Modelling the social and structural determinants of tuberculosis: opportunities and challenges

INTRODUCTION: Despite the close link between tuberculosis (TB) and poverty, most mathematical models of TB have not addressed underlying social and structural determinants. OBJECTIVE: To review studies employing mathematical modelling to evaluate the epidemiological impact of the structural determinants of TB. METHODS: We systematically searched PubMed and personal libraries to identify eligible articles. We extracted data on the modelling techniques employed, research question, types of structural determinants modelled and setting. RESULTS: From 232 records identified, we included eight articles published between 2008 and 2015; six employed population-based dynamic TB transmission models and two non-dynamic analytic models. Seven studies focused on proximal TB determinants (four on nutritional status, one on wealth, one on indoor air pollution, and one examined overcrowding, socio-economic and nutritional status), and one focused on macro-economic influences. CONCLUSIONS: Few modelling studies have attempted to evaluate structural determinants of TB, resulting in key knowledge gaps. Despite the challenges of modelling such a complex system, models must broaden their scope to remain useful for policy making. Given the intersectoral nature of the interrelations between structural determinants and TB outcomes, this work will require multidisciplinary collaborations. A useful starting point would be to focus on developing relatively simple models that can strengthen our knowledge regarding the potential effect of the structural determinants on TB outcomes

The Importance of Heterogeneity to the Epidemiology of Tuberculosis

Although less well-recognised than for other infectious diseases, heterogeneity is a defining feature of TB epidemiology. To advance toward TB elimination, this heterogeneity must be better understood and addressed. Drivers of heterogeneity in TB epidemiology act at the level of the infectious host, organism, susceptible host, environment and distal determinants. These effects may be amplified by social mixing patterns, while the variable latent period between infection and disease may mask heterogeneity in transmission. Reliance on notified cases may lead to misidentification of the most affected groups, as case detection is often poorest where prevalence is highest. Assuming average rates apply across diverse groups and ignoring the effects of cohort selection may result in misunderstanding of the epidemic and the anticipated effects of control measures. Given this substantial heterogeneity, interventions targeting high-risk groups based on location, social determinants or comorbidities could improve efficiency, but raise ethical and equity considerations

Longitudinal analysis of alcohol use and intimate partner violence perpetration among men with HIV in northern Vietnam

Background: Alcohol use is a known risk factor for male-perpetrated intimate partner violence (IPV), although few studies have been conducted globally and among men with HIV (MWH). We estimated the longitudinal effects of alcohol use on IPV perpetration among MWH. Methods: This study is a secondary analysis of randomized controlled trial data among male and female antiretroviral treatment patients with hazardous alcohol use in Thai Nguyen, Vietnam. Analyses were restricted to male participants who were married/cohabitating (N = 313). Alcohol use was assessed as proportion days alcohol abstinent, heavy drinking, and alcohol use disorder (AUD) using the Timeline Followback and Mini International Neuropsychiatric Interview questionnaire. Multilevel modeling was used to estimate the effects of higher versus lower average alcohol use on IPV perpetration (between-person effects) and the effects of time-specific deviations in alcohol use on IPV perpetration (within-person effects). Results: Participants with higher average proportion days alcohol abstinent had decreased odds of IPV perpetration (adjusted Odds Ratio [aOR] = 0.43, p = 0.03) and those with higher average heavy drinking and AUD had increased odds of IPV perpetration (Heavy drinking: aOR = 1.05, p = 0.002; AUD: aOR = 4.74, p < 0.0001). Time-specific increases in proportion days alcohol abstinent were associated with decreased odds of IPV perpetration (aOR = 0.39, p = 0.02) and time-specific increases in AUD were associated with increased odds of IPV perpetration (aOR = 2.95, p = 0.001). Within-person effects for heavy drinking were non-significant. Conclusions: Alcohol use is associated with IPV perpetration among Vietnamese men with HIV. In this context, AUD and frequent drinking are stronger correlates of IPV perpetration as compared to heavy drinking

Comparing a standard and tailored approach to scaling up an evidence-based intervention for antiretroviral therapy for people who inject drugs in Vietnam: Study protocol for a cluster randomized hybrid type III trial

Background: People who inject drugs (PWID) bear a disproportionate burden of HIV infection and experience poor outcomes. A randomized trial demonstrated the efficacy of an integrated System Navigation and Psychosocial Counseling (SNaP) intervention in improving HIV outcomes, including antiretroviral therapy (ART) and medications for opioid use disorder (MOUD) uptake, viral suppression, and mortality. There is limited evidence about how to effectively scale such intervention. This protocol presents a hybrid type III effectiveness-implementation trial comparing two approaches for scaling-up SNaP. We will evaluate the effectiveness of SNaP implementation approaches as well as cost and the characteristics of HIV testing sites achieving successful or unsuccessful implementation of SNaP in Vietnam. Methods: Design: In this cluster randomized controlled trial, two approaches to scaling-up SNaP for PWID in Vietnam will be compared. HIV testing sites (n = 42) were randomized 1:1 to the standard approach or the tailored approach. Intervention mapping was used to develop implementation strategies for both arms. The standard arm will receive a uniform package of these strategies, while implementation strategies for the tailored arm will be designed to address site-specific needs. Participants: HIV-positive PWID participants (n = 6200) will be recruited for medical record assessment at baseline; of those, 1500 will be enrolled for detailed assessments at baseline, 12, and 24 months. Site directors and staff at each of the 42 HIV testing sites will complete surveys at baseline, 12, and 24 months. Outcomes: Implementation outcomes (fidelity, penetration, acceptability) and effectiveness outcomes (ART, MOUD uptake, viral suppression) will be compared between the arms. To measure incremental costs, we will conduct an empirical costing study of each arm and the actual process of implementation from a societal perspective. Qualitative and quantitative site-level data will be used to explore key characteristics of HIV testing sites that successfully or unsuccessfully implement the intervention for each arm. Discussion: Scaling up evidence-based interventions poses substantial challenges. The proposed trial contributes to the field of implementation science by applying a systematic approach to designing and tailoring implementation strategies, conducting a rigorous comparison of two promising implementation approaches, and assessing their incremental costs. Our study will provide critical guidance to Ministries of Health worldwide regarding the most effective, cost-efficient approach to SNaP implementation. Trial registration: NCT03952520 on Clinialtrials.gov. Registered 16 May 2019

Simple inclusion of complex diagnostic algorithms in infectious disease models for economic evaluation

INTRODUCTION: Cost-effectiveness models for infectious disease interventions often require transmission models that capture the indirect benefits from averted subsequent infections. Compartmental models based on ordinary differential equations are commonly used in this context. Decision trees are frequently used in cost-effectiveness modeling and are well suited to describing diagnostic algorithms. However, complex decision trees are laborious to specify as compartmental models and cumbersome to adapt, limiting the detail of algorithms typically included in transmission models. METHODS: We consider an approximation replacing a decision tree with a single holding state for systems where the time scale of the diagnostic algorithm is shorter than time scales associated with disease progression or transmission. We describe recursive algorithms for calculating the outcomes and mean costs and delays associated with decision trees, as well as design strategies for computational implementation. We assess the performance of the approximation in a simple model of transmission/diagnosis and its role in simplifying a model of tuberculosis diagnostics. RESULTS: When diagnostic delays were short relative to recovery rates, our approximation provided a good account of infection dynamics and the cumulative costs of diagnosis and treatment. Proportional errors were below 5% so long as the longest delay in our 2-step algorithm was under 20% of the recovery time scale. Specifying new diagnostic algorithms in our tuberculosis model was reduced from several tens to just a few lines of code. DISCUSSION: For conditions characterized by a diagnostic process that is neither instantaneous nor protracted (relative to transmission dynamics), this novel approach retains the advantages of decision trees while embedding them in more complex models of disease transmission. Concise specification and code reuse increase transparency and reduce potential for error

Endometrioid endometrial carcinoma with atrophic endometrium and poor prognosis

Item does not contain fulltextOBJECTIVE: : Type I endometrial carcinomas are characterized by endometrioid histology, develop from hyper-plastic endometrium, and have a good prognosis. Type II, nonendometrioid carcinomas, arise in atrophic endometrium and have a poor prognosis. However, approximately 20% of cases do not fit within this dualistic model and include endometrioid carcinomas associated with recurrence and possibly with atrophy. We aimed to evaluate grade 1 endometrioid endometrial carcinomas with atrophic endometrium, a putative third type of endometrial carcinoma. METHODS: : Histologic slides of all grade 1 endometrioid endometrial cancers from the Radboud University Medical Centre and Canisius-Wilhelmina Hospital from 1999-2009 and from the Mayo Clinic from 2002-2008 were reviewed. Comparisons were made between patients with atrophic and hyperplastic endometrium. RESULTS: : After review, 527 patients were identified. In 88 patients (16.8%), background endometrium was atrophic and 387 patients (73.3%) had hyperplastic endometrium. Fifty-two patients (9.9%) had proliferative endometrium or no background endometrium and were excluded. Atrophy correlated with older age, low body mass index, advanced International Federation of Gynecology and Obstetrics stage, malignant cells in peritoneal cytology, lymph node metastases, cervical involvement, lymphovascular space invasion, and deep myometrial invasion. Multivariable analysis showed that age (hazard ratio 1.06, 95% confidence interval [Cl] 1.01-1.12), International Federation of Gynecology and Obstetrics stage (hazard ratio 8.47, 95% Cl 1.73-41.57), and background endometrium (hazard ratio 3.11, 95% Cl 1.11-8.70) were predictors of progression-free survival. CONCLUSION: : Atrophic endometrium is an independent prognostic factor for patients with grade 1 endometrioid endometrial carcinoma. Endometrioid carcinoma with atrophy may not follow the hypothesized progression model for type I tumors and may arise through unique carcinogenic pathways. LEVEL OF EVIDENCE: : II

Immunohistochemical and genetic profiles of endometrioid endometrial carcinoma arising from atrophic endometrium

Contains fulltext : 153069.pdf (publisher's version ) (Closed access)OBJECTIVE: Endometrial carcinomas are divided into type I endometrioid endometrial carcinomas (EECs), thought to arise from hyperplastic endometrium, and type II nonendometrioid endometrial carcinomas, thought to arise from atrophic endometrium. However, a minority (20%) of EECs have atrophic background endometrium, which was shown to be a marker of a worse prognosis. This study compares the immunohistochemical and genetic profiles of this possible third type to that of the known two types. METHODS: 43 patients with grade 1 EEC and hyperplastic background endometrium (type I), 43 patients with grade 1 EEC and atrophic background endometrium (type III) and 21 patients with serous carcinoma (type II) were included (n=107). Tissue microarrays of tumor samples were immunohistochemically stained for PTEN, L1CAM, ER, PR, p53, MLH1, PMS2, beta-catenin, E-cadherin and MIB1. The BRAF, KRAS, and PIK3CA genes were analyzed for mutations. RESULTS: A significantly higher expression of ER and PR, and a lower expression of L1CAM, p53 and MLH1 were found in type I and III compared to type II carcinomas. Expression of E-cadherin was significantly reduced in type III compared to type I carcinomas. Mutation analysis showed significantly less mutations of KRAS in type III compared to type I and II carcinomas (p<0.01). CONCLUSION: There appear to be slight immunohistochemical and genetic differences between EECs with hyperplastic and atrophic background endometrium. Carcinogenesis of EEC in atrophic endometrium seems to be characterized by loss of E-cadherin and a lack of KRAS mutations. As expected, endometrioid and serous carcinomas were immunohistochemically different