[Screening and early detection in blood transfusion: when are they indicated?]

Survey of European programmes for the epidemiological surveillance of congenital toxoplasmosis

The objective of this investigation was to describe systems for the epidemiological surveillance of congenital toxoplasmosis implemented in European countries. In September 2004, a questionnaire, adapted from the evaluation criteria published by the United States Centers for Disease Control and Prevention, was sent to a panel of national correspondents in 35 countries in the European geographical area with knowledge of the epidemiological surveillance systems implemented in their countries. Where necessary, we updated the information until July 2007. Responses were received from 28 countries. Some 16 countries reported routine surveillance for toxoplasmosis. In 12 countries (Bulgaria, Cyprus, Czech Republic, England and Wales, Estonia, Ireland, Latvia, Lithuania, Malta, Poland, Scotland and Slovakia), surveillance was designed to detect only symptomatic toxoplasmosis, whether congenital or not. Four countries reported surveillance of congenital toxoplasmosis, on a regional basis in Italy and on a national basis in Denmark, France and Germany. In conclusion, epidemiological surveillance of congenital toxoplasmosis needs to be improved in order to determine the true burden of disease and to assess the effectiveness of and the need for existing prevention programmes.

Systematic screening for unsafe driving due to medical conditions: still debatable

Background

Assessing people's ability to drive has become a public health concern in most industrialized countries. Although age itself is not a predictive factor of an increased risk for dangerous driving, the prevalence of medical conditions that may impair driving increases with age. Because the implementation of a screening for unsafe driving due to medical conditions is a public health issue, its usefulness should be judged using standardised criteria already proposed for screening for chronic disease. The aim of this paper is to propose standardised criteria suitable to assess the scientific validity of screening for unsafe driving due to medical conditions, and identify potential issues to be clarified before screening can be implemented and effective.

Discussion

Using criteria developed for screening for chronic diseases and published studies on driving with medical conditions, we specify six criteria to judge the opportunity of screening for unsafe driving due to medical conditions. This adaptation was needed because of the complexity of the natural history of medical conditions and their potential consequences on driving and road safety. We then illustrate that published studies pleading for or against screening for unsafe driving due to medical conditions fail to provide the needed documentation. Individual criteria were mentioned in 3 to 72% of 36 papers pleading for or against screening. Quantitative estimates of relevant indicators were provided in at most 42% of papers, and some data, such as the definition of an appropriate unsafe driving period were never provided.

Summary

The standardised framework described in this paper provides a template for assessing the effectiveness (or lack of effectiveness) of proposed measures for screening for unsafe driving due to medical conditions. Even if most criteria were mentioned in the published literature pleading for or against such a screening, the failure to find quantitative and evidence-based estimates of relevant indicators provides useful insight for further research.

Dépistage prénatal du cytomégalovirus en France : une augmentation des pratiques de prescription de 2000 à 2003 malgré l’absence de recommandation favorable

BACKGROUND

Screening cytomegalovirus infection in pregnant women is still controversial in 2004 in France. In this context, we evaluated the interest of such a screening in 2004 in France. This paper was designed to describe trends in CMV prenatal screening practices in 2000-2003 in France.

METHODS

This retrospective study, describes the prescription of CMV screening in HIV-negative pregnant women giving birth in the private care sector, according to their occupational category and geographical area. Data were provided by the "Caisse d'Assurance-maladie des Travailleurs Indépendants" (independent workers health insurance fund).

RESULTS

The study included 34.347 women, delivering in 2001-2004 (beginning of pregnancy in 2000-2003). The number of pregnant women screened for CMV increased significantly between 2000 (5.8%, 301/5.177), 2001 (11.1%, 1.130/10.139) and 2002 (22.1%, 2.701/12.223), (p<0.001), then was stable in 2003 (22.0%, 1.496/6.808). The percentage of women screened for CMV, at least once during pregnancy, doubled between 2001 and 2002 (p<0.001) in each occupational category and geographical area. It was significantly different between occupational categories (p<0.01), with a higher percentage of women in the self-employed and commercial agent occupational categories than in the craftsman category. There was also a significant difference between geographical areas (p<0.001), with a higher rate in Paris.

CONCLUSION

This study providing baseline information on CMV practices showed: 1- a significant increase in the frequency of CMV screening among pregnant women over the period 2000-2002 with a stabilization in 2003; 2- a similar trend observed in each occupation category and geographical area but with a markedly higher frequency of screening practices in the Paris area and among self-employed women. A study measuring the effect of the 2004 ANAES recommendation suggesting not to screen for CMV during pregnancy should be conducted.

Cost-effectiveness of testing for human immunodeficiency virus and hepatitis C virus among blood transfusion recipients

OBJECTIVE

To choose the most cost-effective option for detecting human immunodeficiency virus (HIV-1) and hepatitis C virus (HCV) among blood transfusion recipients.

DESIGN

Cost-effectiveness analysis. Effectiveness was expressed as the number of HIV-1 or HCV infections detected, regardless of whether they were related to transfusion. To estimate costs, we assumed hospital insurance would cover costs related to detection and compensation, when granted.

SETTING

A 2,890-bed acute care teaching hospital in Bordeaux, France.

METHODS

Eight options were defined, from the simplest, which would be to do nothing, to a maximal approach, which would be to keep a serum sample in a serum library for a lookback and perform tests for antibody to HIV-1 and to HCV before and 3 months after transfusion. Data on probabilities and costs were taken from the literature and experiences of French hospitals.

RESULTS

The most cost-effective option was to perform viral antibody testing before transfusions (option 3), which would detect 27 infections per 1,000 patients, for an expenditure of US $1,260 per detected patient Option 6, obtaining a serum sample before transfusion and performing tests for antibody to HIV-1 and to HCV 3 months after transfusion, had a similar cost-effectiveness ratio but detected only 16 infections per 1,000 patients. Performing tests before and 3 months after transfusion (option 4), compared with option 3, would detect 1 additional infection for an additional cost of US $8,322.

CONCLUSION

The most cost-effective options are not specific to blood transfusion recipients and might be more suited to all hospitalized patients.

Cost-Effectiveness of Testing for Human Immunodeficiency Virus And Hepatitis C Virus Among Blood Transfusion Recipients

Objective:

To choose the most cost-effective option for detecting human immunodeficiency virus (HIV-1) and hepatitis C virus (HCV) among blood transfusion recipients.

Design:

Cost-effectiveness analysis. Effectiveness was expressed as the number of HIV-1 or HCV infections detected, regardless of whether they were related to transfusion. To estimate costs, we assumed hospital insurance would cover costs related to detection and compensation, when granted.

Setting:

A 2,890-bed acute care teaching hospital in Bordeaux, France.

Methods:

Eight options were defined, from the simplest, which would be to do nothing, to a maximal approach, which would be to keep a serum sample in a serum library for a lookback and perform tests for antibody to HIV-1 and to HCV before and 3 months after transfusion. Data on probabilities and costs were taken from the literature and experiences of French hospitals.

Results:

The most cost-effective option was to perform viral antibody testing before transfusions (option 3), which would detect 27 infections per 1,000 patients, for an expenditure of US $1,260 per detected patient Option 6, obtaining a serum sample before transfusion and performing tests for antibody to HIV-1 and to HCV 3 months after transfusion, had a similar cost-effectiveness ratio but detected only 16 infections per 1,000 patients. Performing tests before and 3 months after transfusion (option 4), compared with option 3, would detect 1 additional infection for an additional cost of US $8,322.

Conclusion:

The most cost-effective options are not specific to blood transfusion recipients and might be more suited to all hospitalized patients.

[Economic analysis versus the principle of guaranteed safety in blood transfusion]

This article shows that policies aimed at reducing risks of infectious agents transmissible through blood unfortunately follow a law of 'diminishing returns': increasing marginal costs have to be devoted for limited reductions in the risks of contamination through blood donations. Therefore, the economic cost-effectiveness analysis is appropriate to identify screening strategies which may minimize costs to reach a certain level of safety. Moreover, economic analysis can contribute to public debates about the level of residual risk that society is willing to accept. Empirical results from French studies about screening for hepatitis C virus (HCV) in individuals who have received blood transfusions and in blood donations are presented to illustrate these points.

[Cost-benefit analysis of screening strategies by human immunodeficiency virus in French blood donors]

BACKGROUND

The residual risk of human immunodeficiency virus (HIV) infection from screened blood transfusion was estimated to be 1.7/10(6) between 1993 and 1995 in France. To orient blood safety policies, we have evaluated what would be, from the perspective of blood banks, the best screening strategy in terms of gain in effectiveness and added costs.

METHODS

A cost-effectiveness analysis compared 20 HIV-testing protocols using (1) available data for performances of the current screening tests; and, (2) national insurance estimates for the cost of tests. Results were expressed as the number of false negative donations that would be avoided and the cost by avoided false negative donation.

RESULTS

For 3 million donated blood units a year and a prevalence of 24 per million, there would be 72 infectious donated blood units, 70.56 of which would be detected by the current screening strategy. The number of additional donated blood infections avoided in all other strategies would be low (between 0.25 and 1.28) with a very high cost (280 million French francs per added false negative avoided or more).

CONCLUSION

A change in screening strategies for blood donations in France is not currently justified. If such a change was to be done, adding p24 antigen detection to the current screening strategy would be one of the worst solutions.

[Feasibility of following up transfused patients]

The aim of this study was to assess the natural history of patients after transfusion and the acceptability of a standardized biological follow-up. In 1995, during 1 month, in 13 French hospitals, a follow-up at 3 and 6 months after blood transfusion was proposed to all blood recipients who had not received any blood transfusion within the past 6 months (eligible patients): screening for red cell antibodies, alanine aminotransferase (ALT) activity and specific viral markers of hepatitis B (hepatitis B surface antigen and antibody to hepatitis virus core antigen), of hepatitis C (antibodies) and of Human Immunodeficiency Virus (antibodies). At the beginning of the study, 296 patients were followed for 6 months. A complete follow-up was available at 3 months for 183 patients (62%), at 6 months for 168 (57%) and after 6 months, 198 patients (67%) have been once followed. Of eligible patients, 76% were alive at six months. After transfusion, the incidence of red cell alloantibodies and elevated ALT concentration were respectively 4% and 17%. At 6 months, one patient had Hepatitis B surface antigen; the responsibility of blood transfusion was excluded. Within the first 24 hours, 68 patients (23%) required another blood transfusion and 42% of units were transfused to patients with malignant disease. Our study quantifies in real conditions the difficulty of a biological follow-up in a transfused population, mostly composed of patients that could not be followed in the hospital where they were transfused.

[Infection risk and efficacy of clinical selection techniques for volunteer blood donors]

One of the objectives of predonation selection is to exclude blood donors with possible infection. Our aim was to evaluate the efficacy of the different blood donor selection techniques. The approach chosen for this review of literature was the best evidence synthesis. A bibliographic search was carried out to identify all articles on the subject published between 1986 and 1996 which presented quantitative results of evaluation. Only nine relevant studies were selected. These referred to self exclusion before interview, health history interview and confidential deferral after donation. None of the articles evaluated the physical examination. The results suggested an efficacy for self exclusion before interview. One study considered the blood donor selection and compared various ways of combining self exclusion before interview, health history interview and confidential deferral after donation. No combination emerged as more effective than the others. This analysis shows that the efficacy of predonation blood donor selection applied to transfusion transmitted infections has not been evaluated adequately. The different techniques of blood donor selection must be considered as public health actions and hence evaluated according to a rigorous methodology using valid criteria.