Epidemiology, clinical features, and mortality rate of Wilson disease in Moroccan children: A pediatric case series.

BACKGROUND AND STUDY AIMS: Wilson's disease is an autosomal recessive disorder, that affects copper metabolism, leading to copper accumulation in the liver, nervous system, and cornea. Data are lacking on the epidemiology, the clinical and laboratory characteristics, treatment, and survival of Wilson's disease in Morocco. The aim of this study was to examine these features and the cause of death in a Moroccan pediatric population. PATIENTS AND METHODS: The study was carried out at the University Hospital Center of Marrakesh, Morocco; 46 children were diagnosed with Wilson's disease from 2008 to 2019. The diagnosis was based on low serum ceruloplasmin, increased urinary copper concentrations, the presence of Kayser-Fleischer rings, a family history of Wilson's disease, and a Leipzig score of ≥ 4. RESULTS: A total of 42 patients were referred to the center for hepatic or neurological manifestations; four patients were asymptomatic. Consanguineous marriage was found in 67.4% of the cases. The mean duration of illness (42 patients) was 4.9 ± 3.9 years. Kayser-Fleischer rings were found in 60.9% of 46 patients. Of the 42 symptomatic patients: 28 of 30 (93.3%) patients had low serum ceruloplasmin (<0.2 g/L), and 24 h urinary copper >100 µg/day was found in 34 of 35 (97.1%) cases. The treatment was established with D-penicillamine for 43 of the 46 patients, with zinc acetate for one patient and with zinc sulfate in for one patient, while one patient was not treated. D-penicillamine was discontinued in nine patients because of adverse effects such as thrombocytopenia, neurological deterioration, pancytopenia, severe vomiting and severe hypersensitivity. In total 28 patients were clinically and biologically stabilized, two patients experienced vision loss, and 16 patients died (38%). The main cause of death was diagnosis made at an advanced stage of disease and stopping treatment. CONCLUSION: Wilson's disease is a rare condition associated with treatement efficacy, but late diagnosis and stopping treatment can lead to a high mortality rate.

The reliability of probability analysis in the prediction of coronary artery disease in two hospitals.

To assess the accuracy of the Bayesian computer program CADENZA for the prediction of coronary artery disease, the authors examined the probabilities generated by the application of this program to the clinical and noninvasive test results of 303 patients in a private referral center and 199 patients in a veterans' hospital. These probabilities were compared with those produced by applying a six-variable discriminant function derived by logistic regression at the private referral center. Two statistical approaches were employed in evaluating the relative performances of the Bayesian program and the discriminant function. The first of these involved the sorting of patients in both test groups into ascending deciles of probability and comparing expected probability with observed angiographic disease prevalence in each decile. The second involved the calculation and comparison of a standardized reliability measure. The latter was significantly lower for the discriminant function both at the private hospital (0.200 for the discriminant function versus -17.5 +/- 1.96 for the Bayesian program) and at the veterans' hospital (-0.8 +/- 1.96 for the discriminant function versus -11.3 for Bayesian program). This suggests that the discriminant function is significantly superior to the Bayesian algorithm CADENZA for predicting coronary artery disease probabilities in subjects who have relatively high pretest disease probabilities.

Methodologic problems in exercise testing research. Are we solving them?

To evaluate the comparative effects of methodologic factors on the reported accuracies of two standard exercise tests, 56 publications comparing the exercise thallium scintigram with the coronary angiogram were analyzed for conformation to five methodologic standards. Analyzed were adequate definition of study group, avoidance of a limited challenge group, avoidance of workup bias, and blinded analysis of the coronary angiogram and myocardial scintigram. Study group characteristics and technical factors were also reviewed. Better conformation with methodologic standards was found than has been reported previously for treadmill exercise testing. Furthermore, study group characteristics and technical factors were better predictors of sensitivity and specificity than were methodologic deficiencies. Only workup bias and test blinding were significantly associated with test accuracy. The percentage of patients with previous myocardial infarction had the highest correlation and was independently and directly related to sensitivity and inversely related to specificity.

Factors affecting sensitivity and specificity of a diagnostic test: the exercise thallium scintigram.

Technical and methodological factors might affect the reported accuracies of diagnostic tests. To assess their influence on the accuracy of exercise thallium scintigraphy, the medical literature (1977 to 1986) was non-selectively searched and meta-analysis was applied to the 56 publications thus retrieved. These were analyzed for year of publication, sex and mean age of patients, percentage of patients with angina pectoris, percentage of patients with prior myocardial infarction, percentage of patients taking beta-blocking medications, and for angiographic referral (workup) bias, blinding of tests, and technical factors. The percentage of patients with myocardial infarction had the highest correlation with sensitivity (0.45, p = 0.0007). Only the inclusion of subjects with prior infarction and the percentage of men in the study group were independently and significantly (p less than 0.05) related to test sensitivity. Both the presence of workup bias and publication year adversely affected specificity (p less than 0.05). Of these two factors, publication year had the strongest association by stepwise linear regression. This analysis suggests that the reported sensitivity of thallium scintigraphy is higher and the specificity lower than that expected in clinical practice because of the presence of workup bias and the inappropriate inclusion of post-infarct patients.

Reliability of Bayesian probability analysis for predicting coronary artery disease in a veterans hospital.

To assess the accuracy of Bayesian probability analysis for the prediction of coronary artery disease, post-test probabilities were generated by the application of three Bayesian algorithms to the clinical and noninvasive test results of 199 patients undergoing angiography in a veterans' hospital. All assumed conditional independence but each used different pre-test and conditional probabilities. Two statistical approaches were employed: (1) Sorting of patients in ascending deciles of probability and comparing expected and observed probabilities in each decile. (2) Calculation of normally distributed reliability statistics which do not depend on probability subsets and the comparison of resulting probability distributions using these statistics. Both statistical approaches revealed that the Bayesian algorithms overestimated disease probability when it was high and underestimated it when low. Though all three algorithms were frequently incorrect, they differed significantly in their accuracies, suggesting that errors in Bayesian analysis are caused by factors other than the assumption of independence. The errors may be due to differences in sensitivity and specificity of tests applied in different institutions.