Michael Sfakianakis

Azathioprine is superior to budesonide in achieving and maintaining mucosal healing and histologic remission in steroid-dependent Crohn's disease.

Background: The effects of azathioprine (AZA) and budesonide (BUD) on mucosal healing and histologic remission of Crohns disease (CD) are insufficiently studied. In this prospective study we evaluated the comparative effects of AZA and BUD on endoscopic and histologic activity in patients with steroid‐dependent Crohns ileocolitis or proximal colitis who had achieved clinical remission on conventional steroids. Methods: Patients were randomized to AZA (2.0–2.5 mg/kg a day) or BUD (6–9 mg a day) for 1 year. The study protocol included clinical examination, laboratory tests, calculation of the Crohns Disease Activity Index (CDAI), completion of the Inflammatory Bowel Disease Questionnaire (IBDQ), at baseline and then every 2 months for 1 year. Ileocolonoscopy with regional biopsies was performed at baseline and then at the end of the study to assess mucosal healing and the histologic activity of CD. Results: Thirty‐eight patients were randomized to AZA and 39 to BUD. At the end of the study 32 and 25 patients in the AZA and BUD groups, respectively, were in clinical remission (P = 0.07). The Crohns Disease Endoscopic Index of Severity (CDEIS) score fell significantly only in the AZA group (P < 0.0001). Complete or near complete healing was achieved in 83% of AZA‐treated patients compared with only 24% of BUD‐treated patients (P < 0.0001). Histologic activity as assessed by an average histology score (AHS) fell significantly only in the AZA group (P < 0.001 versus baseline) and was significantly lower than in the BUD group at the end of the study (P < 0.001). Eight patients in the AZA group were withdrawn for adverse events (n = 6) or relapse of disease compared with 14 patients in the BUD group who were withdrawn for relapse of disease. Conclusions: In patients with steroid‐dependent inflammatory Crohns ileocolitis or proximal colitis who achieve clinical remission with conventional steroids, a 1‐year treatment with AZA was superior to BUD in achieving and maintaining mucosal healing and histologic remission.

A prospective randomized observer-blind 2-year trial of azathioprine monotherapy versus azathioprine and olsalazine for the maintenance of remission of steroid-dependent ulcerative colitis.

OBJECTIVE:The aim of this prospective study was to assess whether the coadministration of azathioprine (AZA) and olsalazine is superior to AZA monotherapy in maintaining remission of steroid-dependent ulcerative colitis (UC).METHODS:Patients with steroid-dependent UC in remission were randomized to receive AZA alone (2.2 mg/kg) or in combination with olsalazine (0.5 g tid). Remission was defined as steroid withdrawal, an Ulcerative Colitis Clinical Activity Index (UCCAI) score of <2, an Ulcerative Colitis Disease Activity Index (UCDAI) score of 0, and a negative colonoscopy and histology. Patients were followed in the outpatient clinic every month for 2 yr. The study protocol included 1) monthly clinical examination, assessment of UCCAI, hematological and biochemical tests, and compliance with treatment; 2) a sigmoidoscopy and completion of inflammatory bowel disease quality-of-life questionnaire (IBD-Q) and UCDAI every 3 months; and 3) total colonoscopy with biopsies at the end of the first and second year of the trial.RESULTS:Seventy patients were randomized to receive AZA alone (n = 34) or with olsalazine (n = 36). Three patients in each group developed side effects or could not comply with treatment and were withdrawn from the study. Three patients receiving AZA relapsed after the first year of the study and three after the second year of the study (19%). In the combination therapy group four patients relapsed after the first year of study and two after the second year of the study (18%). Relapse rates were not significant whether analyzed by intention-to-treat or per protocol. There were no significant differences between groups in time to relapse or discontinuation of treatment, UCCAI, UCDAI, or IBD-Q scores. However, the number of adverse events and the cost of treatment were significantly higher, whereas compliance with treatment was poorer in the combination therapy.CONCLUSION:Patients with steroid-dependent UC successfully maintained in remission on AZA are not in need of 5-aminosalicylic acid compounds.

Reliability of a consecutive k-out-of-r-from-n:F system

The reliability of the consecutive k-out-of-r-from-n:F system is studied. For k=2 an explicit solution is given for n components in line or in cycle in the i.i.d. case. For k>or=3 sharp lower and upper bounds are given for the reliability of the system and demonstrated for different values of n, k, r, p. These bounds are exact for r=n, n-1, n-2, n-3, and for these values the exact analytic solution is also given. >

Does subclinical hypercortisolism adversely affect the bone mineral density of patients with adrenal incidentalomas

objective Subclinical hypercortisolism (SH) is detected increasingly in a substantial proportion of patients with incidentally discovered adrenal adenomas. The clinical implications of SH are currently unclear. Osteoporosis is a well‐known complication of glucocorticoid excess. So far, the impact of SH on bone mineral density (BMD) has been studied in a limited number of reports with discordant results. In the present study we evaluated the BMD in a large cohort of post‐menopausal women with adrenal incidentalomas.

Bone density patterns after normal and premature menopause

OBJECTIVES The investigation of the effect of time and type of menopause on bone mineral density (BMD) at different ages. METHODS Five hundred and fourteen women, who had never received any hormonal substitution were studied in a cross-sectional design: 177 with normal (NMP), 210 with surgical (SUMP) and 127 with premature natural (EMP) menopause. Age at menopause was 49.1+/-3.9, 38.3+/-4.7 and 38.1+/-4.2 years (mean+/-1 S.D.), respectively. BMD was measured at L2-L4 vertebrae and proximal femur by the DEXA method. RESULTS EMP women presented significantly lower vertebral BMD than NMP women in the 45-55-years segments (P<0.001), but did not differ from SUMP women. This group exhibited lower vertebral BMD than NMP between 45 and 50 years (P<0.001). Regarding femoral neck, EMP women exhibited lower values than SUMP in the 45-50 and 55-65 age segments (P<0.001) whereas SUMP women presented significantly higher BMD values than NMP women after 55 years of age (P<0.001). The percentages of women with vertebral BMD (T-score values) in the osteoporotic range were significantly greater in EMP compared with either NMP or SUMP groups (both P<0.001) whereas in femoral neck lower in SUMP than the other two categories. CONCLUSIONS Women with either natural or surgical premature menopause exhibit lower BMD of trabecular bone compared with normal menopause women at the age segments 45-55 and 45-50, respectively. However, surgical menopause women exceed normal menopause women in their mixed bone BMD values after 60 years as well as premature natural menopause women at almost all age segments.

Assessing naïve Bayes as a method for screening credit applicants

The naïve Bayes rule (NBR) is a popular and often highly effective technique for constructing classification rules. This study examines the effectiveness of NBR as a method for constructing classification rules (credit scorecards) in the context of screening credit applicants (credit scoring). For this purpose, the study uses two real-world credit scoring data sets to benchmark NBR against linear discriminant analysis, logistic regression analysis, k-nearest neighbours, classification trees and neural networks. Of the two aforementioned data sets, the first one is taken from a major Greek bank whereas the second one is the Australian Credit Approval data set taken from the UCI Machine Learning Repository (available at http://www.ics.uci.edu/~mlearn/MLRepository.html). The predictive ability of scorecards is measured by the total percentage of correctly classified cases, the Gini coefficient and the bad rate amongst accepts. In each of the data sets, NBR is found to have a lower predictive ability than some of the other five methods under all measures used. Reasons that may negatively affect the predictive ability of NBR relative to that of alternative methods in the context of credit scoring are examined.

A New Family of Nonparametric Quantile Estimators

A new core methodology for creating nonparametric L-quantile estimators is introduced and three new quantile L-estimators (SV1 p , SV2 p , and SV3 p ) are constructed using the new methodology. Monte Carlo simulation was used in order to investigate the performance of the new estimators for small and large samples under normal distribution and a variety of light and heavy-tailed symmetric and asymmetric distributions. The new estimators outperform, in most of the cases studied, the Harrell–Davis quantile estimator and the weighted average at X ([np]) quantile estimator.

Reliability of a general consecutive-k-out-of-n:F system

A linear (circular) consecutive-k-out-of-n:F system consists of n components ordered on a line (circle). Each component and the system have two states: good or failed. The system fails if and only if at least k consecutive components fail. The reliability of such systems is computed. The most general case is examined without any restriction on the components. >

Assessing bids of Greek public organizations service providers using data envelopment analysis

The existing framework for the procurement of products and services for the Greek Public Organizations describes specific criteria structure and fixed-weighted formulas for the assessment of the provider’s bids. This assessment procedure suffers from specific shortcomings: it overestimates the price, it is very sensitive to small changes to performance indicators and especially for the services, is not able to incorporate variable price information. In this paper we develop a Data Envelopment Analysis model that overcomes the above mentioned shortcomings. It uses variable weights that are estimated in favor of each evaluated bid and are properly restricted to comply with the existing framework and to reflect criteria priorities. It also encounters ranges for prices that correspond to minimum and maximum expected number of service calls. For illustration purposes we provide a real case application for the assessment of courier service providers.

Optimal arrangement of components in a consecutive k-out-of-r-from n:F system

Abstract A consecutive k-out-of-r-from n:F system is an ordered linear arrangement of n components that fails if and only if at least k in a “window” of r consecutive components fail. Suppose that all components are interchangeable and that component failures are s-independent. Component failure probabilities need not be equal. In this paper the ordering of the components in order to minimize the probability of system failure is examined. All values of k,r,n for which an optimal configuration can be determined, without knowledge of the component failure probabilities, are given.