Exploring the potential role of allostatic load biomarkers in risk assessment of patients presenting with depressive symptoms

Background: Depression is a major health problem worldwide and the majority of patients presenting with depressive symptoms are managed in primary care. Current approaches for assessing depressive symptoms in primary care are not accurate in predicting future clinical outcomes, which may potentially lead to over or under treatment. The Allostatic Load (AL) theory suggests that by measuring multi-system biomarker levels as a proxy of measuring multi-system physiological dysregulation, it is possible to identify individuals at risk of having adverse health outcomes at a prodromal stage. Allostatic Index (AI) score, calculated by applying statistical formulations to different multi-system biomarkers, have been associated with depressive symptoms. Aims and Objectives: To test the hypothesis, that a combination of allostatic load (AL) biomarkers will form a predictive algorithm in defining clinically meaningful outcomes in a population of patients presenting with depressive symptoms. The key objectives were: 1. To explore the relationship between various allostatic load biomarkers and prevalence of depressive symptoms in patients, especially in patients diagnosed with three common cardiometabolic diseases (Coronary Heart Disease (CHD), Diabetes and Stroke). 2 To explore whether allostatic load biomarkers predict clinical outcomes in patients with depressive symptoms, especially in patients with three common cardiometabolic diseases (CHD, Diabetes and Stroke). 3 To develop a predictive tool to identify individuals with depressive symptoms at highest risk of adverse clinical outcomes. Methods: Datasets used: ‘DepChron’ was a dataset of 35,537 patients with existing cardiometabolic disease collected as a part of routine clinical practice. ‘Psobid’ was a research data source containing health related information from 666 participants recruited from the general population. The clinical outcomes for 3 both datasets were studied using electronic data linkage to hospital and mortality health records, undertaken by Information Services Division, Scotland. Cross-sectional associations between allostatic load biomarkers calculated at baseline, with clinical severity of depression assessed by a symptom score, were assessed using logistic and linear regression models in both datasets. Cox’s proportional hazards survival analysis models were used to assess the relationship of allostatic load biomarkers at baseline and the risk of adverse physical health outcomes at follow-up, in patients with depressive symptoms. The possibility of interaction between depressive symptoms and allostatic load biomarkers in risk prediction of adverse clinical outcomes was studied using the analysis of variance (ANOVA) test. Finally, the value of constructing a risk scoring scale using patient demographics and allostatic load biomarkers for predicting adverse outcomes in depressed patients was investigated using clinical risk prediction modelling and Area Under Curve (AUC) statistics. Key Results: Literature Review Findings. The literature review showed that twelve blood based peripheral biomarkers were statistically significant in predicting six different clinical outcomes in participants with depressive symptoms. Outcomes related to both mental health (depressive symptoms) and physical health were statistically associated with pre-treatment levels of peripheral biomarkers; however only two studies investigated outcomes related to physical health. Cross-sectional Analysis Findings: In DepChron, dysregulation of individual allostatic biomarkers (mainly cardiometabolic) were found to have a non-linear association with increased probability of co-morbid depressive symptoms (as assessed by Hospital Anxiety and Depression Score HADS-D≥8). A composite AI score constructed using five biomarkers did not lead to any improvement in the observed strength of the association. In Psobid, BMI was found to have a significant cross-sectional association with the probability of depressive symptoms (assessed by General Health Questionnaire GHQ-28≥5). BMI, triglycerides, highly sensitive C - reactive 4 protein (CRP) and High Density Lipoprotein-HDL cholesterol were found to have a significant cross-sectional relationship with the continuous measure of GHQ-28. A composite AI score constructed using 12 biomarkers did not show a significant association with depressive symptoms among Psobid participants. Longitudinal Analysis Findings: In DepChron, three clinical outcomes were studied over four years: all-cause death, all-cause hospital admissions and composite major adverse cardiovascular outcome-MACE (cardiovascular death or admission due to MI/stroke/HF). Presence of depressive symptoms and composite AI score calculated using mainly peripheral cardiometabolic biomarkers was found to have a significant association with all three clinical outcomes over the following four years in DepChron patients. There was no evidence of an interaction between AI score and presence of depressive symptoms in risk prediction of any of the three clinical outcomes. There was a statistically significant interaction noted between SBP and depressive symptoms in risk prediction of major adverse cardiovascular outcome, and also between HbA1c and depressive symptoms in risk prediction of all-cause mortality for patients with diabetes. In Psobid, depressive symptoms (assessed by GHQ-28≥5) did not have a statistically significant association with any of the four outcomes under study at seven years: all cause death, all cause hospital admission, MACE and incidence of new cancer. A composite AI score at baseline had a significant association with the risk of MACE at seven years, after adjusting for confounders. A continuous measure of IL-6 observed at baseline had a significant association with the risk of three clinical outcomes- all-cause mortality, all-cause hospital admissions and major adverse cardiovascular event. Raised total cholesterol at baseline was associated with lower risk of all-cause death at seven years while raised waist hip ratio- WHR at baseline was associated with higher risk of MACE at seven years among Psobid participants. There was no significant interaction between depressive symptoms and peripheral biomarkers (individual or combined) in risk prediction of any of the four clinical outcomes under consideration. Risk Scoring System Development: In the DepChron cohort, a scoring system was constructed based on eight baseline demographic and clinical variables to predict the risk of MACE over four years. The AUC value for the risk scoring system was modest at 56.7% (95% CI 55.6 to 57.5%). In Psobid, it was not possible to perform this analysis due to the low event rate observed for the clinical outcomes. Conclusion: Individual peripheral biomarkers were found to have a cross-sectional association with depressive symptoms both in patients with cardiometabolic disease and middle-aged participants recruited from the general population. AI score calculated with different statistical formulations was of no greater benefit in predicting concurrent depressive symptoms or clinical outcomes at follow-up, over and above its individual constituent biomarkers, in either patient cohort. SBP had a significant interaction with depressive symptoms in predicting cardiovascular events in patients with cardiometabolic disease; HbA1c had a significant interaction with depressive symptoms in predicting all-cause mortality in patients with diabetes. Peripheral biomarkers may have a role in predicting clinical outcomes in patients with depressive symptoms, especially for those with existing cardiometabolic disease, and this merits further investigation.

Applied evolution: An integrated approach to studying life history traits in response to drug selection

The use of chemical control measures to reduce the impact of parasite and pest species has frequently resulted in the development of resistance. Thus, resistance management has become a key concern in human and veterinary medicine, and in agricultural production. Although it is known that factors such as gene flow between susceptible and resistant populations, drug type, application methods, and costs of resistance can affect the rate of resistance evolution, less is known about the impacts of density-dependent eco-evolutionary processes that could be altered by drug-induced mortality. The overall aim of this thesis was to take an experimental evolution approach to assess how life history traits respond to drug selection, using a free-living dioecious worm (Caenorhabditis remanei) as a model. In Chapter 2, I defined the relationship between C. remanei survival and Ivermectin dose over a range of concentrations, in order to control the intensity of selection used in the selection experiment described in Chapter 4. The dose-response data were also used to appraise curve-fitting methods, using Akaike Information Criterion (AIC) model selection to compare a series of nonlinear models. The type of model fitted to the dose response data had a significant effect on the estimates of LD50 and LD99, suggesting that failure to fit an appropriate model could give misleading estimates of resistance status. In addition, simulated data were used to establish that a potential cost of resistance could be predicted by comparing survival at the upper asymptote of dose-response curves for resistant and susceptible populations, even when differences were as low as 4%. This approach to dose-response modeling ensures that the maximum amount of useful information relating to resistance is gathered in one study. In Chapter 3, I asked how simulations could be used to inform important design choices used in selection experiments. Specifically, I focused on the effects of both within- and between-line variation on estimated power, when detecting small, medium and large effect sizes. Using mixed-effect models on simulated data, I demonstrated that commonly used designs with realistic levels of variation could be underpowered for substantial effect sizes. Thus, use of simulation-based power analysis provides an effective way to avoid under or overpowering a study designs incorporating variation due to random effects. In Chapter 4, I 3 investigated how Ivermectin dosage and changes in population density affect the rate of resistance evolution. I exposed replicate lines of C. remanei to two doses of Ivermectin (high and low) to assess relative survival of lines selected in drug-treated environments compared to untreated controls over 10 generations. Additionally, I maintained lines where mortality was imposed randomly to control for differences in density between drug treatments and to distinguish between the evolutionary consequences of drug treatment versus ecological processes affected by changes in density-dependent feedback. Intriguingly, both drug-selected and random-mortality lines showed an increase in survivorship when challenged with Ivermectin; the magnitude of this increase varied with the intensity of selection and life-history stage. The results suggest that interactions between density-dependent processes and life history may mediate evolved changes in susceptibility to control measures, which could result in misleading conclusions about the evolution of heritable resistance following drug treatment. In Chapter 5, I investigated whether the apparent changes in drug susceptibility found in Chapter 4 were related to evolved changes in life-history of C. remanei populations after selection in drug-treated and random-mortality environments. Rapid passage of lines in the drug-free environment had no effect on the measured life-history traits. In the drug-free environment, adult size and fecundity of drug-selected lines increased compared to the controls but drug selection did not affect lifespan. In the treated environment, drug-selected lines showed increased lifespan and fecundity relative to controls. Adult size of randomly culled lines responded in a similar way to drug-selected lines in the drug-free environment, but no change in fecundity or lifespan was observed in either environment. The results suggest that life histories of nematodes can respond to selection as a result of the application of control measures. Failure to take these responses into account when applying control measures could result in adverse outcomes, such as larger and more fecund parasites, as well as over-estimation of the development of genetically controlled resistance. In conclusion, my thesis shows that there may be a complex relationship between drug selection, density-dependent regulatory processes and life history of populations challenged with control measures. This relationship could have implications for how resistance is monitored and managed if life histories of parasitic species show such eco-evolutionary responses to drug application.

Septic Shock Sera Containing Circulating Histones Induce Dendritic Cell–Regulated Necrosis in Fatal Septic Shock Patients

International audience

Factors contributing to defaulting scheduled therapy sessions by caregivers of children with congenital disabilities

Background Defaulting scheduled rehabilitation therapy may result in increased adverse outcomes such as permanent disability and increased healthcare costs. Concomitantly, there is evidence to suggest that early and continued rehabilitation of children with congenital disabilities can improve outcomes significantly. This study was conducted to determine factors contributing to caregivers’ defaulting scheduled rehabilitation therapy sessions. Methods A descriptive cross sectional study was carried out at Chitungwiza Central Hospital, a tertiary facility offering in and outpatient rehabilitation services in Zimbabwe. Caregivers of children who had congenital disabilities (N=40) and who had a history of defaulting treatment but were available during the data collection period responded to an interviewer administered questionnaire. Data were analysed for means and frequencies using STATA 13. Results Factors that contributed to caregivers defaulting scheduled therapy included economic constraints (52%), child related factors (43%), caregiver related factors (42%), service centred factors (30%) and psychosocial factors (58%). Majority of the caregivers (98%) were motivated to attend therapy by observable improvements in their children. Other motivators were incentives given in the rehabilitation department (45%), availability of rehabilitation personnel to provide the required services (48%) and psychosocial support from fellow caregivers, families and the rehabilitation staff (68%). Although all the caregivers could not distinguish occupational therapy from physiotherapy services they all reported that therapy was important. Conclusions A combination of psychosocial, economic, child centred and service centred factors contributed to caregivers defaulting scheduled therapy. Interventions that may potentially improve caregiver attendance to scheduled therapy include community outreach services, efficient rehabilitation service provision at the hospitals, and facilitation of income generating programmes for caregivers.

Different Aspects of General Anesthesia in Pediatric Dentistry: A Review

Context:Most child population is able to undergo dental treatment in the conventional setting. However, some children fail to cope with in-office conscious state and cannot respond to usual management modalities. This review aims to discuss the topic further. Evidence Acquisition: A computerized search in databases PubMed, MEDLINE, EMBASE, Google Scholar and Google were performed using dental general anesthesia related keywords. Original and review English-written articles that were limited to child population were retrieved without any limitation of publication date. The suitable papers were selected and carefully studied. A data form designed by author was used to write relevant findings. Results: Preoperative oral examination and comprehensive evaluation of treatment needs is only possible after clinical and radiographic oral examination. Effective collaboration in dental GA team should be made to minimize psychological trauma of children who undergo dental GA. Before conducting comprehensive dental treatment under GA, the general health of the child and the success rate of procedures provided needs to be accurately evaluated. It is noteworthy that determination of the optimal timing for GA dental operation is of great importance. Providing safety with pediatric dental rehabilitation under GA is critical. Conclusions: Besides criteria for case selection of dental GA, some degree of dental practitioner’s judgment is required to make decision. Pre- and post-operative instructions to parents or caregiver decrease the risk of complications. However, trained resuscitation providers, careful monitoring and advanced equipment minimize adverse outcomes.

Étude de l’impact de la prise de médicaments dans le traitement de l’arthrite juvénile sur les événements néfastes à l’accouchement chez la mère et son bébé

La plupart des femmes ayant été atteintes d’arthrite juvénile idiopathique (AJI) continuent de souffrir d’arthrite à l’âge adulte. Certains des médicaments utilisés dans le traitement de l’arthrite tels que les corticostéroïdes et les antiinflammatoires non stéroïdiens (AINS) ne sont pas recommandés durant la grossesse. Le but de ce mémoire est d’estimer l’impact de la prise de ces médicaments sur les événements néfastes à l’accouchement chez ces femmes et leur bébé. Des données administratives sur les prescriptions de médicaments et les hospitalisations d’une cohorte de 1756 femmes ayant souffert d’AJI sont utilisées. Elles ont permis de reconstruire l’historique de consommation de médicaments contre l’arthrite chez les femmes durant la grossesse et l’année précédente. Pour ce faire, deux sous-cohortes de femmes ayant souffert d’AJI ont été formées : une pour la période grossesse et une autre pour la grossesse et l’année précédant celle-ci. Les événements d’intérêt étaient : malformations congénitales, complications néonatales, complications maternelles et petit poids pour l’âge gestationnel. Les proportions de cas présentant l’un de ces événements variaient entre 11,52% et 37,08%. Les médicaments ont été modélisés en terme d’utilisation ou de durée totale de consommation durant la période d’étude. Pour chaque événement, des modèles logistiques ont été estimés pour mesurer l’association entre la prise de médicaments et l’événement, en ajustant pour des variables de confusion potentielles : hypertension avant la grossesse, âge à l’accouchement et obtention du diplôme de secondaire. La consommation de corticostéroïdes semble augmenter statistiquement significativement le risque de présenter des malformations congénitales mais n’avoir aucun impact sur les autres événements. Aucun lien statistiquement significatif n’a été observé entre la consommation de AINS et les événements d’intérêt.

Étude de l’impact de la prise de médicaments dans le traitement de l’arthrite juvénile sur les événements néfastes à l’accouchement chez la mère et son bébé

L'obtention des données a été subventionnée par CIORA (Canadian Initiative for Outcomes in Rheumatology Care). CIORA a aussi financé l'analyse des données effectuées par Justine Zehr. L'Initiative Canadienne Pour Des Resultats En Soins Rhumatologiques (ICORA) a financé l'obtention des données et une partie de l'analyse statistique présentée dans ce mémoire.

The inter-rater reliability of the Risk Instrument for Screening in the Community

Predicting risk of adverse healthcare outcomes is important to enable targeted delivery of interventions. The Risk Instrument for Screening in the Community (RISC), designed for use by public health nurses (PHNs), measures the one-year risk of hospitalisation, institutionalisation and death in community-dwelling older adults according to a five-point global risk score: from low (score 1,2), medium (3) and high (4,5). We examined the inter-rater reliability (IRR) of the RISC between student PHNs (n=32) and expert raters using six cases (two low, medium and high-risk), scored before and after RISC training. Correlations increased for each adverse outcome, statistically significantly for institutionalisation (r=0.72 to 0.80,p=0.04) and hospitalisation, (r=0.51 to 0.71,p<0.01) but not death. Training improved accuracy for low-risk but not all high-risk cases. Overall, the RISC showed good IRR, which increased after RISC training. That reliability reduced for some high-risk cases suggests that the training programme requires adjustment to further improve IRR.

Infección por virus sincitial respiratorio y su relación con valores de IGG en niños críticos

Antecedente: La infección por el virus sincitial respiratorio (VSR) representa una elevada morbimortalidad, y en algunos casos necesidad de manejo en unidades de cuidado intensivo pediátrico (UCIP). La respuesta inmunológica influye de manera directa en la expresión de la severidad y pronóstico de los pacientes con infección respiratoria. Metodología: Estudio de una cohorte retrospectiva de pacientes con infección respiratoria grave secundaria a VSR, sin historia de inmunodeficiencia, atendidos en la UCIP del Hospital Universitario Clínica San Rafael. Se realizó análisis descriptivoglobaly de acuerdo a la categorización de las prueba de IgG. Resultados: De 188 pacientes que ingresaron a la UCIP, 13% presentaron infección por VSR (24), con una edad promedio de 7,3 (DE=3,6) meses. Pertenecían al sexo masculino79,83%. Se encontró que 12,5% tenían un valor de IgGbajo para su edad, 58,33% tenían valores en límite inferior y el 29,17% dentro de rangos normales para su edad. En los pacientes con IgG baja, fue mayor la presentación de choque séptico que no responde a líquidos (100 vs 92 vs 86%), la mediana de días de ventilación mecánica fue mayor (8 vs 6 vs 5 respectivamente), así como la mortalidad (67 vs 7,1 vs 0%). Conclusión: Nuestra serie encontró que aquellos pacientes con niveles bajos o valores en el límite inferior de IgG sérica tuvieron mayor compromiso sistémico, mayor duración de ventilación mecánica y mayor mortalidad. Se necesitan estudios prospectivos que relaciones niveles bajos de IgG con severidad y pronostico en estos pacientes con infección grave por VSR.

Morbilidade evitável relacionada com medicamentos: Desenvolvimento de novos indicadores e validação preliminar para cuidados primários em Portugal

Sumário: A morbilidade evitável relacionada com medicamentos (MERM) é um problema de saúde pública com considerável impacto negativo para os doentes e os sistemas de saúde. Os indicadores de MERM constituem medidas operacionais de gestão do risco terapêutico, uma vez que permitem identificar processos de cuidados de saúde que predizem um resultado clínico negativo potencialmente evitável. O uso destes indicadores pode contribuir para reduzir a morbilidade evitável relacionada com medicamentos, evitando danos desnecessários e desperdício de recursos. Objectivo: Desenvolver novos indicadores de MERM para cuidados primários em Portugal a partir da análise de resumos das características de medicamentos (RCM's) e determinar a validade preliminar de face e de conteúdo dos indicadores derivados para este setting. Métodos: A primeira fase deste estudo consistiu num ensaio piloto, com o intuito de testar uma metodologia de inclusão dos RCM's com base na frequência de dispensa da especialidade farmacêutica no ambulatório. Seguidamente procedeu-se ao desenvolvimento de mais indicadores de MERM utilizando a metodologia testada no ensaio piloto. Os indicadores obtidos foram alvo de uma primeira análise com base em aspectos como duplicações e relevância para cuidados primários, de modo a seleccionar os que poderiam passar à fase de validade preliminar de face e de conteúdo. Procedeu­ se então à pesquisa de evidência clínica em fontes de referência para estes indicadores. Na última fase do estudo estes indicadores, bem como a respectiva evidência clínica, foram analisados por um painel de peritos constituído por quatro académicos (dois médicos de família e dois farmacêuticos), sendo aprovados ou eliminados com base num critério de consenso. Resultados: Obteve-se um total de 64 indicadores de MERM, a partir da análise de 35 RCM's. Sujeitaram-se à determinação da validade preliminar de face e de conteúdo 44 indicadores. Foram aprovados por consenso 28 indicadores, tendo sido excluídos 17 (4 por consenso e 13 sem obtenção de consenso). Conclusão: É exequível derivar novos indicadores de MERM para cuidados primários a partir da análise de RCM's. A validade formal de face e de conteúdo destes indicadores obtidos será objecto de estudo de ulterior investigação. /ABSTRACT: Backgroud: Preventable drug-relate morbidity (PDRM) is a public health problem with significant negative impact at a patient and system level. PDRM indicators are operational measures of therapeutic risk management; they identifying processes of care leading to preventable adverse outcomes. The use of these indicators may contribute to tackle preventable drug related morbidity, avoiding unnecessary harm and waste of resources. Objective: To develop new PDRM indicators to Portuguese primary care based on the analysis of summaries of product characteristics (SPC’s) and to determine their preliminary face and content validity to this setting. Methods: Firstly a pilot study was conducted to test a methodology for including SPC's based on the most frequently sold medicines in the ambulatory. Then more indicators were developed using the previously tested methodology. The indicators obtained were analyzed in respect to aspects such as duplications and relevance for primary care to select those that could proceed to the next stage. Clinical evidence was searched for each of these indicators in gold-standard information sources. Finally, this set of indicators and the respective clinical evidence were analysised by a panel of four experts (two academic general practitioners and two academic pharmacists). Preliminary face and content validity was established by means of consensus. Results: A total of 64 indicators was obtained, based on the analysis of 35 SPCs. Forty­ four indicators were subjected to a preliminary assessment of face and content validity, resulting in 28 consensus-approved indicators. Seventeen indicators were excluded (4 rejected by consensus and 13 that did not reach consensus). Conclusion: lt is feasible to derive new PDRM indicators for primary care based on SPC's. The formal face and content validity of the indicators will be determined in a further study.

Microbial colonisation of follicular fluid : alterations in cytokine expression and adverse assisted reproductive technology outcomes

Previous studies have measured cytokine expression within follicular fluid collected at the time of trans-vaginal oocyte retrieval and compared the profiles with the aetiology of infertility and/or successful or unsuccessful assisted reproductive technology (ART) outcomes. Seventy-one paired follicular fluid and vaginal swab specimens collected from ART patients were cultured to detect microorganisms and then were tested for the presence of cytokines by multiplex fluorescence bead assays. Specimen selection was based on two criteria: whether the follicular fluid specimen was colonised (with microorganisms prior to oocyte retrieval) or contaminated by lower genital tract microflora at the time of oocyte retrieval and; the aetiology of infertility...

A detailed assessment of adverse perioperative outcomes of the elderly treated with radical cystectomy for bladder cancer

Objectifs: Les données provenant des centres de soins tertiaires suggèrent que le taux de mortalité péri-opératoire (MPO) après cystectomie notés pour les patients âgés (septuagénaires et octogénaires) n’excède pas celle des patients plus jeunes. Toutefois, les données provenant de la communauté démontrent un phénomène inverse. Spécifiquement, la MPO est plus élevés chez les ainés. Dans cette thèse nous allons présenter une réévaluation contemporaine du taux de MPO après cystectomie. Méthodes: Entre 1988 et 2006, 12722 cystectomies radicales pour le carcinome urothéliale de la vessie ont été enregistrées dans la banque de données SEER. Le taux de MPO a été évalué dans les analyses de régression logistique univariées et multivariées à 90 jours après cystectomie radicale. Les covariables incluaient: le sexe, l’ethnie, l’année de chirurgie, la région d’origine du patient ainsi que le grade et le stade de la tumeur. Résultats: Parmi tous les patients, 4480 étaient des septuagénaires (35.2%) et 1439 étaient des octogénaires (11.3%). Le taux de MPO à 90 jours était de 4% pour la cohorte entière vs. 2% pour les patients moins de 69 ans vs. 5.4% pour les septuagénaires vs. 9.2% pour les octogénaires. Dans les analyses de régression logistiques multivariées, les septuagénaires (OR=2.80; <0.001) et les octogénaires (OR=5.02; <0.001) avaient reçu un taux de MPO plus augmenté que les patients moins de 70 ans après une cystectomie radicale. Conclusion: Cette analyse épidémiologique basée sur les donnés le plus contemporaines démontre que l’âge avancée représente un facteur de risque pour un taux de MPO plus élevé.