Modelo preditivo para tentativa de suicídio em pacientes internados por uso de crack : uma abordagem por aprendizado de máquina

O suicídio e os comportamentos do espectro suicida constituem um importante problema de saúde que levam a cerca de 800.000 mortes por ano mundialmente, segundo a Organização Mundial da Saúde. Na população de indivíduos com transtornos por uso de substâncias, principalmente de crack-cocaína, as taxas de suicídio e tentativa de suicídio se mostram muito elevadas em comparação à população geral, bem como também é observado a ocorrência de múltiplas comorbidades e condições socioeconômicas desfavoráveis, colocando essa população em situação de especial vulnerabilidade. Modelos teóricos de suicídio propõem explicações para o surgimento de comportamentos suicidas que integram fatores diáteses ou pré-motivacionais com fatores estressores ou precipitadores. Observa-se também uma grande sobreposição de fatores associados aos desfechos de suicídio e dependência química e possivelmente da existência de fatores específicos para esta população e de acordo com o gênero. Portanto, este trabalho objetiva investigar preditores de tentativa de suicídio em uma amostra de homens e mulheres internados por transtorno por uso de crack-cocaína e discutir a respeito dos elementos que podem contribuir para esse cenário. O artigo 1 apresenta um artigo original sobre a aplicação de duas metodologias analíticas de forma estratificada por gênero, uma descritiva e outra preditiva. A primeira sendo a regressão de Poisson com variância robusta a fim de estimar razões de prevalência e identificar fatores associados à tentativa de suicídio; e a segunda sendo o algoritmo Floresta Aleatória de Aprendizado de Máquina supervisionado, a fim de investigar preditores de tentativa de suicídio e avaliar a performance preditiva alcançada. O trabalho consiste de um estudo transversal que utiliza um banco de dados secundários mesclado de duas instituições especializadas no tratamento da dependência química de Porto Alegre/RS, contém uma amostra composta por homens e mulheres internados por transtorno por uso de crack e variáveis oriundas da aplicação de três instrumentos de pesquisa que coletaram informações sociodemográficas, psiquiátricas (transtornos e traumas) e sobre o padrão de uso de drogas. O artigo 2 apresenta um editorial sobre uso de drogas e suicídio a fim de incentivar futuros trabalhos e reforçar a necessidade de políticas públicas, estratégias de tratamento acessíveis e uso de tecnologias promissoras para promoção do bem estar social e redução da desigualdade.Suicide and suicide behaviors are an important health problem that lead to around 800,000 deaths per year worldwide, according to the World Health Organization. In the population of individuals with substance use disorders, especially crack-cocaine, the rates of suicide and attempted suicide are very high compared to the general population, as well as the occurrence of multiple comorbidities and unfavorable socioeconomic conditions, which place this population in a situation of special vulnerability. Theoretical models of suicide propose explanations for the emergence of suicidal behaviors that integrate diathesis or pre-motivational factors with stressors or precipitating factors. There is also a large overlap of factors associated with the outcomes of suicide and substance use disorder and possibly the existence of specific factors for this population and also gender-specific factors. Therefore, this study aims to investigate predictors of attempted suicide in a sample of men and women hospitalized for crack-cocaine disorder and discuss the elements that may contribute to this scenario. Article 1 presents an original article on the application of two analytical methodologies stratified by gender, a descriptive one and a predictive one. The first being the Poisson regression with robust variance in order to estimate prevalence ratios and to identify factors associated with suicide attempt; and the second being the supervised Machine Learning Random Forest algorithm, in order to investigate predictors of attempted suicide and evaluate the predictive performance achieved. The work consists of a cross-sectional study that uses a secondary database merged from two institutions specialized in the treatment of chemical dependence in Porto Alegre / RS, contains a sample composed of men and women hospitalized for crack use disorder and variables from the application of three research instruments that collected sociodemographic and psychiatric information (disorders and traumas) and the pattern of drug use. Article 2 presents an editorial on drug use and suicide in order to encourage future work and reinforce the need for public policies, accessible treatment strategies and the use of promising technologies to promote social welfare and reduce inequality

Prevalence of suicide in cocaine users accessing health services : a systematic review and meta-analysis

Objective: This study reviewed and analyzed the prevalence of suicidal behaviors among cocaine users who sought health services. Methods: This is a systematic review and meta-analysis of studies published until January 2021. PubMed/MEDLINE, Scopus, Embase, PsycINFO, and LILACS were searched. The inclusion criteria were observational (retrospective or prospective), case-control, and/or cross-sectional reports that contained samples of cocaine users aged over 14 years who were assessed in health facilities or were in treatment. The random-effects model was used to calculate the overall prevalence of suicidal behavior with a 95% confidence interval. Subgroup analysis was conducted to investigate sources of heterogeneity. Results: Twenty articles were included, yielding a total of 2,252 cocaine users. The estimated prevalence was 43.59% (95%CI 31.10-57.38) for suicidal ideation and 27.71% (95%CI 21.63-34.73) for suicide attempts. High heterogeneity was found between studies for both outcomes (I2 X 93%), although subgroup analysis considering the quality of the studies showed a significant difference in suicide attempts (p = 0.03). Conclusion: Cocaine use can be considered a risk factor for suicidal behavior, and prevention and early screening measures should be implemented to facilitate adequate treatment

Early discharge predictors among inpatient crack cocaine users

Introduction: High rates of early hospital discharge are often observed in crack cocaine users and are related to adverse outcomes and increased public spending. This study evaluated clinical and sociodemographic factors associated with early treatment discharge among crack users. Methods: The sample comprised 308 men diagnosed with crack cocaine use disorder (crack only), aged 18 to 65 years, admitted between 2013 and 2017 to a male-only hospital unit to treat substance use disorders. Sociodemographic and clinical data were obtained using the Addiction Severity Index, 6th version, and a Sociodemographic Questionnaire. Results: Early discharge (within 7 days) was significantly associated with lack of own income, insufficient family support, being single, and recent homelessness. Regarding drug use, lower treatment retention was related to younger age of crack use onset, recent alcohol use, and nicotine use. Factors such as age, skin color, and educational level showed no relation to the outcome. Conclusion: Our findings suggest that presence of characteristics verifiable at the time of admission may be related to crack users’ treatment retention. Identification of these factors can contribute to target interventions in order to improve treatment adherence in crack cocaine users

Classification of homogeneous regions of vegetation cover in the State of Rio Grande do Sul, Brazil and its temporal dynamics, using AVHRR GIMMS and MODIS data sets

This study aimed to classify the homogeneous regions of vegetation cover, which occur in Rio Grande do Sul, formed by clustering of pixels with same pattern of temporal variability of the Normalized Difference Vegetation Index (NDVI) of AVHRR GIMMS and MODIS series and to compare their temporal dynamics. We use K means cluster analysis for defi ning homogeneous regions, based on the temporal variability of GIMMS (8 km spatial resolution) and MODIS (1 km spatial resolution) NDVI data sets, using monthly images mean from 2000 to 2008 (overlapping period); and we analyzed the annual pattern of NDVI. Accuracy assessment was done with Landsat images. The results show that the temporal variability of GIMMS and MODIS NDVI allows to delimit similar homogeneous regions in order to mapping the main vegetation cover. MODIS series shows a greater detail in the defi nition of the regions, but with compatibility with those generated by GIMMS. The temporal dynamics show a typical seasonal pattern, with variations of NDVI amplitude between the groups, that allow to monitor phenological changes. The deviations from calibration between times series are linear, which would facilitate a correction in order to construct a long synthetic time series for studies of land cover change

Gender differences in progression to crack-cocaine use and the role of sexual and physical violence

Objective: This study aimed to evaluate whether progression from first drug use to crack-cocaine use differs according to gender, and whether the report of sexual or physical violence impacts the time of progression. Methods: We interviewed 896 crack-cocaine users (548 men; 348 women) from addiction treatment units. Cox regression models evaluated the time of progression from first drug use to crack use. We analyzed gender differences according to the absence or presence of sexual or physical violence, also considering whether violence, when present, had occurred before or after the onset of crack use. Results: Women presented a faster progression to crack use regardless of exposure to sexual or physical violence (p o 0.05). Compared to unexposed men, there was a similar progression for men exposed to sexual or physical violence before the first use of crack (p = 0.167 and p = 0.393, respectively). In both genders, we observed a faster progression among individuals exposed to these types of violence after the onset of crack use (p o 0.01). Conclusions: We found a faster progression to crack use among women and among individuals exposed to sexual and physical violence after the onset of crack use. These results encourage differentiated treatment strategies, focused on gender and individual characteristics

Agrometeorological-spectral model to estimate irrigate rice grain yield in the State of Rio Grande do Sul, Brazil

O objetivo deste trabalho foi elaborar e testar um modelo agrometeorológico-espectral para a estimativa da produtividade de grãos de arroz irrigado para o Estado do Rio Grande do Sul. Para as seis regiões orizícolas do Estado, foram utilizados dados de área cultivada e rendimento de grãos de arroz irrigado, dados meteorológicos e imagens do Índice de Vegetação por Diferença Normalizada (NDVI) do sensor Moderate Resolution Imaging Spectroradiometer (MODIS), de agosto a abril, para as safras de 2000/2001 até 2009/2010. A temperatura mínima do ar e o NDVI estão associados ao rendimento de grãos de arroz irrigado em diversos períodos do desenvolvimento da cultura. O modelo agrometeorológico-espectral para estimativa de produtividade de grãos, ajustado através da abordagem orientada pelas relações clima-planta, é adequado às estimativas em nível regional, podendo fornecer estas com cerca de um mês de antecedência ao final da colheita.The objective of this study was to estimate the irrigated rice grain yield through the adjustment of the agrometeorological-spectral model in the State of Rio Grande do Sul, Brazil. For the six rice-growing regions of the State, the data on irrigated rice grain yield and crop area, meteorological data and the Normalized Difference of Vegetation Index (NDVI) images of moderate resolution imaging spectroradiometer (MODIS) sensor were used from August to April, for the 2000/2001 to 2009/2010 crop seasons. The minimum air temperature and NDVI are associated to the irrigated rice grain yield in several crop development periods. The agrometeorological-spectral model to estimate irrigated rice grain yield, adjusted through the oriented approach by the climate-plant relationship, is adequate for the estimates at regional levels. This could predict the estimates one month before the end of the harvest

Increase in serum brain-derived neurotrophic factor levels during early withdrawal in severe alcohol users

Introduction: Changes in brain-derived neurotrophic factor (BDNF) have been linked to the neuroadaptative consequences of chronic alcohol use and associated with disease severity and prognosis. Few studies have evaluated the influence of drug withdrawal and clinical and sociodemographic data on BDNF levels in severe alcohol users. Objectives: Our goals were (1) to evaluate variation in BDNF levels during alcohol withdrawal and, (2) to assess the influence of putative confounding factors on BDNF levels. Methods: Our sample consists of 62 men with alcohol use disorder undergoing a detoxification process. Serum BDNF levels were measured using a commercial sandwich-ELISA kit, at two points: before and after the detoxification period. Results: We found an increase in BDNF levels during alcohol withdrawal (25.4±9.6 at admission vs. 29.8±10.2 ng/ml at discharge; p < 0.001), even after controlling for potential confounders (positive family history, number of days between blood sample collections, and age) (Generalized Estimating Equation: coefficient = -4.37, 95% confidence interval [95%CI] -6.3; -2.4; p < 0.001). Moreover, individuals who had first-degree relative with alcohol dependence had smaller increases in BDNF levels than individuals with no family history (14.8 [95%CI -5.3; 35.6] vs. 35.3 [95%CI 15.4; 74.8]; p = 0.005). Conclusions: In summary, variation in BDNF levels seems to be influenced by withdrawal in severe alcohol users. A positive family history of alcohol dependence could also be a factor that influences variation in this biomarker

Predictive factors associated with driving under the influence among Brazilian drug-using drivers

The incidence of driving under the influence of psychoactive substances (DUI) and its recidivism can be curtailed by the proper identification of specific and predictive characteristics among drug users. In this sense, interpersonal violence (IV), psychiatric comorbidity and impulsivity seem to play an important role in DUI engagement according to previous studies. There are, however, limited data originated from low and middle income countries. In the present study, drug-using Brazilian drivers reporting DUI (n=75) presented a higher prevalence of bipolar disorders (BD; DUI: 8% vs. non-DUI: 0%, p < 0.001), lower prevalence of obsessivecompulsive disorder (OCD; DUI: 0% vs. non-DUI: 12.6%, p < 0.001), and higher prevalence of childhood trauma (DUI: 65.3% vs. non-DUI: 46.8%, p=0.022) than those not reporting DUI (n=79). The evaluation of impulsivity though the Barratt Impulsivity Scale, which give impulsivity scores ranging from 30 to 120, showed higher impulsivity scores in the DUI group (80.4 ± 8) than in the non-DUI group (77.2 ± 10, p=0.045). In general, subjects were young adults (mean age of 36 ± 9 years), Caucasians (58.4%), not married (61.0%), and with elementary schooling (40.3%) with no significant differences in demographic characteristics between drivers with and without DUI behavior A multiple Poisson regression model showed that individuals reporting IV as perpetrators and history of childhood trauma were more likely to report DUI (PR: 1.66, 95%CI 1.22–2.7; PR: 1.57, 95%CI 1.02–2.42, respectively). The overlapping of violent situations (childhood trauma, IV and DUI) in some individuals presented here corroborates literature data suggesting that DUI can be an externalizing expression of a range of risky behavior, such as impulsiveness and aggressiveness. Moreover, while BD and higher impulsivity scores seem to act as risk factors for DUI, OCD was shown as a protective factor. These results corroborate the hypothesis that individuals with high risk for DUI could probably be identified by multidimensional assessment of cognitive, risky taking, and personality traits, which perhaps could facilitate the development of focused interventions