Determinants of Utilization of Maternal Healthcare Services in Ethiopia
Pages 378-390
Wondiber Nega Melese, Shirnevas Darak and Mesay Tefera
DOI: http://dx.doi.org/10.6000/1929-6029.2015.04.04.7
Published: 03 November 2015

Abstract: Utilizing maternal healthcare services, such as antenatal care, professionals’ assistance during delivery and postnatal care contributes significant role in reduction of maternal and child mortality. However, there are many factors both at individual and community level that affect utilization of these required services. To determine the levels of effects of socio-economic and demographic factors on uses of Maternal Healthcare services 7764 women who had given birth at least one times have taken from the 2011 Ethiopian DHS. The results showed that the rate of safe motherhood practices among reproductive age group of women in Ethiopia were too low. About 51 percent of them did not use any health care services during pregnancy, childbirth, and post-delivery periods. As WHO recommend only 6.9 percent of women were attending ANC at least four times, assisted by health professional during delivery and received PNC. The result of logistic regression showed that antenatal care, skilled delivery and postnatal care utilizations were commonly influenced by place of residence, wealth status, women’s and husband’s education and parity. Whereas, mother’s working status and husband’s education were found to be uniquely influence the uses of ANC and PNC services, respectively. In addition, both religious affiliation and age of women were also prominent predictors on utilization of ANC and uses of skilled assistance during delivery. Based on these significant factors, it is important to design and promote uses of maternal healthcare services in order to minimize the risk of maternal and child mortality.

Assessment of the Performance of Imputation Techniques in Observational Studies with Two Measurements
Pages 240-251
Urko Aguirre, Inmaculada Arostegui, Cristóbal Esteban and Jose María Quintana
DOI: http://dx.doi.org/10.6000/1929-6029.2015.04.03.1
Published: 19 August 2015

Abstract: In observational studies with two measurements when the measured outcome pertains to a health related quality of life (HRQoL) variable, one motivation of the research may be to determine the potential predictors of the mean change of the outcome of interest. It is very common in such studies for data to be missing, which can bias the results. Different imputation techniques have been proposed to cope with missing data in outcome variables. We compared five analysis approaches (Complete Case, Available Case, K- Nearest Neighbour, Propensity Score, and a Markov Chain Monte Carlo algorithm) to assess their performance when handling missing data at different missingness rates and mechanisms (MCAR, MAR and MNAR). These strategies were applied to a pre-post study of patients with Chronic Obstructive Pulmonary Disease. We analyzed the relationship of the changes in subjects HRQoL over one year with clinical and socio-demographic characteristics. A simulation study was also performed to illustrate the performance of the imputation methods. Relative and standardized bias was assessed on each scenario. For all missingness mechanisms, not imputing and using MCMC method, both combined with mixed-model analysis, showed lowest standardized bias. Conversely, Propensity Score showed worst bias values. When missingness pattern is MCAR or MAR and rate small, we recommend using mixed models. Nevertheless, when missingness percentage is high, in order to gain sample size and statistical power, MCMC is preferred, although there are no bias differences compared with the mixed models without imputation. For a MNAR scenario, a further sensitivity analysis should be made.

Supplementing Missing Self-Reported Race Data with a Probability Distribution in Logistic Regression Models
Pages 252-259
Stanley Xu, Komal Narwaney, Sophia Newcomer and Jason Glanz
DOI: http://dx.doi.org/10.6000/1929-6029.2015.04.03.2
Published: 19 August 2015

Abstract: Race is often included as an independent variable in health services research, especially in recent studies of racial and ethnic disparities in health care. Although self-reported information on race exists in large electronic health records (EHR) data, these data are sometimes missing. Recently Bayesian Improved Surname Geocoding method (BISG) is used to estimate the probability distribution of race categories for those with missing information on race. The BISG estimated probability distribution has been used in reporting health care measures but not in statistical modellings with dichotomous events as outcomes. We propose two approaches to accommodate available distribution probability of an independent categorical variable (e.g., race) in logistic regression models: 1) a direct substitution approach and 2) a partial information maximum likelihood estimator (PIMLE). In examining the association between race and up-to-dateimmunization status of children by three years old from an integrated health care organization, 11.3% of 14,903 children have missing self-reported race information but have BISG estimated probability distribution for the six race/ethnicity categories. We employed the direct substitution approach and PIMLE approach to analyze the under vaccination data. Both approaches included all observations and thus yielded smaller standard errors of estimated coefficients compared to the complete data analyses. Our simulation study showed that the direct substitution approach and PIMLE yielded nearly unbiased coefficient estimates and preserved efficiency when the missing rate of the independent categorical variable was up to 30%.

Comparative Analysis of the Effects of Three Antithrombotic Regimens on Clinical Outcomes of Patients with Atrial Fibrillation and Recent Percutaneous Coronary Intervention with Stent. A Retrospective Cohort Study
Pages 260-269
Renato De Vecchis, Cesare Baldi and Francesco Piemonte
DOI: http://dx.doi.org/10.6000/1929-6029.2015.04.03.3
Published: 19 August 2015

Abstract: Introduction: Chronic atrial fibrillation (AF), coexisting with a history of recent coronary angioplasty with stent (PCI-S) represents an encoded indication for oral anticoagulation with warfarin (OAC) plus dual antiplatelet therapy (DAPT).

Methods:Using a retrospective cohort study we determined the respective impacts on cardio- vascular outcomes of three different pharmacologic regimens, i.e., triple therapy (TT) with warfarin + clopidogrel and aspirin, dual therapy (DT) with warfarin +clopidogrel or aspirin, dual antiplatelet therapy (DAPT) with clopidogrel + aspirin. Outcomes of interest were all-cause mortality, ischemic cardiac events, ischemic cerebral events, bleeding events. The inclusion criterion was the coexistence of an indication for OAC (e.g., chronic AF) with an indication for dual antiplatelet therapy due to recent PCI-S.

Results: Among the 98 patients enrolled, 48 (49%), 31 (31.6%), and 19(19.4%) patients were prescribed TT, DT, and DAPT, respectively. Throughout a mean follow-up of 378± 15.7days, there were no significant differences between the three regimens for all abovementioned outcomes. In particular, the total frequency of major bleeding was similar in the three groups: 5 cases (10.4%) in TT, one case (3.22%) in DT and no case in DAPT groups (p [chi-square test] = 0.1987).

Conclusions: TT, DT and DAPT displayed similar efficacy and safety. Although the superiority of OAC vs. DAPT for stroke prevention in AF patients has been demonstrated by previous randomized trials, a smaller frequency of high thromboembolic risks' features in DAPT group of the present study may have prevented the observation of a higher incidence of ischemic stroke in this group.

Comparative Study of Human and Automated Screening for Antinuclear Antibodies by Immunofluorescence on HEp-2 Cells
Pages 270-276
Yousr Gorgi, Tarak Dhaouadi, Imen Sfar, Youssra Haouami, Taieb Ben Abdallah, Giuseppe Raso, Donato Cascio, Marco Cipolla, Vincenzo Taormina, Alessandro Fauci, Ignazio Brusca, Giuseppe Friscia, Amel Benammar Elgaaïed, Raja Marrakchi Triki, Asma Gati, Melika Ben Ahmed and Hechmi Louzir
DOI: http://dx.doi.org/10.6000/1929-6029.2015.04.03.4
Published: 19 August 2015

Abstract: Background:Several automated systems had been developed in order to reduce inter-observer variability in indirect immunofluorescence (IIF) interpretation. We aimed to evaluate the performance of a processing system in antinuclear antibodies (ANA) screening on HEp-2 cells.

Patients and Methods:This study included 64 ANA-positive sera and 107 ANA-negative sera that underwent IIF on two commercial kits of HEp-2 cells (BioSystems® and Euroimmun®). IIF results were compared with a novel automated interpretation system, the “CyclopusCADImmuno®” (CAD).

Results:All ANA-positive sera images were recognized as positive by CAD (sensitivity = 100%), while 17 (15.9%) of the ANA-negative sera images were interpreted as positive (specificity = 84.1%), κ=0.799 (SD=0.045). Comparison of IIF pattern determination between human and CAD system revealed on HEp-2 (BioSystems®), a complete concordance in 6 (9.37%) sera, a partial concordance (sharing of at least 1 pattern) in 42 (65.6%) cases and in 16 (25%) sera the pattern interpretation was discordant. Similarly, on HEp-2 (Euroimmun®) the concordance in pattern interpretation was total in 5 (7.8%) sera, partial in 39 (60.9%) and absent in 20 (31.25%). For both tested HEp-2 cells kits agreement was enhanced for the most common patterns, homogenous, fine speckled and coarse speckled. While there was an issue in identification of nucleolar, dots and nuclear membranous patterns by CAD.

Conclusion:Assessment of ANA by IIF on HEp-2 cells using the automated interpretation system, the “CyclopusCADImmuno®” is a reliable method for positive/negative differentiation. Continuous integration of IIF images would improve the pattern identification by the CAD.