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Papers by Ali Ahmed

BMC Medical Research Methodology, 2019

Background: The quality of systematic reviews and meta-analyses (SR/MAs) depends on the extent of... more Background: The quality of systematic reviews and meta-analyses (SR/MAs) depends on the extent of the methods used. We investigated the methodological steps used by authors of SR/MAs of clinical trials via an author survey. Methods: We conducted an email-based cross-sectional study by contacting corresponding authors of SR/MAs that were published in 2015 and 2016 and retrieved through the PubMed database. The 27-item questionnaire was developed to study the methodological steps used by authors when conducting a SR/MA and the demographic characteristics of the respondent. Besides the demographic characteristics, methodological questions regarding the source, extraction and synthesis of data were included. Results: From 10,292 emails sent, 384 authors responded and were included in the final analysis. Manual searches were carried out by 69.2% of authors, while 87.3% do updated searches, 49.2% search grey literature, 74.9% use the Cochrane tool for risk of bias assessment, 69.8% assign more than two reviewers for data extraction, 20.5% use digital software to extract data from graphs, 57.9% use raw data in the meta-analysis, and 43.8% meta-analyze both adjusted and non-adjusted data. There was a positive correlation of years of experience in conducting of SR/MAs with both searching grey literature (P = 0.0003) and use of adjusted and non-adjusted data (P = 0.006). Conclusions: Many authors still do not carry out many of the vital methodological steps to be taken when performing any SR/MA. The experience of the authors in SR/MAs is highly correlated with use of the recommended tips for SR/MA conduct. The optimal methodological approach for researchers conducting a SR/MA should be standardized.

Heart and Vessels, 2010

ABSTRACT The purpose of this study was to evaluate the morphology and composition of atherosclero... more ABSTRACT The purpose of this study was to evaluate the morphology and composition of atherosclerotic coronary plaques in patients with stable coronary artery disease by 64-row multidetector computed tomography (CT) angiography. A total of 56 patients were divided into an ischemia-related (n = 31) and a nonischemia-related lesion group (n = 25) based on myocardial perfusion scintigraphy, invasive angiography, and 1-year clinical follow-up. The 56 lesions detected by CT imaging were analyzed; the severity of stenosis, the lesion length, CT attenuation value, and calcium deposition of the plaques were evaluated. Clinical characteristics and CT findings were compared using univariate and multivariate logistic regression analyses. Ischemia-related lesions exhibited a greater severity of coronary stenosis, were longer (17.8 ± 8.5 vs 9.1 ± 3.9 mm), and had a higher CT attenuation value (101.7 ± 36.7 vs 81.6 ± 32.6 HU) and larger calcium deposition. By univariate logistic analysis, severity of stenosis, lesion length, CT attenuation value, and calcium deposition were significantly associated with ischemia-related plaques. The odds ratio (OR) of these parameters was 6.874 (P = 0.007), 1.371 (P = 0.001), 1.018 (P = 0.044), and 5.400 (P = 0.004), respectively. By multivariate logistic analysis, the severity of stenosis and lesion length were significantly associated with ischemia-related plaques (OR 7.588, P = 0.036 and OR 1.365, P = 0.003, respectively). In conclusion, coronary CT angiography is useful for the identification of morphological differences between ischemia-related and nonischemia-related plaques in patients with stable coronary artery disease.

The Egyptian Journal of Neurology, Psychiatry and Neurosurgery

Background Pregnancy is a recent growing issue in multiple sclerosis (MS) and the update in the d... more Background Pregnancy is a recent growing issue in multiple sclerosis (MS) and the update in the diagnostic criteria of MS and introduction of many disease-modifying therapies (DMTs) may cause changes in the relationship between MS, pregnancy, and breastfeeding. This study aimed to investigate the effect of pregnancy and breastfeeding on MS and vice versa. A retrospective observational study was conducted to include MS women with a history of at least one pregnancy during the last 7 years. Data were collected from the archived files in addition to a self-administrating questionnaire. The annualized relapsing rate (ARR) was calculated before, during, and after pregnancy. Results We included 116 successful pregnancies from 93 MS women with mean age 32.74 ± 5.12 years. Interferon-beta was the commonly used DMT during and after pregnancy. Despite the ARR during the two years preceding the conception was 0.36 (95% CI 0.32–0.41), this rate was significantly decreased during first, second, ...

Antimicrobial agents and chemotherapy, Jan 12, 2018

The rapid spread of strains of malaria parasites resistant to several drugs has threatened global... more The rapid spread of strains of malaria parasites resistant to several drugs has threatened global malaria control. Hence, the aim of this study was to predict the anti-malarial activity of chemical compounds possessing anti-hemozoin formation activity as a new means of anti-malarial drug discovery. After the initialanti-hemozoin formation high-throughput screening (HTS) of 9,600 compounds, a total of 224 hit compounds were identified as hemozoin inhibitors. These 224 compounds were tested forerythrocytic anti-malarial activity at 10 μM using the chloroquine-mefloquine sensitivestrain, 3D7A. Two independent experiments were conducted. The physicochemical properties of the active compounds were extracted from ChemSpider and SciFinder databases. We analyzed the extracted data using Bayesian model averaging (BMA). Our findings revealed that lower numbers of S atoms, lower values of log D pH 3, 4 and 5, and higher values of ACD log D pH 7.4 had a significant association with anti-malaria...

Antimicrobial Agents and Chemotherapy, 2016

It is essential to continue the search for novel antimalarial drugs due to current spread of resi... more It is essential to continue the search for novel antimalarial drugs due to current spread of resistance against artemisinin by Plasmodium falciparum parasites. In this study, we developed in silico models to predict hemozoin inhibitors as a potential first-step screening for novel antimalarials. The in vitro colorimetric high throughput screening assay of hemozoin formation was used to identify hemozoin inhibitors from 9600 structurally diverse compounds. Physicochemical properties of positive hits and randomly selected compounds were extracted from ChemSpider database; they were used for developing prediction models to predict hemozoin inhibitors using two different approaches, i.e. traditional multivariate logistic regression, and Bayesian Modeling Average. Our results showed that a total of 224 positive hits exhibited the ability to inhibit the hemozoin formation with IC 50 ranging from 3.1 μM to 199.5 μM. The “best” model according to traditional multivariate logistic regression...

Scientific reports, Apr 6, 2017

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency overlaps with malaria endemicity although it ... more Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency overlaps with malaria endemicity although it predisposes carriers to hemolysis. This fact supports the protection hypothesis against malaria. The aim of this systematic review is to assess the presence and the extent of protective association between G6PD deficiency and malaria. Thirteen databases were searched for papers reporting any G6PD alteration in malaria patients. Twenty-eight of the included 30 studies were eligible for the meta-analysis. Results showed absence of negative association between G6PD deficiency and uncomplicated falciparum malaria (odds ratio (OR), 0.77; 95% confidence interval (CI), 0.59-1.02; p = 0.07). However, this negative association happened in Africa (OR, 0.59; 95% CI, 0.40-0.86; p = 0.007) but not in Asia (OR, 1.24; 95% CI, 0.96-1.61; p = 0.10), and in the heterozygotes (OR, 0.70; 95% CI, 0.57-0.87; p = 0.001) but not the homo/hemizygous (OR, 0.70; 95% CI, 0.46-1.07; p = 0.10). There was no associati...

While prevalence of Hepatitis B virus (HBV) in patients with end-stage renal failure (ESRF) who a... more While prevalence of Hepatitis B virus (HBV) in patients with end-stage renal failure (ESRF) who are undergoing dialysis has decreased significantly during the past few decades, it still remains a distinct clinical problem. The immunosuppressive nature of renal disease often leads to chronicity of the HBV infection and an opportunity for nosocomial spread of the infection among dialysis patients. Egypt is among the countries with intermediate endemicity of HBsAg (range, 2%-7%). Large-scale geographic heterogeneity in HBV prevalence has been reported worldwide and HBV prevalence is especially heterogeneous in Egypt. Objectives: To assess the prevalence of occult HBV infection (OBI) in hemodialysis patients with or without chronic hepatitis C (HCV) from Minia and Assuit, Upper Egypt, using HBV DNA assays. Patient and Methods: Sera from 145 hemodialysis patients with negative HbsAg were investigated for HBV DNA using real-time polymerase chain reaction (RT-PCR). Only serum samples with repeatedly detectable HBV DNA were considered positive. Patients were divided into 2 groups: HCV RNA positive and HCV RNA negative, based on the results of a third generation enzyme linked immunosorbent assay (ELISA) anti-HCV test and HCV RNA PCR. Results: HBV DNA was detected in 6 of the 145 patients (4.1%) and HBcAb was detected in 29/145 patients (20%). There were no statistically significant differences in the age, duration of hemodialysis, biochemical parameters, serological markers of HBV, or HBV DNA between patients with and without HCV infection. Conclusions: Four percent of the hemodialysis patients had OBI. There was no significant difference in the prevalence of OBI between hemodialysis patients with or without HCV co-infection.

Virologica Sinica, 2019

The relationship between the severity of dengue infection and allergy is still obscure. We conduc... more The relationship between the severity of dengue infection and allergy is still obscure. We conducted an electronic search across 12 databases for relevant articles reporting allergic symptoms, dengue infection, and dengue classification. These studies were categorized according to dengue severity and allergy symptoms, and a meta-analysis was performed by pooling the studies in each category. Among the included 57 articles, pruritus was the most common allergic sign followed by non-specified allergy and asthma (28.6%, 13%, and 6.5%, respectively). Despite the reported significant association of dengue with pruritus and total IgE level (P \ 0.05), in comparison with non-dengue cases and healthy controls, there was no association between the different severe dengue group with pruritus, skin allergy, food allergy or asthma. However, removing the largest study revealed a significant association between asthma with dengue hemorrhagic fever (DHF) rather than dengue fever (DF). In comparison with DF, DHF was associated with IgE positivity. Furthermore, specific-IgE level was higher in secondary DF rather than primary DF. There was a possible association between allergy symptoms and dengue severity progression. Further studies are needed to clarify this association.

Review in Medical virology , 2019

Imported dengue cases are thought to be important source for transmission of autochthonous dengue... more Imported dengue cases are thought to be important source for transmission of autochthonous dengue in Europe. We aimed to investigate the prevalence of dengue in Europe, its severity, and factors associated with it. Out of 5287 reports resulting from the search of nine electronic search engines, we included 174 reports. Meta-analysis was performed by pooling the event rate and 95% confidence interval (CI). Subgroup meta-analyses were performed to test the effect of the covariates. Among 20 284 reported cases, 130 autochthonous dengue cases were reported in eight countries with the highest number of cases reported in Israel (n = 41). The highest number of imported dengue cases was in Germany (n = 6638) then France (n = 6610). Most cases were imported from Southeast Asia (n = 2533) especially Thailand. Dengue infection cases increased with time, with 4157 cases reported in 2010. Second dengue infection and dengue serotype 2 were positively associated with dengue severity. The proportion of autochthonous dengue infection increased with time to reach 14.8% (95% CI, 7.6-26.9) in 2015. The pooled proportion of severe dengue was 6.18% (95% CI, 2.7-13.3). The United Kingdom and France had the highest rate of severe dengue (25%; 95% CI, 6.3-62.3, and 21.4%; 95% CI, 24.5-18.7, respectively). This change may be due to the surveillance efforts instead of true biological phenomenon; thus, the lack of surveillance is an obvious limitation. In conclusion, imported and autochthonous dengue has been increasing in Europe. Severe dengue began to increase recently in Europe. European health authorities should pay more attention for the diagnosis and control of dengue infection among returning travelers, especially the travelers with fever of unknown origin. K E Y W O R D S dengue, Europe, meta-analysis, systematic review Abbreviation list: DF, dengue fever; DHF, Dengue Hemorrhagic Fever; DSS, Dengue Shock Syndrome; CI, confidence interval; DENV-1, dengue virus serotype 1; DENV-2, dengue virus serotype 2; UK, United Kingdom; NO, nitric oxide.

Surgical Innovation, 2019

Purpose. To investigate the knowledge, attitude, and practice of surgeons toward introducing nove... more Purpose. To investigate the knowledge, attitude, and practice of surgeons toward introducing novel surgical techniques in Egypt, Palestine, and Vietnam. Summary Background Data. Despite the recent advances in modern surgical care and its role in advancing the quality and the length of lives, surgery in the developing world has stagnated or even regressed. Methods. A survey was undertaken among the surgeons in 9 hospitals belonging to the 3 countries. Questions were categorized into knowledge, attitude, and practice questions. Meta-analyses were performed to estimate the event rate and compare between knowledge and practice, senior and junior surgeons. Results. A total of 244 responses, with a response rate of 79.7%, were included in the analysis. Regarding knowledge and attitude, the results were satisfactory except that only 55.8% of surgeons appraised their level of education and 43.3% wanted to earn money from the novel procedure. There was a significant difference between knowledge and practice regarding getting informed consent from the patients (P=.024), discussing the novelty of the procedure (P< .001), discussing the alternative procedures (P< .001), discussing the surgeons’ experience and level of skills (P< .001), discussing the risk of the new procedure (P< .001), and monitoring the outcomes after the new procedure (P< .001). Conclusions. Most surgeons have sufficient knowledge and are motivated regarding adopting novel surgical techniques in order to provide the best care for the patients. However, there was a gap between knowledge and practice. Training programs and evidence-based guidelines regarding the introduction of novel surgical techniques are needed to overcome these challenges.

Purpose: The surgical interventions of diverticulitis vary according to its grade and severity. T... more Purpose: The surgical interventions of diverticulitis vary according to its grade and severity. There is a controversy about the best of these different surgical procedures. We aimed to systematically review and meta-analyze randomized controlled trials (RCTs) comparing outcomes and complications between different surgical approaches for acute diverticulitis and its complications. Methods: Nine electronic databases including PubMed, Scopus, and Web of Science were searched for RCTs comparing different surgical procedures for different grades of diver-ticulitis. The risk of bias was assessed using the Cochrane Collaboration tool. The protocol was registered in PROSPERO (CRD42015032290). Results: Outcome data were analyzed from five RCTs comparing laparoscopic sigmoid resection (LSR) (n ¼ 247) versus open sigmoid resection (OSR) (n ¼ 237) for treatment of acute complicated diverticulitis with minimal heterogeneity. There was no significant difference in short-term postoperative overall morbidity (risk ratio (RR) 0.89, 95% confidence interval (CI) 0.61e1.31; P ¼ 0.56) and long-term postoperative major morbidity (RR 0.78, 95% CI 0.46e1.31, P ¼ 0.34). In other six RCTs compared laparoscopic lavage with resection for treatment of perforated diverticulitis with peritonitis, the postoperative mortality rate was non-significant in both short-term (RR 1.55, 95% CI 0.79e3.04; P ¼ 0.21) and long-term (RR 0.67, 95% CI 0.29e1.58; P ¼ 0.36) follow up.