Zubair Ahmad

Dr. Zubair Ahmad


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
5 July 2018 in World Journal of Surgical Oncology
Verified
Journal Article
Open access
PDF file
RIRomana Idrees
Romana Idrees
SFSaira Fatima
Saira Fatima
JAJamshid Abdul-Ghafar
Jamshid Abdul-Ghafar
ARAhmad Raheem
Ahmad Raheem
ZAZubair Ahmad
Zubair Ahmad
Pakistan’s population is ethnically diverse with distinct ethnic groups inhabiting various parts of the country. Cancer statistics obtained from specific regions populated by distinct ethnic groups may vary considerably. There is no national cancer registry. To determine whether there are indeed significant statistical differences in cancer incidence and prevalence, data was recorded from different parts of Pakistan based on the ethnic composition of the population in those parts. Ten papers (original articles) on cancer incidence and prevalence in Pakistan published in the last two decades were selected from PubMed and Google Scholar. Meta-analysis of findings of these studies was performed using Meta-analysis of Observational Studies in Epidemiology (MOOSE) checklist. χ2-based I2 test was used for evaluating heterogeneity and Forest plots were generated for calculating unadjusted prevalence estimates. Oral, gastric, prostate, breast, and colorectal cancers were selected for meta-analysis. I2 values of 75% or greater indicated high heterogeneity. All five types of cancer selected for meta-analysis (performed on studies carrying similar statistical weights) showed extremely high heterogeneity with I2 values of 99.7% for oral cancer, 98.6% for prostate cancer, 98.3% for gastric cancer, 99.8% for breast cancer, and 85.4% for colorectal cancer. p values for all cancers were highly statistically significant. Our findings show that the prevalence rates of different cancer types demonstrate marked variation in different studies depending on the place of origin of the study and dominant ethnic group in that region, and these variations are highly statistically significant. A national cancer registry needs to be established as soon as possible.

14 June 2012 in BMC Gastroenterology
Verified
Journal Article
Open access
PDF file
SAShahab Abid
Shahab Abid
AKAli Khawaja
Ali Khawaja
SBSalima Ahmed Bhimani
Salima Ahmed Bhimani
ZAZubair Ahmad
Zubair Ahmad
SHSaeed Hamid
Saeed Hamid
WJWasim Jafri
Wasim Jafri
Solitary rectal ulcer syndrome (SRUS) is an uncommon although benign defecation disorder. The aim of this study was to evaluate the variable endoscopic manifestations of SRUS and its association with other diseases.

2 February 2023 in Sustainability
Verified
Journal Article
Open access
PDF file
HIHasnain Iftikhar
Hasnain Iftikhar
MKMurad Khan
Murad Khan
ZKZardad Khan
Zardad Khan
FKFaridoon Khan
Faridoon Khan
HAHuda M Alshanbari
Huda M Alshanbari
ZAZubair Ahmad
Zubair Ahmad
In the modern world, chronic kidney disease is one of the most severe diseases that negatively affects human life. It is becoming a growing problem in both developed and underdeveloped countries. An accurate and timely diagnosis of chronic kidney disease is vital in preventing and treating kidney failure. The diagnosis of chronic kidney disease through history has been considered unreliable in many respects. To classify healthy people and people with chronic kidney disease, non-invasive methods like machine learning models are reliable and efficient. In our current work, we predict chronic kidney disease using different machine learning models, including logistic, probit, random forest, decision tree, k-nearest neighbor, and support vector machine with four kernel functions (linear, Laplacian, Bessel, and radial basis kernels). The dataset is a record taken as a case–control study containing chronic kidney disease patients from district Buner, Khyber Pakhtunkhwa, Pakistan. To compare the models in terms of classification and accuracy, we calculated different performance measures, including accuracy, Brier score, sensitivity, Youdent, specificity, and F1 score. The Diebold and Mariano test of comparable prediction accuracy was also conducted to determine whether there is a substantial difference in the accuracy measures of different predictive models. As confirmed by the results, the support vector machine with the Laplace kernel function outperforms all other models, while the random forest is competitive.

26 July 2021 in PLOS ONE
Verified
Journal Article
Open access
PDF file
XLXiaofeng Liu
Xiaofeng Liu
ZAZubair Ahmad
Zubair Ahmad
AGAhmed M. Gemeay
Ahmed M. Gemeay
AAAlanazi Talal Abdulrahman
Alanazi Talal Abdulrahman
EHE. H. Hafez
E. H. Hafez
NKN. Khalil
N. Khalil
Over the past few months, the spread of the current COVID-19 epidemic has caused tremendous damage worldwide, and unstable many countries economically. Detailed scientific analysis of this event is currently underway to come. However, it is very important to have the right facts and figures to take all possible actions that are needed to avoid COVID-19. In the practice and application of big data sciences, it is always of interest to provide the best description of the data under consideration. The recent studies have shown the potential of statistical distributions in modeling data in applied sciences, especially in medical science. In this article, we continue to carry this area of research, and introduce a new statistical model called the arcsine modified Weibull distribution. The proposed model is introduced using the modified Weibull distribution with the arcsine-Xapproach which is based on the trigonometric strategy. The maximum likelihood estimators of the parameters of the new model are obtained and the performance these estimators are assessed by conducting a Monte Carlo simulation study. Finally, the effectiveness and utility of the arcsine modified Weibull distribution are demonstrated by modeling COVID-19 patients data. The data set represents the survival times of fifty-three patients taken from a hospital in China. The practical application shows that the proposed model out-classed the competitive models and can be chosen as a good candidate distribution for modeling COVID-19, and other related data sets.

23 March 2020 in Communications in Statistics - Simulation and Computation
Verified
Journal Article
Closed access
ZAZubair Ahmad
Zubair Ahmad
EMEisa Mahmoudi
Eisa Mahmoudi
SDSanku Dey
Sanku Dey
Heavy tailed distributions play very significant role in the study of actuarial and financial risk management data but the probability distributions proposed to model such data are scanty. Actuaries often search for new and appropriate statistical models to address data related to financial risk problems. In this work, we propose a new family of heavy tailed distributions. Some basic properties of this new family of heavy tailed distributions are obtained. A special sub-model of the proposed family, called a new heavy tailed Weibull model is considered in detail. The maximum likelihood estimators of the model parameters are obtained. A Monte Carlo simulation study is carried out to evaluate the performance of these estimators. Furthermore, some actuarial measures such as value at risk and tail value at risk are calculated. A simulation study based on these actuarial measures is done. Finally, an application of the proposed model to a heavy tailed insurance loss data set is presented.

27 August 2020 in PLOS ONE
Verified
Journal Article
Open access
PDF file
WZWei Zhao
Wei Zhao
SKSaima K. Khosa
Saima K. Khosa
ZAZubair Ahmad
Zubair Ahmad
MAMuhammad Aslam
Muhammad Aslam
Ahmed Z. AfifyAhmed Z. Afify
Ahmed Z. Afify
In the present study, a new class of heavy tailed distributions using the T-X family approach is introduced. The proposed family is called type-I heavy tailed family. A special model of the proposed class, named Type-I Heavy Tailed Weibull (TI-HTW) model is studied in detail. We adopt the approach of maximum likelihood estimation for estimating its parameters, and assess the maximum likelihood performance based on biases and mean squared errors via a Monte Carlo simulation framework. Actuarial quantities such as value at risk and tail value at risk are derived. A simulation study for these actuarial measures is conducted, proving that the proposed TI-HTW is a heavy-tailed model. Finally, we provide a comparative study to illustrate the proposed method by analyzing three real data sets from different disciplines such as reliability engineering, bio-medical and financial sciences. The analytical results of the new TI-HTW model are compared with the Weibull and some other non-nested distributions. The Baysesian analysis is discussed to measure the model complexity based on the deviance information criterion.