Statistical methodology for analyzing ordinal outcomes of traumatic brain injury

Statistical analysis of data for treatment of traumatic brain injury (TBI) from randomized clinical trials (RCTs) regularly fails to identify statistically significant changes in patient condition. Patient outcome is typically measured on an ordinal scale which is then analyzed with statistical methods that lack sensitivity to detect changes across all measured outcomes, have restrictive assumptions, or lack adequate statistical power. The conventional binary regression model, the proportional odds model, partial proportional odds model, and the continuation ratio model are four standard methods applied in the analysis of ordinal variables, traditionally deemed effective in a number of cases. To overcome their known deficiencies in some scenarios, the sliding dichotomy model was recently developed to accurately analyze the changes in patient condition across ordinal scales and has had several productive applications in specific cases. This study compares the sample size, type I error rate and power among these models. This study attempts to detect the consistency among the contemporary models and also the weakness of the sliding dichotomy model in controlling the type I error rate. A few recommendations for handling ordinal variables in applied research are also proposed. This study used data from Corticosteroid Randomisation after Significant Head Injury (CRASH), a baseline observed data set consisting of 10,008 patients, as the primary data set. Varying the sample sizes, the number of covariates, the band size of the sliding dichotomy approach and randomizing the treatment effect created different scenarios. A number of possible contexts that might occur in practical clinical trials was simulated to try and test the applicability of the models. For each scenario, the effect on statistical power and type I error rates of the models was assessed. Another supplementary primary data set, already collected from Bangladesh, was applied to compare the two data sets. Apart from these two, we tested two other non-clinical trial data sets to assess the models' application in the field of public health. Although previous studies have suggested that smaller samples sizes can maintain desired power for some applications of the sliding dichotomy model, the results of this study indicate that consideration of the type I error rates does not encourage this approach, due to the risk of false-positive inferences from application of this method. The model could not even maintain the error rate even when the sample size was high (over 1000); often times the type I error rate were higher than 5%. Inconsistent results were observed from all the models applied to different data sets. These inconsistencies across all the ordinal methods suggest that researchers may find value in evaluating multiple methods and using goodness of fit statistics to help report and interpret results, and also encourages use of meta-analysis in some studies. However, this is not the best or ultimate solution to inconsistent performance of methods. Specific problems with the current methods were detected as part of this research and some potential solutions were outlined. Empirical studies with both clinical and non-clinical data are required to devise a model that can adequately balance the errors and statistical power, and have less (or no) restrictive assumptions

How do drivers avoid crashes: the role of driving headway

Rear-end crashes are a major part of road injury burden, accounting for one-third of all vehicle-to-vehicle crashes in New South Wales, Australia. Close following or driving with short headways is a key cause, yet the role of driver behaviour in rear-end crash risk is not well researched. The primary aim of this research was to develop a better understanding of rear-end crashes by assessing headways on Australian roads and investigating driver behaviour and performance associated with close following in crash and non-crash scenarios. Two systematic reviews of headway were conducted. First, a review of research on headway identified the need for a consistent and accurate definition of headway, so the thesis puts forward an improved definition. The second review identified the range of external factors that increase the risk of short headway and increase crash risk including speed, task engagement, lead vehicle type, traffic conditions, road characteristics, weather/visibility, drug use, driving fatigue, innovative lane markings, and various warning systems. These factors were then explored in New South Wales data on rear-end casualty and multiple vehicle crashes. The modelling of these associated factors were confirmed as contributing factors in rear-end crashes, congruent with the review of headway. Higher speed, free flowing traffic, volitional task engagement, low cue environments, and collision warning lead to longer headway. Despite lower fatalities, higher odds of injury were observed for rear-end crashes than other crash types. Rear-end crashes were more likely to lead to multiple vehicle crashes, which had a higher chance of fatality than other types of crashes. Finally, naturalistic driving study data was used to investigate headway during normal driving, exploring close following at different speeds and classifying potential risky driving at various headways. In 64 hrs accumulated across 2101 trips, short headways of under 1 s occurred in around 15% of driving. Common manoeuvres to avoid rear-end crashes when close following were changing lanes, or braking, almost always by the following driver. Headway was associated with both driver speed and posted speed limits, decreasing as posted speed limits increased. Over-the-speed-limit driving was observed in all headway scenarios, but especially in higher speed zones. The findings challenge the notion that rear-end crashes are less severe with low injuries. Road users should be made aware of how frequently safe headways are violated and severity of injury outcomes. Driver education, community engagement, application of driver assistance technology consistent with driver behaviour and safety campaigns need to focus on safer speed and headway management to reduce rear-end crash risk

Does income inequality matters for accessing health facility? Evidence from Bangladesh

Accessibility to health facilities is the key for improving the worldwide public health scenario. This paper investigates whether micro-level health status improves gradually for every income class despite the existence of growing income inequality as the macro-level economy flourishes. In this paper, Bangladesh is chosen as a sample for assessing the hypothesis. Bangladesh Demographic and Health Surveys (BDHS) of 2007, 2011 and 2014 were applied in this paper. Three different models were applied for robustness. The proportional odds model showed the highest Pseudo−R2 and it was fitted to determine the relationship between wealth index and various health components. The direction of the relationship between wealth index and various health components over the years was explored by the trend of the odds ratios. The fitted models showed that most of the health components (e.g. family health consciousness, women’s empowerment and reproductive health) significantly influenced wealth index at 5% level for all three data sets. However, the odds showed a shift towards one (Odds = 1), which reflects a reduction of influence on household economic status from 2007 to 2014. From 2007 to 2014, Bangladesh has doubled its per-capita GDP and showed remarkable achievements in Millennium Development Goals (MDGs) despite increasing inequality. Most health parameters showed less influence on wealth as the economy progressed. The pattern suggests that health accessibility increases as the country advances economically even though high inequality exists. Therefore, overall development of a country is beneficial even for the most vulnerable part of the economic quantile because it enables access to health service despite their insolvency

A quantitative approach to influential factors in One Day International cricket: analysis based on Bangladesh

The Bangladesh Cricket Team has performed well in the recent past with steady traits of improvement. Apart from the players’ performance, some external factors are associated with the outcome of a cricket match. This paper investigates prematch toss, batting sequence, match time, opposition team’s origin and time (in years) as independent factors influencing the performance of the Bangladesh team. Outcomes of 314 One Day International (ODI) matches were fitted with a typical logistic regression model and modified Poisson model to explore the association of these factors with match results. Both models showed consistency, although the logistic model outcomes were extreme with wider confidence intervals for odds ratios, compared to the risk ratios of the modified Poisson regression model. Bangladesh, a country where cricket reflects nationalism, has shown significant improvement over time. They tend to perform better in day matches, play superior cricket against non-Asian teams and take full home advantage

Shewhart control chart for individual measurement: an application in a weaving mill

Control Chart is a very common quality control tool in Industrial sector. Statistical quality control technique is used to determine the control limits and for exploring the changes that require improving the process. In real life there are many situations where the sample size used for process monitoring is one and then control chart for individual measurement is used. The data collected from a weaving mill provided six months of data on four characteristics for each bale of thread namely Fiber Fineness (Mic), Whiteness (Rd), Yellowness (+b) and Spinning consistency index (SCI). Moving Range Chart and Individual Measurement Chart has been applied on each of the characteristics to find out quality of bales of thread on those months and to determine a standard range for each parameter. After evaluating around 70 quality control charts the suggested range for Fiber Fineness, Whiteness, Yellowness and Spinning Consistency index should be 3.162075 to 4.396583, 75.08009 to 81.50754, 6.953162 to 9.434838 and 116.4203 to 185.8005 respectively. Garments industry is the largest export industry for Bangladesh constituting 75% of total export accumulating 10.5% of the country’s GDP but still they lack in terms of quality control. In this paper an overview of quality control process is done on a leading garments industry in Bangladesh, specifically a weaving mill. This also paves a way to use other quality control processes and a chance to compare with these processes to determine a more suitable process for garments industries

Socioeconomic transition and its influence on Body Mass Index (BMI) pattern in Bangladesh

Bangladesh is an underdeveloped country that has recently joined the ranks of low-middle income countries. This study aims to investigate how socioeconomic and developmental factors have influenced women towards a shift in their Body Mass Index (BMI). The trend was analyzed using data on ever-married women from six nationwide surveys covering the years 1996 to 2014, conducted by the Bangladesh Demographic and Health Survey (BDHS). To assess the relationship between the socio-economic factors and BMI, binary regression models were fitted for six surveys and forest plots were applied to display the results. Factors such as age, education, residence, economic status and contraceptive use were found to have had an increasing influence on BMI over the years that were being analyzed. Age and education for women were potential factors influencing BMI. Growing urbanization and economic inequality were found to have been substantial over time and marital status and contraceptive use were influential whilst the employment status of women held no consequence. Rapid urbanization allied with growing wealth inequality and dietary alteration seems to have forced a change in the capacity of women in Bangladesh to control their weight. Additional information is still needed on such factors as the amount of time that women are inactive and sitting down, for example, as well as their daily calorie intake in order to assemble all the pieces for addressing necessary health policy changes in Bangladesh. These factors will also help to indicate a shift of focus from rural malnutrition to urban obesity

A national assessment of elective cesarean sections in Bangladesh and the need for health literacy and accessibility

There has been a gradual rise in the number of cesarean sections (CSs) in Bangladesh. The present study identified the cohort of women, who were more likely to opt for an elective CS based on their sociodemographic characteristics, pre-delivery care history, and media exposure, using the Bangladesh Multiple Indicator Cluster Survey-2019. The survey stratification adjusted logistic regression model and interpretable machine learning method of building classification trees were utilized to analyze a sample of 9202 women, alongside district-wise heat maps. One-in-five births (20%) were elective CSs in the 2 years prior to the survey. Women residing in affluent households with educated house-heads, who accessed antenatal care prior to delivery (AOR 4.12; 95% CI 3.06, 5.54) with regular access to media (AOR 1.31; 95% CI 1.10, 1.56) and who owned a mobile phone (AOR 1.25; 95% CI 1.04, 1.50) were more likely to opt for elective CSs, which suggests that health access and health literacy were crucial factors in women's mode of delivery. Spatial analyses revealed that women living in larger cities had more elective CS deliveries, pointing towards the availability of better health and access to multiple safe delivery options in peripheral areas

A systematic assessment on COVID‐19 preparedness and transition strategy in Bangladesh

Rationale, aims and objectives: The COVID-19 pandemic of 2020 has overpowered the most advanced health systems worldwide with thousands of daily deaths. The current study conducted a situation analysis on the pandemic preparedness of Bangladesh and provided recommendations on the transition to the new reality and gradual restoration of normalcy. Method: A complex adaptive system (CAS) framework was theorized based on four structural dimensions obtained from the crisis and complexity theory to help evaluate the health system of Bangladesh. Data sourced from published reports from the government, nongovernmental organizations and mainstream media up to 15 June 2020 were used to conduct a qualitative analysis and visualize the spatial distribution of countrywide COVID-19 cases. Results: The findings suggested that Bangladesh severely lacked the preparedness to tackle the spread of COVID-19 with both short- and long-term implications for health, the economy, and good governance. Absence of planning and coordination, disproportionate resource allocations, challenged infrastructure, adherence to bureaucratic delay, lack of synchronized risk communication, failing leadership of concerned authorities and incoherent decision-making have led to a precarious situation that will have dire ramifications causing many uncertainties in the coming days. Conclusions: Implementation of response protocols addressing the needs of the community and the stakeholders from the central level is urgently needed. The development of mechanisms for dynamic decision-making based on regular feedback and long-term planning for a smooth transition between the new reality and normalcy should also be urgently addressed in Bangladesh

Adolescent transport and unintentional injuries: a systematic analysis using the Global Burden of Disease Study 2019

Background: Globally, transport and unintentional injuries persist as leading preventable causes of mortality and morbidity for adolescents. We sought to report comprehensive trends in injury-related mortality and morbidity for adolescents aged 10–24 years during the past three decades. Methods: Using the Global Burden of Disease, Injuries, and Risk Factors 2019 Study, we analysed mortality and disability-adjusted life-years (DALYs) attributed to transport and unintentional injuries for adolescents in 204 countries. Burden is reported in absolute numbers and age-standardised rates per 100 000 population by sex, age group (10–14, 15–19, and 20–24 years), and sociodemographic index (SDI) with 95% uncertainty intervals (UIs). We report percentage changes in deaths and DALYs between 1990 and 2019. Findings: In 2019, 369 061 deaths (of which 214 337 [58%] were transport related) and 31·1 million DALYs (of which 16·2 million [52%] were transport related) among adolescents aged 10–24 years were caused by transport and unintentional injuries combined. If compared with other causes, transport and unintentional injuries combined accounted for 25% of deaths and 14% of DALYs in 2019, and showed little improvement from 1990 when such injuries accounted for 26% of adolescent deaths and 17% of adolescent DALYs. Throughout adolescence, transport and unintentional injury fatality rates increased by age group. The unintentional injury burden was higher among males than females for all injury types, except for injuries related to fire, heat, and hot substances, or to adverse effects of medical treatment. From 1990 to 2019, global mortality rates declined by 34·4% (from 17·5 to 11·5 per 100 000) for transport injuries, and by 47·7% (from 15·9 to 8·3 per 100 000) for unintentional injuries. However, in low-SDI nations the absolute number of deaths increased (by 80·5% to 42 774 for transport injuries and by 39·4% to 31 961 for unintentional injuries). In the high-SDI quintile in 2010–19, the rate per 100 000 of transport injury DALYs was reduced by 16·7%, from 838 in 2010 to 699 in 2019. This was a substantially slower pace of reduction compared with the 48·5% reduction between 1990 and 2010, from 1626 per 100 000 in 1990 to 838 per 100 000 in 2010. Between 2010 and 2019, the rate of unintentional injury DALYs per 100 000 also remained largely unchanged in high-SDI countries (555 in 2010 vs 554 in 2019; 0·2% reduction). The number and rate of adolescent deaths and DALYs owing to environmental heat and cold exposure increased for the high-SDI quintile during 2010–19. Interpretation: As other causes of mortality are addressed, inadequate progress in reducing transport and unintentional injury mortality as a proportion of adolescent deaths becomes apparent. The relative shift in the burden of injury from high-SDI countries to low and low–middle-SDI countries necessitates focused action, including global donor, government, and industry investment in injury prevention. The persisting burden of DALYs related to transport and unintentional injuries indicates a need to prioritise innovative measures for the primary prevention of adolescent injury. Funding: Bill & Melinda Gates Foundation