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Dive into the research topics where Konstantinos C. Fragkos is active.

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Featured researches published by Konstantinos C. Fragkos.


The American Journal of Clinical Nutrition | 2014

The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials

Eirini Dimidi; S. Christodoulides; Konstantinos C. Fragkos; S. Mark Scott; Kevin Whelan

BACKGROUND Functional constipation is a prevalent, burdensome gastrointestinal disorder whose treatment remains challenging. Probiotics have been increasingly investigated in its management. OBJECTIVE The aim was to investigate the effect of probiotics on gut transit time, stool output, and constipation symptoms in adults with functional constipation via a systematic review and meta-analysis of randomized controlled trials (RCTs). DESIGN Studies were identified by searching 4 electronic databases, back-searching reference lists, contacting authors, and hand-searching abstracts. RCTs that reported administration of probiotics in adults with functional constipation were included. Two reviewers independently performed the screening, data extraction, and bias assessment. Outcome data were synthesized by using weighted mean differences (WMDs) or standardized mean differences (SMDs) with the use of a random-effects model. RESULTS A total of 660 records were identified of which 14 were eligible (1182 patients). Overall, probiotics significantly reduced whole gut transit time by 12.4 h (95% CI: -22.3, -2.5 h) and increased stool frequency by 1.3 bowel movements/wk (95% CI: 0.7, 1.9 bowel movements/wk), and this was significant for Bifidobacterium lactis (WMD: 1.5 bowel movements/wk; 95% CI: 0.7, 2.3 bowel movements/wk) but not for Lactobacillus casei Shirota (WMD: -0.2 bowel movements/wk; 95% CI: -0.8, 0.9 bowel movements/wk). Probiotics improved stool consistency (SMD: +0.55; 95% CI: 0.27, 0.82), and this was significant for B. lactis (SMD: +0.46; 95% CI: 0.08, 0.85) but not for L. casei Shirota (SMD: +0.26; 95% CI: -0.30, 0.82). No serious adverse events were reported. Attrition and reporting bias were high, whereas selection bias was unclear due to inadequate reporting. CONCLUSIONS Probiotics may improve whole gut transit time, stool frequency, and stool consistency, with subgroup analysis indicating beneficial effects of B. lactis in particular. However, caution is needed with the interpretation of these data due to their high heterogeneity and risk of bias. Adequately powered RCTs are required to better determine the species or strains, doses, and duration of use of probiotics that are most efficacious.


Electronic Commerce Research | 2012

Critical review of the e-loyalty literature: a purchase-centred framework

Aikaterini C. Valvi; Konstantinos C. Fragkos

Over the last few years, the concept of online loyalty has been examined extensively in the literature, and it remains a topic of constant inquiry for both academics and marketing managers. The tremendous development of the Internet for both marketing and e-commerce settings, in conjunction with the growing desire of consumers to purchase online, has promoted two main outcomes: (a) increasing numbers of Business-to-Customer companies running businesses online and (b) the development of a variety of different e-loyalty research models. However, current research lacks a systematic review of the literature that provides a general conceptual framework on e-loyalty, which would help managers understand their customers better, take advantage of industry-related factors, and improve their service quality. The present study is an attempt to critically synthesize results from multiple empirical studies on e-loyalty. Our findings illustrate that 62 instruments for measuring e-loyalty–with two or more items—are currently in use, influenced predominantly by Zeithaml et al. (J. Marketing 60(2):31–46, 1996) and Oliver (Satisfaction: a behavioral perspective on the consumer. New York: McGraw Hill, 1997). Additionally, we propose a new general conceptual framework, which leads to e-loyalty dividing antecedents into prepurchase, during-purchase and after-purchase factors, based on the act of purchase. To conclude, a number of managerial implementations are suggested in order to help marketing managers increase their customers’ e-loyalty by making crucial changes in each purchase stage.


Alimentary Pharmacology & Therapeutics | 2016

Systematic review with meta-analysis: effect of fibre supplementation on chronic idiopathic constipation in adults

S. Christodoulides; Eirini Dimidi; Konstantinos C. Fragkos; Adam D. Farmer; Kevin Whelan; S. M. Scott

Chronic idiopathic constipation is a common symptom‐based gastrointestinal disorder responsible for a substantial economic health service burden. Current guidelines recommend the use of fibre as a first‐line treatment.


Nutrients | 2013

Assessing eating disorder risk: the pivotal role of achievement anxiety, depression and female gender in non-clinical samples.

Konstantinos C. Fragkos; Christos C. Frangos

The objective of the present study was to assess factors predicting eating disorder risk in a sample of undergraduate students. A structured questionnaire was employed on a random sample (n = 1865) consisting of the following sections: demographics, SCOFF (Sick, Control, One stone, Fat, Food) questionnaire for screening eating disorders and the Achievement Anxiety Test and the Depression, Anxiety and Stress Scale. The students at risk for eating disorders (SCOFF score ≥2) were 39.7%. Eating disorder risk was more frequent in females, students with divorced parents, students who lived alone, students who were seeking a romantic relationship or were married, students who were at a post-secondary vocational institute/college (private-public) educational level and who were more likely to have marks under merit level. Also, the mean scores for the psychological factors of depression, stress and anxiety were higher in students with eating disorder risk. A logistic regression model was produced depicting that depression, stress, female gender, being married and searching for a romantic relationship were risk factors of having an eating disorder risk. The suggested psychological model examined with structural equation modelling signified the role of academic anxiety as an immediate precursor of general anxiety. Hence, college populations in Greece need organized infrastructures of nutrition health services and campaigns to assist in reducing the risk of eating disorders.


Clinical Nutrition | 2013

Development and validation of the disease-specific Short Bowel Syndrome-Quality of Life (SBS-QoL™) scale.

P. Berghöfer; Konstantinos C. Fragkos; Janet P. Baxter; Alastair Forbes; Francisca Joly; H. Heinze; S. Loth; M. Pertkiewicz; Bernard Messing; Palle B. Jeppesen

BACKGROUND & AIMS Subjects with short bowel syndrome (SBS) have impaired quality of life (QoL). No disease-specific instrument has been available to measure treatment-induced changes in QoL over time. Therefore, the aim was to develop and validate an SBS-specific QoL scale. METHODS Classical test theory and Food and Drug Administration (FDA) guidance were applied for development and validation of the SBS-QoL™. Procedures included item generation and raw scale construction. Factor analysis, construct validity and internal consistency were assessed in a non-interventional observation, test re-test reliability and responsiveness in a randomised clinical study. RESULTS The SBS-QoL™ comprises 17 items including two subscales. Subjects assessed the scale as easy to handle and comprehensible. Good construct validity was shown by comparison with the Home Parenteral Nutrition-Quality Of Life questionnaire as an external scale, which yielded moderately high correlation (r ≥ 0.7). High internal consistency was demonstrated (Cronbachs alpha: 0.94). Also the test re-test reliability was high (r ≥ 0.95), indicating reliable reproducibility of results. The Responsiveness Index (1.84) indicated the ability of the scale to detect changes in QoL over time. CONCLUSIONS The SBS-QoL™ is an easy to handle and comprehensible SBS-specific subject-reported QoL scale. It is valid, reliable and sensitive with excellent psychometric characteristics to measure treatment-induced changes in QoL over time in subjects with SBS.


Thorax | 2016

The validity of health-related quality of life questionnaires in bronchiectasis: a systematic review and meta-analysis

Arietta Spinou; Konstantinos C. Fragkos; Kai K. Lee; Caroline Elston; Richard J. Siegert; Michael R. Loebinger; Rob Wilson; Rachel Garrod; Surinder S. Birring

Background A range of questionnaires have been used to assess health-related quality of life (HRQOL) in bronchiectasis. A systematic review was conducted to evaluate their psychometric properties and assess associations between HRQOL and clinical measures. Methods Five electronic databases were searched. Studies eligible for inclusion were those that investigated the validity of HRQOL questionnaires and/or their association with other outcomes in adults with bronchiectasis. Patients with cystic fibrosis were excluded. The identified questionnaires were assessed for convergent, discriminant and cross-cultural translation validity; missing data, floor and ceiling effects, internal consistency, responsiveness and test-retest reliability. A meta-analysis was conducted to estimate the strength of associations between HRQOL and clinical measures. Results From 1918 studies identified, 43 studies were included in the systematic review, of which 38 were suitable for the meta-analysis. Nine HRQOL questionnaires were identified, with the most widely used being: St Georges Respiratory Questionnaire, Leicester Cough Questionnaire, Quality of Life–Bronchiectasis and Short Form-36. HRQOL questionnaires had moderate to good internal consistency and good test-retest reliability. Only 8 of 18 studies that used translated HRQOL questionnaires reported or referred to the validity of the translated questionnaire. There was a stronger correlation (mean r (95% CI)) between HRQOL and subjective outcome measures, such as dyspnoea (0.55 (0.41 to 0.68)) and fatigue (0.42 (0.23 to 0.58)) compared with objective measures; exercise capacity (−0.41 (−0.54 to −0.24)), FEV1% predicted (−0.31 (−0.40 to −0.23)) and extent of bronchiectasis on CT scan (0.35 (0.03 to 0.61)); all p<0.001. Conclusions This review supports most HRQOL questionnaires used in bronchiectasis have good psychometric properties. There was a weak to moderate association between HRQOL and objective outcome measures. This suggests that HRQOL questionnaires assess a unique aspect of health not captured by objective measures.


International Scholarly Research Notices | 2014

Publication Bias in Meta-Analysis: Confidence Intervals for Rosenthal’s Fail-Safe Number

Konstantinos C. Fragkos; Michail Tsagris; Christos C. Frangos

The purpose of the present paper is to assess the efficacy of confidence intervals for Rosenthals fail-safe number. Although Rosenthals estimator is highly used by researchers, its statistical properties are largely unexplored. First of all, we developed statistical theory which allowed us to produce confidence intervals for Rosenthals fail-safe number. This was produced by discerning whether the number of studies analysed in a meta-analysis is fixed or random. Each case produces different variance estimators. For a given number of studies and a given distribution, we provided five variance estimators. Confidence intervals are examined with a normal approximation and a nonparametric bootstrap. The accuracy of the different confidence interval estimates was then tested by methods of simulation under different distributional assumptions. The half normal distribution variance estimator has the best probability coverage. Finally, we provide a table of lower confidence intervals for Rosenthals estimator.


Industrial and Commercial Training | 2013

Crisis communication strategies: A case of British Petroleum

Aikaterini C. Valvi; Konstantinos C. Fragkos

Purpose – Every unexpected and sudden event (crisis) operates as a threat for an organizations reputation. British Petroleum (BP) came face to face with a crisis on 20 April 2010 when an explosion in the Deepwater Horizon oil drilling rig caused a huge oil spillage in the Gulf of Mexico. The present case study aims to describe BPs serious communication mistakes with its stakeholders managing a serious hit to BPs reputation. Design/methodology/approach – The present case study attempts to provide a detailed outline of BPs communication failures by conducting in-depth investigation of secondary data (newspapers, audiovisual material, social network sites). Findings – BPs crisis communication was a weak link in its crisis management strategy. The lessons to learn are various, both for practitioners and researchers. Practitioners should learn from the leadership, culture and public relations (PR) mistakes made by BP and avoid them in a crisis of their organisation. They should select those strategies tha...


Journal of Marketing Research & Case Studies , 2012 (927167) (2012) | 2012

Factors Affecting Customers’ Decision for Taking out Bank Loans: A Case of Greek Customers

Christos C. Frangos; Konstantinos C. Fragkos; Ioannis Sotiropoulos; Giannis Manolopoulos; Aikaterini C. Valvi

The concept of loyalty has received much consideration from both academics and practitioners in various industries and is a predominant research topic in the banking industry. Identifying the factors that affect customers’ decision to take out a loan from a particular bank has become an essential asset for many banks in their effort to attract new customers and to maintain existing ones. The purpose of the present study is to identify factors that influence Greek customers’ decision to take out a loan from commercial banks. A number of variables (demographics, service quality and satisfaction) have been examined as potential factors influencing customers’ decision to take out a loan. A randomly selected sample of Greek citizens (n=277) was chosen in order to test our hypotheses. A questionnaire with self-determined scales was created after ensuring the instrument’s validity through confirmatory factor analysis. Logistic regression results show that personal marital status, customer service, shop design and interest rates are the most significant predictors of taking loans. Several managerial implications suggest bank managers should focus on giving loans to single individuals as well as change their interest rates policies by decreasing rates for all kinds of loans, especially housing loans.


Inflammatory Bowel Diseases | 2016

Incidence and Severity of Prepouch Ileitis: A Distinct Disease Entity or a Manifestation of Refractory Pouchitis?

Mark A. Samaan; Djuna de Jong; Saloomeh Sahami; S Morgan; Konstantinos C. Fragkos; S Subramaniam; Klaartje Kok; Jesica Makanyanga; I Barnova; H Saravanapavan; I Parisi; Simona Di Caro; Roser Vega; F. Rahman; Sara McCartney; Stuart Bloom; Gijs R. van den Brink; M. Lowenberg; Cyriel Y. Ponsioen; Christianne J. Buskens; Pieter J. Tanis; Anthony de Buck van Overstraeten; Andre DʼHoore; Willem A. Bemelman; Geert DʼHaens

Background:Restorative proctocolectomy with ileal pouch–anal anastomosis is the operation of choice for patients with treatment-refractory ulcerative colitis. However, after this intervention, up to 50% of patients develop pouchitis. Moreover, a subgroup will also develop inflammation in the afferent ileum proximal to the pouch, a condition named prepouch ileitis (PI). Methods:Data on 546 patients who underwent ileal pouch–anal anastomosis for ulcerative colitis were retrospectively collected from 3 tertiary inflammatory bowel disease referral centers in the Netherlands, Belgium, and England. PI was considered present if there was endoscopic and histological inflammation in the afferent limb proximal to the pouch. Crohns disease was excluded by reviewing the histology of colectomy resection specimens. Results:PI was present in 33/546 (6%) patients and all of these had concurrent pouchitis. One hundred forty-four (26%) patients had pouchitis without PI and 369 (68%) patients did not have inflammatory pouch disease. Of the 33 patients with PI, 6 (18%) received no specific treatment, 9 (27%) responded to antibiotics, and 18 (54%) required escalation in therapy to steroids/immunomodulators or anti–tumor necrosis factor agents. Potent immunosuppressive treatment was required more frequently in patients with PI than those with pouchitis alone. Conclusions:PI is less common and more treatment refractory than pouchitis alone. Once PI is diagnosed, clinicians should be aware that response to antibiotic therapy is less likely than in pouchitis alone. Immunomodulatory therapy and escalation to anti–tumor necrosis factor agents should be considered early in cases of nonresponse. The suggestion that PI represents misdiagnosed Crohns disease could not be substantiated in our cohort.

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Alastair Forbes

University of East Anglia

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Christos C. Frangos

Technological Educational Institute of Athens

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F. Rahman

University College Hospital

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S. Christodoulides

Queen Mary University of London

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S. M. Scott

Queen Mary University of London

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I Barnova

University College Hospital

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S Morgan

University College Hospital

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