Independent and joint contributions of physical disability and chronic pain to incident opioid use disorder and opioid overdose among Medicaid patients

BACKGROUND

Chronic pain has been extensively explored as a risk factor for opioid misuse, resulting in increased focus on opioid prescribing practices for individuals with such conditions. Physical disability sometimes co-occurs with chronic pain but may also represent an independent risk factor for opioid misuse. However, previous research has not disentangled whether disability contributes to risk independent of chronic pain.

METHODS

Here, we estimate the independent and joint adjusted associations between having a physical disability and co-occurring chronic pain condition at time of Medicaid enrollment on subsequent 18-month risk of incident opioid use disorder (OUD) and non-fatal, unintentional opioid overdose among non-elderly, adult Medicaid beneficiaries (2016-2019).

RESULTS

We find robust evidence that having a physical disability approximately doubles the risk of incident OUD or opioid overdose, and physical disability co-occurring with chronic pain increases the risks approximately sixfold as compared to having neither chronic pain nor disability. In absolute numbers, those with neither a physical disability nor chronic pain condition have a 1.8% adjusted risk of incident OUD over 18 months of follow-up, those with physical disability alone have an 2.9% incident risk, those with chronic pain alone have a 3.6% incident risk, and those with co-occurring physical disability and chronic pain have a 11.1% incident risk.

CONCLUSIONS

These findings suggest that those with a physical disability should receive increased attention from the medical and healthcare communities to reduce their risk of opioid misuse and attendant negative outcomes.

Practical causal mediation analysis: extending nonparametric estimators to accommodate multiple mediators and multiple intermediate confounders

Mediation analysis is appealing for its ability to improve understanding of the mechanistic drivers of causal effects, but real-world data complexities challenge its successful implementation, including (i) the existence of post-exposure variables that also affect mediators and outcomes (thus, confounding the mediator-outcome relationship), that may also be (ii) multivariate, and (iii) the existence of multivariate mediators. All three challenges are present in the mediation analysis we consider here, where our goal is to estimate the indirect effects of receiving a Section 8 housing voucher as a young child on the risk of developing a psychiatric mood disorder in adolescence that operate through mediators related to neighborhood poverty, the school environment, and instability of the neighborhood and school environments, considered together and separately. Interventional direct and indirect effects (IDE/IIE) accommodate post-exposure variables that confound the mediator-outcome relationship, but currently, no readily implementable nonparametric estimator for IDE/IIE exists that allows for both multivariate mediators and multivariate post-exposure intermediate confounders. The absence of such an IDE/IIE estimator that can easily accommodate both multivariate mediators and post-exposure confounders represents a significant limitation for real-world analyses, because when considering each mediator subgroup separately, the remaining mediator subgroups (or a subset of them) become post-exposure intermediate confounders. We address this gap by extending a recently developed nonparametric estimator for the IDE/IIE to allow for easy incorporation of multivariate mediators and multivariate post-exposure confounders simultaneously. We apply the proposed estimation approach to our analysis, including walking through a strategy to account for other, possibly co-occurring intermediate variables when considering each mediator subgroup separately.

Has the opening of Amazon fulfillment centers affected demand for disability insurance?

An estimated 17.6% of blue-collar, manufacturing jobs were lost in the United States between 1970 and 2016. These jobs, often union-represented, provided relatively generous pay and benefits, creating a path to the middle class for individuals without a four-year college degree. Evidence suggests the closure of manufacturing facilities and resulting decline in economic opportunity increased demand for disability insurance (SSDI) among blue-collar workers. In recent years, the opening of Amazon Fulfillment Centers (FCs) has accelerated around the country, driving a wave of blue-collar job creation. We estimated the extent to which the opening of FCs affected SSDI application rates, including rates of approvals and denials, using a synthetic control group approach. We found that FC openings were associated with a 1.4% reduction in the SSDI application rate over the subsequent three years, translating to 5,528 fewer applications per year across commuting zones with an FC opening. Our findings are consistent with FC openings improving economic opportunities in local labor markets, though our confidence intervals were wide and included the null.

Optimally Choosing Medication Type for Patients With Opioid Use Disorder

Patients with opioid use disorder (OUD) tend to get assigned to one of 3 medications based on the treatment program to which the patient presents (e.g., opioid treatment programs tend to treat patients with methadone, while office-based practices tend to prescribe buprenorphine). It is possible that optimally matching patients with treatment type would reduce the risk of return to regular opioid use (RROU). We analyzed data from 3 comparative effectiveness trials from the US National Institute on Drug Abuse Clinical Trials Network (CTN0027, 2006-2010; CTN0030, 2006-2009; and CTN0051 2014-2017), in which patients with OUD (n = 1,459) were assigned to treatment with either injection extended-release naltrexone (XR-NTX), sublingual buprenorphine-naloxone (BUP-NX), or oral methadone. We learned an individualized rule by which to assign medication type such that risk of RROU during 12 weeks of treatment would be minimized, and then estimated the amount by which RROU risk could be reduced if the rule were applied. Applying our estimated treatment rule would reduce risk of RROU compared with treating everyone with methadone (relative risk (RR) = 0.79, 95% confidence interval (CI): 0.60, 0.97) or treating everyone with XR-NTX (RR = 0.71, 95% CI: 0.47, 0.96). Applying the estimated treatment rule would have resulted in a similar risk of RROU to that of with treating everyone with BUP-NX (RR = 0.92, 95% CI: 0.73, 1.11).

Buprenorphine & methadone dosing strategies to reduce risk of relapse in the treatment of opioid use disorder

BACKGROUND

Although there is consensus that having a "high-enough" dose of buprenorphine (BUP-NX) or methadone is important for reducing relapse to opioid use, there is debate about what this dose is and how it should be attained. We estimated the extent to which different dosing strategies would affect risk of relapse over 12 weeks of treatment, separately for BUP-NX and methadone.

METHODS

This was a secondary analysis of three comparative effectiveness trials. We examined four dosing strategies: 1) increasing dose in response to participant-specific opioid use, 2) increasing dose weekly until some minimum dose (16 mg BUP, 100 mg methadone) was reached, 3) increasing dose weekly until some minimum and increasing dose in response to opioid use thereafter (referred to as the "hybrid strategy"), and 4) keeping dose constant after the first 2 weeks of treatment. We used a longitudinal sequentially doubly robust estimator to estimate contrasts between dosing strategies on risk of relapse.

RESULTS

For BUP-NX, increasing dose following the hybrid strategy resulted in the lowest risk of relapse. For methadone, holding dose constant resulted in greatest risk of relapse; the other three strategies performed similarly. For example, the hybrid strategy reduced week 12 relapse risk by 13 % (RR: 0.87, 95 %CI: 0.83-0.95) and by 20 % (RR: 0.80, 95 %CI: 0.71-0.90) for BUP-NX and methadone respectively, as compared to holding dose constant.

CONCLUSIONS

Doses should be targeted toward minimum thresholds and, in the case of BUP-NX, raised when patients continue to use opioids.

Hypertension resolution after adrenalectomy for primary hyperaldosteronism: Which is the best predictive model?

BACKGROUND

We aimed to compare the predictive performance of three distinct clinical models purported to predict the resolution of aldosteronoma-associated hypertension after adrenalectomy.

METHODS

A tri-institutional database of aldosteronoma patients who underwent adrenalectomy between 2004 and 2019 was retrospectively reviewed. The three models of interest incorporate various preoperative clinical factors, such as age and sex. The predictive accuracy, as measured by area under the curve of receiver operator characteristic, was estimated. Receiver operator characteristic was evaluated across the whole cohort, then stratified by treatment location.

RESULTS

A total of 200 patients were included (91 American, 109 French). The clinicodemographic variables between groups were similar; the French cohort had a lower mean body mass index (P = .02). The overall complete clinical resolution of hypertension after adrenalectomy for the entire data set was 45.5% (n = 91). The regression coefficients in the Utsumi et al (2014) Japanese model produced a superior overall area under the curve (0.78, 95% confidence interval [CI] [0.71-0.84]). This model also performed best when the cohort was stratified by treatment location (French area under the curve = 0.74, 95% CI [0.64-0.83], US area under the curve = 0.82, 95% CI [0.72-0.91]).

CONCLUSION

When comparing three predictive models of aldosteronoma-associated hypertension resolution after adrenalectomy, the Utsumi et al model demonstrated the highest predictive validity across all cohorts. Counseling based on this model regarding probability of cure is recommended.

Reducing Campylobacter and Salmonella infection: two studies of the economic cost and attitude to adoption of on-farm biosecurity measures

To date there has been little research in the UK on farmer adoption of biosecurity measures to control food-borne zoonoses that have little or no impact on animal health or production but which threaten public health. Campylobacteriosis and salmonellosis are the two most common causes of food-borne infectious intestinal disease in people in Great Britain, causing approximately 57,000 and 13,000 reported cases in 2007 respectively (Anon 2008a) with an important cost to society. Poultry are an important source of both infections, while pigs may also contribute to human salmonellosis. However, these infections in poultry and pigs seldom cause disease. Research has shown that improved farm biosecurity may reduce the prevalence of these infections in livestock and if the majority of farmers were prepared to enhance biosecurity then there could be an important impact on public health. This article reports on the findings of two studies of farmer attitudes to and cost of the adoption of on-farm biosecurity measures to reduce the risk of animal diseases and therefore enhance food safety. One study, of Campylobacter infection among broiler flocks, is based on a survey of farmers faced with a hypothetical biosecurity intervention, while the other study, of Salmonella infection among pigs, is based on the participation of a group of farmers in an intervention study. In both cases, the results show a clear inverse relationship between the willingness of farmers to adopt a biosecurity measure and its estimated cost. This finding has implications for the success of on-farm biosecurity-enhancement policies based on voluntary adoption by farmers. In particular, financial inducements or penalties to farmers could be necessary to facilitate adoption of these measures.

Analysis of human megakaryocytic cells using dual-color immunofluorescence labeling

BACKGROUND

Megakaryocytes are classically identified by their cellular morphology and expression of platelet glycoproteins.

METHODS

In this study, the expression of GPIIIa (CD61) on hemopoietic cells was analyzed by dual-fluorescence flow cytometry.

RESULTS

All monocytic cells (CD14+) were shown to coexpress CD61. As the expression of platelet protein on these monocytic cells cannot be reduced by treating the cells with anticoagulant (ethlyenediaminetetraacetic acid [EDTA]), this observation is not simply due to platelet adhesion. When sorted CD61(lo)CD14+ cells were studied by light and electron microscopy, platelets or platelet fragments could not be detected on the cell surface. These cells were found to have typical monocytic morphology but no megakaryocytic characteristics.

CONCLUSIONS

This finding demonstrates that without careful definition, the quantitation of megakaryocytic cells will be inappropriately high. A clear and unambiguous criteria for the identification of megakaryocytic cells is described based on the high expression of platelet glycoprotein (e.g., CD61(hi) or CD41(hi)) but not the monocyte marker (CD14(neg)).

Modified thrombopoietic response to 5-FU in mice following transplantation of Lin-Sca-1+ bone marrow cells

An experimental murine model of bone marrow transplantation (BMT) has been used to study the mechanisms of platelet production following transplantation. A defined primitive population of hematopoietic bone marrow cells (1000 Lin-Sca-1+) was isolated and transplanted into lethally irradiated (13 Gy) syngeneic recipient mice. Platelet counts, but neither red nor white blood cell (WBC) counts, were low 30 days after transplantation. By 90 days, platelet levels had normalized in transplanted mice, but this occurred from a reduced megakaryocyte progenitor (CFU-Mk) pool, implying that altered bone marrow control was involved in platelet production. To assess the capacity of the bone marrow of these compensated mice to sustain platelet production, the rate and degree of recovery were examined following administration of 150 mg/kg of 5-fluorouracil (5-FU) 90 days after transplantation. Transplanted mice showed a delay, both in platelet recovery and rebound thrombocytosis, after 5-FU administration when compared to normal littermates treated with 5-FU. The regeneration and expansion of bone marrow CFU-Mk and mature megakaryocytes was retarded in the transplanted mice and explained the altered platelet kinetics. The onset of increased platelet and mature megakaryocyte size, however, was not different between the two groups, indicating that the transplanted mice responded normally to the mechanisms controlling megakaryocyte development and platelet formation. The data suggest that following BMT a limitation in the proliferative capacity of primitive hematopoietic cells results in a smaller pool of megakaryocyte precursors. Compensatory adjustment within the megakaryocyte lineage, nevertheless, results in normalization of megakaryocyte and platelet number. The ability of transplanted mice to sustain platelet production when challenged with increased platelet demand is not limited by megakaryocytic maturation but by a restriction in proliferation or differentiation from the stem cell pool.

Compensatory mechanisms in platelet production: lack of a paracrine response in W/Wv mice treated with 5-fluorouracil

W/Wv mice maintain normal platelet levels despite having a reduced functional stem cell pool, indicating that platelet production in these mice is compensated by altered megakaryocytopoiesis. In this study the effect of 5-fluorouracil (5-FU) treatment on platelet production in W/Wv mice and their congenic normal littermates was assessed. Recovery of circulating platelet levels occurred 11 days after 5-FU administration in W/Wv mice and subsequently did not increase above control values. In contrast, normal littermates showed an increased platelet count by day 8 and significant thrombocytosis between days 11 and 14. Investigation of bone marrow megakaryocytopoiesis in W/Wv mice showed there was no recovery in the number of megakaryocyte progenitors (CFU-Meg) per femur between days 3 and 5, but control values were reached by day 10. In addition, by day 8 the number of mature megakaryocytes per unit volume of bone marrow in these mice had not returned to control values, although the megakaryocytes were of an increased size. In comparison, the number of CFU-Meg per femur in normal mice treated with 5-FU began to recover after day 3, returned to control values by day 8 and increased to supranormal levels by day 14. Bone marrow megakaryocyte concentration was increased 2-fold over the control by day 8 and an increase in mean megakaryocyte size was also observed. The data suggest that platelet production in mice is dependent on the rate of establishment of both the progenitor cell and megakaryocyte pools. The inability of W/Wv mice to enhance and accelerate progenitor cell levels led to a reduced bone marrow response and failure to produce a marked thrombocytosis.

Acquired amegakaryocytic thrombocytopaenia in a child

A boy aged 5 years is described with amegakaryocytic thrombocytopaenia, which was associated with defective granulopoiesis and erythropoiesis, but did not evolve into marrow aplasia. Marrow cultures confirmed the presence of abnormalities in each of the haemopoietic lineages and identified defective maturation of megakaryocytic precursors. The was no evidence of a humoral inhibitor of megakaryopoiesis. The patient's blood cell counts responded to treatment with oxymetholone.

Acquired amegakaryocytic thrombocytopenia: report of a case and review of literature

We describe a 55-year-old female with acquired amegakaryocytic thrombocytopenia who has been successfully treated with antithymocyte globulin. In-vitro studies assessing megakaryocytopoiesis in the presence of the patient's plasma and peripheral blood adherent cells showed normal or increased stimulation. This patient brings to 30 the number of adult cases of acquired amegakaryocytic thrombocytopenia now reported in the English literature. Review of this material suggests that it may be more common than has been appreciated. Several pathogenic mechanisms, especially immune mechanisms, have been identified; good, sustained remissions have been achieved in eight patients who were treated with immunosuppressive agents.

Generation of murine hematopoietic precursor cells from macrophage high-proliferative-potential colony-forming cells

High-proliferative-potential colony-forming cells (HPP-CFC) have been described as primitive murine macrophage progenitors. We have previously demonstrated the existence of two populations of HPP-CFC: one population, termed HPP-CFC-1, is stimulated by the combination of macrophage colony-stimulating factor (CSF-1) plus haemopoietin-1 (H-1) and actively generates a second population of HPP-CFC, termed HPP-CFC-2. HPP-CFC-2 are stimulated by CSF-1 plus interleukin-3 and generate macrophage CFC that differentiate to form mature macrophages. In this study, we have demonstrated that HPP-CFC-1, when stimulated by CSF-1 plus H-1, generate colony-forming cells (CFC) for the megakaryocyte and granulocyte lineages in addition to HPP-CFC-2 and M-CFC. No CFC were detected with erythroid potential. In addition, HPP-CFC-1 generated cells that formed day-13 spleen colonies, cells that repopulated the bone marrow, cells with platelet-repopulating ability, and cells with erythroid-repopulating ability in lethally irradiated mice. These data support previous data that the HPP-CFC-1 represent a primitive hemopoietic cell population and demonstrate the multipotentiality but not totipotentiality of these cells.

Human megakaryocytes. IV. Growth and characterization of clonable megakaryocyte progenitors in agar

Human megakaryocyte progenitors were cloned in semisolid agar from unfractionated bone marrow cells and recognized by their capability of producing discrete megakaryocyte colonies. Megakaryocyte colonies were identified in situ by immunofluorescence, using antibodies against platelet glycoproteins Ib, IIb, and IIIa, as well as von Willebrand factor (vWf), which are regarded as distinct protein markers for the megakaryocyte-platelet lineage. Megakaryocyte colonies typically contained 20-50 cells arranged in compact configurations, with high nuclear-cytoplasmic ratios, diameters between 10 and 14 micron, and round, oval, or indented nuclei. Colony numbers peaked at days 6 and 7, with a mean of 17.9 megakaryocyte colonies (range, 8-33) per 2 X 10(5) unseparated marrow cells. The in vitro growth characteristics and kinetics of megakaryocytes grown in agar are different from those described for the plasma clot and methylcellulose systems, which suggests selection of distinct progenitor subsets. Consequently, this assay may be a useful complement to other approaches in characterizing the megakaryocyte progenitor population.