Decreased bone density in men on methadone maintenance therapy

Opioid-induced androgen deficiency in men: Prevalence, pathophysiology, and efficacy of testosterone therapy

BACKGROUND

Opioid analgesics are frequently prescribed for the treatment of chronic pain and are a common cause of male androgen deficiency. Despite its high prevalence, this adverse effect of chronic opioid use remains underappreciated by clinicians. As a result, androgen deficiency remains underdiagnosed and likely undertreated. This focused review discusses the expanding literature on opioid-induced androgen deficiency and the efficacy of testosterone therapy, with a particular focus on its anti-nociceptive effects.

METHODS

Original and review articles on opioid-induced male androgen deficiency published from 1950 through June 2024 were retrieved from PubMed using the key terms "opioids," "hypogonadism," "low testosterone," and "testosterone therapy." References within the retrieved publications were also researched.

RESULTS

Opioids suppress the gonadal axis mainly by inhibiting GnRH synthesis and secretion. The prevalence of opioid-induced androgen deficiency in men varies between 20% and 80% and is influenced by the type of opioid used, duration of exposure, age of the cohort, and how low testosterone was defined. Limited data from clinical trials suggest that testosterone therapy improves libido, body composition, and certain domains of quality of life. Early evidence also suggests that testosterone has anti-nociceptive properties, confirming findings from preclinical and population studies.

CONCLUSION

Chronic opioid use is a common but underappreciated cause of androgen deficiency in men. There is a need to raise awareness among clinicians regarding this adverse effect of opioid use. Testosterone therapy could be considered in men with unequivocal androgen deficiency after a thorough clinical evaluation. Ongoing clinical trials will shed further light on the efficacy of testosterone therapy, particularly regarding its anti-nociceptive effects.

Exogenous Opioids and the Human Endocrine System: An Endocrine Society Scientific Statement

The use and misuse of opioids are a growing global problem. Although the effects of these drugs on the human endocrine system have been studied for decades, attention on their related clinical consequences, particularly on the hypothalamic-pituitary system and bone health, has intensified over recent years. This Statement appraises research data related to the impact of opioids on the gonadal and adrenal function. Whereas hypogonadism is well recognized as a side effect of opioids, the significance of their inhibitory actions on the hypothalamic-pituitary-adrenal system and the occurrence of clinically relevant adrenal insufficiency is not fully elucidated. The often-inconsistent results of studies investigating how opioids affect the secretion of GH, prolactin, arginine vasopressin, and oxytocin are assessed. The accumulating evidence of opioid actions on bone metabolism and their negative sequelae on bone mineral density and risk of fracture are also reviewed. In each section, available data on diagnostic and management approaches for opioid endocrine sequelae are described. This Statement highlights a plethora of gaps in research associated with the effects and clinical consequences of opioids on the endocrine system. It is anticipated that addressing these gaps will improve the care of people using or misusing opioids worldwide. The Statement is not intended to serve as a guideline or dictate treatment decisions.

Two Weeks of Continuous Opioid Treatment in an Adenine-Induced Mouse Model of Chronic Kidney Disease Exacerbates the Bone Inflammatory State and Increases Osteoclasts

Patients with chronic kidney disease (CKD) report high pain levels, but reduced renal clearance eliminates many analgesic options; therefore, 30-50% of CKD patients have chronic opioid prescriptions. Opioid use in CKD is associated with higher fracture rates. Opioids may directly alter bone turnover directly through effects on bone cells and indirectly via increasing inflammation. We hypothesized that continuous opioid exposure would exacerbate the high bone turnover state of CKD and be associated with elevated measures of inflammation. Male C57Bl/6J mice after 8 weeks of adenine-induced CKD (AD) and non-AD controls (CON) had 14-day osmotic pumps (0.25-µL/hr release) containing either saline or 50-mg/mL oxycodone (OXY) surgically implanted in the subscapular region. After 2 weeks, all AD mice had elevated blood urea nitrogen, parathyroid hormone, and serum markers of bone turnover compared to controls with no effect of OXY. Immunohistochemical staining of the distal femur showed increased numbers of osteocytes positive for the mu opioid and for toll-like receptor 4 (TLR4) due to OXY. Osteocyte protein expression of tumor necrosis factor-α (TNF-α) and RANKL were higher due to both AD and OXY so that AD + OXY mice had the highest values. Trabecular osteoclast-covered surfaces were also significantly higher due to both AD and OXY, resulting in AD + OXY mice having 4.5-fold higher osteoclast-covered surfaces than untreated CON. These data demonstrate that opioids are associated with a pro-inflammatory state in osteocytes which increases the pro-resorptive state of CKD.

Morphine-induced osteolysis and hypersensitivity is mediated through toll-like receptor-4 in a murine model of metastatic breast cancer

ABSTRACT

The propensity for breast cancer to metastasize to bone is coupled to the most common complaint among breast cancer patients: bone pain. Classically, this type of pain is treated using escalating doses of opioids, which lack long-term efficacy due to analgesic tolerance, opioid-induced hypersensitivity, and have recently been linked to enhanced bone loss. To date, the molecular mechanisms underlying these adverse effects have not been fully explored. Using an immunocompetent murine model of metastatic breast cancer, we demonstrated that sustained morphine infusion induced a significant increase in osteolysis and hypersensitivity within the ipsilateral femur through the activation of toll-like receptor-4 (TLR4). Pharmacological blockade with TAK242 (resatorvid) as well as the use of a TLR4 genetic knockout ameliorated the chronic morphine-induced osteolysis and hypersensitivity. Genetic MOR knockout did not mitigate chronic morphine hypersensitivity or bone loss. In vitro studies using RAW264.7 murine macrophages precursor cells demonstrated morphine-enhanced osteoclastogenesis that was inhibited by the TLR4 antagonist. Together, these data indicate that morphine induces osteolysis and hypersensitivity that are mediated, in part, through a TLR4 receptor mechanism.

Illicit drug use is associated with lower bone mineral density and bone strength

Objectives

To evaluate the association of illicit drug use with bone mineral density (BMD) and hip geometric parameters at the narrow neck.

Methods

This is a cross-sectional matched cohort study conducted in the Hong Kong Chinese population. Associations with illicit drug use were estimated using linear regression for BMD (lumbar spine and femoral neck) and hip geometrical parameters (cross-sectional area [CSA], cross-sectional moment of inertia [CSMI], section modulus [SM], average cortical thickness [ACT] and BMD at the narrow neck) after adjusting for age, body mass index (BMI), smoking status, drinking status, physical activity, and history of antipsychotic and antidepressant use. Mean difference and 95% confidence intervals (95% CI) were calculated between 108 illicit drug users and 108 controls using an adjusted linear model and cluster-robust standard errors after matching by age and sex. The false discovery rate was used to correct for multiple testing.

Results

Illicit drug users had a significantly lower BMD (g/cm2) at the lumbar spine (mean difference: -0.062; 95% CI: -0.108 to -0.015), and femoral neck (mean difference: -0.058; 95% CI: -0.106 to -0.010) in the fully adjusted model. Illicit drug users also had a significantly lower CSA (mean difference: -0.238 cm2; 95% CI: -0.462 to -0.013), ACT (mean difference: -0.018 cm; 95% CI: -0.030 to -0.006) and BMD (mean difference: -0.070 g/cm2; 95% CI: -0.128 to -0.012) at the narrow neck.

Conclusions

Illicit drug use is associated with lower BMD and bone strength. Future studies evaluating the risk of illicit drug use with fragility fracture are warranted.

Transitioning off methadone: A qualitative study exploring why patients discontinue methadone treatment for opioid use disorder

INTRODUCTION

Patients who discontinue methadone for opioid use disorder are at increased risk of overdose and death. We know little about how patients make the decision to stop treatment. This study explored reasons why patients discontinue methadone treatment.

METHODS

We conducted 20 individual semi-structured patient interviews and two staff focus groups, each with five participants, at two opioid treatment programs in Baltimore, MD, in the United States from June 2021 to May 2022. Patient interviews and staff focus groups covered three domains: 1) reasons why patients may want to discontinue methadone; 2) perspectives about the ideal length of methadone treatment; and 3) changes that could improve retention. We used a modified grounded theory approach to code interviews, identify emergent themes, and develop a conceptual model.

RESULTS

We identified three themes related to patients' internal relationships to methadone: patients (1) viewed methadone as a bridge to opioid-free recovery, (2) believed that long-term methadone damages the body, and (3) felt that methadone increases craving for cocaine; and three themes related to their external relationships with opioid treatment programs and society at large: patients (4) viewed daily dosing as burdensome, (5) feared methadone inaccessibility could trigger relapse, and (6) experienced stigma from friends, family, and peers. Patients with internal reasons planned to stop as soon as possible and asked for education about perceived side effects and treatment for cocaine craving to promote retention. Patients with external reasons were willing to continue for longer and asked for adaptive take-home policies and reduced societal stigma around methadone.

CONCLUSIONS

Patients want to discontinue methadone either because of their internal relationship to methadone and its real or perceived side effects, or because of their external experiences with opioid treatment programs and societal stigma of methadone. To improve retention, clinical and policy changes should consider responses to both of these categories of reasons.

Angiotensin-Related Peptides and Their Role in Pain Regulation

Angiotensin (Ang)-generating system has been confirmed to play an important role in the regulation of fluid balance and blood pressure and is essential for the maintenance of biological functions. Ang-related peptides and their receptors are found throughout the body and exhibit diverse physiological effects. Accordingly, elucidating novel physiological roles of Ang-generating system has attracted considerable research attention worldwide. Ang-generating system consists of the classical Ang-converting enzyme (ACE)/Ang II/AT1 or AT2 receptor axis and the ACE2/Ang (1-7)/MAS1 receptor axis, which negatively regulates AT1 receptor-mediated responses. These Ang system components are expressed in various tissues and organs, forming a local Ang-generating system. Recent findings indicate that changes in the expression of Ang system components under pathological conditions are involved in the development of neuropathy, inflammation, and their associated pain. Here, we summarized the effects of changes in the Ang system on pain transmission in various organs and tissues involved in pain development process.

The association of opioid consumption and osteoporosis in old men: Bushehr Elderly Health (BEH) program

In a population of 1156 men aged ≥ 60 years, opioid drug use was reported by 4.1% (n = 47) of participants. Among opioids, opium was the most prevalent consuming drug (83%). Adjusting for potential confounders, opioid consumption showed a positive association with osteoporosis.

PURPOSE

Limited evidence suggest a relationship between opioid consumption and osteoporosis. This study aims to investigate the possible association of osteoporosis and drug use among older adult men of Bushehr, Iran.

METHODS

In this study, 1156 men aged ≥ 60 years of Bushehr Elderly Health (BEH) were included. Bone density and trabecular bone score (TBS) were measured using dual-energy X-ray absorptiometry. Total osteoporosis was noted based on osteoporosis at either site of the lumbar spine, femoral neck, and total hip densitometry. Drug use was defined as a self-reported current use of opioid drugs, either regular (daily) use or irregular consumption. Multivariable modified Poisson regression analysis was used for investigating the association of opioids and osteoporosis, reporting the adjusted prevalence ratio (APR) with 95% confidence interval (CI). The association between drug use and TBS was evaluated using a linear regression model.

RESULTS

Opioid drug use was reported by 4.1% (n = 47) of participants. Among drug users, opium was the most prevalent consuming drug (83%). In all, 38.3% of drug users and 22.4% of non-users had osteoporosis (p-value = 0.011). Multivariable analysis showed that adjusting by age, education, smoking, alcohol consumption, body mass index, diabetes, and physical activity, a positive and significant association was detected between opioid drug use and the likelihood of osteoporosis (APR: 1.46, 95%CI: 1.02-2.10). Considering the potential confounders, the results also showed a negative association between drug consumption and TBS (β: - 0.027, 95%CI: - 0.053, - 0.001).

CONCLUSION

Opioid drug use has a positive association with osteoporosis in elderly men, independent of other conventional risk factors. Elderly drug users might be at a higher risk for osteoporotic fractures, given the effect of substance use on cognition. So, osteoporosis among drug users would be of importance, especially in countries where opium consumption is prevalent.

Sustained Morphine Delivery Suppresses Bone Formation and Alters Metabolic and Circulating miRNA Profiles in Male C57BL/6J Mice

Opioid use is detrimental to bone health, causing both indirect and direct effects on bone turnover. Although the mechanisms of these effects are not entirely clear, recent studies have linked chronic opioid use to alterations in circulating miRNAs. Here, we developed a model of opioid-induced bone loss to understand bone turnover and identify candidate miRNA-mediated regulatory mechanisms. We evaluated the effects of sustained morphine treatment on male and female C57BL/6J mice by treating with vehicle (0.9% saline) or morphine (17 mg/kg) using subcutaneous osmotic minipumps for 25 days. Morphine-treated mice had higher energy expenditure and respiratory quotient, indicating a shift toward carbohydrate metabolism. Micro-computed tomography (μCT) analysis indicated a sex difference in the bone outcome, where male mice treated with morphine had reduced trabecular bone volume fraction (Tb.BV/TV) (15%) and trabecular bone mineral density (BMD) (14%) in the distal femur compared with vehicle. Conversely, bone microarchitecture was not changed in females after morphine treatment. Histomorphometric analysis demonstrated that in males, morphine reduced bone formation rate compared with vehicle, but osteoclast parameters were not different. Furthermore, morphine reduced bone formation marker gene expression in the tibia of males (Bglap and Dmp1). Circulating miRNA profile changes were evident in males, with 14 differentially expressed miRNAs associated with morphine treatment compared with two differentially expressed miRNAs in females. In males, target analysis indicated hypoxia-inducible factor (HIF) signaling pathway was targeted by miR-223-3p and fatty acid metabolism by miR-484, -223-3p, and -328-3p. Consequently, expression of miR-223-3p targets, including Igf1r and Stat3, was lower in morphine-treated bone. In summary, we have established a model where morphine leads to a lower trabecular bone formation in males and identified potential mediating miRNAs. Understanding the sex-specific mechanisms of bone loss from opioids will be important for improving management of the adverse effects of opioids on the skeleton. © 2022 American Society for Bone and Mineral Research (ASBMR).

Long-term opioid treatment and endocrine measures in patients with cancer-related pain: a systematic review

OBJECTIVES

Opioid analgesics are the main stay for cancer pain management; however, long-term opioid treatment (L-TOT) may suppress the endocrine system. This systemic review aimed at investigating effects of L-TOT on the endocrine system in patients with cancer-related pain.

METHODS

A search on MEDLINE, EMBASE and Web of Science databases was performed. Inclusion criteria were clinical studies investigating endocrine measures in adult patients with cancer-related pain in L-TOT (≥4 weeks). Outcomes and quality of evidence were assessed.

RESULTS

A total of 252 abstracts were identified; out of which 247 were excluded and five cross-sectional studies were included and analyzed. L-TOT was associated with lower serum concentration levels of total- and free testosterone in males, follicular stimulating hormone in females, and luteinizing hormone in both sexes. Moreover, higher morphine equivalent daily doses (MEDDs) were correlated with higher levels of cortisol and lower levels of LH in both sexes, and lower levels of total- and free testosterone in males. Sexual dysfunction was associated with low sex hormone levels. Level of evidence was low/very low.

CONCLUSIONS

The studies identified demonstrated that patients with cancer-related pain in L-TOT may have gonadal hypofunction causing sexual dysfunction, which may be correlated with opioid dose level. In addition, high serum concentrations of cortisol were positively correlated with high opioid dose levels. However, the evidence was weak and further research is necessary. PROSPERO, ID-number: CRD42020213059.

How Do Drugs Affect the Skeleton? Implications for Forensic Anthropology

Simple Summary

Forensic anthropologists analyze human remains to assist in the identification of the deceased, predominantly by assessing age-at-death, sex, stature, ancestry and any unique identifying features. Whilst methods have been established to create this biological profile of the skeleton, these may be influenced by a number of factors. This paper, for the first time, provides an overview from a reading of the clinical and pharmacological literature to explore whether the intake of drugs can affect the skeleton and whether these may have implications for forensic anthropology casework. In effect, drugs such as tobacco, heroin, and prescription medications can alter bone mineral density, can increase the risk of fractures, destroy bone and changes to the dentition. By considering how drugs can affect the skeleton, forensic anthropologists can be aware of this when attempting to identify the deceased.

Abstract

Forensic anthropologists rely on a number of parameters when analyzing human skeletal remains to assist in the identification of the deceased, predominantly age-at-death, sex, stature, ancestry or population affinity, and any unique identifying features. During the examination of human remains, it is important to be aware that the skeletal features considered when applying anthropological methods may be influenced and modified by a number of factors, and particular to this article, prescription drugs (including medical and non-medical use) and other commonly used drugs. In view of this, this paper aims to review the medical, clinical and pharmacological literature to enable an assessment of those drug groups that as side effects have the potential to have an adverse effect on the skeleton, and explore whether or not they can influence the estimation of age-at-death, sex and other indicators of the biological profile. Moreover, it may be that the observation of certain alterations or inconsistencies in the skeleton may relate to the use of drugs or medication, and this in turn may help narrow down the list of missing persons to which a set of human remains could belong. The information gathered from the clinical and medical literature has been extracted with a forensic anthropological perspective and provides an awareness on how several drugs, such as opioids, cocaine, corticosteroids, non-steroidal anti-inflammatory drugs, alcohol, tobacco and others have notable effects on bone. Through different mechanisms, drugs can alter bone mineral density, causing osteopenia, osteoporosis, increase the risk of fractures, osteonecrosis, and oral changes. Not much has been written on the influence of drugs on the skeleton from the forensic anthropological practitioner perspective; and this review, in spite of its limitations and the requirement of further research, aims to investigate the current knowledge of the possible effects of both prescription and recreational drugs on bones, contributing to providing a better awareness in forensic anthropological practice and assisting in the identification process of the deceased.

Crosstalk between skeletal and neural tissues is critical for skeletal health

Emerging evidence in the literature describes a physical and functional association between the neural and skeletal systems that forms a neuro-osteogenic network. This communication between bone cells and neural tissues within the skeleton is important in facilitating bone skeletal growth, homeostasis and repair. The growth and repair of the skeleton is dependent on correct neural innervation for correct skeletal developmental growth and fracture repair, while pathological conditions such as osteoporosis are accelerated by disruptions to sympathetic innervation. To date, different molecular mechanisms have been reported to mediate communication between bone and neural populations. This review highlights the important role of various cell surface receptors, cytokines and associated ligands as potential regulators of skeletal development, homeostasis, and repair, by mediating interactions between the skeletal and nervous systems. Specifically, this review describes how Bone Morphogenetic Proteins (BMPs), Eph/ephrin, Chemokine CXCL12, Calcitonin Gene-related Peptide (CGRP), Netrins, Neurotrophins (NTs), Slit/Robo and the Semaphorins (Semas) contribute to the cross talk between bone cells and peripheral nerves, and the importance of these interactions in maintaining skeletal health.

Factors Associated with Low Bone Density in Opioid Substitution Therapy Patients: A Systematic Review

Background: Long-term opioid therapy is a risk factor for low bone mineral density (BMD). However, other factors may also contribute to low BMD. Several studies have examined the variables that might contribute to low BMD in patients receiving opioid replacement therapy (OST). However, to our knowledge, there was no systemic review conducted to address this particular issue. Thus, we reviewed the articles on the factors associated with low BMD in the population of opioid use disorder receiving substitution therapy. Methods: The articles that examined correlates or risk factors of low BMD in OST population were retrieved from OVID, SCOPUS, and PUBMED from inception until July 2020 by two independent investigators. Results: A total of 429 articles from three databases were retrieved initially. After screening based on eligibility criteria, five articles were included in the final analysis. The risk factors or correlates found to be significantly associated with low BMD in the OST population include male gender, low body mass index, low testosterone level, methadone or heroin use, and longer duration of heavy alcohol use. The review limitations include small sample sizes and inconsistent definition of variables. Conclusion: OST patients should be screened for BMD and its associated factors. Guidelines and training of practitioners involving in the OST service should be provided to increase the detection of low BMD in the OST population.

Opioids and the Hypothalamic-Pituitary-Gonadal (HPG) Axis

CONTEXT

Hypogonadism is a well-established consequence of opioid use. It has been reported in both men and women, although more widely studied in men.

EVIDENCE ACQUISITION

PubMed was searched for articles in English until December 2019 for opioids and hypogonadism. Bibliography of retrieved articles was searched for relevant articles.

EVIDENCE SYNTHESIS

The prevalence of opioid-induced hypogonadism (OIH) varies between studies but was reported to be 69% in a recent systematic review. There is large heterogeneity in the studies, with different factors shown to have stronger association with hypogonadism such as specific types of opioids, higher doses, and longer durations of use. The consequences of OIH include sexual dysfunction, depression, decreased quality of life, and low bone density. There is paucity of randomized controlled trials assessing the efficacy of testosterone replacement therapy (TRT) for OIH in men, and even less studies on treating OIH in women. TRT studies in men reported varying outcomes with some studies favoring and others showing no clear benefit of TRT on different measures.

CONCLUSIONS

Despite the high prevalence of OIH, it remains underrecognized and undertreated with multiple endocrine and metabolic consequences. A reasonable approach in patients using opioids includes informing them of this complication and its potential consequences, screening for signs and symptoms of hypogonadism then sex hormone levels if prolonged opioid use > 3 months, and treating patients diagnosed with hypogonadism, if and when clinically indicated, with sex hormones if chronic opioids are planned to be continued for ≥ 6 months.

The Effect of Opiates on Bone Formation and Bone Healing

PURPOSE OF REVIEW

Opioids have been shown to be associated with an increased risk of fracture. The purpose of this paper is to review recent research into the effects of opioids on bone formation and bone healing in animal models and in human studies.

RECENT FINDINGS

Most opioids, such as morphine and fentanyl, negatively affected bone remodeling and bone healing in animal models. Conversely, remifentanil has been recently shown to promote in vitro osteoblast differentiation and to inhibit differentiation and maturation of osteoclasts, therefore reducing bone resorption. According to the possible negative role of opioids in bone healing, opioid antagonists have been shown to enhance bone mineralization, suggesting a possible therapeutic role in the future for osteoporosis. Other neuropeptides, such as the vasoactive intestinal peptide (VIP) and the neuropeptide Y (NPY), have been proved to promote osteogenesis. The increased risk of fractures among opioid users may be related to their central nervous system side effects or to the reduced bone density, partly due to their endocrine effects, and partly to their direct activity on bone cells. Clinical data strongly suggested a potential negative effect of opioids in bone healing. The risk of nonunion fracture is significantly increased in opioid users, and bone mass density was reduced in patients under long-term opioid treatment. The direct effects of opioids on bone remodeling appears evident from these reports. Not all opioids have the same potential for negatively impacting bone healing. Opioid antagonists may increase bone density and could represent a possible future treatment for low bone mass density pathologies. However, further trials are warranted to clarify the clinical relevance of these emerging findings from animal studies.

Hip Fracture Risk among Hemodialysis-Dependent Patients Prescribed Opioids and Gabapentinoids

BACKGROUND

Despite opioids' known association with hip fracture risk in the general population, they are commonly prescribed to patients with ESKD. Whether use of opioids or gabapentinoids (also used to treat pain in patients with ESKD) contributes to hip fracture risk in patients with ESKD on hemodialysis remains unknown.

METHODS

In a case-control study nested within the US Renal Data System, we identified all hip fracture events recorded among patients dependent on hemodialysis from January 2009 through September 2015. Eligible cases were risk-set matched on index date with ten eligible controls. We required >1 year of Medicare Parts A and B coverage and >3 years of part D coverage to study cumulative longer-term exposure. To examine new, short-term exposure, we selected individuals with >18 months of Part D coverage and no prior opioid or gabapentinoid use between 18 and 7 months before index. We used conditional logistic regression to estimate unadjusted and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CI).

RESULTS

For the longer-term analyses, we identified 4912 first-time hip fracture cases and 49,120 controls. Opioid use was associated with increased hip fracture risk (adjusted OR, 1.39; 95% CI, 1.26 to 1.53). Subgroups of low, moderate, and high use yielded adjusted ORs of 1.33 (95% CI, 1.20 to 1.47), 1.53 (95% CI, 1.36 to 1.72), and 1.66 (95% CI, 1.45 to 1.90), respectively. The association with hip fractures was also elevated with new, short-term use (adjusted OR, 1.38; 95% CI, 1.25 to 1.52). There were no associations between gabapentinoid use and hip fracture.

CONCLUSIONS

Among patients dependent on hemodialysis in the United States, both short-term and longer-term use of opioid analgesics were associated with hip fracture events.

An updated analysis of opioids increasing the risk of fractures

Objective

To assess the relationship between opioid therapy for chronic noncancer pain and fracture risk by a meta-analysis of cohort studies and case-control studies.

Methods

The included cohort studies and case-control studies were identified by searching the PubMed and EMBASE databases from their inception until May 24, 2019. The outcome of interest was a fracture. This information was independently screened by two authors. When the heterogeneity among studies was significant, a random effects model was used to determine the overall combined risk estimate.

Results

In total, 12 cohort studies and 6 case-control studies were included. We used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of the included literature, and 14 of the studies were considered high-quality studies. The overall relative risk of opioid therapy and fractures was 1.78 (95% confidence interval (CI) 1.53–2.07). Subgroup analyses revealed sources of heterogeneity, sensitivity analysis was stable, and no publication bias was observed.

Conclusions

The meta-analysis showed that the use of opioids significantly increased the risk of fracture.

Alcohol and Bone Turnover Markers among People Living with HIV and Substance Use Disorder

BACKGROUND

Although unhealthy alcohol use and low bone density are prevalent among people living with HIV (PLWH), it is not clear whether alcohol use is associated with bone turnover markers (BTMs), and if so, at what quantity and frequency. The study objective was to examine the association between alcohol and BTMs in PLWH with substance use disorder.

METHODS

We studied a prospective cohort recruited from 2 HIV clinics who met criteria for DSM-IV substance dependence or reported ever injection drug use. Outcomes were BTM of (i) bone formation (serum procollagen type 1 N-terminal propeptide [P1NP]) and (ii) bone resorption (serum C-telopeptide type 1 collagen [CTx]). Alcohol consumption measures included (i) mean number of drinks/d (Timeline Follow-Back [TLFB]) (primary predictor), (ii) any alcohol use on ≥20 of the past 30 days, and phosphatidylethanol (PEth), a biomarker of recent alcohol consumption. Linear regression analysis examined associations between (i) each alcohol measure and each BTM and (ii) change in alcohol and change in BTM over 12 months.

RESULTS

Among 198 participants, baseline characteristics were as follows: The median age was 50 years; 38% were female; 93% were prescribed antiretroviral medications; 13% had ≥20 drinking days/month; mean drinks/day was 1.93 (SD 3.89); change in mean drinks/day was -0.42 (SD 4.18); mean P1NP was 73.1 ng/ml (SD 34.5); and mean CTx was 0.36 ng/ml (SD 0.34). Higher drinks/day was significantly associated with lower P1NP (slope -1.09 ng/ml; 95% confidence interval [CI] -1.94, -0.23, per each additional drink). On average, those who drank on ≥ 20 days/month had lower P1NP (-15.45 ng/ml; 95% CI: -26.23, -4.67) than those who did not. Similarly, PEth level ≥ 8ng/ml was associated with lower P1NP. An increase in drinks/d was associated with a decrease in P1NP nonsignificantly (-1.14; 95% CI: -2.40, +0.12; p = 0.08, per each additional drink). No significant associations were detected between either alcohol measure and CTx.

CONCLUSIONS

In this sample of PLWH with substance use disorder, greater alcohol consumption was associated with lower serum levels of bone formation markers.

Opioid-induced endocrinopathies

The use of opioids is becoming a global epidemic, leading to a rise in the occurrence and recognition of the effects of opioid drugs on the endocrine system. Nonetheless, opioid-induced endocrinopathies still remain underdiagnosed, mainly because of symptom under-reporting by patients and poor clinician awareness. Hypogonadism is the most well recognised consequence of opioid use, but the inhibitory effects of opioid drugs on the hypothalamo-pituitary-adrenal axis and their negative effects on bone health also require attention. Hyperprolactinaemia might be detected in opioid users, but clinically relevant thyroid dysfunction has not been identified. The effects of opioids on other hormones have not been clearly defined. Assessment of gonadal and adrenal function (particularly if high index of clinical suspicion of hypogonadism or hypoadrenalism) and evaluation of bone health are advised in people that use opiods. Discontinuation or reduction of opioid dose and appropriate hormone replacement are the management approaches that should be considered for hypogonadism and hypoadrenalism. Further research is needed to facilitate the development of evidence-based guidelines on the diagnosis and optimal management of opioid-induced endocrinopathies.

Dichotomic effects of clinically used drugs on tumor growth, bone remodeling and pain management

Improvements in the survival of breast cancer patients have led to the emergence of bone health and pain management as key aspects of patient’s quality of life. Here, we used a female rat MRMT-1 model of breast cancer-induced bone pain to compare the effects of three drugs used clinically morphine, nabilone and zoledronate on tumor progression, bone remodeling and pain relief. We found that chronic morphine reduced the mechanical hypersensitivity induced by the proliferation of the luminal B aggressive breast cancer cells in the tumor-bearing femur and prevented spinal neuronal and astrocyte activation. Using MTT cell viability assay and MRI coupled to ¹⁸FDG PET imaging followed by ex vivo 3D µCT, we further demonstrated that morphine did not directly exert tumor growth promoting or inhibiting effects on MRMT-1 cancer cells but induced detrimental effects on bone healing by disturbing the balance between bone formation and breakdown. In sharp contrast, both the FDA-approved bisphosphonate zoledronate and the synthetic cannabinoid nabilone prescribed as antiemetics to patients receiving chemotherapy were effective in limiting the osteolytic bone destruction, thus preserving the bone architecture. The protective effect of nabilone on bone metabolism was further accompanied by a direct inhibition of tumor growth. As opposed to zoledronate, nabilone was however not able to manage bone tumor-induced pain and reactive gliosis. Altogether, our results revealed that morphine, nabilone and zoledronate exert disparate effects on tumor growth, bone metabolism and pain control. These findings also support the use of nabilone as an adjuvant therapy for bone metastases.

Association between opioid use disorder and fractures: a population-based study

AIMS

To test whether fractures and osteoporosis are more prevalent among patients with opioid use disorder (OUD) than patients without OUD in Taiwan.

DESIGN

We conducted a retrospective cohort study using data from the National Health Insurance Research Database (NHIRD) in Taiwan.

SETTING

Taiwan.

PARTICIPANTS

The number of adult patients with OUD and without OUD was 3695 and 14 780, respectively. We established both cohorts from 1 January 1998 to 31 December 2011 to observe the incidence of fracture. The occurrence of fracture was followed-up until the end of 2011.

MEASUREMENTS

The primary measure was incidence of fracture. The relative risk of fracture was estimated using the Cox proportional hazard model after adjusting for age, sex, index year and comorbidities. Comorbidities included diabetes mellitus, hyperlipidemia, stroke, chronic obstructive pulmonary disease, heart failure, alcohol-related illness, osteoporosis, end-stage renal disease, obesity and rheumatoid arthritis, using the International Classification of Diseases, 9th revision, clinical modification.

FINDINGS

Patients with OUD were 4.13 times more likely to suffer fractures than patients without OUD [incidence rate (IR) per 1000 person-years = 23.0 versus 5.47, adjusted hazard ratio (HR) = 3.74, 95% confidence interval (CI) = 3.27-4.29]. Compared with the control group, the risk of fracture was higher among the patients with OUD. Risk of fracture was higher in male elderly patients with diabetes mellitus, alcohol-related illness or osteoporosis. The cumulative incidences of fracture over 14 years of patients with OUD and without OUD differed significantly.

CONCLUSIONS

Taiwanese patients with opioid use disorder appear to have a higher adjusted hazard ratio for fracture than Taiwanese patients without opioid use disorder.

Using nominal group technique to identify barriers, facilitators, and preferences among patients seeking treatment for opioid use disorder: A needs assessment for decision making support

BACKGROUND

The opioid crisis requires rapid scale-up of evidence-based interventions to treat opioid use disorder (OUD), of which pharmacologic therapies with methadone, buprenorphine or long-acting naltrexone are most effective. With recently-developed formulations, there are unprecedented treatment options. Even when pharmacologic treatment is accessible, however, uptake remains low, suggesting individual-level barriers. Decision aids are an evidence-based strategy that may overcome these barriers. This study aims to inform such a tool by describing and rank-ordering patients' considerations when deciding whether to start medication and, if starting, choosing a medication.

METHODS

Adults with OUD (N = 81) attending an addiction treatment center or syringe exchange program completed focus groups using nominal group technique, a consensus method that generates and ranks response. The qualitative component generates a broad array of responses, followed by rank-ordering to prioritize responses. Responses to questions about starting any medications and the pros and cons of five specific medications were ranked and coded.

RESULTS

The decision to initiate pharmacologic therapy and choose among medications was influenced by six key attributes in decreasing priority: (1) benefits, (2) side effects of treatment, (3) medication delivery strategies, (4) convenience, (5) how expectations for treatment are met, and (6) how medication (especially methadone) can represents trading one addiction for another.

CONCLUSIONS

Pharmacologic properties, logistical factors, and managing expectations were important themes in decision-making for starting, choosing, and staying on medications, and to a lesser degree, negative views about medications, specifically OAT, as an addiction itself. Desire for more control over treatment persisted in all themes. This study identified specific knowledge gaps, expectations, and priorities which are important for developing a decision aid for OUD treatment relevant to the target group. Nominal group technique is an established mixed-methodology that we have applied to a new population and purpose, that of conducting needs assessment for decision aid development.

Peripherally restricted cannabinoid 1 receptor agonist as a novel analgesic in cancer-induced bone pain

Many malignant cancers, including breast cancer, have a propensity to invade bones, leading to excruciating bone pain. Opioids are the primary analgesics used to alleviate this cancer-induced bone pain (CIBP) but are associated with numerous severe side effects, including enhanced bone degradation, which significantly impairs patients' quality of life. By contrast, agonists activating only peripheral CB1 receptors (CB1Rs) have been shown to effectively alleviate multiple chronic pain conditions with limited side effects, yet no studies have evaluated their role(s) in CIBP. Here, we demonstrate for the first time that a peripherally selective CB1R agonist can effectively suppress CIBP. Our studies using a syngeneic murine model of CIBP show that both acute and sustained administration of a peripherally restricted CB1R agonist, 4-{2-[-(1E)-1[(4-propylnaphthalen-1-yl)methylidene]-1H-inden-3-yl]ethyl}morpholine (PrNMI), significantly alleviated spontaneous pain behaviors in the animals. This analgesic effect by PrNMI can be reversed by a systemic administration but not spinal injection of SR141716, a selective CB1R antagonist. In addition, the cancer-induced bone loss in the animals was not exacerbated by a repeated administration of PrNMI. Furthermore, catalepsy and hypothermia, the common side effects induced by cannabinoids, were measured at the supratherapeutic doses of PrNMI tested. PrNMI induced mild sedation, yet no anxiety or a decrease in limb movements was detected. Overall, our studies demonstrate that CIBP can be effectively managed by using a peripherally restricted CB1R agonist, PrNMI, without inducing dose-limiting central side effects. Thus, targeting peripheral CB1Rs could be an alternative therapeutic strategy for the treatment of CIBP.

MECHANISMS OF ENDOCRINOLOGY: Endocrinology of opioids

The use of opioids has grown substantially over the past two decades reaching the dimensions of a global epidemic. These drugs have effects on multiple levels of the endocrine system through mechanisms which are still not fully elucidated, and awareness of their endocrine sequelae is vital for all specialists prescribing or managing patients on them. Hypogonadism is the most well-recognised consequence of opioid use (prevalence 21–86%) which, however, may remain undiagnosed with potential adverse outcomes for the patients. Although less frequent, cortisol deficiency can also be found. Furthermore, there is a negative impact on bone health (with reduced bone mineral density and increased fracture risk) and occasionally hyperprolactinaemia, whereas the clinical significance of alterations in other hormones remains to be clarified. Discontinuation or reduction of the opioid and, in cases of chronic pain, consideration of alternative therapies for pain relief are potential management options. Hormonal replacement, especially when the above measures are not practically feasible, needs to be considered. Further studies are needed to clearly establish the prevalence of hormonal abnormalities with various regimes, doses and routes of opioids and to address reliably the long-term benefits and risks of hormonal treatment in patients on opioids. Until evidence-based, safe and cost-effective clinical guidelines become available, periodical assessment of the gonadal and adrenal function (particularly when relevant clinical manifestations are present) and evaluation of the bone health status are advised.

Opioids delay healing of spinal fusion: a rabbit posterolateral lumbar fusion model

BACKGROUND CONTEXT

Opioid use is prevalent in the management of pre- and postoperative pain in patients undergoing spinal fusion. There is evidence that opioids downregulate osteoblasts in vitro, and a previous study found that morphine delays the maturation and remodeling of callus in a rat femur fracture model. However, the effect of opioids on healing of spinal fusion has not been investigated before. Isolating the effect of opioid exposure in humans would be limited by the numerous confounding factors that affect fusion healing. Therefore, we have used a well-established rabbit model to study the process of spinal fusion healing that closely mimics humans.

PURPOSE

The objective of this work was to study the effect of systemic opioids on the process of healing of spinal fusion in a rabbit posterolateral spinal fusion model.

STUDY DESIGN/SETTING

This is a preclinical animal study.

MATERIALS AND METHODS

Twenty-four adult New Zealand white rabbits were studied in two groups after approval from the Institutional Animal Care and Use Committee (IACUC). The opioid group (n=12) received 4 weeks' preoperative and 6 weeks' postoperative transdermal fentanyl. Serum fentanyl levels were measured just before surgery and 4 weeks postoperatively to ensure adequate levels. The control group (n=12) received only perioperative pain control as necessary. All animals underwent a bilateral L5-L6 posterolateral spinal fusion using iliac crest autograft. Animals were euthanized at the 6-week postoperative time point, and assessment of fusion was done by manual palpation, plain radiographs, microcomputed tomography (microCT), and histology.

RESULTS

Twelve animals in the control group and 11 animals in the opioid group were available for analysis at the end of 6 weeks. The fusion scores on manual palpation, radiographs, and microCT were not statistically different. Three-dimensional microCT morphometry found that the fusion mass in the opioid group had a lower bone volume (p=.09), a lower trabecular number (p=.02), and a higher trabecular separation (p=.02) compared with the control group. Histologic analysis found areas of incorporation of autograft and unincorporated graft fragments in both groups. In the control group, there was remodeling of de novo woven bone to lamellar organization with incorporation of osteocytes, formation of mature marrow, and relative paucity of hypertrophied osteoblasts lining new bone. Sections from the opioid group showed formation of de novo woven bone, and hypertrophied osteoblasts were seen lining the new bone. There were no sections showing lamellar organization and development of mature marrow elements in the opioid group. Less dense trabeculae on microCT correlated with histologic findings of relatively immature fusion mass in the opioid group.

CONCLUSIONS

Systemic opioids led to an inferior quality fusion mass with delay in maturation and remodeling at 6 weeks in this rabbit spinal fusion model. These preliminary results lay the foundation for further research to investigate underlying cellular mechanisms, the temporal fusion process, and the dose-duration relationship of opioids responsible for our findings.

Positives and negatives of nonsteroidal anti-inflammatory drugs in bone healing: the effects of these drugs on bone repair

Tissue damage following injury triggers the processes of coagulation, inflammation and healing. In tissues surrounding the bone, the result of the healing process is a scar, while bone tissue has a unique ability to achieve shape, strength and pre-injury function. Bone healing is a process of regeneration rather than classic recovery. The result of this process is the formation of new, healthy bone tissue instead of a scar. Many factors can inhibit or impair the bone healing process, and their influence is critical during the stages of inflammation and angiogenesis and finally on the clinical outcome. Nonsteroidal anti-inflammatory drugs (NSAIDs) play an essential role associated with their analgesic potency and anti-inflammatory effects. NSAIDs are also the most often used drugs in patients who require pain control and inflammation reduction due to musculoskeletal diseases or injures. Although their analgesic effect is well documented, NSAIDs also interfere with bone healing; therefore, the relative benefits and disadvantages connected with their administration should be taken into consideration. Despite the negative effect, NSAIDs have beneficial properties, but their clinical benefits in relation to dose and time of use are still unclear. Therefore, in this review, we focus on bone healing with relation to the impact of NSAIDs.

Effects of analgesics on bone mineral density: A longitudinal analysis of the prospective SWAN cohort with three-group matching weights

PURPOSE

To examine the effects of analgesics on bone mineral density (BMD), which have not been examined in a longitudinal study with multiple measurements.

METHODS

We investigated changes in BMD associated with new use of analgesics in a prospective longitudinal cohort of mid-life women. BMD and medication use were measured annually. We compared BMD among new users of acetaminophen, NSAIDs, and opioids. Adjustment for baseline covariates was conducted through propensity score matching weights. On-treatment analysis was conducted with inverse probability of censoring weights. Analysis based on the initial treatment group was also conducted to provide insights into selection bias. Repeated BMD measurements were examined with generalized estimating equations.

RESULTS

We identified 71 acetaminophen new users, 659 NSAID new users, and 84 opioid new users among 2365 participants. In the on-treatment analysis, the opioid group in comparison to the acetaminophen group had an additional average BMD decline of -0.06% [-1.24, 1.11] per year in the spine and -0.45% [-1.51, 0.61] per year in the femoral neck. BMD mean trajectories over time suggested a fifth-year decline in the opioid persistent users compared with other 2 groups. In the initial treatment group analysis, all 3 groups showed similar trajectories.

CONCLUSION

The BMD decline over time was similar among the 3 groups. However, 5 years of continuous opioid use may be associated with a greater BMD decline than 5 years on other analgesics. Further studies examining the relationship between very long-term persistent opioid use and BMD are warranted.

Angiotensin-(1-7)/Mas receptor as an antinociceptive agent in cancer-induced bone pain

Many cancerous solid tumors metastasize to the bone and induce pain (cancer-induced bone pain [CIBP]). Cancer-induced bone pain is often severe because of enhanced inflammation, rapid bone degradation, and disease progression. Opioids are prescribed to manage this pain, but they may enhance bone loss and increase tumor proliferation, further compromising patient quality of life. Angiotensin-(1-7) (Ang-(1-7)) binds and activates the Mas receptor (MasR). Angiotensin-(1-7)/MasR activation modulates inflammatory signaling after acute tissue insult, yet no studies have investigated whether Ang-(1-7)/MasR play a role in CIBP. We hypothesized that Ang-(1-7) inhibits CIBP by targeting MasR in a murine model of breast CIBP. 66.1 breast cancer cells were implanted into the femur of BALB/cAnNHsd mice as a model of CIBP. Spontaneous and evoked pain behaviors were assessed before and after acute and chronic administration of Ang-(1-7). Tissues were collected from animals for ex vivo analyses of MasR expression, tumor burden, and bone integrity. Cancer inoculation increased spontaneous pain behaviors by day 7 that were significantly reduced after a single injection of Ang-(1-7) and after sustained administration. Preadministration of A-779 a selective MasR antagonist prevented this reduction, whereas pretreatment with the AT2 antagonist had no effect; an AT1 antagonist enhanced the antinociceptive activity of Ang-(1-7) in CIBP. Repeated Ang-(1-7) administration did not significantly change tumor burden or bone remodeling. Data here suggest that Ang-(1-7)/MasR activation significantly attenuates CIBP, while lacking many side effects seen with opioids. Thus, Ang-(1-7) may be an alternative therapeutic strategy for the nearly 90% of patients with advanced-stage cancer who experience excruciating pain.

A comparison of bone quality and its determinants in young opioid-dependent women with healthy control group

BACKGROUND

Little is known about bone quality and its determinants in patients with opioid addiction. The goal of this study was to compare bone quality and its determinants in young opioid addicted women with a local group of young healthy women.

METHOD

Using cross-sectional design, 104 women (mean age 29.9 yrs, range: 20-40 yrs, SD=7.8) with previous opioid addiction and current methadone substitution (3-30mg, daily) for 1-16 weeks were compared to 117 healthy women (mean age 31.0 yrs, range: 20-40 yrs, SD=5.9). Bone quality was examined with quantitative ultrasound. Anthropometric characteristics (body weight, fat free mass (FFM), fat mass) were obtained by bioelectrical impedance analysis. Substance use and other risk factors for low bone quality were assessed by questionnaire-based interviews.

RESULTS

More than one-quarter (34%) of patients had osteopenia (n=31) or osteoporosis (n=4), compared to 16% of the healthy control group having osteopenia (n=18). Bivariate correlation analysis demonstrated that age, body weight, and FFM correlated with bone quality (p<0.05) in healthy women, which were not found in patients. Multivariate analyses showed that in healthy controls, the determinants of bone quality were age, body height, physical activity, and BMI, but in patients, the determinant of bone quality was duration of drug intake.

CONCLUSIONS

Long-term opioid dependence in young women may lead to low bone quality. Efforts to increase awareness of low bone quality in young opioid addicted women should be considered so that effective treatment may be employed to lower future fracture risk.

Bone mineral density and its determinants in men with opioid dependence

Data on the influence of opioid substitution therapy (OST) on skeletal health in men is limited. This cross-sectional study aimed to determine the prevalence of low bone mass in male drug users and to evaluate the relationship between endogenous testosterone and bone mass. We recruited 144 men on long-term opioid maintenance therapy followed in the Center of Addiction Medicine in Basel, Switzerland. Data on medical and drug history, fracture risk and history of falls were collected. Bone mineral density (BMD) was evaluated by densitometry and serum was collected for measurements of gonadal hormones and bone markers. 35 healthy age- and BMI-matched men served as the control group. The study participants received OST with methadone (69 %), morphine (25 %) or buprenorphine (6 %). Overall, 74.3 % of men had low bone mass, with comparable bone mass irrespective of OST type. In older men (≥40 years, n = 106), 29.2 % of individuals were osteoporotic (mean T-score -3.0 ± 0.4 SD) and 48.1 % were diagnosed with osteopenia (mean T-score -1.7 ± 0.4 SD). In younger men (n = 38), 65.8 % of men had low bone mass. In all age groups, BMD was significantly lower than in age-and BMI-matched controls. In multivariate analyses, serum free testosterone (fT) was significantly associated with low BMD at the lumbar spine (p = 0.02), but not at the hip. When analysed by quartiles of fT, lumbar spine BMD decreased progressively with decreasing testosterone levels. We conclude that low bone mass is highly prevalent in middle-aged men on long-term opioid dependency, a finding which may partly be determined by partial androgen deficiency.

Opioid receptor agonists may favorably affect bone mechanical properties in rats with estrogen deficiency-induced osteoporosis

The results of epidemiological, clinical, and in vivo and in vitro experimental studies on the effect of opioid analgesics on bone are inconsistent. The aim of the present study was to investigate the effect of morphine (an agonist of opioid receptors), buprenorphine (a partial μ opioid receptor agonist and κ opioid receptor antagonist), and naloxone (an antagonist of opioid receptors) on the skeletal system of female rats in vivo. The experiments were carried out on 3-month-old Wistar rats, divided into two groups: nonovariectomized (intact; NOVX) rats and ovariectomized (OVX) rats. The bilateral ovariectomy was performed 7 days before the start of drug administration. Morphine hydrochloride (20 mg/kg/day s.c.), buprenorphine (0.05 mg/kg/day s.c.), or naloxone hydrochloride dihydrate (2 mg/kg/day s.c.) were administered for 4 weeks to NOVX and OVX rats. In OVX rats, the use of morphine and buprenorphine counteracted the development of osteoporotic changes in the skeletal system induced by estrogen deficiency. Morphine and buprenorphine beneficially affected also the skeletal system of NOVX rats, but the effects were much weaker than those in OVX rats. Naloxone generally did not affect the rat skeletal system. The results confirmed the role of opioid receptors in the regulation of bone remodeling processes and demonstrated, in experimental conditions, that the use of opioid analgesics at moderate doses may exert beneficial effects on the skeletal system, especially in estrogen deficiency.

The unsolved case of "bone-impairing analgesics": the endocrine effects of opioids on bone metabolism

The current literature describes the possible risks for bone fracture in chronic analgesics users. There are three main hypotheses that could explain the increased risk of fracture associated with central analgesics, such as opioids: 1) the increased risk of falls caused by central nervous system effects, including sedation and dizziness; 2) reduced bone mass density caused by the direct opioid effect on osteoblasts; and 3) chronic opioid-induced hypogonadism. The impact of opioids varies by sex and among the type of opioid used (less, for example, for tapentadol and buprenorphine). Opioid-associated androgen deficiency is correlated with an increased risk of osteoporosis; thus, despite that standards have not been established for monitoring and treating opioid-induced hypogonadism or hypoadrenalism, all patients chronically taking opioids (particularly at doses ≥100 mg morphine daily) should be monitored for the early detection of hormonal impairment and low bone mass density.

Evaluating the affect and reversibility of opioid-induced androgen deficiency in an orthopaedic animal fracture model

BACKGROUND

Opioid pain medications are the basis for analgesia after orthopaedic injuries and procedures. However, opioids have many adverse effects, including opioid-induced androgen deficiency.

QUESTIONS/PURPOSES

We evaluated the occurrence and affect of opioid-induced androgen deficiency on osseous union and its ability to be reversed. Additional focus was placed on its perioperative onset and its duration in an orthopaedic animal model.

METHODS

A femoral osteotomy was created in 75 Sprague-Dawley rats. Postoperatively, animals were randomized into three treatment groups: control, morphine, and morphine plus testosterone. Testosterone levels were recorded preoperatively and at 48 hours, 4 weeks, and 8 weeks postoperatively. Some animals were euthanized at 4 weeks and others at 8 weeks postoperatively. Histology and micro-CT scans were used to evaluate callus. Three-point bend testing was performed to evaluate callus strength.

RESULTS

Serum testosterone levels in the morphine group showed decreased baseline levels of 2.2 ng/mL, 1.4 ng/mL, and 1.4 ng/mL (p < 0.001), whereas the morphine plus testosterone supplementation group showed increased serum levels at 41.7 ng/mL, 11.8 ng/mL, and 19.8 ng/mL (p < 0.001) compared with control animals (3.3 ng/mL, 5.8 ng/mL, 5.2 ng/mL) at 48 hours, 4 weeks, and 8 weeks, respectively. Compared with control animals, histology and micro-CT showed an impedance of callus maturation in the two experimental groups. Morphine-treated animals showed reduction in callus strength at 8 weeks (30% of the contralateral unfractured femur strength compared with 49% seen in the control animals at 8 weeks; p = 0.048); this finding was not fully reversed by testosterone supplementation (33% of the contralateral femur strength; p = 0.171).

CONCLUSIONS

Opioid-induced androgen deficiency occurred in this orthopaedic animal model. Although we previously showed that morphine inhibits callus maturation, the current study did not show a rescue of the morphine-treated animals with testosterone supplementation in either morphologic or mechanical testing. Testosterone suppression associated with opioid administration occurred almost immediately (within 48 hours) and was suppressed continually throughout the 8-week duration of study.

CLINICAL RELEVANCE

Opioid-induced androgen deficiency occurs during the perioperative orthopaedic period. Although its clinical relevance remains unknown, further evaluation is needed to determine if supplementation is warranted during the perioperative period.

Postoperative opioid administration inhibits bone healing in an animal model

BACKGROUND

The current mainstay of orthopaedic pain control is opioid analgesics but there are few studies in the literature evaluating the effects of opioids on bone healing.

QUESTIONS/PURPOSES

The purpose of this study was to use a rat fracture model to evaluate the effects of opioid administration on osseous union in the acute (4 weeks) and subacute (8 weeks) setting in an operatively stabilized fracture. We asked the following question: does morphine administration alter (1) fracture callus strength; (2) callus volume and formation; and (3) morphology and early remodeling to final osseous union?

METHODS

A 0.4-mm femoral osteotomy gap was created in 50 Sprague-Dawley rats using an established model. Postoperatively, rats were randomized to control versus morphine-treated study groups. Equal numbers of rats from each group were euthanized at 4 weeks and 8 weeks postoperatively. Three-point bend biomechanical testing was performed to evaluate postoperative callus strength. Micro-CT scans and histological analyses were used to evaluate postoperative callus volume and formation, morphology, and features of early remodeling.

RESULTS

Biomechanical testing identified a statistically significant (p = 0.048) reduction in callus strength in morphine-treated animals 8 weeks postoperatively compared with controls. Radiographic and histological analysis showed delayed callus maturation and lack of remodeling in the morphine group compared with control animals at 8 weeks. Micro-CT analysis expressed remodeling and resorption as a decrease in callus volume over the two time points. The control group had significant levels of resorption decreasing 29% (p = 0.023) over the 4-week to 8-week time interval. Morphine administration inhibited callus resorption and remodeling with only a 13% decrease (p = 0.393) in callus volume comparing these time points. The callus inhibition associated with morphine administration was not as evident in the acute, 4-week time setting.

CONCLUSIONS

Morphine administration inhibited callus strength in this animal model. This finding is likely consistent with the observation that the callus and healing bone appear to have a decreased rate of maturation and remodeling seen at 8 weeks.

CLINICAL RELEVANCE

This study identifies that administration of an opioid pain medication leads to weaker callus and impedes callus maturation compared with controls. These findings may provide the impetus to alter our current orthopaedic analgesic gold standard toward more multimodal and opioid-limiting pain control regimens.

Antisocial personality disorder is associated with receipt of physical disability benefits in substance abuse treatment patients

BACKGROUND

Opioid dependence is growing at an alarming rate in the United States, and opioid dependent patients have substantial medical, as well as psychiatric, conditions that impact their ability to work. This study evaluated the association between antisocial personality disorder (ASPD) and receipt of physical disability payments in methadone maintenance patients.

METHODS

Using data from 115 drug and alcohol abusing methadone maintained patients participating in two clinical trials, baseline characteristics of individuals receiving (n=22) and those not receiving (n=93) physical disability benefits were compared, and a logistic regression evaluated unique predictors of disability status.

RESULTS

Both an ASPD diagnosis and severity of medical problems were significant predictors of disability receipt, ps<.05. After controlling for other variables that differed between groups, patients with ASPD were more than five times likelier to receive physical disability benefits than patients without ASPD (odds ratio=5.66; 95% confidence interval=1.58-20.28).

CONCLUSIONS

These results demonstrate a role of ASPD in the receipt of disability benefits in substance abusers and suggest the need for greater understanding of the reasons for high rates of physical disability benefits in this population.

Opioid use for noncancer pain and risk of fracture in adults: a nested case-control study using the general practice research database

Opioid use has been reported to be associated with increased fracture risks. In a nested case-control study using the United Kingdom-based General Practice Research Database, we tested the hypotheses that fracture risk was associated with 1) an elevated risk of falls caused by the acute central nervous system effects of opioids including sedation and dizziness, and 2) osteoporosis caused by chronic opioid-induced hypogonadism. Among a cohort of adults aged 18-80 years without cancer who received ≥1 opioid prescription during 1990-2008, we selected cases with a first diagnosed fracture of the hip, humerus, or wrist; up to 4 controls, matched by age, sex, index date (date of the first diagnosed fracture), and general practice, were randomly selected for each case. Adjusted odds ratios and 95% confidence intervals were estimated by using conditional logistic regression. Current use of 1 prescription was associated with a strong risk of fracture (adjusted odds ratio = 2.70, 95% confidence interval: 2.34, 3.13). The risk decreased with increasing use. There was no association with current use of >20 opioid prescriptions. The findings were consistent for all study fractures and for most common opioids, suggesting that acute central nervous system effects of opioids rather than chronic opioid-induced hypogonadism play a key role in fracture risk.

Opioid-induced biochemical alterations of the neuroendocrine axis

Exogenous opioids have been used for decades to palliate cancer-related pain and other cancer-related manifestations and, more recently, to treat patients with pain not related to oncologic disease. While the goal of opioid treatment is symptomatic relief and improved quality of life, these patients often suffer from adverse side effects, including endocrine system abnormalities, of which hypogonadism is the best known. Opioids may interact with other hypothalamic-pituitary pathways and endocrine end organs, and in most cases these interactions are subtle and the effects unclear. The long-term effects of these agents on the endocrine system are still largely unknown. This article discusses the various effects of opioid agents on the endocrine system and provides information that allows early recognition of side effects that may alter the quality of life of patients affected by pain, awareness of the potential complications in opioid addicts, and detection and treatment of side effects in participants of an opioid detoxification program.