in noncancer patients, and chronic use of opioids is associated with overdose and abuse.

OBJECTIVES

We aimed to evaluate the prevalence and risk factors associated with chronic opioid use (COU) following surgery among noncancer patients.

DESIGN

A nationwide case-control study.

SETTING

Retrospective analysis of the annual national patient sample data from 2012 to 2018 in South Korea.

PATIENTS

Adults without cancer who had undergone surgery and received noninjectable opioids during hospital stay.

MAIN OUTCOME MEASURES

COU during 3 months following surgery.

RESULTS

A total of 15 543 participants were included, and the prevalence overall and in opioid-naïve users was 8.1 and 5.7%, respectively. Prior exposure patterns of opioids [intermittent user, adjusted odds ratio (aOR) 2.35; 95% CI, 2.00 to 2.77, and continuous user, aOR 8.58; 95% CI, 6.54 to 11.24] and concomitant use of benzodiazepine (in continuous user, aOR 18.60; 95% CI 11.70 to 29.55) were strongly associated with COU compared with naïve users. Morphine milligram equivalent, type of opioid strength at discharge and prescription of nonopioid analgesics at discharge were also associated with COU. Compared with minor surgery, knee (aOR 1.49; 95% CI 1.17 to 1.89), spine (aOR 1.65; 95% CI 1.33 to 2.06) and shoulder (aOR 2.54; 95% CI 1.97 to 3.27) procedures showed a significantly positive association with COU. Sensitivity analysis in opioid-naïve patients showed similar results.

CONCLUSION

About 8.1% of noncancer patients who had undergone surgery and were prescribed noninjectable opioids became chronic opioid users in Korea. Identified risk factors could be used to derive strategies for safe opioid use in noncancer patients in the future.

Association between opioid-related deaths and persistent opioid prescribing in primary care in England: a nested case-control study

AIM

This study aimed to evaluate the association between opioid-related deaths and persistent opioid utilisation in the United Kingdom (UK).

METHODS

This nested case-control study used the UK Clinical Practice Research Datalink, linking the Office for National Statistics death registration. Adult opioid users with recorded opioid-related death between 2000 and 2015 were included and matched to four opioid users (controls) based on a disease risk score. Persistent opioid utilisation (opioid prescriptions ≥3 quarters/year and oral morphine equivalent dose ≥4500 mg/year) and psychotropic prescriptions were identified annually during the three patient-years before the date of opioid-related death. Conditional logistic regression was used to assess the association between persistent opioid utilisation and opioid-related death, and the results were reported as adjusted odds ratios (aOR) and 95% confidence intervals (95%CI).

RESULTS

Of the 902,149 opioid users, 230 opioid-related deaths (cases) and 920 controls were identified. Persistent opioid utilisation was significantly associated with an increased risk of opioid-related deaths (aOR: 1.9; 95%CI: 1.2, 2.9) when persistent opioid utilisation was defined by both annual dose and number of quarters. Concurrent prescription of opioids and tricyclic antidepressants (aOR: 2.0; 95%CI: 1.2, 3.5) or higher dose of benzodiazepine (aOR: 6.5; 95%CI: 4.0, 10.4) or gabapentinoids (aOR: 6.2; 95%CI: 2.9, 13.5) were associated with opioid-related death.

CONCLUSION

Persistent opioid prescribing and concurrent prescribing of psychotropics were associated with a higher risk of opioid-related death and should be avoided in clinical practice. An evidence-based indicator to monitor the safety of prescribed opioids during opioid de-prescribing is needed.

Musculoskeletal Disorders, Pain Medication, and in-Hospital Mortality among Patients with COVID-19 in South Korea: A Population-Based Cohort Study

We aimed to investigate whether comorbid musculoskeletal disorders (MSD)s and pain medication use was associated with in-hospital mortality among patients with coronavirus disease 2019 (COVID-19). Adult patients (≥20 years old) with a positive COVID-19 diagnosis until 5 June 2020 were included in this study, based on the National Health Insurance COVID-19 database in South Korea. MSDs included osteoarthritis, neck pain, lower back pain, rheumatoid arthritis, and others, while pain medication included paracetamol, gabapentin, pregabalin, glucocorticoid, nonsteroidal anti-inflammatory drugs (NSAIDs), opioids (strong and weak opioids), and benzodiazepine. Primary endpoint was in-hospital mortality. A total of 7713 patients with COVID-19 were included, and in-hospital mortality was observed in 248 (3.2%) patients. In multivariate logistic regression analysis, no MSDs (p > 0.05) were significantly associated with in-hospital mortality. However, in-hospital mortality was 12.73 times higher in users of strong opioids (odds ratio: 12.73, 95% confidence interval: 2.44–16.64; p = 0.002), while use of paracetamol (p = 0.973), gabapentin or pregabalin (p = 0.424), glucocorticoid (p = 0.673), NSAIDs (p = 0.979), weak opioids (p = 0.876), and benzodiazepine (p = 0.324) was not associated with in-hospital mortality. In South Korea, underlying MSDs were not associated with increased in-hospital mortality among patients with COVID-19. However, use of strong opioids was significantly associated with increased in-hospital mortality among the patients.

Acupuncture combined with multidisciplinary care for recovery after traumatic multiple rib fractures: a prospective feasibility cohort study

INTRODUCTION

Acute pain significantly delays early physiological recovery and results in chronic functional disability in patients with traumatic multiple rib fractures (MRFs). This prospective cohort study aimed to investigate the feasibility of acupuncture combined with multidisciplinary care during recovery in patients with traumatic MRFs.

METHODS

Twenty patients with traumatic MRFs who were admitted to a regional trauma centre in South Korea were enrolled. A combination of acupuncture and multidisciplinary inpatient ward management was provided at the trauma ward. Patients were permitted to continue acupuncture treatments at outpatient clinics for 3 months after the traumatic events. Clinical outcomes, including pain, acute physiological recovery, quality of life, patient satisfaction with the care provided, respiratory function and use of opioids, were evaluated up to 6 months after trauma.

RESULTS

Seventeen (85%) participants completed the 6-month follow-up. One patient withdrew consent during admission due to discomfort after three sessions of acupuncture. The proportion of patients with above-moderate level of pain decreased from 95% at baseline to 41% at 6 months. Quality of life appeared to deteriorate consistently throughout the study period. Around 80% of respondents expressed satisfaction with the acupuncture treatments and stated that they found acupuncture to be acceptable. Over 94% of respondents reported slight or considerable improvement.

CONCLUSION

The provision of acupuncture combined with multidisciplinary care for recovery in patients with traumatic MRFs was feasible in a regional trauma centre in South Korea. Randomised trials are needed to investigate the role of acupuncture combined with multidisciplinary care in the future.

TRIAL REGISTRATION NUMBER

KCT0002911 (Clinical Research Information Service).

Trends in opioid prescribing practices in South Korea, 2009-2019: Are we safe from an opioid epidemic?

Opioid prescribing data can guide regulation policy by informing trends and types of opioids prescribed and geographic variations. In South Korea, the nationwide data on prescribing opioids remain unclear. We aimed to evaluate an 11-year trend of opioid prescription in South Korea, both nationally and by administrative districts. A population-based cross-sectional analysis of opioid prescriptions dispensed nationwide in outpatient departments between January 1, 2009, and December 31, 2019, was conducted for this study. Data were obtained from the Health Insurance Review & Assessment Service. The types of opioids prescribed were categorized into total, strong, and extended-release and long-acting formulation. Trends in the prescription rate per 1000 persons were examined over time nationally and across administrative districts. There are significant increasing trends for total, strong, and extended-release and long-acting opioid prescriptions (rate per 1000 persons in 2009 and 2019: total opioids, 347.5 and 531.3; strong opioids, 0.6 and 15.2; extended-release and long-acting opioids, 6.8 and 82.0). The pattern of dispensing opioids increased from 2009 to 2013 and slowed down from 2013 to 2019. The rate of opioid prescriptions issued between administrative districts nearly doubled for all types of opioids. Prescription opioid dispensing increased substantially over the study period. The increase in the prescription of total opioids was largely attributed to an increase in the prescription of weak opioids. However, the increase in prescriptions of extended-release and long-acting opioids could be a future concern. These data may inform government organizations to create regulations and interventions for prescribing opioids.

Effect of Opioids on All-cause Mortality and Opioid Addiction in Total Hip Arthroplasty: a Korea Nationwide Cohort Study

BACKGROUND

The purpose of this study was to investigate the use of opioids before and after total hip arthroplasty (THA), to find out the effect of opioid use on mortality in patients with THA, and to analyze whether preoperative opioid use is a risk factor for sustained opioid use after surgery using Korean nationwide cohort data.

METHODS

This retrospective nationwide study identified subjects from the Korean National Health Insurance Service-Sample cohort (NHIS-Sample) compiled by the Korean NHIS. The index date (time zero) was defined as 90 days after an admission to a hospital to fulfill the eligibility criteria of the THA.

RESULTS

In the comparison of death risk according to current use and the defined daily dose of tramadol and strong opioids in each patient group according to past opioid use, there were no statistically significant differences in the adjusted hazard ratio for death compared to the current non-users in all groups (P > 0.05). Past tramadol and strong opioid use in current users increased the risk of the sustained use of tramadol and strong opioids 1.45-fold (adjusted rate ratio [aRR]; 95% confidence interval [CI], 1.12-1.87; P = 0.004) and 1.65-fold (aRR; 95% CI, 1.43-1.91; P < 0.001), respectively, compared to past non-users.

CONCLUSION

In THA patients, the use of opioids within 6 months before surgery and within 3 months after surgery does not affect postoperative mortality, but a past-use history of opioid is a risk factor for sustained opioid use. Even after THA, the use of strong opioids is observed to increase compared to before surgery.

Cost-Effectiveness of an Opioid Abuse-Prevention Program Using the Narcotics Information Management System in South Korea

OBJECTIVES

To assess the cost-effectiveness of an opioid abuse-prevention program embedded in the Narcotics Information Management System ("the Network System to Prevent Doctor-Shopping for Narcotics") in South Korea.

METHODS

Using a Markov model with a 1-year cycle length and 30-year time horizon, we estimated the incremental cost-utility ratio (ICUR) of implementing an opioid abuse-prevention program in patients prescribed outpatient opioids from a Korean healthcare payer's perspective. The model has 6 health states: no opioid use, therapeutic opioid use, opioid abuse, overdose, overdose death, and all-cause death. Patient characteristics, healthcare costs, and transition probabilities were estimated from national population-based data and published literature. Age- and sex-specific utilities of the general Korean population were used for the no-use state, whereas the other health-state utilities were obtained from published studies. Costs (in 2019 US dollars) included the expenses of the program, opioids, and overdoses. An annual 5% discount rate was applied to the costs and quality-adjusted life-years (QALYs). Parameter uncertainties were explored via deterministic and probabilistic sensitivity analyses.

RESULTS

The program was associated with 2.27 fewer overdoses per 100 000 person-years, with an ICUR of $227/QALY. The ICURs were generally robust to parameter changes, although the program's effect on abuse reduction was the most influential parameter. Probabilistic sensitivity analysis showed that the program reached a 100% probability of cost-effectiveness at a willingness-to-pay threshold of $900/QALY.

CONCLUSIONS

The opioid abuse-prevention program appears to be cost-effective in South Korea. Mandatory use of the program should be considered to maximize clinical and economic benefits of the program.

Frailty modifies the association between opioid use and mortality in chronic kidney disease patients with diabetes: a population-based cohort study

The prevalence of chronic pain in patients with chronic kidney disease (CKD) and diabetes mellitus is high and correlates with higher frailty risk, but satisfactory pain control frequently fails, necessitating opioid initiation. We aimed to examine whether opioid use affected their outcomes and whether such a relationship was modified by frailty. From the longitudinal cohort of diabetes patients (n = 840,000), we identified opioid users with CKD (n = 26,029) and propensity score-matched them to opioid-naïve patients in a 1:1 ratio. We analyzed the associations between opioid use and long-term mortality according to baseline frailty status, defined by the modified FRAIL scale. Among all, 20.3% did not have any FRAIL items, while 57.2%, 20.6%, and 1.9% had 1, 2, and at least 3 positive FRAIL items, respectively. After 4.2 years, 16.4% died. Cox proportional hazard regression showed that opioid users exhibited an 18% higher mortality risk (HR 1.183, 95% CI 1.13-1.24) with a dose- and duration-responsive relationship, compared to opioid-naive ones. Furthermore, the mortality risk posed by opioids was observed only in CKD patients without frailty but not in those with frailty. In conclusion, opioid use increased mortality among patients with CKD, while this negative outcome influence was not observed among frail ones.

All-cause mortality among males living with and without HIV initiating long-term opioid therapy, and its association with opioid dose, opioid interruption and other factors

BACKGROUND

While the relationship between long-term opioid therapy (LTOT) dose and overdose is well-established, LTOT's association with all-cause mortality is less understood, especially among people living with HIV (PLWH). There is also limited information regarding the association of LTOT cessation or interruption with mortality.

METHODS

Among PLWH and matched uninfected male veterans in care, we identified those who initiated LTOT. Using time-updated cox regression, we examined the association between all-cause mortality, unnatural death, and overdose, and opioid use categorized as 1-20 (reference group), 21-50, 51-90, and ≥ 91 mg morphine equivalent daily dose (MEDD).

RESULTS

There were 22,996 patients on LTOT, 6,578 (29 %) PLWH and 16,418 (71 %) uninfected. Among 5,222 (23 %) deaths, 12 % were unnatural deaths and 6 % overdoses. MEDD was associated with risk of all 3 outcomes; compared to patients on 1-20 mg MEDD, adjusted risk for all-cause mortality monotonically increased (Hazard Ratios (HR) [95 % CI] for 21-50 mg MEDD = 1.36 [1.21, 1.52], 51-90 mg MEDD = 2.06 [1.82, 2.35], and ≥ 91 mg MEDD = 3.03 [2.71, 3.39]). Similar results were seen in models stratified by HIV. LTOT interruption was also associated with all-cause, unnatural, and overdose mortality (HR [95 % CI] 2.30 [2.09, 2.53], 1.47 [1.13, 1.91] and 1.52 [1.04, 2.23], respectively).

CONCLUSIONS

Among PLWH and uninfected patients on LTOT we observed a strong dose-response relationship with all 3 mortality outcomes. Opioid risk mitigation approaches should be expanded to address the potential effects of higher dose on all-cause mortality in addition to unnatural and overdose fatalities.

Long-term opioid use among patients with chronic gout: a cross-sectional study of a sample cohort in South Korea

OBJECTIVES

This study aimed to determine trends in the prevalence of chronic opioid users among patients with chronic gout in South Korea from 2002 to 2015 and to investigate the factors associated with chronic opioid use among patients with chronic gout.

METHODS

We performed a population-based cohort study and extracted data from the National Health Insurance Service database in South Korea. We included all adult patients (age ≥ 18 years) with a diagnostic code of M1A* (chronic gout) according to the International Classification of Disease (10th revision).

RESULTS

The prevalence of chronic opioid users among patients with chronic gout has gradually increased from 4.0% in 2002 to 19.4% in 2015. After excluding the patients who had a history of cancer or other rheumatic diseases, a total of 18,042 patients with chronic gout were included in this cross-sectional cohort study in 2015, of which 993 (5.5%) were long-term opioid users. In a multivariable model, older age, female sex, Charlson Comorbidity Index > 2, long-term use of other analgesics, such as pregabalin, gabapentin, paracetamol, and glucocorticoids, and the use of other gout medication (colchicine) were independently associated with higher rates of long-term opioid use among patients with chronic gout.

CONCLUSION

Chronic opioid users among patients with chronic gout increased from 2002 to 2015 in South Korea. Female sex, older age, comorbid status, and the use of other non-opioid analgesics were independently associated with higher rates of long-term opioid use among patients with chronic gout. Key Points • Chronic opioid users among patients with chronic gout have increased from 2002 to 2015 in South Korea. • Among patients with chronic gout, 5.5% were long-term opioid users. • Female sex, older age, comorbid status, and the use of other non-opioid analgesics were associated with higher rates of long-term opioid use.

Patients' perception about opioids and addiction in South Korea

Background

Chronic pain affects approximately 22% of the world’s population. Opioids can be useful in chronic pain management. However, some patients have negative perception of opioids. The purpose of this research was to evaluate patients’ perception about opioids and investigate problems associated with prescribing and taking opioids in South Korea.

Methods

Patients who visited a pain clinic in 14 university hospitals of South Korea from September through October 2018 were asked to complete anonymous questionnaires about taking opioids.

Results

Of the 368 patients that were surveyed (female 53.3%, male 46.7%), 56.8% were prescribed opioids. In the opioid group, 92.8% patients had heard of opioids from their doctor and 72.6% of them had a positive perception about opioids. The side effects associated with opioid use were constipation (35.4%), dizziness (24.6%), nausea and vomiting (17.4%), dysuria (6.2%), and addiction (2.0%). In the no opioid group, the primary sources of information about opioids were doctors (49.2%), mass media (30.8%), and the internet (16.2%). The main reasons why 39.0% patients did not take opioids were fear of addiction (57.7%) and side effects (38.5%). There were 71.5% and 60.9% patients in the opioid and no opioid group, respectively, who wished to take opioids when their numeric rating scale pain score was ≥ 7.

Conclusions

Perception of opioids among patients who take them was either neutral or positive. However, 39.0% patients who have not been prescribed opioids did not want an opioid prescription, citing fear of addiction and side effects as the primary reasons.

Five-year mortality trends associated with chronic pancreatitis in South Korea: A population based cohort study

BACKGROUND

Chronic pancreatitis (CP) is associated with all-cause and cancer-related mortality; however, the risk of mortality associated with alcoholic and non-alcoholic CP remains controversial. This study investigated whether CP increased the risk of 5-year all-cause and cancer-specific mortality compared to a control population.

METHODS

This population-based study used data from a sample cohort of the National Health Insurance Service (NHIS) database in South Korea. CP was defined as disease code K86.0 (alcohol-induced CP) and K86.1 (other CP and non-alcoholic CP) from the tenth edition of the International Classification of Diseases.

RESULTS

The prevalence of chronic alcoholic pancreatitis increased from 0.01% in 2002 to 0.07% in 2015, and the prevalence of chronic non-alcoholic pancreatitis increased from 0.08% in 2002 to 0.50% in 2015. In the 2010 NHIS cohort (n = 826,909), CP was associated with an increased risk of 5-year all-cause mortality (hazard ratio [HR] = 1.25, 95% confidence interval [CI]: 1.25 to 1.66, P < 0.001). Additionally, non-alcoholic CP was associated with an increased risk of 5-year all-cause mortality (HR = 1.47, 95% CI: 1.27 to 1.71, P < 0.001); in contrast, alcohol-induced CP was not significantly associated with mortality risk (P = 0.569). Similar tendencies were observed for the 5-year cancer-related mortality risk.

CONCLUSIONS

In South Korea, the prevalence of alcoholic and non-alcoholic CP increased during 2002-2015. CP may be an independent risk factor for 5-year all-cause and cancer-related mortality. In this study, this association was more evident in patients with non-alcoholic CP.

Medicolegal Consideration to Prevent Medical Malpractice Regarding Opioid Administration: An Analysis of Judicial Opinion in South Korea

PURPOSE

Although the use of opioids is increasing in South Korea, there have been no studies on the serious complications caused by the opioids. The aim of this study was to investigate the rare but serious complications through medicolegal analysis.

MATERIALS AND METHODS

From January 1994 to December 2019, we retrospectively reviewed the closed cases of lawsuits involving the complications of opioids using the database of judgments of the Supreme Court of Korea. General characteristics, opioid-induced complications, and judicial characteristics were analyzed.

RESULTS

Of the 46 cases, 31 cases of complications were finally included in the analysis. There were 28 (90.3%) cases of opioid administration for acute pain and 3 (9.7%) cases for chronic pain. The most commonly prescribed opioid was pethidine (n = 13, 41.9%), and the most common complication was respiratory depression (n = 17, 54.8%). All except two cases were associated with permanent injuries, including 18 (58%) deaths. Twelve (38.7%) cases were ruled in favor of the plaintiff in the claims for damages, with a median payment of United States dollar (USD) 126,346 (IQR: USD 77,275-379,219). Of these cases, the most frequently admitted complaint by the court was the neglect of observation (n = 10, 32.3%), followed by the inappropriate drug choice (n = 4, 12.9%). Eleven (36.7%) cases were plaintiffs' claims for violating explanation obligations, of which 2 (6.7%) were recognized in the court.

CONCLUSION

Our results suggest that physicians must be aware of the serious complications related to opioids and health policies to prevent such complications and malpractice should be adopted.

Outcomes of Patients With Advanced Gastrointestinal Cancer in Relationship to Opioid Use: Findings From Eight Clinical Trials

BACKGROUND

This study assessed the patterns of opioid use among patients with advanced gastrointestinal cancers who were included in 8 clinical trials and evaluated the impact of opioid use on survival outcomes of included patients.

METHODS

Deidentified datasets from 8 clinical trials evaluating first-line systemic treatment of advanced gastrointestinal cancers were accessed from the Project Data Sphere platform (ClinicalTrial.gov identifiers: NCT01124786, NCT00844649, NCT00290966, NCT00678535, NCT00699374, NCT00272051, NCT00305188, and NCT00384176). These trials evaluated patients with pancreatic carcinoma, gastric carcinoma, hepatocellular carcinoma (HCC), and colorectal carcinoma. Multivariable logistic regression analysis was used to evaluate factors predicting the use of opioids. Kaplan-Meier survival estimates were used to compare survival outcomes in each disease entity among patients who did or did not receive opioid treatment. Multivariable Cox regression analysis was then used to further assess the impact of opioid use on survival outcomes in each disease entity.

RESULTS

A total of 3,441 participants were included in the current analysis. The following factors predicted a higher probability of opioid use within logistic regression analysis: younger age at diagnosis (odds ratio [OR], 0.990; 95% CI, 0.984-0.997; P=.004), nonwhite race (OR for white vs nonwhite, 0.749; 95% CI, 0.600-0.933; P=.010), higher ECOG score (OR for 1 vs 0, 1.751; 95% CI, 1.490-2.058; P<.001), and pancreatic primary site (OR for colorectal vs pancreatic, 0.241; 95% CI, 0.198-0.295; P<.001). Use of opioids was consistently associated with worse overall survival (OS) in Kaplan-Meier survival estimates of each disease entity (P=.008 for pancreatic cancer; P<.001 for gastric cancer, HCC, and colorectal cancer). In multivariable Cox regression analysis, opioid use was associated with worse OS among patients with pancreatic cancer (hazard ratio [HR], 1.245; 95% CI, 1.063-1.459; P=.007), gastric cancer (HR, 1.725; 95% CI, 1.403-2.122; P<.001), HCC (HR, 1.841; 95% CI, 1.480-2.290; P<.001), and colorectal cancer (HR, 1.651; 95% CI, 1.380-1.975; P<.001).

CONCLUSIONS

Study findings suggest that opioid use is consistently associated with worse OS among patients with different gastrointestinal cancers. Further studies are needed to understand the underlying mechanisms of this observation and its potential implications.

Pre-operative chronic opioid or glucocorticoid use and mortality after noncardiac surgery: A retrospective cohort study

BACKGROUND

The chronic use of opioids and glucocorticoids is associated with serious side effects. Moreover, both medications are related to poor long-term postoperative outcomes.

OBJECTIVE

The study aimed to investigate the association between pre-operative chronic opioid and glucocorticoid use and 90-day mortality after noncardiac surgery.

DESIGN

Retrospective, population-based cohort study.

SETTING

Single tertiary academic hospital.

PATIENTS

The study enrolled adult (≥18 years of age) patients admitted to Seoul National University Bundang Hospital, between January 2012 and December 2018 for planned, elective, noncardiac surgery.

MAIN OUTCOME MEASURES

The study compared the 90-day mortality for patients using opioids or glucocorticoids chronically (≥3 months) prior to surgery and for opioid-naïve and glucocorticoid-naïve patients.

RESULTS

A total of 112 606 patients were included in the study. Among them, 107 843 (95.9%) were opioid-naïve and glucocorticoid-naïve patients; 3373 (3.0%), 1199 (1.1%) and 191 patients (0.2%) were chronic users of opioids, glucocorticoids or both, respectively. In the multivariable model, compared with opioid-naïve and glucocorticoid-naïve patients, the odds of dying within 90 days were significantly higher for chronic users of opioids [3.56-fold; 95% confidence intervals (CIs) 2.36 to 5.38; P < 0.001], glucocorticoids (4.17-fold; 95% CI 3.28 to 5.29; P < 0.001) and combined opioids and glucocorticoids (7.66-fold; 95% CI 3.91 to 15.01; P < 0.001).

CONCLUSION

Chronic pre-operative use of opioids and glucocorticoids, together or individually, were associated with increased 90-day mortalities after noncardiac surgery, compared with opioid-naïve and glucocorticoid-naïve patients. Our results suggest that chronic pre-operative use of opioids and glucocorticoids should be managed carefully.

Long-term incidence of chronic postsurgical pain after thoracic surgery for lung cancer: a 10-year single-center retrospective study

BACKGROUND

The long-term incidence of chronic postsurgical pain (CPSP) after thoracic surgery has not yet been reported.

METHODS

We retrospectively reviewed the electronic medical records of 4218 consecutive patients who underwent thoracic surgery for lung cancer between 2007 and 2016. We evaluated the long-term incidence of CPSP after thoracic surgery at intervals of 3 months for 36 months. A Cox proportional hazard regression analysis was performed to investigate the predictors of CPSP after thoracic surgery.

RESULTS

A total of 3200 patients were included in the analysis. Of these, 459 (14.3%) and 558 (17.4%) patients were diagnosed with CPSP within 3 and 36 months after surgery, respectively. Furthermore, the incidence of CPSP decreased over time. Additionally, 99 (3.1%) patients were newly diagnosed with CPSP at least 6 months after surgery. Female sex (HR 1.20, 95% CI 1.00 to 1.43; p=0.04), longer duration of surgery (HR 1.11, 95% CI 1.03 to 1.20; p<0.01), higher 11-point Numeric Rating Scale score at first outpatient visit after surgery (HR 1.29, 95% CI 1.24 to 1.34; p<0.001), postoperative chemotherapy (HR 1.55, 95% CI 1.26 to 1.90; p<0.001), and postoperative radiation therapy (HR 1.35, 95% CI 1.05 to 1.74; p=0.02) were significant predictors of CPSP for 36 months after surgery.

CONCLUSION

Our study showed a decreasing trend in the incidence of CPSP as well as delayed-onset or recurrent CPSP after thoracic surgery. A better understanding of the progression of CPSP after thoracic surgery may provide important information on its prediction and treatment.

Evaluation of opioid discontinuation after non-orthopaedic surgery among chronic opioid users: a population-based cohort study

BACKGROUND

Many patients use opioids chronically before surgery; it is unclear if surgery alters the likelihood of ongoing opioid consumption in these patients.

METHODS

We performed a population-based matched cohort study of adults in Ontario, Canada undergoing one of 16 non-orthopaedic surgical procedures and who were chronically using opioids, defined as (1) an opioid prescription that overlapped the index date and (2) either a total of 120 or more cumulative calendar days of filled opioid prescriptions, or 10 or more prescriptions filled in the prior year. Each surgical patient was matched based on age, sex, Charlson comorbidity index, and daily preoperative opioid dose to three non-surgical patients who were also chronic opioid users. The primary outcome was time to opioid discontinuation.

RESULTS

The cohort included 4755 surgical and 14 265 matched non-surgical patients. After adjustment for sociodemographic characteristics and comorbidities, surgery was associated with an increased likelihood of opioid discontinuation (adjusted hazard ratio: 1.34, 95% confidence interval [CI]: 1.27, 1.42). Among surgical patients, factors associated with a reduced odds of discontinuation included a mean preoperative opioid dose above 90 morphine milligram equivalents (adjusted odds ratio [aOR]: 0.39; 95% CI: 0.32, 0.49) or filling a prescription for oxycodone (aOR: 0.73; 95% CI: 0.56, 0.98). Receipt of an in-patient Acute Pain Service consultation (aOR: 1.34; 95% CI: 1.06, 1.69) or residing in the highest neighbourhood income quintile (aOR: 1.35; 95% CI: 1.04, 1.79) were associated with a greater odds of opioid discontinuation.

CONCLUSIONS

For chronic opioid users, surgery was associated with an increased likelihood of discontinuation of opioids in the following year compared with non-surgical chronic opioid users.