30 research outputs found

    Maximizing performance: augmented feedback, focus of attention, and/or reward?

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    Different approaches like providing augmented feedback (aF), applying an external focus of attention (EF), or rewarding participants with money (RE) have been shown to instantly enhance motor performance. So far, these approaches have been tested either in separate studies or directly against each other. However, there is no study that combined aF, EF, and/or RE to test whether this provokes additional benefits. The aim of the present study was therefore to identify the most powerful combination.Methods: Eighteen participants performed maximal countermovement jumps in six different conditions: neutral (NE), aF, RE, aF + EF, aF + RE, and aF + EF + RE.Results: Participants demonstrated the highest jump heights with aF + EF, followed by aF + EF + RE, aF + RE, aF, RE, and finally, NE. Activity of the M. rectus femoris differed significantly between conditions resulting in lower muscular activity in aF + EF and aF + EF + RE compared with NE. All other parameters, such as ground reaction forces and joint angles, were comparable across conditions.Conclusions: This is the first study showing superior performance when combining aF with EF. As reduced muscular activity was found only in conditions with EF, it is argued in line with the constrained action hypothesis that adopting an EF improves movement efficiency. In contrast, aF seems to rather enhance (intrinsic) motivation. However, monetary reward did not further amplify performance

    Alignment of Multiple Configurations Using Hierarchical Models

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    We describe a method for aligning multiple unlabeled configurations simultane- ously. Specifically, we extend the two-configuration matching approach of Green and Mardia (2006) to the multiple configuration setting. Our approach is based on the in- troduction of a set of hidden locations underlying the observed configuration points. A Poisson process prior is assigned to these locations, resulting in a simplified formu- lation of the model. We make use of a structure containing the relevant information on the matches, of which there are different types to take into account. Bayesian inference can be made simultaneously on the matching and the relative transformations between the configurations. We focus on the particular case of rigid-body transformations and Gaussian observation errors. We apply our method to a problem in chemoinformatics: the alignment of steroid molecules. Supplementary materials are available online

    Combining individual patient data from randomized and non-randomized studies to predict real-world effectiveness of interventions.

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    Meta-analysis of randomized controlled trials is generally considered the most reliable source of estimates of relative treatment effects. However, in the last few years, there has been interest in using non-randomized studies to complement evidence from randomized controlled trials. Several meta-analytical models have been proposed to this end. Such models mainly focussed on estimating the average relative effects of interventions. In real-life clinical practice, when deciding on how to treat a patient, it might be of great interest to have personalized predictions of absolute outcomes under several available treatment options. This paper describes a general framework for developing models that combine individual patient data from randomized controlled trials and non-randomized study when aiming to predict outcomes for a set of competing medical interventions applied in real-world clinical settings. We also discuss methods for measuring the models' performance to identify the optimal model to use in each setting. We focus on the case of continuous outcomes and illustrate our methods using a data set from rheumatoid arthritis, comprising patient-level data from three randomized controlled trials and two registries from Switzerland and Britain

    Immunodeficiency and Cancer in 3.5 Million People Living With Human Immunodeficiency Virus (HIV):the South African HIV Cancer Match Study

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    BACKGROUND We analysed associations between immunodeficiency and cancer incidence in a nationwide cohort of people living with the human immunodeficiency virus (HIV) in South Africa. METHODS We used data from the South African HIV Cancer Match study built on HIV-related laboratory measurements from the National Health Laboratory Services and cancer records from the National Cancer Registry. We evaluated associations between time-updated CD4 cell count and cancer incidence rates using Cox proportional hazards models. We reported adjusted hazard ratios (aHR) over a grid of CD4 values and estimated the aHR per 100 CD4 cells/µl decrease. RESULTS Of 3,532,266 people living with HIV (PLWH), 15,078 developed cancer. The most common cancers were cervical cancer (4,150 cases), Kaposi sarcoma (2,262 cases), and non-Hodgkin lymphoma (1,060 cases). The association between lower CD4 cell count and higher cancer incidence rates was strongest for conjunctival cancer (aHR per 100 CD4 cells/µl decrease: 1.46, 95% confidence interval [CI] 1.38-1.54), Kaposi sarcoma (aHR 1.23, 95% CI 1.20-1.26), and non-Hodgkin lymphoma (aHR 1.18, 95% CI 1.14-1.22). Among infection-unrelated cancers, lower CD4 cell counts were associated with higher incidence rates of oesophageal cancer (aHR 1.06, 95 CI 1.00-1.11), but not breast, lung, or prostate cancer. CONCLUSIONS Lower CD4 cell counts were associated with an increased risk of developing various infection-related cancers among PLWH. Reducing HIV-induced immunodeficiency may be a potent cancer prevention strategy among PLWH in sub-Saharan Africa, a region heavily burdened by cancers attributable to infections

    Cancer treatment and survival among cervical cancer patients living with or without HIV in South Africa.

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    Objective To compare cancer treatment and all-cause mortality between HIV-positive and HIV-negative cervical cancer patients in South Africa. Methods We assessed cancer treatment and all-cause mortality in HIV-positive and HIV-negative cervical cancer patients who received cancer treatment within 180 days of diagnosis using reimbursement claims data from a private medical insurance scheme in South Africa between 01/2011 and 07/2020. We assessed treatment provision using logistic regression and factors associated with all-cause mortality using Cox regression. We assigned missing values for histology and ethnicity using multiple imputation. Results Of 483 included women, 136 (28 %) were HIV-positive at cancer diagnosis (median age: 45.7 years), and 347 (72 %) were HIV-negative (median age: 54.1 years). Among 285 patients with available ICD-O-3 morphology claims codes, the proportion with cervical adenocarcinoma was substantially lower in HIV-positive (4 %) than in HIV-negative patients (26 %). Most HIV-positive patients (67 %) were on antiretroviral therapy at cancer diagnosis. HIV-positive patients were more likely to receive radiotherapy (adjusted odds ratio [aOR] 1.90, 95 % confidence interval [CI] 1.05-3.45) or chemotherapy (aOR 2.02, 95 %CI 0.92-4.43) and less likely to undergo surgery (aOR 0.53, 95 %CI 0.31-0.90) than HIV-negative patients. HIV-positive patients were at a higher risk of death from all causes than HIV-negative patients (adjusted hazard ratio 1.52, 95 %CI 1.06-2.19). Other factors associated with higher all-cause mortality included age > 60 years and metastases at diagnosis. Conclusions HIV-positive cervical cancer patients in South Africa had higher all-cause mortality than HIV-negative patients which could be explained by differences in tumour progression, clinical care, and HIV-specific mortality

    Cervical precancer and cancer incidence among insured women with and without HIV in South Africa.

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    HIV infection increases the risk of developing cervical cancer; however, longitudinal studies in sub-Saharan Africa comparing cervical cancer rates between women living with HIV (WLWH) and women without HIV are scarce. To address this gap, we compared cervical precancer and cancer incidence rates between WLWH and women without HIV in South Africa using reimbursement claims data from a medical insurance scheme from January 2011 to June 2020. We used Royston-Parmar flexible parametric survival models to estimate cervical precancer and cancer incidence rates as a continuous function of age, stratified by HIV status. Our study population consisted of 518 048 women, with exclusions based on the endpoint of interest. To analyse cervical cancer incidence, we included 517 312 women, of whom 564 developed cervical cancer. WLWH had an ~3-fold higher risk of developing cervical precancer and cancer than women without HIV (adjusted hazard ratio for cervical cancer: 2.99; 95% confidence interval [CI]: 2.40-3.73). For all endpoints of interest, the estimated incidence rates were higher in WLWH than women without HIV. Cervical cancer rates among WLWH increased at early ages and peaked at 49 years (122/100 000 person-years; 95% CI: 100-147), whereas, in women without HIV, incidence rates peaked at 56 years (40/100 000 person-years; 95% CI: 36-45). Cervical precancer rates peaked in women in their 30s. Analyses of age-specific cervical cancer rates by HIV status are essential to inform the design of targeted cervical cancer prevention policies in Southern Africa and other regions with a double burden of HIV and cervical cancer

    Cohort profile: the South African HIV Cancer Match (SAM) Study, a national population-based cohort.

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    PURPOSE The South African HIV Cancer Match (SAM) Study is a national cohort of people living with HIV (PLWH). It was created using probabilistic record linkages of routine laboratory records of PLWH retrieved by National Health Laboratory Services (NHLS) and cancer data from the National Cancer Registry. The SAM Study aims to assess the spectrum and risk of cancer in PLWH in the context of the evolving South African HIV epidemic. The SAM Study's overarching goal is to inform cancer prevention and control programmes in PLWH in the era of antiretroviral treatment in South Africa. PARTICIPANTS PLWH (both adults and children) who accessed HIV care in public sector facilities and had HIV diagnostic or monitoring laboratory tests from NHLS. FINDINGS TO DATE The SAM cohort currently includes 5 248 648 PLWH for the period 2004 to 2014; 69% of these are women. The median age at cohort entry was 33.0 years (IQR: 26.2-40.9). The overall cancer incidence in males and females was 235.9 (95% CI: 231.5 to 240.5) and 183.7 (181.2-186.2) per 100 000 person-years, respectively.Using data from the SAM Study, we examined national cancer incidence in PLWH and the association of different cancers with immunodeficiency. Cancers with the highest incidence rates were Kaposi sarcoma, cervix, breast, non-Hodgkin's lymphoma and eye cancer. FUTURE PLANS The SAM Study is a unique, evolving resource for research and surveillance of malignancies in PLWH. The SAM Study will be regularly updated. We plan to enrich the SAM Study through record linkages with other laboratory data within the NHLS (eg, tuberculosis, diabetes and lipid profile data), mortality data and socioeconomic data to facilitate comprehensive epidemiological research of comorbidities among PLWH

    Life years lost associated with mental illness: A cohort study of beneficiaries of a South African medical insurance scheme.

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    BACKGROUND People with mental illness have a reduced life expectancy, but the extent of the mortality gap and the contribution of natural and unnatural causes to excess mortality among people with mental illness in South Africa are unknown. METHODS We analysed reimbursement claims from South African medical insurance scheme beneficiaries aged 15-85 years. We estimated excess life years lost (LYL) associated with organic, substance use, psychotic, mood, anxiety, eating, personality, developmental or any mental disorders. RESULTS We followed 1,070,183 beneficiaries for a median of three years, of whom 282,926 (26.4 %) received mental health diagnoses. Men with a mental health diagnosis lost 3.83 life years (95 % CI 3.58-4.10) compared to men without. Women with a mental health diagnosis lost 2.19 life years (1.97-2.41) compared to women without. Excess mortality varied by sex and diagnosis, from 11.50 LYL (95 % CI 9.79-13.07) among men with alcohol use disorder to 0.87 LYL (0.40-1.43) among women with generalised anxiety disorder. Most LYL were attributable to natural causes (men: 3.42, women: 1.94). A considerable number of LYL were attributable to unnatural causes among men with bipolar (1.52) or substance use (2.45) disorder. LIMITATIONS Mental diagnoses are based on reimbursement claims. CONCLUSIONS Premature mortality among South African individuals with mental disorders is high. Our findings support interventions for the prevention, early detection, and treatment of physical comorbidities in this population. Targeted programs for suicide prevention and substance use treatment, particularly among men, can help reduce excess mortality from unnatural causes

    Mortality from suicide among people living with HIV and the general Swiss population: 1988-2017.

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    In many countries, mortality due to suicide is higher among people living with HIV than in the general population. We aimed to analyse trends in suicide mortality before and after the introduction of triple combination antiretroviral therapy (cART), and to identify risk factors associated with death from suicide in Switzerland. We analysed data from the Swiss HIV Cohort Study from the pre-cART (1988-1995), earlier cART (1996-2008) and later cART (2009-2017) eras. We used multivariable Cox regression to assess risk factors for death due to suicide in the ART era and computed standardized mortality ratios (SMRs) to compare mortality rates due to suicide among persons living with HIV with the general population living in Switzerland, using data from the Swiss National Cohort. We included 20,136 persons living with HIV, of whom 204 (1.0%) died by suicide. In men, SMRs for suicide declined from 12.9 (95% CI 10.4-16.0) in the pre-cART era to 2.4 (95% CI 1.2-5.1) in the earlier cART and 3.1 (95% CI 2.3-4.3) in the later cART era. In women, the corresponding ratios declined from 14.2 (95% CI 7.9-25.7) to 10.2 (3.8-27.1) and to 3.3 (95% CI 1.5-7.4). Factors associated with death due to suicide included gender (adjusted hazard ratio 0.58 (95% CI 0.38-0.87) comparing women with men), nationality (1.95 (95% CI 1.34-2.83) comparing Swiss with other), Centers for Disease Control and Prevention clinical stage (0.33 (95% CI 0.24-0.46) comparing stage A with C), transmission group (2.64 (95% CI 1.71-4.09) for injection drug use and 2.10 (95% CI 1.36-3.24) for sex between men compared to other), and mental health (2.32 (95% CI 1.71-3.14) for a history of psychiatric treatment vs. no history). There was no association with age. Suicide rates have decreased substantially among people living with HIV in the last three decades but have remained about three times higher than in the general population since the introduction of cART. Continued emphasis on suicide prevention among men and women living with HIV is important

    Mental Health, ART Adherence, and Viral Suppression Among Adolescents and Adults Living with HIV in South Africa: A Cohort Study.

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    We followed adolescents and adults living with HIV aged older than 15 years who enrolled in a South African private-sector HIV programme to examine adherence and viral non-suppression (viral load > 400 copies/mL) of participants with (20,743, 38%) and without (33,635, 62%) mental health diagnoses. Mental health diagnoses were associated with unfavourable adherence patterns. The risk of viral non-suppression was higher among patients with organic mental disorders [adjusted risk ratio (aRR) 1.55, 95% confidence interval (CI) 1.22-1.96], substance use disorders (aRR 1.53, 95% CI 1.19-1.97), serious mental disorders (aRR 1.30, 95% CI 1.09-1.54), and depression (aRR 1.19, 95% CI 1.10-1.28) when compared with patients without mental health diagnoses. The risk of viral non-suppression was also higher among males, adolescents (15-19 years), and young adults (20-24 years). Our study highlights the need for psychosocial interventions to improve HIV treatment outcomes-particularly of adolescents and young adults-and supports strengthening mental health services in HIV treatment programmes
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