A latent class linear mixed model for monotonic continuous processes measured with error.

Motivated by measurement errors in radiographic diagnosis of osteoarthritis, we propose a Bayesian approach to identify latent classes in a model with continuous response subject to a monotonic, that is, non-decreasing or non-increasing, process with measurement error. A latent class linear mixed model has been introduced to consider measurement error while the monotonic process is accounted for via truncated normal distributions. The main purpose is to classify the response trajectories through the latent classes to better describe the disease progression within homogeneous subpopulations.

Incomplete Antiretroviral Therapy Adherence Is Associated with Lower CD4-CD8 Ratio in Virally Suppressed Patients with HIV Infection in Mexico.

Suboptimal adherence to antiretroviral therapy (ART) in people with HIV, even during sustained viral suppression, is associated with persistent inflammation, immune activation, and coagulopathy. Persistently low CD4-CD8 Ratio has been also associated with residual inflammation, is a good predictor of increased risk of death and more widely available than inflammatory biomarkers. We tested the hypothesis that the CD4-CD8 Ratio is associated with ART adherence during periods of complete viral suppression. We used the Medication Possession Ratio based in pharmacy registries as measure of adherence and time-varying, routine care CD4 and CD8 measurements as outcome. We used a linear mixed model for longitudinal data, including fixed effects for sex, age, education, date of ART initiation, AIDS-related conditions, and baseline CD4 to model the outcome. In 988 adults with a median follow-up of 4.13 years, higher ART adherence was independently associated with a modest increase in CD4-CD8. For each increasing percentage point in adherence, the CD4-CD8 Ratio increased 0.000857 (95% confidence interval [CI] -0.000494 to 0.002209, p = .213731) in the first year after achieving viral suppression; 0.001057 (95% CI 0.000262-0.001853, p = .009160) in years 1 to 3; 0.000323 (95% CI -0.000448 to 0.001095, p = .411441) in years 3 to 5; and 0.000850 (95% CI 0.000272-0.001429, p = .003946) 5-10 years after achieving viral suppression. The magnitude of the effect of adherence over CD4-CD8 Ratios varied over time and by baseline CD4 count, with increasing adherence having a larger effect early after ART initiation in people with higher baseline CD4 (>500 cells/µL) and in later years in people with lower baseline CD4 count (≥200 cells/µL). Our findings expand on previous evidence suggesting that the benefits of optimal adherence to modern ART regimens goes beyond maintaining viral suppression. These results highlight the importance of including objective measurements of adherence as part of routine care, even in patients with complete HIV suppression over long-term follow-up.

Mixed kernel SVR addressing Parkinson's progression from voice features.

Parkinson's Disease (PD) is a progressive neurodegenerative disease with multiple motor and non-motor characteristics. PD patients commonly face vocal impairments during the early stages of the disease. In this article, the aim is to explain the Unified Parkinson's Disease Rating Scale (UPDRS) as a measure of the progression of Parkinson's disease using a set of covariates obtained from voice signals. In particular, a Support Vector Regression (SVR) model based on a combination of kernel functions is introduced. Theoretically, this proposal, that relies on a mixed kernel (global and local) produces an admissible kernel function. The optimal fitting was obtained for the combination given by the product of radial and polynomial basis. Important results are the non-linear relationships inferred from the features to the response, as well as a considerable improvement in prediction performance metrics, when compared to other learning approaches. Furthermore, with knowledge on factors such as age and gender, it is possible to describe the dynamics of patients' UPDRS from the data collected during their monitoring. In summary, these advances could expand learning processes and intelligent systems to assist in monitoring the evolution of Parkinson's disease.

Risk assessment in COVID-19 patients: A multiclass classification approach.

Understanding SARS-CoV-2 infection that causes COVID-19 disease among the population was fundamental to determine the risk factors associated with severe cases or even death. Amidst the study of the pandemic, Artificial Intelligence (AI) and Machine Learning (ML) have been successfully applied in many areas such as biomedicine. Using a dataset from the Mexican Ministry of Health, we performed a multiclass classification scheme for the detection of risks in COVID-19 patients and implemented three Machine Learning algorithms achieving the following accuracy measures: Random Forest (89.86%), GBM (89.37%) XGBoost (89.97%). The key findings are the identification of relevant components associated with different severities of COVID-19 disease. Among these factors, we found sex, age, days elapsed from the beginning of symptoms, symptoms such as dyspnea and polypnea; and other comorbidities such as diabetes and hypertension. This setting allows us to establish predicting algorithms to model the risk that an individual or a specific group of people face after contracting COVID-19 and the factors associated with developing complications or receiving appropriate treatment.

Comprehensive health evaluation of an urban wetland using quality indices and decision trees.

In a world where pristine water is becoming scarcer, the need to reuse water becomes imperative. In this context explaining the water quality, purpose fitness and the parameters or conditions of the water body to adjust so as to improve its quality, are of great relevance. The goal of the present study was the use of water, riverine, and biodiversity quality indices to assess the condition of the studied urban wetland, since no single index can provide a complete health assessment of a water body. Decision trees were also used to elucidate the best water parameters to mend in order to recover the overall health of the urban wetland. The decision trees identified relevant physicochemical parameters as well as their approximate concentration at which a healthy water environment can be sustained for zooplankton and proved to be a powerful and simple alternative to customary approaches. Suspended particles and phosphates proved to be important parameters with concentrations approximately lower than 88 mg L-1 and 11 mg L-1, respectively, for a good biodiversity index of zooplankton. Ammonia, total coliforms, BOD, nitrates, and sodium were the main parameters that affected the water quality index. The vegetation coverage and its structure were the driving factors in the riverine quality index of the wetland.

A hidden Markov model addressing measurement errors in the response and replicated covariates for continuous nondecreasing processes.

Motivated by a study tracking the progression of Parkinson's disease (PD) based on features extracted from voice recordings, an inhomogeneous hidden Markov model with continuous state-space is proposed. The approach addresses the measurement error in the response, the within-subject variability of the replicated covariates and presumed nondecreasing response. A Bayesian framework is described and an efficient Markov chain Monte Carlo method is developed. The model performance is evaluated through a simulation-based example and the analysis of a PD tracking progression dataset is presented. Although the approach was motivated by a PD tracking progression problem, it can be applied to any monotonic nondecreasing process whose continuous response variable is subject to measurement errors and where replicated covariates play a key role.

Diabetic by HbA1c, Normal by OGTT: A Frequent Finding in the Mexico City Diabetes Study.

CONTEXT: The agreement between glucose-based and hemoglobin A1c (HbA1c)-based American Diabetes Association criteria in the diagnosis of normal glucose tolerance, prediabetes, or diabetes is under scrutiny. A need to explore the issue among different populations exists. OBJECTIVE: Examine the results obtained with both methods in the diagnosis of the glycemic status. DESIGN: The Mexico City Diabetes Study is a population-based, prospective investigation. SETTING: Low-income elder urban community. PARTICIPANTS: All 854 participants without known diabetes had both oral glucose tolerance test (OGTT) and HbA1c measurements on the same day of the 2008 phase. INTERVENTIONS: Standardized protocol: questionnaires, anthropometry, and biomarkers. MAIN OUTCOME: Diagnostic classification of American Diabetes Association criteria. RESULTS: We found by OGTT normal glucose tolerance (NGT) in 512 (59.9%) participants, prediabetes [impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT)] in 261 (30.5%), and diabetes in 81 (9.4%). In total, 232 in the NGT group (45.3%) and 158 in the prediabetes group (60.5%) had HbA1c ≥6.5%. Body mass index, waist circumference, and blood pressure were significantly different among OGTT-defined diabetic status groups but not in the HbA1c-diagnosed group. We identified 404 participants in the NGT group with confirmed NGT throughout all phases of the Mexico City Diabetes Study. Of these, 184 (45.5%) had HbA1c ≥6.5%. In a vital/diabetes status follow-up performed subsequently, we found that, of these, 133 remained nondiabetic, 3 had prediabetes, 7 had diabetes, and 13 had died without diabetes; we were unable to ascertain the glycemic status in 5 and vital status in 23. CONCLUSIONS: Normal OGTT coexisting with elevated HbA1c is a common finding in this cohort. It is possible that this finding is not mediated by hyperglycemia. This might occur in similar populations.

A D2-like receptor family agonist produces analgesia in mechanonociception but not in thermonociception at the spinal cord level in rats.

The administration of dopaminergic drugs produces analgesia in individuals experiencing different types of pain. Analgesia induced by these drugs at the spinal cord level is mediated by D2-like agonists, which specifically inhibit the detection of nociceptive stimuli by sensory afferents. The extent of the analgesia provided by spinal dopamine agonists remains controversial, and the cellular mechanism of this analgesic process is poorly understood. The objective of this study was to evaluate the analgesic effect of quinpirole, a D2-like agonist, based on two nociceptive tests and at various doses that were selected to specifically activate dopamine receptors. We found that intrathecal quinpirole administration produces analgesia of mechanical but not thermal nociception and that the analgesic effect of quinpirole is reversed by a mix of D2, D3, and D4 receptor-specific antagonists, suggesting that the activation of all D2-like receptors is involved in the analgesia produced by intrathecal quinpirole. The differential effect on thermal and mechanical nociception was also tested upon the activation of µ-opioid receptors. As reported previously, low doses of the µ-opioid receptor agonist DAMGO produced analgesia of only thermonociception. This evidence shows that a D2-like receptor agonist administered at the spinal cord level produces analgesia specific to mechanonociception but not thermonociception.

[Interpersonal relationships: perception of the communication, treatment and adverse experiences encountered by users of medical units that belong to the Coordinating Commission of the National Institutes of Health and High Specialty Hospitals (CCINSHAE)]. / Las relaciones interpersonales: percepción de la comunicación, trato y experiencias adversas en los usuarios de las unidades médicas pertenecientes a la Comisión Coordinadora de Institutos Nacionales de Salud y Hospitales de Alta Especialidad (CCINSHAE).

INTRODUCTION: User's perception with regard to the attention they received in healthcare units is increasingly being taken into account by the health service providers in order to improve the quality of their service. AIM: Describe how the users perceive the health services provided by the CCINSHAE with regard to the communication with the physicians, the attention of the staff and the adverse personal and institutional experiences and to explore their relation with user's demographic characteristics, health condition, physical limitations to carry out daily activities and service area. METHODS: A questionnaire was designed to collect information about the user and his/her opinion with regard to the healthcare units, the communication with the physicians, the attention of the staff and the adverse personal and institutional experiences. The data were analyzed with STATA using sample weights. RESULTS: A total of 2,176 individuals were interviewed after they had received attention and represent a population of 1,457,964 users, over 6 months, of the CCINSAHE. We then calculated four binary variables that reflect the perception of the users. These four variables were significantly associated with the type of health unit where the user received attention, schooling, limitations to carry out daily activities, facilities provided to the relatives, family income, the use of alternative medicine, and the area of attention. DISCUSSION: A fundamental aspect of the service provided by the healthcare institutions is the communication between the physicians and the users. We found that the perception of the users with regard to the communication with the physician, the attention of the staff, and the adverse personal and institutional experiences was associated with the type of healthcare unit. The federal reference hospitals produced the most unfavorable perception while the regional hospitals produced the most favorable impression. This study enables the decision-making personnel to determine what needs to be modified in order to improve the service provided by the health units.

[Sleep deprivation effects on cognitive, psychomotor skills and its relationship with personal characteristics of resident doctors]. / Efectos de la privación de sueño en las habilidades cognitivas, psicomotoras y su relación con las características personales de los médicos residentes.

BACKGROUND: In countries such as United States and European Nations changes have been proposed regarding to duty and academic structure of specialists in training, this implies adjustments in the norms concerning the number of hours a week that residents work. The main argument which has underpinned such transformations is based on the assumption that excessive working hours (more than 16 hours uninterrupted) cause cognitive and psychomotor disorders in residents. OBJECTIVE: To evaluate the association between sleep deprivation and cognitive and psychomotor skills of a sample of residents of different specialties of Medicine. METHODS: Longitudinal study with measurements pre and post shifts, in 31 residents of Medicine. The measured variables were: cognitive and psychomotor skills, demographic data and conditions of the shift, quality of sleep and psychopathology. RESULTS: 81% residents showed detriment in at least one of the tests, however, in psychomotor skills significant different results were found in CPR maneuvers between pre and post shift with an improvement in scores. CONCLUSIONS: Sleep deprivation causes detriment of cognitive and psychomotor skills. While our results can't be generalized, they may constitute a precedent for possible changes in the working hours of medical residencies.

Antecedentes: en países como Estados Unidos y las naciones europeas se han propuesto cambios a la estructura asistencial y académica de los médicos especialistas en formación que proponen transformaciones a las normas relativas al número de horas que trabajan a la semana los residentes. El argumento principal que sustenta esas transformaciones se basa en el supuesto de que las horas de trabajo excesivas (más de 16 horas ininterrumpidas) provocan alteraciones cognitivas y psicomotrices en los residentes. Objetivo: evaluar la asociación entre la privación de sueño y las habilidades cognitivas y psicomotoras de una muestra de residentes de diferentes especialidades médicas. Material y métodos: estudio longitudinal, con mediciones pre y post guardia, en 31 residentes de Medicina. Se midieron las variables de: habilidades cognitivas y psicomotoras, datos sociodemográficos y de condiciones de guardia, calidad de sueño y psicopatología. resultados: 81% de los residentes tuvo detrimento en, al menos, una de las pruebas realizadas; sin embargo, en los resultados de las habilidades psicomotoras y en la maniobra de reanimación cardiopulmonar básica se encontró una diferencia significativa en los momentos pre y post guardia con mejoría en las puntuaciones. Conclusiones: la privación de sueño disminuye las habilidades cognitivas y psicomotoras. Si bien nuestros resultados no son generalizables, pueden constituir un precedente para fundamentar posibles cambios referentes a las guardias en las residencias médicas.