Direct costs of transfusion reactions - an expert judgement approach.

BACKGROUND AND OBJECTIVES: Despite increasingly meticulous haemovigilance reporting throughout the world, a systematic assessment of the cost of transfusion reactions is still lacking. This is partly caused by the fact that such an assessment requires a subjective expert assessment of the additional costs linked to the adverse reaction. Data on the cost of transfusion reactions could support decision-making regarding blood transfusion safety measures. MATERIALS AND METHODS: Thirteen experts from nine hospitals were asked to estimate the additional care required following various types of transfusion reactions. Additional care was quantified as the proportion of reactions requiring care, and the amount of care required (e.g. hospitalization days, additional physician's time). Experts were also asked to provide, per type of transfusion reaction, an estimate of the proportion of transfusion reactions preventable. Structured quantitative expert elicitation methods were applied to obtain and combine expert estimates. RESULTS: The estimated annual in-hospital cost of transfusion reactions in the Netherlands is €933 356 per year (€1.52 per transfusion). Two-thirds (64%) of these are incurred by non-serious transfusion reactions. Circulatory overload, TRALI and anaphylaxis clearly dominate the costs of serious adverse transfusion reactions (66% in total); non-haemolytic transfusion reactions incur 46% of the cost of non-serious transfusion reactions. Additional safety measures targeting circulatory overload and new antibody formation potentially offer the highest cost reduction. CONCLUSION: In-hospital costs of transfusion reactions are substantial but contribute to less than 1% of the total cost of transfusion in the Netherlands. A considerable part of these costs (24%) might be preventable.

Impairment of the chondrogenic phase of endochondral ossification in vivo by inhibition of cyclooxygenase-2.

Many studies have reported on the effects of cyclooxygenase-2 (COX-2) inhibition on osteogenesis. However, far less is known about the effects of COX-2 inhibition on chondrogenic differentiation. Previous studies conducted by our group show that COX-2 inhibition influences in vitro chondrogenic differentiation. Importantly, this might have consequences on endochondral ossification processes occurring in vivo, such as bone fracture healing, growth plate development and ectopic generation of cartilage. The goal of our study was to investigate, in vivo, the effect of COX-2 inhibition by celecoxib on the cartilaginous phase of three different endochondral ossification scenarios. 10 mg/kg/day celecoxib or placebo were orally administered for 25 d to skeletally-immature New Zealand White rabbits (n = 6 per group). Endochondral ossification during fracture healing of a non-critical size defect in the ulna, femoral growth plate and ectopically-induced cartilaginous tissue were examined by radiography, micro-computed tomography (µ-CT), histology and gene expression analysis. Celecoxib treatment resulted in delayed bone fracture healing, alterations in growth plate development and progression of mineralisation. In addition, chondrogenic differentiation of ectopically-induced cartilaginous tissue was severely impaired by celecoxib. In conclusion, we found that celecoxib impaired the chondrogenic phase of endochondral ossification.

An assessment of differences in costs and health benefits of serology and NAT screening of donations for blood transfusion in different Western countries.

BACKGROUND AND OBJECTIVES: The cost-utility of safety interventions is becoming increasingly important as a driver of implementation decisions. The aim of this study was to compare the cost-utility of different blood screening strategies in various settings, and to analyse the extent and cause of differences in health economic results. MATERIALS AND METHODS: For eight Western countries (Australia, Canada, Denmark, Finland, France, The Netherlands, UK and the United States of America), data were collected on donor and recipient populations, blood products, screening tests, and on patient treatment practices and costs. An existing ISBT web-tool model was used to assess the cost-utility of various strategies for HIV, HCV and HBV screening. RESULTS: The cost-utility ratio of serology screening for these eight countries ranges between -11 000 and 92 000 US$ per QALY, and for NAT between -12 000 and 113 000 US$ per QALY when compared to no screening. Combined serology and NAT ranges between 600 and 217 000 US$ per QALY. The incremental cost-utility of NAT after implementation of serology screening ranges from 2 231 000 to 15 778 000 US$ per QALY. CONCLUSION: There are substantial differences in costs per QALY between countries for various HIV, HBV and HCV screening strategies. These differences are primarily caused by costs of screening tests and infection rates in the donor population. Within each country, similar cost per QALY results for serology and NAT compared to no screening, coupled with evidence of limited value of serology and NAT together prompts the need for further discussion on the acceptability of parallel testing by serology and NAT.

Development of a web-based application and multicountry analysis framework for assessing interdicted infections and cost-utility of screening donated blood for HIV, HCV and HBV.

BACKGROUND AND OBJECTIVES: Most countries test donations for HIV, HCV and HBV using serology with or without nucleic acid testing (NAT). Cost-utility analyses provide information on the relative value of different screening options. The aim of this project was to develop an open access risk assessment and cost-utility analysis web-tool for assessing HIV, HCV and HBV screening options (http://www.isbtweb.org/working-parties/transfusion-transmitted-infectious-diseases/). An analysis for six countries (Brazil, Ghana, the Netherlands, South Africa, Thailand and USA) was conducted. MATERIALS AND METHODS: Four strategies; (1) antibody assays (Abs) for HIV and HCV + HBsAg, (2) antibody assays that include antigens for HIV and HCV (Combo) + HBsAg, (3) NAT in minipools of variable size (MP NAT) and (4) individual donation (ID) NAT can be evaluated using the tool. Country-specific data on donors, donation testing results, recipient outcomes and costs are entered using the online interface. Results obtained include the number infections interdicted using each screening options, and the (incremental and average) cost-utility of the options. RESULTS: In each of the six countries evaluated, the use of antibody assays is cost effective or even cost saving. NAT has varying cost-utility depending on the setting, and where adopted, the incremental cost-utility exceeds any previously defined or proposed threshold in each country. CONCLUSION: The web-tool allows an assessment of infectious units interdicted and value for money of different testing strategies. Regardless of gross national income (GNI) per capita, countries appear willing to dedicate healthcare resources to blood supply safety in excess of that for other sectors of health care.

Insight into "Calculated Risk": An Application to the Prioritization of Emerging Infectious Diseases for Blood Transfusion Safety.

Increasing identification of transmissions of emerging infectious diseases (EIDs) by blood transfusion raised the question which of these EIDs poses the highest risk to blood safety. For a number of the EIDs that are perceived to be a threat to blood safety, evidence on actual disease or transmission characteristics is lacking, which might render measures against such EIDs disputable. On the other hand, the fact that we call them "emerging" implies almost by definition that we are uncertain about at least some of their characteristics. So what is the relative importance of various disease and transmission characteristics, and how are these influenced by the degree of uncertainty associated with their actual values? We identified the likelihood of transmission by blood transfusion, the presence of an asymptomatic phase of infection, prevalence of infection, and the disease impact as the main characteristics of the perceived risk of disease transmission by blood transfusion. A group of experts in the field of infectious diseases and blood transfusion ranked sets of (hypothetical) diseases with varying degrees of uncertainty associated with their disease characteristics, and used probabilistic inversion to obtain probability distributions for the weight of each of these risk characteristics. These distribution weights can be used to rank both existing and newly emerging infectious diseases with (partially) known characteristics. Analyses show that in case there is a lack of data concerning disease characteristics, it is the uncertainty concerning the asymptomatic phase and the disease impact that are the most important drivers of the perceived risk. On the other hand, if disease characteristics are well established, it is the prevalence of infection and the transmissibility of the disease by blood transfusion that will drive the perceived risk. The risk prioritization model derived provides an easy to obtain and rational expert assessment of the relative importance of an (emerging) infectious disease, requiring only a limited amount of information. Such a model might be used to justify a rational and proportional response to an emerging infectious disease, especially in situations where little or no specific information is available.

Modelling lifelong effects of different prophylactic treatment strategies for severe haemophilia A.

BACKGROUND: Lifelong prophylactic replacement therapy with clotting factor concentrates is recommended for severe haemophilia. The prophylactic dose determines both clinical outcome and treatment cost. In the absence of clinical studies, computer simulation was used to explore lifelong effects and clotting factor consumption for various prophylactic dose levels, and optimize strategies for switching between prophylactic and on-demand treatment. DESIGN AND METHODS: Individual patients' lifetime joint bleeds, radiological arthropathy (Pettersson score, 0-78) and consumption were simulated for each treatment strategy. Treatment effectiveness (expressed as % of patients maintaining a lifetime Pettersson score ≤14) and clotting factor consumption were modelled for lifelong prophylaxis at dose levels 1000-4500 IU kg(-1) year(-1) , for on-demand treatment and for switching strategies. Treatment efficiency (consumption per unit of effectiveness) was used to compare strategies. RESULTS: Compared to lifelong on-demand treatment, lifelong prophylaxis at 1000 IU kg(-1) year(-1) increased effectiveness from 21 to 36%, at an additional consumption of 0.9 × 10(6) IU kg(-1) . For lifelong prophylaxis, each additional 1000 IU kg(-1) year(-1) resulted in a proportional increase in consumption by ±5 × 10(6) IU kg(-1) but a less than proportional reduction in arthropathy by ±50%; consequently, increasing consumption progressively diminished treatment efficiency. Switching strategies slightly reduce effectiveness and consumption. Optimum switching criteria were similar across prophylactic dose levels. CONCLUSION: According to the simulation model, low-dose prophylaxis (1000 IU kg(-1) year(-1) ) improved outcome at a limited increase in consumption compared to on-demand treatment. Increasing prophylactic dose further improved health outcomes, but at decreasing efficiency. Optimal prophylactic dose should therefore be selected balancing acceptable health impact and available budget.

A novel approach to detect test-seeking behaviour in the blood donor population: making the invisible visible.

BACKGROUND AND OBJECTIVES: Individuals may donate blood in order to determine their infection status after exposure to an increased infection risk. Such test-seeking behaviour decreases transfusion safety. Instances of test seeking are difficult to substantiate as donors are unlikely to admit to such behaviour. However, manifestation in a population of repeat donors may be determined using statistical inference. MATERIALS AND METHODS: Test-seeking donors would be highly motivated to donate following infection risk, influencing the timing of their donation. Donation intervals within 2005-2014 of all Dutch blood donors who acquired syphilis (N = 50), HIV (N = 13), HTLV (N = 4) or HCV (N = 2) were compared to donation intervals of uninfected blood donors (N = 7 327 836) using the Anderson-Darling test. We adjusted for length bias as well as for age, gender and donation type of the infected. Additionally, the power of the proposed method was investigated by simulation. RESULTS: Among the Dutch donors who acquired infection, we found only a non-significant overrepresentation of short donation intervals (P = 0·54). However, we show by simulation that both relatively short and long donation intervals among infected donors can reveal test seeking. The power of the method is >90% if among 69 infected donors >35 (51%) are test seeking, or if among 320 infected donors >90 (30%) are test seeking. CONCLUSION: We show how statistical analysis may be used to reveal the extent of test seeking in repeat blood donor populations. In the Dutch setting, indications for test-seeking behaviour were not statistically significant. This may, however, be due to the low number of infected individuals.

Prediction of the anti-RhD donor population size for managerial decision-making.

BACKGROUND: Rhesus D (RhD)-negative women pregnant with a RhD-positive child receive prophylactic injections to prevent haemolytic disease of the newborn. Because of the success of the prophylaxis, the number of naturally immunized women has decreased, thereby also decreasing the number of potential donors who provide the plasma from which the prophylaxis is made. As the current donor pool is ageing, the availability of the prophylaxis is threatened. OBJECTIVES: Objectives are to investigate whether the anti-D population and the changes therein can be described by a relatively simple model, to determine the impact of ageing of the anti-D donors on the decline of the population and how many new donors should be recruited to meet future supply demand. METHODS: Data on Dutch anti-D donors in 1994-2013 were used to simulate the donor population size and age composition for various donor recruitment scenarios. RESULTS: With a continuous influx of 27 new donors per year and a donor stopping rate of 10% per year, the population size will stabilize at 195 donors, with 2·3% of donors stopping annually due to reaching the donor age limit. A formula is derived to estimate which donor recruitment and retention efforts are required to maintain a prespecified donor pool. CONCLUSION: A relatively simple model can already describe and predict the size of the anti-D donor population and the impact of ageing accurately.

Estimating the risk of dengue transmission from Dutch blood donors travelling to Suriname and the Dutch Caribbean.

BACKGROUND: The risk of dengue transmitted by travellers is known. Methods to estimate the transmission by transfusion (TT) risk from blood donors travelling to risk areas are available, for instance, the European Up-Front Risk Assessment Tool (EUFRAT). This study aimed to validate the estimated risk from travelling donors obtained from EUFRAT. METHODS: Surveillance data on notified dengue cases in Suriname and the Dutch Caribbean islands (Aruba, Curaçao, St. Maarten, Bonaire, St. Eustatius and Saba) in 2001-2011 was used to calculate local incidence rates. Information on travel and donation behaviour of Dutch donors was collected. With the EUFRAT model, the TT risks from Dutch travelling donors were calculated. Model estimates were compared with the number of infections in Dutch travellers found by laboratory tests in the Netherlands. RESULTS: The expected cumulative number of donors becoming infected during travels to Suriname and the Dutch Caribbean from 2001 to 2011 was estimated at 5 (95% CI, 2-11) and 86 (45-179), respectively. The infection risk inferred from the laboratory-based study was 19 (9-61) and 28 (14-92). Given the independence of the data sources, these estimates are remarkably close. The model estimated that 0·02 (0·001-0·06) and 0·40 (0·01-1·4) recipients would have been infected by these travelling donors. CONCLUSIONS: The EUFRAT model provided an estimate close to actual observed number of dengue infections. The dengue TT risk among Dutch travelling donors can be estimated using basic transmission, travel and donation information. The TT risk from Dutch donors travelling to Suriname and the Dutch Caribbean is small.

Quality indicators for the hospital transfusion chain: a national survey conducted in 100 dutch hospitals.

BACKGROUND: The 2011 Dutch Blood Transfusion Guideline for hospitals incorporates seven internal quality indicators for evaluation of the hospital transfusion chain. The indicators aim to measure guideline compliance as shown by the instatement of a hospital transfusion committee and transfusion safety officer (structural indicators), observance of transfusion triggers and mandatory traceability of labile blood components (process indicators). STUDY DESIGN AND METHODS: Two voluntary online surveys were sent to all Dutch hospitals for operational years 2011 and 2012 to assess compliance with the guideline recommendations. RESULTS: Most hospitals had a hospital transfusion committee and had appointed a transfusion safety officer (TSO). In 2012, only 23% of hospitals complied with the recommended minimum of four annual transfusion committee meetings and 8 h/week for the TSO. Compliance with the recommended pretransfusion haemoglobin threshold for RBC transfusion was achieved by 90% of hospitals in over 80% of transfusions; 58% of hospitals measured the pretransfusion platelet count in over 80% of platelet transfusions and 87% of hospitals complied with the legally mandatory traceability of blood components in over 95% of transfusions. CONCLUSION: With the current blood transfusion indicators, it is feasible to monitor aspects of the quality of the hospital transfusion chain and blood transfusion practice and to assess guideline compliance. The results from this study suggest that there are opportunities for significant improvement in blood transfusion practice in the Netherlands. These indicators could potentially be used for national and international benchmarking of blood transfusion practice.

Estimating unknown parameters in haemophilia using expert judgement elicitation.

The increasing attention to healthcare costs and treatment efficiency has led to an increasing demand for quantitative data concerning patient and treatment characteristics in haemophilia. However, most of these data are difficult to obtain. The aim of this study was to use expert judgement elicitation (EJE) to estimate currently unavailable key parameters for treatment models in severe haemophilia A. Using a formal expert elicitation procedure, 19 international experts provided information on (i) natural bleeding frequency according to age and onset of bleeding, (ii) treatment of bleeds, (iii) time needed to control bleeding after starting secondary prophylaxis, (iv) dose requirements for secondary prophylaxis according to onset of bleeding, and (v) life-expectancy. For each parameter experts provided their quantitative estimates (median, P10, P90), which were combined using a graphical method. In addition, information was obtained concerning key decision parameters of haemophilia treatment. There was most agreement between experts regarding bleeding frequencies for patients treated on demand with an average onset of joint bleeding (1.7 years): median 12 joint bleeds per year (95% confidence interval 0.9-36) for patients ≤ 18, and 11 (0.8-61) for adult patients. Less agreement was observed concerning estimated effective dose for secondary prophylaxis in adults: median 2000 IU every other day The majority (63%) of experts expected that a single minor joint bleed could cause irreversible damage, and would accept up to three minor joint bleeds or one trauma related joint bleed annually on prophylaxis. Expert judgement elicitation allowed structured capturing of quantitative expert estimates. It generated novel data to be used in computer modelling, clinical care, and trial design.

Validity of assessing inhibitor development in haemophilia PUPs using registry data: the EUHASS project.

Inhibitory antibodies to exogenous FVIII/FIX are a major complication of haemophilia treatment. Up to 30% of previously untreated patients (PUPs) with severe haemophilia A develop inhibitors, most likely during the initial 50 exposure days to concentrate. In addition to classical cohort studies, a European monitoring system (EUHASS) has been set up to evaluate inhibitor development in PUPs. The present study addresses the reliability of estimating the cumulative incidence of inhibitor development in this registry. Data from the retrospective CANAL cohort study, including 288 PUPs with severe haemophilia A and complete treatment records until the 50th exposure to FVIII, were used to simulate the consequences of several cross-sectional sampling techniques on the estimated incidence of inhibitors. Both mathematical calculus and computer modelling were applied to study the effects of sample size and the introduction of a new product. For existing concentrates, both longitudinal cohort study methods and the EUHASS method yielded similar estimates of the cumulative incidence of inhibitor cases over a 5-year time period: 27.9% (95% CI: 21-36) vs. 29.4% (22-38). For a newly introduced concentrate, a reliable estimate of inhibitor incidence with the EUHASS method could only be made after 3-4 years, even in large datasets. The results from EUHASS in inhibitor incidence in PUPs are expected to be valid. After introduction of a new concentrate, the inhibitor incidence on this concentrate can only be reliably determined after an observation period of several years.

Cost-effectiveness of targeted screening for hepatitis C in The Netherlands.

On account of the serious complications of hepatitis C virus (HCV) infection and the improved treatment possibilities, the need to improve HCV awareness and case-finding is increasingly recognized. To optimize a future national campaign with this objective, three pilot campaigns were executed in three regions in The Netherlands. One campaign was aimed at the general population, a second (similar) campaign was extended with a support programme for primary care and a third campaign was specifically aimed at hard-drug users. Data from the pilot campaigns were used to build a mathematical model to estimate the incremental cost-effectiveness ratio of the different campaigns. The campaign aimed at the general public without support for primary care did not improve case-finding and was therefore not cost-effective. The similar campaign accompanied by additional support for primary care and the campaign aimed at hard-drug users emerged as cost-effective interventions for identification of HCV carriers.

Inhibition of cyclooxygenase-2 impacts chondrocyte hypertrophic differentiation during endochondral ossification.

Skeletogenesis and bone fracture healing involve endochondral ossification, a process during which cartilaginous primordia are gradually replaced by bone tissue. In line with a role for cyclooxygenase-2 (COX-2) in the endochondral ossification process, non-steroidal anti-inflammatory drugs (NSAIDs) were reported to negatively affect bone fracture healing due to impaired osteogenesis. However, a role for COX-2 activity in the chondrogenic phase of endochondral ossification has not been addressed before. We show that COX-2 activity fulfils an important regulatory function in chondrocyte hypertrophic differentiation. Our data reveal essential cross-talk between COX-2 and bone morphogenic protein-2 (BMP-2) during chondrocyte hypertrophic differentiation. BMP-2 mediated chondrocyte hypertrophy is associated with increased COX-2 expression and pharmacological inhibition of COX-2 activity by NSAIDs (e.g., Celecoxib) decreases hypertrophic differentiation in various chondrogenic models in vitro and in vivo, while leaving early chondrogenic development unaltered. Our findings demonstrate that COX-2 activity is a novel factor partaking in chondrocyte hypertrophy in the context of endochondral ossification and these observations provide a novel etiological perspective on the adverse effects of NSAIDs on bone fracture healing and have important implications for the use of NSAIDs during endochondral skeletal development.

Survival after transfusion in the Netherlands.

BACKGROUND: Cost-effectiveness analyses of blood safety interventions require estimates of the life expectancy after blood product transfusion. These are best derived from survival after blood transfusion, per age group and blood component type. STUDY DESIGN AND METHODS: In the PROTON (PROfiles of TransfusiON recipients) study transfusion recipient data was collected from a hospital sample covering 28% of the total blood use between 1996 and 2006 in the Netherlands. The dataset includes date of transfusion, blood component type transfused and recipient identification details. PROTON data were individually matched to mortality data of the Netherlands. Survival after first transfusion and after any transfusion was calculated, per blood component type and age group. PROTON mortality rates were compared to mortality rates in the general population. The results were used to estimate survival beyond the study period and to estimate life expectancy after transfusion. RESULTS: Of all 2,405,012 blood product transfusions in the PROTON dataset, 92% was matched to the national Dutch Municipal Population Register, which registers all deaths. After 1 year, survival after any transfusion was 65·4%, 70·4% and 53·9% for RBC, FFP and PLT respectively. After 5 years, this was 46·6%, 58·8% and 39·3% for RBC, FFP and PLT, respectively. Ten years after transfusion, mortality rates of recipients are still elevated in comparison with the general population. CONCLUSION: Mortality rates of transfusion recipients are higher than those of the general population, but the increase diminishes over time. The mortality rates found for the Netherlands are lower than those found in comparable studies for other countries.

7-Tesla MRI Evaluation of the Knee, 25 Years after Cartilage Repair Surgery: The Influence of Intralesional Osteophytes on Biochemical Quality of Cartilage.

OBJECTIVE: To evaluate the morphological and biochemical quality of cartilage transplants and surrounding articular cartilage of patients 25 years after perichondrium transplantation (PT) and autologous chondrocyte transplantation (ACT) as measured by ultra-high-field 7-Tesla (7T) magnetic resonance imaging (MRI) and to present these findings next to clinical outcome. DESIGN: Seven PT patients and 5 ACT patients who underwent surgery on the femoral condyle between 1986 and 1996 were included. Patient-reported outcome measures (PROMs) were assessed by the clinical questionnaires: Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), and Visual Analogue Scale (VAS) for knee pain. The morphological (MOCART score) and biochemical quality (glycosaminoglycans [GAGs] content and collagen integrity) of cartilage transplants and surrounding articular cartilage were analyzed by 7T MRI. The results of the PT and ACT patients were compared. Finally, a detailed morphological analysis of the grafts alone was performed. RESULTS: No statistically significant difference was found for the PROMs and MOCART scores of PT and ACT patients. Evaluation of the graft alone showed poor repair tissue quality and high prevalence of intralesional osteophyte formation in both the PT and ACT patients. Penetration of the graft surface by the intralesional osteophyte was related to biochemically damaged opposing tibial cartilage; GAG content was significantly lower in patients with an osteophyte penetrating the graft surface. CONCLUSIONS: Both PT and ACT patients have a high incidence of intralesional osteophyte formation 25 years after surgery. The resulting biochemical damage to the opposing tibial cartilage might be dependent on osteophyte morphology.

The PROTON study: profiles of blood product transfusion recipients in the Netherlands.

BACKGROUND: Transfusion recipient data are needed for correct estimation of cost-effectiveness in terms of recipient outcomes after transfusion. Also, such data are essential for monitoring blood use, estimation of future blood use and benchmarking. STUDY DESIGN AND METHODS: A sample of 20 of 93 Dutch hospitals was selected. Datasets containing all blood product transfusions between 1996 and 2006 were extracted from hospital blood bank computer systems, containing transfusion date, blood product type and recipient characteristics such as gender, address, date of birth. The datasets were appended and matched to national hospitalization datasets including primary discharge diagnoses (ICD-9). Using these data, we estimated distributions of blood recipient characteristics in the Netherlands. RESULTS: The dataset contains information on 290,043 patients who received 2,405,012 blood products (1,720,075 RBC, 443,697 FFP, 241,240 PLT) from 1996 to 2006. This is 28% of total blood use in the Netherlands during this period. Comparable diagnosis and age distributions of all hospitalizations indicate included hospitals to be representative, per hospital category, for the Netherlands. Of all red blood cells (RBC), fresh-frozen plasma (FFP) and platelets (PLT), respectively 1.7%, 2.5% and 4.5% were transfused to neonates. Recipients of 65 years or older received 57.6% of RBC, 41.4% of FFP and 29.0% of PLT. Most of the blood products were transfused to patients with diseases of the circulary system (25.1%) or neoplasms (22.0%). CONCLUSION: Transfusion data from a limited sample of hospitals can be used to estimate national distributions of blood recipient characteristics.

Cost-effectiveness of additional hepatitis B virus nucleic acid testing of individual donations or minipools of six donations in the Netherlands.

BACKGROUND: To further reduce the risk of hepatitis B virus (HBV) transmission by blood transfusion, nucleic acid testing (NAT) can be employed. The aim of this study is to estimate the incremental cost-effectiveness ratio (ICER) in the Netherlands of employing a triplex NAT assay aimed at HBV nucleic acid detection in individual donations (ID-NAT) or in minipools of 6 donations (MP-6-NAT), compared to a triplex NAT assay in minipools of 24 donations (MP-24-NAT). STUDY DESIGN AND METHODS: A mathematical model was made of the whole transfusion chain from donors to recipients of blood in the Netherlands. The annual number of avoided HBV transmissions was estimated with the window-period incidence model. The natural history of a HBV infection in recipients is described by a Markov model. RESULTS: The ICER of adding HBV MP-6-NAT or HBV ID-NAT in the Netherlands is Euro303,218 (95% confidence interval [CI], Euro233,001-Euro408,388) and Euro518,995 (95% CI, Euro399,359-Euro699,120) per quality-adjusted life-year, respectively. The ICER strongly correlates with the age of transfusion recipients. CONCLUSION: The cost-effectiveness of additional HBV NAT is limited by the limited loss of life caused by HBV transmission. Despite a higher effectiveness, HBV ID-NAT is less cost-effective than MP-6-NAT due to higher costs. A future equivalent participation of immigrants from HBV-endemic countries in the donor base renders HBV NAT only slightly more cost-effective.

Monitoring viral incidence rates: tools for the implementation of European Union regulations.

BACKGROUND AND OBJECTIVES: European legislation requires manufacturers of plasma products to report epidemiological data on human immunodeficiency virus, hepatitis B virus and hepatitis C virus in donor populations. The incidence rates of such infections are directly related to the risk of infection transmission. We propose two statistical tests to evaluate these incidence rates. MATERIALS AND METHODS: Infection data of the four Dutch blood collection centres from 2003 through 2006 were analysed. For transversal comparison of centres and detection of increased incidence rates, a new statistical test was developed (outlier test). For longitudinal detection of trends in incidence rates, a generic test for trend is proposed. The power and risk of non-detection are evaluated for both tests. RESULTS: Application of the outlier test did not reveal any significantly increased incidence rates among centres in The Netherlands. The test for trend showed no significant increase in incidence rates in individual centres, but on national level a statistically significant increase in hepatitis C virus incidence was observed (P-value of 0.01). CONCLUSION: The proposed tests allow signalling of outlier centres and trends in incidence rates both at individual centre and at national levels. Graphical support and the use of as much relevant historical data as possible is recommended. The statistical tests described are generic and can be applied by any blood establishment and plasma fractionation institute.