Warfarin therapy in the HIV medical home model: low rates of therapeutic anticoagulation despite adherence and differences in dosing based on specific antiretrovirals

Platelet and HIV Interactions and Their Contribution to Non-AIDS Comorbidities

Platelets are anucleate cytoplasmic cell fragments that circulate in the blood, where they are involved in regulating hemostasis. Beyond their normal physiologic role, platelets have emerged as versatile effectors of immune response. During an infection, cell surface receptors enable platelets to recognize viruses, resulting in their activation. Activated platelets release biologically active molecules that further trigger host immune responses to protect the body against infection. Their impact on the immune response is also associated with the recruitment of circulating leukocytes to the site of infection. They can also aggregate with leukocytes, including lymphocytes, monocytes, and neutrophils, to immobilize pathogens and prevent viral dissemination. Despite their host protective role, platelets have also been shown to be associated with various pathophysiological processes. In this review, we will summarize platelet and HIV interactions during infection. We will also highlight and discuss platelet and platelet-derived mediators, how they interact with immune cells, and the multifaceted responsibilities of platelets in HIV infection. Furthermore, we will give an overview of non-AIDS comorbidities linked to platelet dysfunction and the impact of antiretroviral therapy on platelet function.

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Elevated Risk of Venous Thromboembolism in People Living with HIV

Human immunodeficiency virus (HIV) has been generally considered as a highly adaptive and rapidly evolving virus. It still constitutes a major public health problem all over the world despite an effective outcome in the prevention and reversal of the development and prognosis by using antiretroviral therapy. The salient question lies in the more frequent emergence of a series of comorbidities along with the prolongation of the life, which deeply affects the survival in such group. Venous thromboembolism (VTE) has been recognized to be the third most common cardiovascular condition within people living with HIV (PWH). In terms of its mechanism of action, the occurrence of VTE is quite multifactorial and complex in HIV. Prior exploration concerning the etiology of VTE in PWH identifies general, disease-specific, and miscellaneous factors for explaining its occurrence and development. VTE has constituted an important role in PWH and may increase its all-cause mortality. Therefore, it is quite necessary to understand VTE from the following aspects of epidemiology, pathophysiology, molecular mechanisms, and therapeutic interventions so as to balance the risks and benefits of anticoagulation and optimize corresponding treatment.

The Youngbloods. Get Together. Hypercoagulation, Complement, and NET Formation in HIV/SIV Pathogenesis

Chronic, systemic T-cell immune activation and inflammation (IA/INFL) have been reported to be associated with disease progression in persons with HIV (PWH) since the inception of the AIDS pandemic. IA/INFL persist in PWH on antiretroviral therapy (ART), despite complete viral suppression and increases their susceptibility to serious non-AIDS events (SNAEs). Increased IA/INFL also occur during pathogenic SIV infections of macaques, while natural hosts of SIVs that control chronic IA/INFL do not progress to AIDS, despite having persistent high viral replication and severe acute CD4+ T-cell loss. Moreover, natural hosts of SIVs do not present with SNAEs. Multiple mechanisms drive HIV-associated IA/INFL, including the virus itself, persistent gut dysfunction, coinfections (CMV, HCV, HBV), proinflammatory lipids, ART toxicity, comorbidities, and behavioral factors (diet, smoking, and alcohol). Other mechanisms could also significantly contribute to IA/INFL during HIV/SIV infection, notably, a hypercoagulable state, characterized by elevated coagulation biomarkers, including D-dimer and tissue factor, which can accurately identify patients at risk for thromboembolic events and death. Coagulation biomarkers strongly correlate with INFL and predict the risk of SNAE-induced end-organ damage. Meanwhile, the complement system is also involved in the pathogenesis of HIV comorbidities. Despite prolonged viral suppression, PWH on ART have high plasma levels of C3a. HIV/SIV infections also trigger neutrophil extracellular traps (NETs) formation that contribute to the elimination of viral particles and infected CD4+ T-cells. However, as SIV infection progresses, generation of NETs can become excessive, fueling IA/INFL, destruction of multiple immune cells subsets, and microthrombotic events, contributing to further tissue damages and SNAEs. Tackling residual IA/INFL has the potential to improve the clinical course of HIV infection. Therefore, therapeutics targeting new pathways that can fuel IA/INFL such as hypercoagulation, complement activation and excessive formation of NETs might be beneficial for PWH and should be considered and evaluated.

Venous thromboembolic disease in adults admitted to hospital in a setting with a high burden of HIV and TB

BACKGROUND

HIV and tuberculosis (TB) independently cause an increased risk for venous thromboembolic disease (VTE): deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Data from high HIV and TB burden settings describing VTE are scarce. The Wells' DVT and PE scores are widely used but their utility in these settings has not been reported on extensively.

OBJECTIVES

To evaluate new onset VTE, compare clinical characteristics by HIV status, and the presence or absence of TB disease in our setting. We also calculate the Wells' score for all patients.

METHODS

A prospective cohort of adult in-patients with radiologically confirmed VTE were recruited into the study between September 2015 and May 2016. Demographics, presence of TB, HIV status, duration of treatment, CD4 count, viral load, VTE risk factors, and parameters to calculate the Wells' score were collected.

RESULTS

We recruited 100 patients. Most of the patients were HIV-infected (n=59), 39 had TB disease and 32 were HIV/TB co-infected. Most of the patients had DVT only (n=83); 11 had PE, and 6 had both DVT and PE. More than a third of patients on antiretroviral treatment (ART) (43%; n=18/42) were on treatment for <6 months. Half of the patients (51%; n=20/39) were on TB treatment for <1 month. The median (interquartile range (IQR)) DVT and PE Wells' score in all sub-groups was 3.0 (1.0 - 4.0) and 3.0 (2.5 - 4.5), respectively.

CONCLUSION

HIV/TB co-infection appears to confer a risk for VTE, especially early after initiation of ART and/or TB treatment, and therefore requires careful monitoring for VTE and early initiation of thrombo-prophylaxis.

Venous thromboembolism in people living with HIV infection (PWH)

The risk of venous thromboembolism (VTE) and of recurrent VTE remain elevated in people living with HIV compared to controls still with contemporary antiretroviral therapy (ART). The pathophysiology of VTE in HIV is multi factorial and includes an interplay among traditional risk factors, HIV-specific factors, behavioral factors, exposure to ART and other therapies, coinfections, and co-morbidities.

Developing and Validating a Clinical Warfarin Dose-Initiation Model for Black-African Patients in South Africa and Uganda

Warfarin remains the oral anticoagulant of choice in sub-Saharan Africa. However, dosing is challenging due to a highly variable clinical response for a given dose. This study aimed to develop and validate a clinical warfarin dose-initiation model in sub-Saharan Black-African patients. For the development cohort, we used data from 364 patients who were recruited from 8 outpatient clinics and hospital departments in Uganda and South Africa (June 2018-July 2019). Validation was undertaken using the International Warfarin Pharmacogenetics Consortium (IWPC) dataset (690 black patients). Four predictors (age, weight, target International Normalized Ratio range, and HIV status) were included in the final model, which achieved mean absolute errors (MAEs; mean of absolute differences between true dose and dose predicted by the model) of 11.6 (95% confidence interval (CI) 10.4-12.8) and 12.5 (95% CI 11.6-13.4) mg/week in the development and validation cohorts, respectively. Two other clinical models, IWPC and Gage, respectively, obtained MAEs of 12.5 (95% CI 11.3-13.7) and 12.7 (95% CI 11.5-13.8) mg/week in the development cohort, and 12.1 (95% CI 11.2-13.0) and 12.2 (95% CI 11.4-13.1) mg/week in the validation cohort. Compared with fixed dose-initiation, our model decreased the percentage of patients at high risk of suboptimal anticoagulation by 7.5% (1.5-13.7%) and 11.9% (7.1-16.8%) in the development and validation cohorts, respectively. The clinical utility of this model will be tested in a prospective study. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? ☑ Warfarin dosing remains challenging due to a highly variable clinical response for a given dose. WHAT QUESTION DID THIS STUDY ADDRESS? ☑ Can a clinical dose-initiation model be developed and validated for sub-Saharan Black-African patients? WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? ☑ We have developed the first warfarin dose-initiation clinical model for Black-African patients in Uganda and South Africa. HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE? ☑ We will be implementing and validating this model in a prospective cohort to inform future large-scale implementation. More optimized dosing should improve the quality of warfarin anticoagulation in these two developing countries.

Stroke and Systemic Thromboembolism Prevention in People Living With Human Immunodeficiency Virus With Atrial Fibrillation: A Review of Its Implications for Clinical Practice

In the last few decades, types of diseases affecting people living with human immunodeficiency virus (PLHIV) have shifted as the population ages, with cardiovascular disease becoming a leading cause of death in this population. Atrial fibrillation (AF) is an increasingly common arrhythmia both in the general population and in PLHIV, with an estimated prevalence of 2% to 3% among PLHIV. Prevention of stroke and systemic thromboembolism (SSE) with antithrombotic therapy is a cornerstone of AF treatment and substantially decreases AF-related morbidity and mortality. Although updated guidelines extensively discuss this issue, they do not address the peculiarities of PLHIV. The role of human immunodeficiency virus (HIV) infection as an independent factor for SSE in individuals with AF and whether the presence of HIV should alter the threshold for SSE thromboprophylaxis are unknown. Nevertheless, a growing body of evidence describes the increasing burden of comorbidities such as hypertension and stroke in PLHIV, which predispose them to AF and SSE. In the absence of HIV-specific AF guidelines, PLHIV with AF should be comprehensively assessed for their risk of SSE and bleeding using commonly available scores despite them having been primarily validated in the non-HIV population. Both vitamin K antagonists and direct oral anticoagulants can be used in PLHIV. Addressing HIV-related comorbidities and potential drug-drug interactions with antiretrovirals is crucial to prevent SSE and reduce adverse reactions of oral anticoagulants. This review summarizes the current guidelines for SSE prevention in patients with AF and describes key considerations for their implementation among PLHIV receiving antiretroviral therapy.

Are we successfully managing cardiovascular disease in people living with HIV?

PURPOSE OF REVIEW

The aim of this study was to discuss the most recent research in the management of cardiovascular disease (CVD) in people living with HIV (PLWHIV) with a focus on screening, primary and secondary prevention.

RECENT FINDINGS

The cause of CVD in PLWHIV is complex and multifactorial and creates a demand for a multifaceted approach to screening and prevention. Current screening and management of CVD risk factors in PLWHIV is suboptimal, reasons for this are not clear and the data are still scarce both in the primary and secondary preventive setting. There are no optimal routine risk screening tools available to accurately detect early and subclinical disease; PLWHIV are undertreated with preventive drugs such as statins and aspirin and antihypertensives; there are still no programmes that have been shown significantly efficient over time with regards to improved smoking cessation, increased physical activity and optimal diet, and recent reports call for intensified focus on HIV-positive women as a particularly vulnerable subgroup.

SUMMARY

There is a need for further studies investigating barriers to optimal CVD risk factor management in PLWHIV and an increased focus of CVD prevention in HIV-positive women.

Use of direct oral anticoagulants for treatment of atrial fibrillation in patients with HIV: a review

PURPOSE OF REVIEW

Atrial fibrillation is increasingly common in the ageing population. Patients with atrial fibrillation and HIV have a higher stroke risk, with guidelines recommending anticoagulation in the majority. Whilst anticoagulation options have diversified in the last decade for the general population, there is limited evidence for the safety and efficacy of these medications when used concurrently with antiretroviral therapy. We review the potential for patients with HIV on antiretroviral therapy to have direct-acting oral anticoagulations (DOACs).

RECENT FINDINGS

Several case reports have been published in the past 5 years, as well as theoretical analyses of anticipated drug interactions, which provide a starting point to guide use of DOACs with antiretroviral medications.

SUMMARY

Caution is needed when prescribing DOACs in patients with atrial fibrillation and HIV due to potential drug interactions. Studies are lacking and current advice is based on case reports, expert opinion and knowledge of theoretical interactions.

The therapeutic effect of fraxetin on ethanol-induced hepatic fibrosis by enhancing ethanol metabolism, inhibiting oxidative stress and modulating inflammatory mediators in rats

The present study was designed to investigate the possible protective effects of fraxetin against ethanol induced liver fibrosis in rats. Rats were underwent intragastric administration of ethanol (5.0-9.5 g/kg) once a day for 24 weeks. Effect of fraxetin against ethanol induced liver fibrosis was investigated by giving 20 or 50 mg/kg fraxetin. At the end of experiment, the livers were collected for histopathological analyses, protein extraction, and enzymatic activities. Our results indicated that fraxetin significantly corrected ethanol-induced hepatic fibrosis, as evidenced by the decrease in serum ALT and AST, the attenuation of histopathological changes. Fraxetin also expedited ethanol metabolism by enhancing the alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activities. Besides, fraxetin alleviated lipid peroxidation, enhanced hepatic antioxidant capabilities, inhibited CYP2E1 activity, and reduced the inflammatory mediators, including TNF-α and IL-1β via up-regulation of hemeoxygenase-1 (HO-1) protein. In summary, the hepatoprotection of fraxetin is mostly attributed to its antioxidant capability, alcohol metabolism, and anti-inflammation effect.

CHA2DS2-VASc Score, Warfarin Use, and Risk for Thromboembolic Events Among HIV-Infected Persons With Atrial Fibrillation

BACKGROUND

The prevalence of atrial fibrillation in the HIV-infected population is growing, but the ability of the CHA2DS2-VASc score to predict thromboembolic (TE) risk is unknown in this population.

SETTING

Within the Veterans Affairs HIV Clinical Case Registry, 914 patients had an atrial fibrillation diagnosis between 1997 and 2011 and no previous TE events.

METHODS

We compared TE incidence by CHA2DS2-VASc scores and stratified by warfarin use. Using Cox proportional hazards regression with adjustment for competing risks, we modeled associations of CHA2DS2-VASc scores and warfarin use with TE risk.

RESULTS

At baseline, the distribution of CHA2DS2-VASc scores was 0 (n = 208), 1 (n = 285), and 2+ (n = 421); 34 patients developed 38 TE events during a median of 3.8 years follow-up. Event rates by CHA2DS2-VASc scores of 0, 1, and 2+ were 5.4, 9.3, and 8.1 per 1000 person years, respectively; multivariate-adjusted hazards ratios (HRs) were 1.70 (95% confidence interval: 0.65 to 4.45) for CHA2DS2-VASc score 1 (P = 0.28) and HR = 1.34 (0.51, 3.48) for score 2+ versus 0 (P = 0.55). Baseline warfarin use was associated with increased TE risk, although not statistically significant [HR 2.06 (0.86, 4.93), P = 0.11] with similar results when modeled as time-updated use and duration of use.

CONCLUSION

In this national registry of HIV-infected veterans with atrial fibrillation, CHA2DS2-VASc scores were only weakly associated with TE risk. Furthermore, warfarin did not seem to be effective at preventing TE events. These results should raise concerns about the optimal strategy for TE prevention among HIV-infected persons with atrial fibrillation.

Comparison of the therapeutic dose of warfarin in HIV-infected and HIV-uninfected patients: a study of clinical practice

BACKGROUND

People infected with HIV are prone to venous thrombosis. Treatment of thrombosis is primarily with warfarin. No studies have addressed the effects of HIV infection on warfarin dose. The aims of this study were to determine whether the therapeutic dose of warfarin and induction time to therapeutic dose in HIV-infected patients differ from that in HIV-uninfected patients.

METHODS

A prospective and retrospective descriptive study of induction time to therapeutic warfarin dose, as well as of ambulant therapeutic warfarin dose, was performed. HIV-infected and HIV-uninfected patients being treated after deep venous thrombosis with or without pulmonary embolism were compared. Sex and use of antiretroviral drugs (ARVs) were also compared in the groups.

RESULTS

234 patients were entered into the study. Induction time to therapeutic warfarin dose did not differ between the 2 groups. The mean therapeutic dose of warfarin was higher in the HIV-infected than the HIV-uninfected group: 6.06 vs 5.72 mg/day, but this was not statistically significant (p=0.29). There was no difference in therapeutic warfarin dose between ARV-naïve groups-HIV-uninfected and HIV-infected patients not on ARVs.

CONCLUSIONS

There appears to be little effect of HIV infection on warfarin dosing. Warfarin therapy should be administered conventionally in HIV-infected patients.

Venous Thromboembolism Requiring Extended Anticoagulation Among HIV-Infected Patients in a Rural, Resource-Constrained Setting in Western Kenya

BACKGROUND

HIV-infected patients are at an increased risk of developing venous thromboembolism (VTE), and minimal data are available to describe the need for extended treatment.

OBJECTIVE

To evaluate the frequency of and determine predictive risk factors for extended anticoagulation of VTE in HIV-infected patients in rural, western Kenya.

METHODS

A retrospective chart review was conducted at the Anticoagulation Monitoring Service affiliated with Moi Teaching and Referral Hospital and the Academic Model Providing Access to Healthcare. Data were collected on patients who were HIV-infected and receiving anticoagulation for lower-limb deep vein thrombosis. The need for extended anticoagulation, defined as receiving ≥7 months of warfarin therapy, was established based on patient symptoms or Doppler ultrasound-confirmed diagnosis. Evaluation of the secondary outcomes utilized a univariate analysis to identify risk factors associated with extended anticoagulation.

RESULTS

A total of 71 patients were included in the analysis; 27 patients (38%) required extended anticoagulation. The univariate analysis showed a statistically significant association between the need for extended anticoagulation and achieving a therapeutic international normalized ratio within 21 days in both the unadjusted and adjusted analysis. Patients with a history of opportunistic infections required an extended duration of anticoagulation in the adjusted analysis: odds ratio = 3.42; 95% CI = 1.04-11.32; P = 0.04.

CONCLUSIONS

This study shows that there may be a need for increased duration of anticoagulation in HIV-infected patients, with a need to address the issue of long-term management. Guideline recommendations are needed to address the complexity of treatment issues in this population.

Evaluation of a Potential Interaction Between New Regimens to Treat Hepatitis C and Warfarin

OBJECTIVE

New regimens to treat hepatitis C virus infection have expanded the eligible patient population to include more patients receiving concurrent warfarin. The primary objective of this study was to assess whether a drug interaction occurs when these regimens are added to warfarin therapy.

METHODS

This was a retrospective cohort design using a nationwide database of the Veterans Affairs Health System. Patients on warfarin therapy treated with sofosbuvir or ombitasvir, paritaprevir-ritonavir, and dasabuvir (OBV-PTV/r-DSV) from March 2014 through October 2015 were identified. The warfarin dose response was calculated using a warfarin sensitivity index (WSI) defined as the steady-state INR divided by the mean daily warfarin dose. The primary outcome was the change in WSI from hepatitis C treatment initiation to completion.

RESULTS

The final sample consisted of 271 patients. The WSI decreased 23% from a mean baseline value of 0.53 to 0.39 (decrease of 0.14; 95% CI = 0.11 to 0.16; P < 0.001). OBV-PTV/r-DSV produced a significantly greater decrease than any sofosbuvir regimen. Concurrent ribavirin accounted for an additional decrease in warfarin sensitivity of -0.09 (95% CI = -0.06 to -0.12; P < 0.001). The percentage of subtherapeutic INR results increased from 26% prior to hepatitis C treatment to 58% during treatment.

CONCLUSIONS

Results indicate a clinically significant reduction in warfarin dose-response when hepatitis C treatment regimens were added to warfarin. They were most profound with OBV-PTV/r-DSV. Ribavirin was associated with an additive effect. Clinicians should be aware of this potential drug interaction to closely monitor and minimize subtherapeutic levels of anticoagulation.

The neurobiology of HIV and its impact on cognitive reserve: A review of cognitive interventions for an aging population

The medications used to treat HIV have reduced the severity of cognitive deficits; yet, nearly half of adults with HIV still exhibit some degree of cognitive deficits, referred to as HIV-associated neurocognitive disorder or HAND. These cognitive deficits interfere with everyday functioning such as emotional regulation, medication adherence, instrumental activities of daily living, and even driving a vehicle. As adults are expected to live a normal lifespan, the process of aging in this clinical population may exacerbate such cognitive deficits. Therefore, it is important to understand the neurobiological mechanisms of HIV on cognitive reserve and develop interventions that are either neuroprotective or compensate for such cognitive deficits. Within the context of cognitive reserve, this article delivers a state of the science perspective on the causes of HAND and provides possible interventions for addressing such cognitive deficits. Suggestions for future research are also provided.

Drug interactions and antiretroviral drug monitoring

Owing to the improved longevity afforded by combination antiretroviral therapy (cART), HIV-infected individuals are developing several non-AIDS-related comorbid conditions. Consequently, medical management of the HIV-infected population is increasingly complex, with a growing list of potential drug-drug interactions (DDIs). This article reviews some of the most relevant and emerging potential interactions between antiretroviral medications and other agents. The most common DDIs are those involving protease inhibitors or non-nucleoside reverse transcriptase inhibitors, which alter the cytochrome P450 enzyme system and/or drug transporters such as p-glycoprotein. Of note are the new agents for the treatment of chronic hepatitis C virus infection. These new classes of drugs and others drugs that are increasingly used in this patient population represent a significant challenge with regard to achieving the goals of effective HIV suppression and minimization of drug-related toxicities. Awareness of DDIs and a multidisciplinary approach are imperative in reaching these goals.

Venous thromboembolism among HIV-positive patients and anticoagulation clinic outcomes integrated within the HIV primary care setting

The purpose of this study was to explore factors associated with venous thromboembolism (VTE) among a cohort of HIV-infected patients and to describe early outcomes of warfarin anticoagulation therapy treated in a pharmacist-based anticoagulation clinic (ACC). A nested case-control study was conducted using the University of Alabama at Birmingham 1917 HIV Clinic Cohort. Conditional logistic regression was used to estimate factors associated with VTE. Among HIV-infected VTE cases, ACC-managed patients were compared to primary care provider (PCP)-managed patients to determine Time within Therapeutic INR Range (TTR). CD4 < 200 cells/µl (OR = 4.50; 95% CI = 1.52, 13.37; p = 0.007) and prior surgical procedures (13.20; 1.56; 111.4; p = 0.018) demonstrated positive associations with VTE, whereas longer HIV duration demonstrated a negative association (0.87; 0.78, 0.98; p = 0.019). TTR was 56.2% among ACC-managed patients compared to 30.5% of PCP-managed patients (p = 0.174). Overall, prior surgical procedures and low CD4 count were associated with an increased risk of VTE among HIV-infected patients. Despite small sample size, patients managed in ACC tend to achieve greater proportion of TTR compared to those managed by PCPs, suggesting that this model of therapy may provide additional benefits to HIV-infected patients.

Exploring the medical home in Ryan White HIV care settings: a pilot study

Amid increased attention to the cost of health care, health information technology, and specialization and fragmentation in medicine, the medical home has achieved recognition as a model for more effective and efficient health care. Little data are available on recently funded HIV medical home demonstration projects, and no research richly describes existing medical home characteristics, implementation challenges, and impact on outcomes in longstanding HIV outpatient settings. The Ryan White HIV/AIDS Program (RWP) provides federal funding for primary and specialty care for people living with HIV. Although RWP clinics developed independently of the medical home model, existing data indirectly support that, with emphasis on primary, comprehensive, and patient-centered care, RWP clinics operate as medical homes. This study explores the development, definition, and implementation of medical home characteristics by RWP-funded providers in order to better understand how it fits with broader debates about medical homes and health care reform.

The role of competitive binding to human serum albumin on efavirenz-warfarin interaction: a nuclear magnetic resonance study

The potential for co-prescription of the anti-human immunodeficiency virus (anti-HIV) drug efavirenz (EFV) and the oral anticoagulant warfarin (WAR) is currently high as EFV is a drug of choice for HIV type 1 infection and because cardiovascular disease is increasing among HIV-infected individuals. However, clinical reports of EFV-WAR interaction, leading to WAR overdosing, call for elucidation of the mechanisms involved in this drug-drug interaction. Here we present the first report demonstrating competition of the two drugs for the same binding site of human serum albumin. Using ligand-based nuclear magnetic resonance experiments, this study proves that EFV has an effect on the concentration of free WAR. This previously unidentified EFV-WAR interaction represents a potential risk factor that should be taken into account when considering treatment options.

Conformity of pediatric/adolescent HIV clinics to the patient-centered medical home care model

The patient-centered medical home (PCMH) has been introduced as a model for providing high-quality, comprehensive, patient-centered care that is both accessible and coordinated, and may provide a framework for optimizing the care of youth living with HIV (YLH). We surveyed six pediatric/adolescent HIV clinics caring for 578 patients (median age 19 years, 51% male, and 82% black) in July 2011 to assess conformity to the PCMH. Clinics completed a 50-item survey covering the six domains of the PCMH: (1) comprehensive care, (2) patient-centered care, (3) coordinated care, (4) accessible services, (5) quality and safety, and (6) health information technology. To determine conformity to the PCMH, a novel point-based scoring system was devised. Points were tabulated across clinics by domain to obtain an aggregate assessment of PCMH conformity. All six clinics responded. Overall, clinics attained a mean 75.8% [95% CI, 63.3-88.3%] on PCMH measures-scoring highest on patient-centered care (94.7%), coordinated care (83.3%), and quality and safety measures (76.7%), and lowest on health information technology (70.0%), accessible services (69.1%), and comprehensive care (61.1%). Clinics moderately conformed to the PCMH model. Areas for improvement include access to care, comprehensive care, and health information technology. Future studies are warranted to determine whether greater clinic PCMH conformity improves clinical outcomes and cost savings for YLH.