A Gaussian Copula Regression Approach for Modelling Repeated Data in Medical Research
Reka Karuppusami,
Gomathi Sudhakar,
Juliya Pearl Joseph Johnson,
Ramamani Mariappan,
Jansi Rani,
Belavendra Antonisamy,
Prasanna S. Premkumar
Issue:
Volume 8, Issue 2, June 2023
Pages:
22-30
Received:
27 June 2023
Accepted:
19 July 2023
Published:
31 July 2023
Abstract: In repeated measures data, the observations tend to be correlated within each subject, and such data are often analyzed using Generalized Estimating Equations (GEE), which are robust to assumptions that many methods hold. The main limitation of GEE is that its method of estimation is quasi-likelihood. The recent framework of the copula is very popular for handling repeated data. The maximum likelihood-based analysis for repeated data can be obtained using Gaussian copula regression. The purpose of this study is to show the handling and analysis of the repeated data using the Gaussian copula regression approach and compare the findings with GEE. The prospective, double-blinded, randomized controlled trial data for this study was obtained from the Department of Anesthesia, Christian Medical College, and Vellore. ASA I and II patients were randomized into three groups. Hemodynamic parameters were obtained for 88 patients at thirteen-time points. The outcome of interest was mean arterial pressure. Both GEE and Gaussian copula regression were compared assuming four different correlation structures. The optimal correlation structures were selected with the Akaike Information Criterion (AIC) and Correlation Information Criterion (CIC) goodness of fit criteria according to the method of estimation of Gaussian copula regression and GEE, respectively. The correlation structures, unstructured and autoregressive, were found to be optimal for Gaussian copula regression and GEE based on AIC and CIC criteria values respectively. A comparison between the estimated values of the selected models showed no major differences. Gaussian copula regression found that intrathecal morphine has a significant reduction in MAP over time, this significance is considered important as the study uses randomized controlled trial data. Both methods have almost similar results, but Gaussian copula regression provides better results by identifying significant findings associated with the outcome using maximum likelihood estimation that GEE fails to identify using quasi-likelihood estimation.
Abstract: In repeated measures data, the observations tend to be correlated within each subject, and such data are often analyzed using Generalized Estimating Equations (GEE), which are robust to assumptions that many methods hold. The main limitation of GEE is that its method of estimation is quasi-likelihood. The recent framework of the copula is very popu...
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Malaria Infection Socio-Economic Factors in the Outpatients in District Hospitals, Sub-Saharan Africa
Tuyapeni Sharon Grace,
Sheehama Jacob,
Hermine Iita
Issue:
Volume 8, Issue 2, June 2023
Pages:
31-36
Received:
27 February 2023
Accepted:
8 May 2023
Published:
13 September 2023
Abstract: Malaria has become a threat in Namibia, more especially in Engela District since 2010, with cases being reported to increase and the number of deaths rising as well. With the rising of these cases, the economy was slowly decreasing due to purchasing of mosquito nets, repellents and others. Based on a malaria case investigation done in Namibia for 5 years, it is stated that the incidence fell from 53.6 to 3.6 cases per 1000 population, and then increased again to 47.3/1000. A preliminary search will be conducted in the databases such as: Google Scholar, the PubMed, and the Library. This scoping review was also conducted by using key words such as malaria, social factors, economic factors, effects and outpatients. Scoping review framework used in the study is by Joanna Briggs Institute that will be followed throughout the review process and the reporting of the main review will follow the PRISMA-ScR. The evaluation of the studies that have occurred some have indicated gaps in their research due to reasons unknown. The use of long lasting insecticide nets was indicated although not all were in accordance with the WHO requirements of malaria prevention. Lack of income, strong social support was also observed and indicated to be the major cause of Malaria in many areas of the world. This scoping review will assist in the mapping out of evidence on the socioeconomic factors of malaria effects on outpatients which can help out the Health Professional with the right approaches to be used in terms of elimination of malaria, educating the patients about malaria itself before prescribing them medications.
Abstract: Malaria has become a threat in Namibia, more especially in Engela District since 2010, with cases being reported to increase and the number of deaths rising as well. With the rising of these cases, the economy was slowly decreasing due to purchasing of mosquito nets, repellents and others. Based on a malaria case investigation done in Namibia for 5...
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