144 research outputs found
Adverse birth outcome: a comparative analysis between cesarean section and vaginal delivery at Felegehiwot Referral Hospital, Northwest Ethiopia: a retrospective record review [Corrigendum]
No full textAbebe Eyowas F, Negasi AK, Aynalem GE, Worku AG. Pediatric Health, Medicine and Therapeutics. 2016;7:65–70On page 65 Abel Fekadu Dadi should have been listed as an author. The incorrect author list was:Fantu Abebe Eyowas1Ashebir Kidane Negasi1Gizachew Eyassu Aynalem1Abebaw Gebeyehu Worku2The correct author list should have been:Fantu Abebe Eyowas1Ashebir Kidane Negasi1Gizachew Eyassu Aynalem1Abebaw Gebeyehu Worku2Abel Fekadu Dadi2Read the original articl
Flexible two-piece distributions for right censored survival data
No full textAn important complexity in censored data is that only partial information on the variables of interest is observed. In recent years, a large family of asymmetric distributions and maximum likelihood estimation for the parameters in that family has been studied, in the complete data case. In this paper, we exploit the appealing family of quantile-based asymmetric distributions to obtain flexible distributions for modelling right censored survival data. The flexible distributions can be generated using a variety of symmetric distributions and monotonic link functions. The interesting feature of this family is that the location parameter coincides with an index-parameter quantile of the distribution. This family is also suitable to characterize different shapes of the hazard function (constant, increasing, decreasing, bathtub and upside-down bathtub or unimodal shapes). Statistical inference is done for the whole family of distributions. The parameter estimation is carried out by optimizing a non-differentiable likelihood function. The asymptotic properties of the estimators are established. The finite-sample performance of the proposed method and the impact of censorship are investigated via simulations. Finally, the methodology is illustrated on two real data examples (times to weaning in breast-fed data and German Breast Cancer data).sponsorship: The authors are grateful to the editor, and associate editor and reviewers for their valuable comments that led to an improvement of the manuscript. The second author gratefully acknowledge support from Research Grant FWO G0D6619N of the Flemish Science Foundation, and from the C16/20/002 project of the Research Fund KU Leuven. (Flemish Science Foundation|FWO G0D6619N, Research Fund KU Leuven|C16/20/002)status: Published onlin
A hybrid hazard-based model using two-piece distributions
No full textCox proportional hazards model is widely used to study the relationship between the survival time of an event and covariates. Its primary objective is parameter estimation assuming a constant relative hazard throughout the entire follow-up time. The baseline hazard is thus treated as a nuisance parameter. However, if the interest is to predict possible outcomes like specific quantiles of the distribution (e.g. median survival time), survival and hazard functions, it may be more convenient to use a parametric baseline distribution. Such a parametric model should however be flexible enough to allow for various shapes of e.g. the hazard function. In this paper we propose flexible hazard-based models for right censored data using a large class of two-piece asymmetric baseline distributions. The effect of covariates is characterized through timescale changes on hazard progression and on the relative hazard ratio; and can take three possible functional forms: parametric, semi-parametric (partly linear) and non-parametric. In the first case, the usual full likelihood estimation method is applied. In the semi-parametric and non-parametric settings a general profile (local) likelihood estimation approach is proposed. An extensive simulation study investigates the finite-sample performances of the proposed method. Its use in data analysis is illustrated in real data examples.The authors thank the reviewers for their valuable comments that led to an improvement
of the manuscript. The second author gratefully acknowledges support from Research Grant C16/20/002
project of the Research Fund KU Leuven
Two-piece distribution based semi-parametric quantile regression for right censored data
No full textWidely used methods such as Cox proportional hazards, accelerated failure time, and Bennet proportional odds models do not model the quantiles directly, but rather allow to assess the influence of the covariates only on the location of the distribution. Quantile regression allows to assess the effects of covariates, not only on a location parameter (such as a mean or median) but also on specific percentiles of the conditional distribution. In recent years, a large family of flexible two-piece asymmetric distributions where the location parameter coincides with a specific quantile of the distribution has been studied. In a conditional (regression) setting the use of such a family of two-piece asymmetric distributions has only been investigated in the complete data case in the literature. In this paper, we propose a semi-parametric procedure to estimate the conditional quantile curves of two-piece asymmetric distributions based on right censored survival data. We use a local likelihood estimation technique in a multi-parameter functional form, via which the effect of a covariate on the location, scale, and index of the conditional survival distribution can be assessed. The finite sample performance of the estimators is investigated via simulations, and the methodology is illustrated on real data examples.The authors are grateful to an Associate Editor and two reviewers for their comments which led to an improvement of the manuscript. We thank the authors of Christou and Akritas (2019) to provide us with the R code to calculate their estimator in the SIQR model. The second author gratefully acknowledges support from Research Grant FWO G0D6619N of the Flemish Science Foundation, and from the C16/20/002 project of the Research Fund KU Leuven. The resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation - Flanders (FWO) and the Flemish Government
Incidence, predictors and biomarkers for antiretroviral and/or anti-tuberculosis drugs induced liver injury
No full textAnti-tuberculosis and/or antiretroviral drugs induced liver injury (DILI) is a major challenge when managing TB and/or HIV patients. The aims of this thesis were to identify incidence, risk factors, and management of DILI among 4 different treatment groups namely; HIV positive individuals with no TB co-infection and had a CD4 count of 200 cells/μl (taking anti-TB alone = arm 3), HIV negative TB patients (taking anti-TB alone = arm 4).Newly diagnosed TB and/or HIV patients were prospectively followed for 56-weeks after initiation of anti-TB and/or ARV treatment. All patients were evaluated clinically and biochemically for development of DILI in each visit. Laboratory tests performed include; hepatitis B surface antigen and anti-hepatitis C virus antibody. Liver enzymes and function tests were measured before and during therapy. Associations of DILI with CYP2B6, CYP3A5, NAT2 and UGT2B7, ABCB1, SLCO1B1 genotypes as well as plasma efavirenz and 8-hydroxyefavirenz concentrations were evaluated.In the pilot study which involved HIV positive and negative TB patients (n=197), who were taking anti-TB alone, the incidence of DILI was 17.3%. DILI was noted to have a statistically significant association with having a lower CD4 count and concomitant drug intake.The main study, which involved the 4 different arms (n=953) showed that incidence of DILI was still high and significantly associated with the specific arm the patient belonged to. The highest incidence was observed in arm-2 (23.5%) >arm-3 (11.6%) >arm-1 (8.1%) >arm-4 (2.8%). DILI was significantly associated with lower baseline platelet, albumin, and CD4 count. Moreover, higher plasma viral load, EFV level, baseline ALT, AST, ALP, and CYP2B6*6 were also good predictors for development of DILI among arm 1 patients. Similarly, a statistically significant association between 2 DILI and female sex, higher plasma efavirenz level, efavirenz/8-hydroxyefavirenz ratio, baseline AST, ALT, lower haemoglobin, and serum albumin was observed among participants in arm 2. NAT2 slow-acetylator, CYP2B6*6/*6, and ABCB1 3435TT genotype were also seen to contribute for development of DILI in arm 2 patients. The median time for development of DILI was 1-2 weeks after initiation of treatment, depending on the arm, with the majority developing it in the first 8 weeks.In conclusion anti-TB and/or ARV DILI is found to be a major problem among TB and/or HIV patients in Ethiopia. Hence, regular monitoring of liver enzymes during early therapy is recommended for better management. Particularly among those with an underlying risk factors; female, concurrent anti-TB and ART, advance HIV disease, elevated liver enzymes, lower haemoglobin, albumin and BMI at baseline, elevated plasma efavirenz level, having CYP2B6*6/*6 and ABCB13435TT genotype and slow acetylation status.List of scientific papersI. Getnet Yimer, Getachew Aderaye, Wondwossen Amogne, Eyasu Makonnen, Eleni Aklillu, Lars Lindquist, Lawrence Yamuah, Beniyam Feleke, and Abraham Aseffa. Anti-Tuberculosis Therapy-Induced Hepatotoxicity among Ethiopian HIV Positive and Negative Patients. PLoS ONE. 2008; 3(3): e1809. https://doi.org/10.1371/journal.pone.0001809 II. G Yimer, W Amogne, A Habtewold, E Makonnen, N Ueda, A Suda, A Worku, WE Haefeli, J Burhenne, G Aderaye, L Lindquist and E Aklillu. High plasma efavirenz level and CYP2B6*6 are associated with efavirenzbased HAART-induced liver injury in the treatment of naïve HIV patients from Ethiopia: a prospective cohort study. Pharmacogenomics J. 2011 Aug 23; 21862974. https://doi.org/10.1038/tpj.2011.34 III. Getnet Yimer, Nobuhisa Ueda, Abiy Habtewold, Wondwossen Amogne, Akira Suda, Klaus-Dieter Riedel, Jürgen Burhenne, Getachew Aderaye, Lars Lindquist, Eyasu Makonnen, Eleni Aklillu. Pharmacogenetic & Pharmacokinetic biomarker for efavirenz-based ARV and rifampicin-based anti-TB drug induced liver injury in TB-HIV infected patients. PLoS ONE. 2011; 6(12): e27810. https://doi.org/10.1371/journal.pone.0027810 IV. Getnet Yimer, Marcus Gry, Getachew Aderaye, Wondwossen Amogne, Abiy Habtewold, Eyasu Makonnen, Ina Schuppe-Koistinen, Lars Lindquist, Eleni Aklillu. TB-HIV co-infection and concomitant anti-TB and HAART increases the risk for drug induced liver injury: A prospective four arm cohort study. [Manuscript]</p
Longer delays in diagnosis and treatment ofpulmonary tuberculosis in pastoralist setting, Eastern Ethiopia
No full textPurpose: This study aimed to assess the extent of patient, health system and total delays in diagnosis and treatment of pulmonary tuberculosis (TB) in Somali pastoralist setting, Ethiopia. Patients and Methods: A cross-sectional study among 444 confirmed new pulmonary TB patients aged ≥15 years in 5 TB care units was conducted between December 2017 and October 2018. Data were collected using a structured questionnaire and record review. We measured delays from symptom onset to provider visit, provider visit to diagnosis and diagnosis to treatment initiation. Delays were summarized using median days. Mann- Whitney and Kruskal-Wallis tests were used to compare delays between categories of explanatory variables. The Log-binomial regression model was used to reveal factors associated with health system delay ≥15 days, presented in adjusted prevalence ratio (APR) with 95% confidence interval (CI). Results: The median age of patients was 30 years, ranged from 15 to 82. The majority (62.4%) were male, and nearly half (46.4%) were pastoralists. The median patient, health system and total delays were 30 (19-48.5), 14 (4.5-29.5) and 50 (35-73.5) days, respec-tively. The median patient delay (35.5 days) and total delay (58.5 days) among pastoralists were substantially higher than the equivalent delays among non-pastoralists [p<0.001]. Of all, 3.8% of patients (16 of 18 were pastoralists) delayed longer than 6 months without initiating treatment. Factors associated with health system delay ≥15 days were mild symptoms [APR (95% CI) = 1.4 (1.1-1.7)], smear-negativity [APR (95% CI) = 1.2 (1.01- 1.5)], first visit to health centers [APR (95% CI) = 1.6 (1.3-2.0)] and multiple provider contacts [APR (95% CI) = 5.8 (3.5-9.6)]. Conclusion: Delay in diagnosis and treatment remains a major challenge of tuberculosis control targets in pastoralist settings of Ethiopia. Efforts to expand services tailored to transhumance patterns and diagnostic capacity of primary healthcare units need to be prioritized. © 2020 Getnet et al.Purpose: This study aimed to assess the extent of patient, health system and total delays in diagnosis and treatment of pulmonary tuberculosis (TB) in Somali pastoralist setting, Ethiopia. Patients and Methods: A cross-sectional study among 444 confirmed new pulmonary TB patients aged ≥15 years in 5 TB care units was conducted between December 2017 and October 2018. Data were collected using a structured questionnaire and record review. We measured delays from symptom onset to provider visit, provider visit to diagnosis and diagnosis to treatment initiation. Delays were summarized using median days. Mann- Whitney and Kruskal-Wallis tests were used to compare delays between categories of explanatory variables. The Log-binomial regression model was used to reveal factors associated with health system delay ≥15 days, presented in adjusted prevalence ratio (APR) with 95% confidence interval (CI). Results: The median age of patients was 30 years, ranged from 15 to 82. The majority (62.4%) were male, and nearly half (46.4%) were pastoralists. The median patient, health system and total delays were 30 (19-48.5), 14 (4.5-29.5) and 50 (35-73.5) days, respec-tively. The median patient delay (35.5 days) and total delay (58.5 days) among pastoralists were substantially higher than the equivalent delays among non-pastoralists [p<0.001]. Of all, 3.8% of patients (16 of 18 were pastoralists) delayed longer than 6 months without initiating treatment. Factors associated with health system delay ≥15 days were mild symptoms [APR (95% CI) = 1.4 (1.1-1.7)], smear-negativity [APR (95% CI) = 1.2 (1.01- 1.5)], first visit to health centers [APR (95% CI) = 1.6 (1.3-2.0)] and multiple provider contacts [APR (95% CI) = 5.8 (3.5-9.6)]. Conclusion: Delay in diagnosis and treatment remains a major challenge of tuberculosis control targets in pastoralist settings of Ethiopia. Efforts to expand services tailored to transhumance patterns and diagnostic capacity of primary healthcare units need to be prioritized. © 2020 Getnet et al
Factors associated with diarrheal morbidity among under-five children in Jigjiga town, Somali Regional State, eastern Ethiopia: a cross-sectional study
No full textEffect of Different Levels of Dried Sugar Cane Tops Inclusion on the Performance of Washera Sheep Fed Basal Diet of Grass Hay, Ethiopia
No full textCopyright: © 2015 Worku A, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background: Ruminants feed largely on crop resides as their basal diet. Despite their vast use as a livestock feed, crop residues are naturally of low quality and do not fulfill the nutrient requirement of animals. Thus, the deficit in the basal feed of quantity can be covered with sugar cane tops that are potential feed for better performance of animals. This study aimed with to evaluate the effect of different level of Dried Sugar Can tops inclusion on carcass characteristics and Economic Feasibility of Washera sheep fed a basal diet of grass hay. Methodology: A study was conducted at Bure Agricultural Technical Vocational Educational Training (ATVET) College using twenty yearling Washera sheep with initial body weight (BW) of 18.15 ± 1.85 (mean ± SD). The experimental design was randomized complete block design, and sheep were blocked into five blocks of four animals based on their initial BW and randomly assigned to one of the treatments within a block. Treatments were hay ad libitum+100 g/head/d CM for T1 and an additional 120 g, 240 g and 360 g SCT per head/day on dry matter basis for T2, T3 and T4, respectively. The experiment consisted 90 days of Growth trials followed by evaluation of carcass components at the end
Optimization of TB/HIV co-treatment in Ethiopian patients
No full textTuberculosis (TB) and HIV infection act with deadly synergy. HIV is the most important risk factor for latent TB reactivation and active TB progression following exposure or reinfection while TB accelerates HIV progression. TB is the most frequent cause of morbidity and mortality in HIV infection. Anti-TB therapy (ATT) must precede initiation of combination Antiretroviral Therapy (cART), TB being the most immediate threat. Undoubtedly cART benefits; however, important clinical challenges emerge when cART is initiated during TB therapy. Optimization TB and HIV cotreatment is therefore required.Paper II: We hypothesized that by initiating efavirenz (EFV)-based cART earlier than the second week of ATT in patients with CD4 counts Paper I and IV: We investigated DILI during TB/HIV cotreatment and HIV-treatment with EFV-based cART. DILI is the most important treatment limiting factor for continuation of both ATT and/or cART. Multiple evidences show that TB/HIV coinfected patients experience higher rate of adverse drug reactions than those without HIV. Both are prospective cohort studies and analysis was made with multivariate Cox regression model. Outcome measures were incidence rates for DILI, ATT and/or cART interruptions as well as assessment of risk factors. Paper I on EFV-based cART in HIV-infected patients with baseline CD4 counts Paper III evaluated Ethiopian HIV-1 subtype C virus (HIV-1CET) at near full length genome level for phylogenetic analysis, genotypic drug resistance and viral tropism. The results showed high diversity among HIV-1CET strains compared to other geographical locations suggesting introduction of HIV-1C in the country occurred in early phase of HIV- 1C epidemic. Primary drug resistant mutations were identified in List of scientific papersI. G Yimer, W Amogne, A Habtewold, E Makonnen, N Ueda1, A Suda, A Worku, WE Haefeli, J Burhenne, G Aderaye, L Lindquist and E Aklillu. High plasma efavirenz level and CYP2B6*6 are associated with efavirenz-based HAARTinduced liver injury in the treatment of naïve HIV patients from Ethiopia: a prospective cohort study. The Pharmacogenomics Journal 2012 Dec;12(6):499-506. https://doi.org/10.1038/tpj.2011.34 II. Wondwossen Amogne, Getachew Aderaye, Abiy Habtewold, Getnet Yimer, Eyasu Makonnen, Alemayhu Worku, Anders Sonnerborg, Eleni Aklillu, Lars Lindquist. Efficacy and Safety of Antiretroviral Therapy Initiated One Week after Tuberculosis Therapy in Patients with CD4 Counts https://doi.org/10.1371/journal.pone.0122587 III. Wondwossen Amogne, Irene Bontell, Sebastian Grossmann, Getachew Aderaye, Lars Lindquist, Anders Sönnerborg, Ujjwal Neogi. Phylogenetic analysis of near full-length genome reveals high intra-HIV-1 subtype C diversity but a strong geographical cluster in Ethiopia abstain in subgenomic region. [Manuscript]IV. Wondwossen Amogne, Getachew Aderaye, Eleni Aklillu, Abiy Habtewold, Getnet Yimer, Eyasu Makonnen, Alemayhu Worku, Anders Sonnerborg, Lars Lindquist. Evaluation of severe antituberculosis Drug-Induced Liver Injury, the effect of concurrent antiretroviral therapy timing and Hy’s Law in Tuberculosis and HIV coinfected patients: A Prospective cohort study. [Manuscript]</p
A Child with Malignant Ovarian Tumor and Mullerian Anomally (Mayer Rokitansky Kuster Hauser Syndrome)
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