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Research Article: Survival Analysis of Under Five Mortality in Rural Parts of Ethiopia
Pages 266-281
Yared Seyoum and M.K. Sharma
DOI:
http://dx.doi.org/10.6000/1929-6029.2014.03.03.6
Published: 05 August 2014


Abstract: Child mortality is a factor that is associated with the well-being of a population and it is taken as an indicator of health development and socioeconomic status. According to the 2011 UN report during the last 10 years, the death rate for children under five has decreased by 35% worldwide. UNICEF in 2008 reported that Ethiopia has reduced under-five mortality by 40 percent over the past 15 years. From the EDHS 2011 report child mortality rate in Ethiopia was reduced from 50/1000 deaths in 2005 to 31/1000 deaths in 2011. The Ethiopian Demographic and Health Survey data are used for the study. In this paper we have attempted to find out the impact of socioeconomic, demographic and environmental factors in the context of under five mortality. In this attempt we first analyzed our data using Kaplan-Meier non-parametric method of estimation of survival function and also using lifetable. We have also used Log-Rank test to compare different survival functions and found that sex, type of birth, religion, mothers’ education, birth order, maternity age, source of drinking water and region have statistically significant difference in the under five survival time. We have also used Cox proportional hazard model to identify the covariates which influence the under five mortality. But we found that our data do not fulfill the proportionality assumption of Cox proportional model in case of infant and child mortality. Then we applied stratified Cox proportional model to our data to find out the potential covariates which influence under five mortality and found birth order, mothers’ education level, sex, type of birth and the interaction of birth order and sex as vital factors for the deaths occurring under the age of five. The Cox proportional hazard models which were used separately for each stratum also identified mothers’ educational level, sex, type of birth, and the interaction of sex and water supply as the risk factors for the death of infants. Whereas for child stratum; type of birth, mothers’ education, sex and the interaction of water supply and sex were the risk factors associated with the death of children.

Keywords: Under five mortality, maternal, socioeconomic and environmental factor.
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Forecasting Rate of Decline in Infant Mortality in South Asia Using Random Walk Approximation
Pages 282-290
Tapan Kumar Chakrabarty
DOI:
http://dx.doi.org/10.6000/1929-6029.2014.03.03.7
Published: 05 August 2014


Abstract: The Millennium Development Goal 4 (MDG 4) of United Nations had set the target of reducing high rates of under-five and infant mortality (IMR) by two thirds to be reached by 2015 using 1990 as the benchmark year. By the availability of time series data on IMR from United Nations Inter-agency Group for Child Mortality Estimation (UN IGME, 2012), led by UNICEF, WHO, the World Bank and United Nations, it has become possible to track the rate of progress towards this goal. Using the UN IGME 2012 data for all the South Asian Countries, I have considered three specific issues in this article. (1) How does the South Asian Countries fair in reducing the IMR towards this MDG target? Although the time series data exhibit declining trends for all the countries in South Asia, to what extent such trends are attributed by their average annual progress trajectory over the period for which data are available? (2) Whether deterministic or stochastic trend can attribute the IMR decline in South Asian countries and what alternative time series models be used to forecast the decline in Infant Mortality? Can we find a serviceable representative model for the entire region? (3) In case, a satisfactory representative model for the entire region exists, how do we assess the forecast accuracy for this model and quantify the propagation of forecast error?

Keywords: Infant mortality, ARIMA model, random walk, MDGs, demographic forecast, unit root test.
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Conditional Two Level Mixture with Known Mixing Proportions: Applications to School and Student Level Overweight and Obesity Data from Birmingham, England
Pages 298-308
Shakir Hussain, Mehdi AL-Alak and Ghazi Shukur
DOI:
http://dx.doi.org/10.6000/1929-6029.2014.03.03.9
Published: 05 August 2014


Abstract: Two Level (TL) models allow the total variation in the outcome to be decomposed as level one and level two or ‘individual and group’ variance components. Two Level Mixture (TLM) models can be used to explore unobserved heterogeneity that represents different qualitative relationships in the outcome.

In this paper, we extend the standard TL model by introducing constraints to guide the TLM algorithm towards a more appropriate data partitioning. Our constraints-based methods combine the mixing proportions estimated by parametric Expectation Maximization (EM) of the outcome and the random component from the TL model. This forms new two level mixing conditional (TLMc) approach by means of prior information. The new framework advantages are: 1. avoiding trial and error tactic used by TLM for choosing the best BIC (Bayesian Information Criterion), 2. permitting meaningful parameter estimates for distinct classes in the coefficient space and finally 3. allowing smaller residual variances. We show the benefit of our method using overweight and obesity from Body Mass Index (BMI) for students in year 6. We apply these methods on hierarchical BMI data to estimate student multiple deprivation and school Club effects.

Keywords: Parametric Expectation Maximization, Multilevel Mixture, Conditional Multilevel Mixture Known Mix, Overweight and Obesity Data.
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Total Hip and Knee Replacement in Eastern Libya: A Post-Conflict Case Series
Pages 291-297
Eman Elzwai, Rasha Elhnid, Zuhir Bodalal, Mustafa El Fadli and Salem Langhi
DOI:
http://dx.doi.org/10.6000/1929-6029.2014.03.03.8
Published: 05 August 2014


Abstract: Background: Total knee replacement (TKR) and total hip replacement (THR) are effective procedures for alleviating pain and improving hip and knee function. Literature has not covered the experience of developing countries with arthroplasty – especially in an unstable post-conflict setting.

Methods: Patient records were obtained from a major surgical center in Benghazi where total joint arthroplasties (TJA) are performed for a period of twenty months and key parameters were analyzed. The patients were followed up on an outpatient basis at regular time intervals (one week, one month, three months and six months) and any complications were documented.

Results: A total of 135 total knee (81.5%, n=110) and total hip (18.5%, n=25) replacements were done in Benghazi mostly on elderly (mean age=60.2 years) females (72.2%, n=100). The most common causative pathology in both groups was osteoarthritis (80.6%, n=108). The most common complication was superficial infection (4.4%, n=6) by Staph aureus. The Harris Hip Score and Knee Society Score were used to determine the functional outcomes of THR and TKR respectively – both showing high values. The Short form 36 (SF36) health survey was carried out to assess the patients' satisfaction levels. For all the axes, the obtained score was over 80%.

Discussions: THR and TKR are major orthopedic surgeries that constitute an advancement in the treatment of chronic joint pain. Most of the demographic features of our patients match up well with previous literature – with certain exceptions. There was no difference in thromboembolic incidence between the group of patients who received LMWH and those who simply started early mobilization and physiotherapy. Despite a number of hindrances faced by the hospital due to the conflict (i.e. funding limitations and drug shortages), a low rate of complications was maintained. No thromboembolic incidents or mortalities occurred.

Conclusions: Libyan surgeons have had a good experience with TJA and patients have been satisfied with the outcomes.

Keywords: Total knee replacement, Total hip replacement, postoperative morbidity, Knee society score, Hip Harris score, SF36 health survey, Libya.
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An Independent and External Validation of the ACC NCDR Bleeding Risk Score among a National Multi-Site Community Hospital Registry of Cardiac Interventions
Pages 153-160
David R. Dobies, Kimberly R. Barber and Amanda L. Cohoon
DOI:
http://dx.doi.org/10.6000/1929-6029.2014.03.02.9
Published: 14 May 2014Open Access


Abstract: Background: An accurate tool with good discrimination for bleeding would be useful to clinicians for improved management of all their patients. Bleeding risk models have been published but not externally validated in independent clinical dataset. We chose the NCDR PCI score to validate within a large, multi-site community datasets. The aim of the study was to determine the diagnostic utility of this bleeding risk score tool.

Methods: This is a large-scale retrospective analysis utilizing American College of Cardiology data from a 37-hospital health system. The central repository of PCI procedures between 6-1-2009 and 6-30-2012 was utilized to validate the NCDR PCI bleeding risk score (BRS) among 4693 patients. The primary endpoint was major bleeding. Discriminant analysis calculating the receiver operating characteristic curve was performed.

Results:There were 143 (3.0%) major bleeds. Mean bleeding risk score was 14.7 (range 3 – 42). Incidence of bleeding by risk category: low (0.5%), intermediate (1.7%), and high risk (7.6%). Patients given heparin had 113 (3.7%) major bleeds and those given bivalirudin had 30 (2.1%) major bleeds. Tool accuracy was poor to fair (AUC 0.78 heparin, 0.65 bivalirudin). Overall accuracy was 0.71 (CI: 0.66-0.76). Accuracy did not improve when confined to just the intermediate risk group (AUC 0.58; CI: 0.55-0.67).

Conclusion:Bleeding risk tools have low predictive value. Adjustment for anticoagulation use resulted in poor discrimination because bivalirudin differentially biases outcomes toward no bleeding. The current state of bleeding risk tools provides little support for diagnostic utility in regards to major bleeding and therefore have limited clinical applicability.

Keywords: Major bleeding, bleeding risk model, anticoagulant, percutaneous coronary intervention, cardiovascular.

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