Ascertainment bias in dementias: a secondary to tertiary centre analysis in Central Italy and conceptual review.

BACKGROUND AND AIMS: Ascertainment bias (AB) indicates a bias of an evaluation centre in estimating the prevalence/incidence of a disease due to the specific expertise of the centre. The aim of our study was to evaluate classification of different types of dementia in new cases appearing in secondary and tertiary centres, in order to evidence possible occurrence of AB in the various (secondary to tertiary) dementia centres. METHODS: To assess the mechanism of AB, the rates of new cases of the different forms of dementia reported by different centres were compared. The centres involved in the study were 11 hospital-based centres including a tertiary centre, located in the University Department of Clinical Neurology. The tertiary centre is endowed with state-of-the-art diagnostic facilities and its scientific production is prominently focused on dementia with Lewy bodies (DLB) thus suggesting the possible occurrence of a bias. Four main categories of dementia were identified: Alzheimer's disease (AD), DLB, fronto-temporal dementia (FTD), vascular dementia (VaD), with other forms in a category apart. The classification rate of new cases of dementia in the tertiary centre was compared with rates reported by secondary centres and rates of recoding were calculated during a follow-up of 2 years. RESULTS: The study classified 2,042 newly diagnosed cases of dementia in a population of 1,370,000 inhabitants of which 315,000 were older than 65. AD was categorized in 48-52 % of cases, DLB in 25-28 %, FTD in 2-4 % and VaD in 17-28 %. During the 2-year follow-up the diagnosis was re-classified in 40 patients (3 %). The rate of recoding was 5 % in the tertiary centre, 2-8 % in referrals from secondary to tertiary centre, 2-10 % in recodings performed in secondary centres and addressed to tertiary centre. Recoding or percentages of new cases of AD or DLB were not different in the comparison between secondary or between secondary and tertiary centres. FTD and VaD were instead significantly recoded. CONCLUSION: The results of the study suggest that in a homogeneous area, AB is not interfering with diagnosis of AD or DLB.

Hyperhomocysteinemia in preeclampsia is associated to higher risk pressure profiles.

Homocysteine levels have been determined with Chromatography on HPLC column, between the 20th and the 24th week of pregnancy, in women with analogous characteristics (a) normotensive, (b) with pregnancy-induced hypertension (PIH), low (LR), medium (MR), high risk (HR). The group they belonged to was confirmed after natural or caesarean delivery. All the patients were submitted to 24 hour blood pressure monitoring for the evaluation of further pressure risk parameters: mean arterial pressure (MAP), non dippers, percentages of pressure peaks. Homocysteine levels in normotensive pregnant women (5.8 +/- 1.7 microM) were low. Significant high levels of homocysteine were present proportionally to the risk degree of PIH. Higher levels of homocysteine statistically significant were present in non dippers of all groups (MR p < 0.05; HR p < 0.01). A direct correlation between plasmatic homocisteine levels and pressure profiles was found out in non dippers (r = 0.56, r = 0.55, r = 0.50 respectively) and in dippers (r = 0.7, r = 0.75, r = 0.60 respectively), and also between levels of homocysteine, MAP value, and pathological percentages of systolic and diastolic nocturnal peaks. In pregnant women presenting preeclampsia afterwards, high levels of homocysteine were not different from mean values present in high risk PIH pregnant women (13.3 +/- 1.9 vs. 16.4 +/- 1.7 microM). High levels of homocysteine early determined in the second trimester of PIH pregnancies seem to be associated to a pregnancy higher risk, coexisting with dangerous pressure profiles. High levels confirm a pregnant woman to belong to a higher or lower risk degree of vascular damage, but in the same group context high levels of homocisteine do not allow to identify those pregnant women who will develop eclampsia.

[Identification and evaluation of liver damage in subjects exposed to occupational risk from general anesthetics]. / Identificazione e valutazione del danno epatico in soggetti esposti a rischio occupazionale da anestetici generali.

BACKGROUND: The program Hepascore was produced by an interdisciplinary group working in the Laboratory of Clinical Informatics of the San Giovanni Battista Hospital in Turin with the aim of supporting physicians in the early diagnosis of hepatic damage and in its qualitative and quantitative characterization. The methodology used by this program can be useful especially for investigations concerning Industrial Medicine, which intend to control the occupational risk due to environmental exposure, not only to perform an early diagnosis (secondary prevention), but also to control the temporal evolution of the disease, by comparing significant data in a reproducible way. OBJECTIVE: This study was conducted with the aim of monitoring, by using the screening protocol of Hepascore, a group of workers exposed to an occupational risk by general anaesthetics, assessing the reliability of the proposed model and comparing it to the conventional approach in a cost/effectiveness analysis. METHODS: We evaluated 280 subjects (nurses and physicians) professionally exposed to anaesthetic gas; the environmental presence of anaesthetic agents was tested in all operating room of the hospital by the measurement of halogenated anaesthetics and nitrogen protoxide in the air. All the 280 subjects were submitted to a complete clinical evaluation and laboratory analyses, as recommended by monitoring protocols; in parallel, but independently from the clinical evaluation, also the sequential way used in the program Hepascore (a first screening phase evaluating only a few laboratory parameters, followed by a confirmation phase based on a larger number of blood tests with more restricted limits) was performed. The protocol applied in this study foresaw that subjects in which clinical evaluation and/or Hepascore brought to suspect a 'likely' liver alteration, had to be investigated thoroughly and to be reevaluated after 6 months by clinical examination and by Hepascore. RESULTS: The environmental determinations did never demonstrate the presence of anaesthetics over the threshold value (50 ppm for the N2O and 2 ppm for halogenated anaesthetics). The conventional clinical evaluation recognized as pathological 22 subjects with one or more liver parameters altered, which were explained as mild cytolytic or cholestatic alterations. The screening protocol carried out by Hepascore in the preliminary phase evidenced as pathological 38 subjects on 280 and 22 of them (corresponding to the 22 subjects identified by the clinical evaluation) were confirmed in the following phase (disease likely). CONCLUSIONS: This fact confirms that the sequential approach used by Hepascore provides the same outcomes obtained by performing all tests in the entire population under study, allowing a saving of 57% of the total cost spent for the traditional evaluation. The sequential approach proposed by Hepascore could be employed in all the clinical settings in which an evaluation of liver functional state is required, both in presence of environmental risk factors and in the case of a programme for the optimization of the population's food habits.

An electronic medical diary for computer assisted patient management.

The Electronic Medical Diary (EMD) is a tool for supporting the daily registration and storage of clinical events related to a specific patient. The collection of all patient-specific clinical data forms the patient database (PDB) which can be defined as a computer-based record able to replace the traditional paper record. The PDB is organized according to the clinical database (CDB), which is a structured terminology of most important clinical data, and may be connected with the many online tools (OLT) which can improve the flow of information within the hospital information system (HIS). In this paper we present the preliminary results of a project aimed at creating an EMD designed in accordance with the methodological model based on the problem-oriented approach. This EMD is patient-centered and each action it enables is related to at least one of the identified problems and one of the current diagnostic hypotheses. The permanent link of the EMD with the CDB is one of the most important features of the prototype here described. It allows the standardization of patients' data, their sharing among all operators involved, and a better organization of the patient management process.

Emerging risk factors and assessment of organ damage in postmenopausal hypertensive women.

The numerous risk factors for acute cerebrocardiovascular events present in postmenopausal women have attracted a multidisciplinary approach. In hypertensive patients and postmenopausal intensive alike, the need for stratification of risk based on blood pressure, association of other risk factors and organ damage is becoming more and more evident. This study investigated some emerging factors, such as endothelial dysfunction, adhesion molecules and elevated homocysteine levels that may be markers of organ damage. It also examined the current importance of carotid US intima-media thickness assessment, cardiac US imaging and 24 hour ambulatory blood pressure monitoring (ABPM) in detecting organ damage. The study results indicated that the conventional stratification of cerebrocardiovascular risk in these patients is changing. The new approach in postmenopausal hypertensives tends to assess the presence of other emerging factors. Furthermore, assessment of organ damage is crucial for determining disease development and outcome that may be positively influenced by suitable pharmacological treatment.

Clinical database. Structure, development strategies and expected clinical applications.

The paper provides the description of a data-base developed to include in a quite structured format most clinical data used for patient management in a hospital setting. The system was aimed at achieving a reasonable compromise between the significant but complex solutions the research offers and the real needs of medical practice. First of all, the paper defines the requirements for designing a computerized clinical database according to a patient-centered clinical approach. Then, it describes the structure of a prototype aimed at classifying clinical data as a hierachy and describing them according to a structural approach. Next, problems related to the management and upgrading of the system are identified and possible solutions described, with a particular emphasis or knowledge acquisition, refinement and specialization, and on problems related to the functional aspects required for clinical applications. Finally, some meaningful clinical applications are outlined, which use the computerized clinical database as the standard for knowledge organization and data sharing.

[Pathophysiological and therapeutic implications of nitric oxide in hepatology]. / Implicazioni fisiopatologiche e terapeutiche del monossido di azoto in epatologia.

The L-arginine/nitric oxide (NO) pathway has been recognized as a main regulator of several cell functions. Accordingly, there is an increasing number of pathophysiological conditions in which a precise knowledge of NO status could prove helpful in understanding the mechanisms involved in disease development, prevention and treatment. These include several hepatic disorders, such as liver cirrhosis and associated hyperdynamic circulation with portal hypertension, ischaemia-reperfusion injury occurring during liver transplantation, and chronic cholestatic conditions. Overall, NO seems to exert a dual role in the pathobiology of liver diseases: one mostly beneficial, due to its vasoactive effects; and one mostly negative, due to its local toxic effects. Protective actions are primarily mediated via vasodilation, antithrombosis, inhibition of neutrophil adhesion and inhibition of apoptosis. Deleterious effects are dependent upon the formation of highly reactive substances during oxidative stress. In this review aspects related to NO implications in the homeostasis of liver functions as well as in the pathogenesis of some relevant hepatic clinical syndromes will be discussed in view of possible therapeutic options.

Hyperhomocysteinemia in menopausal hypertension: an added risk factor and a dangerous association for organ damage.

Hyperhomocysteinemia is widely recognised as an emerging risk factor of endothelial dysfunction and vascular damage. In this study we wanted to verify if it, when associated to arterial hypertension--traditional risk factor--represents a higher added risk of organ damage during menopause, which is a condition connected to a higher incidence of cerebrovascular diseases. A survey of 30 postmenopausal women with similar characteristics (BMI, age, absence of relevant pathologies such as diabetes, metabolic disorders and absence of smoking) was selected (menopause had occurred from 12 to 16 months at the moment of observation). At the moment of the observation they had not gone through any continuous pharmacological therapy. They were subdivided into 3 groups: normotensive; hypertensive (with 2nd degree hypertension: mild to moderate) without organ damage; hypertensive with organ damage (TIA, ischaemic heart disease, etc.). The carotid IMT, measured with ultrasound method, was considered as an organ damage parameter. 43% of the patients had high levels of homocysteine (> 15 micromol/l), which are levels considered at risk in other surveys. The highest levels of homocysteine were recorded in hypertensive women with episodes of acute cerebrovascular damage (micromol/l = 24.3 +/- 8.9). In this group, a positive correlation (r = 0.7) was obtained between homocysteine levels and carotid IMT. The possible coexistence of hyperhomocysteinemia and arterial hypertension, even though without particularly high values for both of them, in menopause may represent a dangerous association responsible for a significant organ damage and, therefore, for acute cerebrovascular events.

A modular approach for representing and executing clinical guidelines.

In this paper, we propose an approach for managing clinical guidelines. We outline a modular architecture, allowing us to separate two conceptually distinct aspects: the representation (and acquisition) of clinical guidelines and their execution. We propose an expressive formalism, which allows one to deal with the context-dependent character of clinical guidelines and also takes into account different temporal aspects. We also describe our tool for acquiring clinical guidelines, which provides a user-friendly interface to physicians, and automatically detects many forms of syntactic and semantic inconsistencies in the guidelines being acquired. In the second part of the paper, we describe a flexible engine for executing clinical guidelines (e.g. for clinical decision support applications, for medical education, or for integrating guidelines into the clinical practice), focusing our attention on temporal issues.

Time-dependent modifications of splanchnic circulation in female pigs submitted to end-to-side portacaval anastomosis.

Fractional systemic bioavailability of orally administered drugs was found to be unexpectedly low in liver cirrhosis, even after surgical portal-systemic shunting. Fecal loss or intestinal first-pass elimination were assumed to explain the finding. In this paper we evaluated alternative pathophysiological interpretations relating low bioavailability to adaptive circulatory modifications. D-Sorbitol was used because its hepatic extraction is very high and hepatic removal follows a flow-dependent clearance regimen. D-Sorbitol bioavailability was measured at steady state in pigs submitted to end-to-side portacaval anastomosis, immediately after surgery and four weeks later. Intestinal first-pass elimination dependent on fecal loss and intraluminal degradation was excluded by administering D-sorbitol into the superior mesenteric artery. Almost complete bioavailability was observed immediately after surgery (N = 6, 0.96+/-0.08); four weeks later the bioavailability dropped (-36.8+/-18.7%; P < 0.001) while hepatic clearance significantly increased (+83.6+/-47.9%; P < 0.01). Experimental data support the hypothesis that adaptive circulatory changes spontaneously occur after some time, leading to a lower than expected portal bioavailability.

Evidence of an increased nitric oxide production in primary biliary cirrhosis.

OBJECTIVE: Although possible implications of nitric oxide in the pathophysiology of liver cirrhosis have been extensively studied, until now few articles have addressed the assessment of nitric oxide production in primary biliary cirrhosis. This study was directed to evaluate circulating nitrosyl-hemoglobin levels as well as neutrophil elastase and soluble adhesion molecule concentrations in this condition, by assuming these parameters as possible markers of either inflammatory response or neutrophil activation. METHODS: Laboratory investigations were performed in 30 patients with primary biliary cirrhosis, in 13 patients with postviral and/or alcoholic cirrhosis, and in a group of eight subjects with chronic hepatitis. RESULTS: Although no difference was detected with respect to chronic hepatitis subjects, higher levels of nitrosyl-hemoglobin adducts were found in primary biliary cirrhosis patients than in postviral or alcoholic cirrhotics and in normal subjects (3.55+/-1.75 arbitrary units vs 1.95+/-0.57 and 0.84+/-0.34, p = 0.0004 and p < 0.0001, respectively). Similarly, more elevated concentrations of neutrophil elastase (213.7+/-192.0 microg/L vs 51.1+/-34.3 and 38.0+/-11.5, p < 0.0001 and p < 0.0001, respectively) as well as of soluble forms of intercellular adhesion molecule 1 and endothelial-leukocyte adhesion molecule 1 were shown in primary biliary cirrhosis patients than in subjects with cirrhosis of other etiologies and in controls. CONCLUSIONS: Highly enhanced nitric oxide production in primary biliary cirrhosis could be related to the development of strong inflammation and at least partially to neutrophil activation, thus suggesting a putative role of these cellular mediators in the development of liver damage owing to their ability to synthesize and release a wide variety of important factors, including elastase and nitric oxide.

Executing clinical guidelines: temporal issues.

In our previous work, we proposed a domain-independent language to describe clinical guidelines and a graphical tool to acquire them. In this paper, we describe an approach to execute clinical guidelines. We propose a flexible execution engine that can be used in clinical decision support applications, and also for medical education, or for integrating guidelines into the clinical workflow. We also focus our attention on temporal issues in the execution of guidelines, including the treatment of composite, concurrent and/or cyclic actions.

Primary leiomyosarcoma of the diaphragm in a 23-year-old male: a case report.

Primary neoplasms of the diaphragm are extremely rare and their diagnosis is often difficult. We present a case of leiomyosarcoma of the diaphragm in a 23-year-old male presenting with aspecific abdominal discomfort. The final diagnosis was achieved on the basis of histopathological findings after surgery. The role of different imaging techniques as diagnostic tools is also discussed.

Objective assessment of the contribution of each diagnostic test and of the ordering sequence in jaundice caused by pancreatobiliary carcinoma.

BACKGROUND: Computer-assisted diagnostic systems are not substantially more accurate than the clinician in the differential diagnosis of jaundice but may help in optimal selection and sequencing of tests. The present study aimed to assess with an electronic diagnostic tool the pattern of ordering tests and the diagnostic contribution and related financial cost of each test in jaundiced patients with pancreatobiliary carcinoma, in an effort to make the clinician's diagnostic behaviour more efficient and economical. METHODS: Clinical and diagnostic test data were prospectively gathered from 356 jaundiced patients with pancreatobiliary carcinoma and entered in a Bayesian diagnostic programme. The test results were added to the existing diagnostic evidence, and the programme calculated the diagnostic contribution of each test. RESULTS: A total of 1804 diagnostic tests were ordered. Quantitative assessment of the diagnostic contribution of each test showed that percutaneous transhepatic cholangiography and computed tomography were associated with the highest provision of information. The most cost-effective tests were ultrasonography and liver function tests. CONCLUSIONS: It is possible to determine objectively the diagnostic contribution of each test in establishing the diagnosis of pancreatobiliary carcinoma. The observed physician behaviour in ordering the various diagnostic tests might be improved with regard to its efficacy and its cost-effectiveness profile.

Validation of ICTERUS, a knowledge-based expert system for Jaundice diagnosis.

The study aimed to describe an example of the assessment and validation of knowledge-based clinical expert systems. The paper focuses on ICTERUS, an expert system for jaundice diagnosis. It describes system design, the methodology applied for upgrading and validating the program, and the most important outcomes of the validation procedure. The clinical validation of the system on a very large European database (Euricterus Project) shows that diagnostic conclusions are reliable in about 70% of eligible cases. This figure appears acceptable for a system which provides decision support only on the basis of clinical data, assuming that the final decision is achieved under user responsibility. Expected biases, limitations and inconsistencies in the practical application of the system are discussed.

Hepatic arterial infusion chemotherapy for unresectable confined liver metastases: prediction of systemic toxicity with the application of a scintigraphic and pharmacokinetic approach.

PURPOSE: The incorrect positioning of the arterial Port-a-Cath or the presence of anatomic or functional hepatic arteriovenous shunting may explain the occurrence of systemic toxicity of hepatic arterial infusion of floxuridine in patients with liver metastases. The aim of our study was to predict the occurrence of systemic toxic effects from this treatment using a scintigraphic and pharmacokinetic approach. METHODS: A group of 26 patients were studied. Before treatment, Tc-99m-labelled macroaggregated albumin arterial perfusion scintigraphy was performed to verify the correct positioning of the catheter, to evaluate the percentage of pulmonary uptake of the tracer, reflecting intrahepatic arteriovenous anatomic shunting, and to qualitatively assess the perfusion pattern of the metastases with respect to the normal liver parenchyma (SPECT images). Hepatic arteriovenous functional shunting was assessed through the bioavailability of intraarterially administered D-sorbitol. Treatment was then started and systemic toxic effects were evaluated according to WHO recommendations. RESULTS: No correlation was found between anatomic shunting (

[HEPASCORE: a decision-support system for the identification, clinical staging and functional assessment of hepatopathies]. / HEPASCORE: un sistema di supporto alla decisione per l'identificazione, la stadiazione clinica e la valutazione funzionale delle epatopatie.

A decision support system (HEPASCORE) has been developed to optimize the application of objective criteria for qualitative and quantitative assessment of liver function; clinical and laboratory data are automatically processed, and conclusions are explained. Early recognition of abnormal liver states is performed according to a sequential approach, based at first on clinical rules utilizing data from history and physical examination, then confirming or denying the hypothesis by means of selected laboratory tests. Once an abnormal condition is defined, clinical severity can be evaluated by use of suitable scores, either prognostic or focused on major clinical complications. In addition, selected sets of biochemical tests can be used to score one or more functional aspects. Lastly, whenever quantitative estimates of residual liver function are requested, dynamic tests can be applied to measure meaningful parameters such as functioning liver mass and functional hepatic plasma flow. HEPASCORE has been successfully applied to exclude liver abnormalities in subjects at risk, to follow up liver patients, to predict the natural outcomes of severe liver diseases, to foresee the adverse effects of drugs undergoing first-pass liver extraction and the side effects of invasive procedures. While the proposals contained in the system could be further modified for specific needs, they reflect a satisfactory methodological approach, and the program serves as a useful support to decisions regarding the identification and functional evaluation of hepatopathies. The system was developed with Microsoft Access 7.0 and runs on a personal computer under Windows 95.

A systems approach in hepatology.

Systems analysis has been applied to hepatology with the aim of providing a reasonable organisation of domain knowledge and supporting the improvement of clinical performance. To this extent liver structures and functions have been classified and defined, clinical parameters have been carefully selected and suitably associated to describe individual liver functions, and methodological criteria for clinical evaluation have been assessed. Three major outcomes of such an approach, respectively concerning the development of a shareable clinical database, the application of a suitable methodology for clinical reasoning, and the computer-based support to medical decision-making, have been discussed.