Predictors of time to relapse in amphetamine-type substance users in the matrix treatment program in Iran : a Cox proportional hazard model application

Background: The aim of this study was to determine which predictors influence the risk of relapse among a cohort of amphetamine-type substance (ATS) users in Iran. Methods: A Cox proportional hazards model was conducted to determine factors associated with the relapse time in the Matrix treatment program provided by the Iranian National Center of Addiction Studies (INCAS) between March 2010 and October 2011. Results: Participating in more treatment sessions was associated with a lower probability of relapse. On the other hand, patients with less family support, longer dependence on ATS, and those with an experience of casual sex and a history of criminal offenses were more likely to relapse. Conclusion: This study broadens our understanding of factors influencing the risk of relapse in ATS use among an Iranian sample. The findings can guide practitioners during the treatment program

Evaluating Risk Measures and Capital Allocations Based on Multi-Losses Driven by a Heavy-Tailed Background Risk: The Multivariate Pareto-II Model

Evaluating risk measures, premiums, and capital allocation based on dependent multi-losses is a notoriously difficult task. In this paper, we demonstrate how this can be successfully accomplished when losses follow the multivariate Pareto distribution of the second kind, which is an attractive model for multi-losses whose dependence and tail heaviness are influenced by a heavy-tailed background risk. A particular attention is given to the distortion and weighted risk measures and allocations, as well as their special cases such as the conditional layer expectation, tail value at risk, and the truncated tail value at risk. We derive formulas that are either of closed form or follow well-defined recursive procedures. In either case, their computational use is straightforward

Determinants of the population growth of the West Nile virus mosquito vector Culex pipiens in a repeatedly affected area in Italy

Background The recent spread of West Nile Virus in temperate countries has raised concern. Predicting the likelihood of transmission is crucial to ascertain the threat to Public and Veterinary Health. However, accurate models of West Nile Virus (WNV) expansion in Europe may be hampered by limited understanding of the population dynamics of their primary mosquito vectors and their response to environmental changes.<p></p> Methods We used data collected in north-eastern Italy (2009–2011) to analyze the determinants of the population growth rate of the primary WNV vector Culex pipiens. A series of alternative growth models were fitted to longitudinal data on mosquito abundance to evaluate the strength of evidence for regulation by intrinsic density-dependent and/or extrinsic environmental factors. Model-averaging algorithms were then used to estimate the relative importance of intrinsic and extrinsic variables in describing the variations of per-capita growth rates.<p></p> Results Results indicate a much greater contribution of density-dependence in regulating vector population growth rates than of any environmental factor on its own. Analysis of an average model of Cx. pipiens growth revealed that the most significant predictors of their population dynamics was the length of daylight, estimated population size and temperature conditions in the 15 day period prior to sampling. Other extrinsic variables (including measures of precipitation, number of rainy days, and humidity) had only a minor influence on Cx. pipiens growth rates.<p></p> Conclusions These results indicate the need to incorporate density dependence in combination with key environmental factors for robust prediction of Cx. pipiens population expansion and WNV transmission risk. We hypothesize that detailed analysis of the determinants of mosquito vector growth rate as conducted here can help identify when and where an increase in vector population size and associated WNV transmission risk should be expected.<p></p&gt

Malnutrition, functional ability and mortality among older people aged ⩾60 years: a 7-year longitudinal study

BACKGROUND/OBJECTIVES: This study aimed to assess the association between risk of malnutrition and 7-year mortality, controlling for functional ability, socio-demographics, lifestyle behavior and diseases, and investigate the interaction between risk of malnutrition and functional ability on the risk of mortality. SUBJECTS/METHODS: A longitudinal study on home-living and special-housing residents aged [greater than or equal to] 60 years was conducted. Of 2312 randomly invited participants, 1402 responded and 1203 provided information on both nutritional status and functional ability. The risk of malnutrition was estimated by the occurrence of at least one anthropometric measure (BMI, MAC and CC) below cut-off in addition to the presence of at least one subjective measure (decreased food intake, weight loss and eating difficulty). RESULTS: At baseline, 8.6% of subjects were at risk of malnutrition and during the 7-year follow-up 34.6% subjects died. The risk of malnutrition was independently associated with 7-year mortality (hazard ratio (HR) 1.84, 95% confidence interval (CI) 1.28-2.65). Additional independent predictors were dementia (HR 2.76, 95% CI 1.85-4.10), activity of daily living (ADL) dependence (HR 2.08, 95% CI 1.62-2.67), heart disease (HR 1.44, 95% CI 1.16-1.78), diabetes (HR 1.41, 95% CI 1.03-1.93) and older age (HR 1.09, 95% CI 1.07-1.10). Moreover, the risk of malnutrition and ADL dependence in combination predicted the poorest survival rate (18.7%, P < 0.001). CONCLUSIONS: The risk of malnutrition significantly increases the risk of mortality in older people. Moreover, risk of malnutrition and ADL dependence together explain a significantly poorer survival rate; however, the importance of this interaction decreased in the multivariable model and risk of malnutrition and ADL dependence independently explained a significant risk of mortality

Pressure-dependence of arterial stiffness: potential clinical implications

Background: Arterial stiffness measures such as pulse wave velocity (PWV) have a known dependence on actual blood pressure, requiring consideration in cardiovascular risk assessment and management. Given the impact of ageing on arterial wall structure, the pressure-dependence of PWV may vary with age. Methods: Using a noninvasive model-based approach, combining carotid artery echo-tracking and tonometry waveforms, we obtained pressure-area curves in 23 hypertensive patients at baseline and after 3 months of antihypertensive treatment. We predicted the follow-up PWV decrease using modelled baseline curves and follow-up pressures. In addition, on the basis of these curves, we estimated PWV values for two age groups (mean ages 41 and 64 years) at predefined hypertensive (160/90 mmHg) and normotensive (120/80mmHg) pressure ranges. Results: Follow-up measurements showed a near 1 m/s decrease in carotid PWV when compared with baseline, which fully agreed with our model-prediction given the roughly 10mmHg decrease in diastolic pressure. The stiffness-blood pressure-age pattern was in close agreement with corresponding data from the 'Reference Values for Arterial Stiffness' study, linking the physical and empirical bases of our findings. Conclusion: Our study demonstrates that the innate pressure-dependence of arterial stiffness may have implications for the clinical use of arterial stiffness measurements, both in risk assessment and in treatment monitoring of individual patients. We propose a number of clinically feasible approaches to account for the blood pressure effect on PWV measurements

Psychometric examination and factorial validity of the Exercise Dependence Scale-Revised in Italian exercisers

Background and aims: The purpose of this study was to verify the factorial structure, internal validity, reliability, and criterion validity of the 21-item Exercise Dependence Scale-Revised (EDS-R) in an Italian sample. Methods: Italian voluntary (N = 519) users of gyms who had a history of regular exercise for over a year completed the EDS-R and measures of exercise frequency. Results and conclusions: Confirmatory factor analyses demonstrated a good fit to the hypothesized 7-factor model, and adequate internal consistency for the scale was evidenced. Criterion validity was evidenced by significant correlations among all the subscale of the EDS and exercise frequency. Finally, individuals at risk for exercise dependence reported more exercise behavior compared to the nondependent-symptomatic and nondependent-asymptomatic groups. These results suggest that the seven subscales of the Italian version of the EDS are measuring the construct of exercise dependence as defined by the DSM-IV criteria for substance dependence and also confirm previous research using the EDS-R in other languages. More research is needed to examine the psychometric properties of the EDS-R in diverse populations with various research designs

Risk of self-harm after the diagnosis of psychiatric disorders in Hong Kong, 2000–10: a nested case-control study

Background Psychiatric disorders are established risk factors for self-harm. However, variation in risk of self-harm by specific psychiatric disorder, stratified by gender and age, is rarely examined using population representative samples. This study aims to investigate the risk of self-harm following the diagnosis of different psychiatric disorders based on inpatient records retrieved from the Hong Kong Clinical Data Analysis and Reporting System (CDARS). Method A cohort of 86,353 people with a first-recorded diagnosis of depression, alcohol abuse/dependence, personality disorders, bipolar disorders, anxiety disorders, schizophrenia, or substance abuse/dependence, along with 134,857 matched controls, were followed between 2000 and 2010. For each diagnostic category, a Cox proportional hazard regression model was fitted to estimate the adjusted hazard ratio (aHR) (95% confidence intervals) of associated self-harm, adjusting for gender, age, admission time, district of residence, and comorbidities. Outcomes The personality disorders and substance abuse/dependence groups had the highest self-harm incidences of 3,174 and 3,018 per 100,000 patient-years, respectively. The highest risk of self-harm was found in the substance abuse/dependence group (aHR, 9·6; 95% CI, 8·4-11·0), followed by the groups with personality disorders (3·7; 2·8-4·9) and alcohol abuse/dependence (3·2; 2·9-3·7). When stratified by gender and age, the highest risk was found in substance abuse/dependence group for both genders (female: aHR, 7·7; 95% CI, 6·0-9·8; male: 10·5; 95% CI, 8·9-12·4) and all age groups (adolescent: aHR, 9·6; 95% CI, 7·2-12·7; young: 10·2; 95% CI, 8·4-12·3; middle-aged: 11·2; 95% CI, 8·0-15·6; Elderly: 3·2; 95% CI, 1·7-6·1). Interpretation First-recorded diagnosis of psychiatric disorders were significantly associated with elevated risks of subsequent self-harm. The associations varied considerably by diagnostic categories across gender-age subgroups. This finding highlighted the needs to develop more efficient and targeted preventive measures in psychiatric care management. Specific attention should be paid to demographic characteristics linked to increased risk within the same diagnostic category

An intervention to stop smoking among patients suspected of TB - evaluation of an integrated approach

<p>Abstract</p> <p>Background</p> <p>In many low- and middle-income countries, where tobacco use is common, tuberculosis is also a major problem. Tobacco use increases the risk of developing tuberculosis, secondary mortality, poor treatment compliance and relapses. In countries with TB epidemic, even a modest relative risk leads to a significant attributable risk. Treating tobacco dependence, therefore, is likely to have benefits for controlling tuberculosis in addition to reducing the non-communicable disease burden associated with smoking. In poorly resourced health systems which face a dual burden of disease secondary to tuberculosis and tobacco, an integrated approach to tackle tobacco dependence in TB control could be economically desirable. During TB screening, health professionals come across large numbers of patients with respiratory symptoms, a significant proportion of which are likely to be tobacco users. These clinical encounters, considered to be "teachable moments", provide a window of opportunity to offer treatment for tobacco dependence.</p> <p>Methods/Design</p> <p>We aim to develop and trial a complex intervention to reduce tobacco dependence among TB suspects based on the WHO 'five steps to quit' model. This model relies on assessing personal motivation to quit tobacco use and uses it as the basis for assessing suitability for the different therapeutic options for tobacco dependence.</p> <p>We will use the Medical Research Council framework approach for evaluating complex interventions to: (a) design an evidence-based treatment package (likely to consist of training materials for health professionals and education tools for patients); (b) pilot the package to determine the delivery modalities in TB programme (c) assess the incremental cost-effectiveness of the package compared to usual care using a cluster RCT design; (d) to determine barriers and drivers to the provision of treatment of tobacco dependence within TB programmes; and (e) support long term implementation. The main outcomes to assess the effectiveness would be point abstinence at 4 weeks and continuous abstinence up to 6 months.</p> <p>Discussion</p> <p>This work will be carried out in Pakistan and is expected to have relevance for other low and middle income countries with high tobacco use and TB incidence. This will enhance our knowledge of the cost-effectiveness of treating tobacco dependence in patients suspected of TB.</p> <p>Trial Registration</p> <p>Trial Registration Number: ISRCTN08829879</p

Identifying risk factors associated with smear positivity of pulmonary tuberculosis in Kazakhstan

Background Sputum smear-positive tuberculosis (TB) patients have a high risk of transmission and are of great epidemiological and infection control significance. Little is known about the smearpositive populations in high TB burden regions, such as Kazakhstan. The objective of this study is to characterize the smear-positive population in Kazakhstan and identify associated modifiable risk factors. Methods Data on incident TB cases’ (identified between April 2012 and March 2014) socio-demographic, risk behavior, and comorbidity characteristics were collected in four regions of Kazakhstan through structured survey and medical record review. We used multivariable logistic regression to determine factors associated with smear positivity. Results Of the total sample, 193 (34.3%) of the 562 study participants tested smear-positive. In the final adjusted multivariable logistic regression model, sex (adjusted odds ratio (aOR) = 2.0, 95% CI:1.3–3.1, p < 0.01), incarceration (aOR = 3.6, 95% CI:1.2–11.1, p = 0.03), alcohol dependence (aOR = 2.6, 95% CI:1.2–5.7, p = 0.02), diabetes (aOR = 5.0, 95% CI:2.4–10.7, p < 0.01), and physician access (aOR = 2.7, 95% CI:1.3–5.5p < 0.01) were associated with smear-positivity. Conclusions Incarceration, alcohol dependence, diabetes, and physician access are associated with smear positivity among incident TB cases in Kazakhstan. To stem the TB epidemic, screening, treatment and prevention policies should address these factors

Economics of dialysis dependence following renal replacement therapy for critically ill acute kidney injury patients.

BACKGROUND: The obective of this study was to perform a cost-effectiveness analysis comparing intermittent with continuous renal replacement therapy (IRRT versus CRRT) as initial therapy for acute kidney injury (AKI) in the intensive care unit (ICU). METHODS: Assuming some patients would potentially be eligible for either modality, we modeled life year gained, the quality-adjusted life years (QALYs) and healthcare costs for a cohort of 1000 IRRT patients and a cohort of 1000 CRRT patients. We used a 1-year, 5-year and a lifetime horizon. A Markov model with two health states for AKI survivors was designed: dialysis dependence and dialysis independence. We applied Weibull regression from published estimates to fit survival curves for CRRT and IRRT patients and to fit the proportion of dialysis dependence among CRRT and IRRT survivors. We then applied a risk ratio reported in a large retrospective cohort study to the fitted CRRT estimates in order to determine the proportion of dialysis dependence for IRRT survivors. We conducted sensitivity analyses based on a range of differences for daily implementation cost between CRRT and IRRT (base case: CRRT day $632 more expensive than IRRT day; range from$200 to $1000) and a range of risk ratios for dialysis dependence for CRRT as compared with IRRT (from 0.65 to 0.95; base case: 0.80). RESULTS: Continuous renal replacement therapy was associated with a marginally greater gain in QALY as compared with IRRT (1.093 versus 1.078). Despite higher upfront costs for CRRT in the ICU ($4046 for CRRT versus $1423 for IRRT in average), the 5-year total cost including the cost of dialysis dependence was lower for CRRT ($37 780 for CRRT versus $39 448 for IRRT on average). The base case incremental cost-effectiveness analysis showed that CRRT dominated IRRT. This dominance was confirmed by extensive sensitivity analysis. CONCLUSIONS: Initial CRRT is cost-effective compared with initial IRRT by reducing the rate of long-term dialysis dependence among critically ill AKI survivors