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.

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.

Hepatitis C virus infection from blood and blood products.

The addition of second-generation HCV epitopes in antibody detection assays has increased the sensitivity and specificity of blood donor testing, to prevent post-transfusion hepatitis non-A, non-B (PTH-NANB), later characterized as Hepatitis C. However, it is not clear whether all HCV infectious donors are detected by second-generation anti-HCV testing. Prospective studies on PTH-NANB were left with some unresolved cases. The use of second-generation anti-HCV assays in blood banks presented a problem with a relatively large number of indeterminate reactivities in supplemental assay such as RIBA-2. These indeterminate reactivities may be solved by the use of polymerase chain reaction (PCR). PCR is more and more used as an extra confirmatory assay to resolve RIBA indeterminate results on blood donors. However, a European study on the proficiency of HCV PCR in different countries revealed that only a minority of the reference laboratories perform this test faultless. Lately, third-generation RIBA was developed, which was originally designed to resolve RIBA-2 indeterminate cases. RIBA-3 was shown to be more sensitive and specific in early HCV infection and blood donors than RIBA-2. Third-generation anti-HCV testing will become standard practice. Some questions, however, remain unanswered. Do we miss any rare HCV infectious donors, of other genotypes, with third-generation assays, based only on the type 1 sequence of HCV? Can we improve HCV detection in the early phase of infection? What is the role of sporadic HCV transmission? How can we standardize HCV nucleic acid detection methods?

HCV and blood transfusion.

Posttransfusion hepatitis remains a threat to transfusion therapy. Testing for increased ALT levels has been used in an attempt to reduce this risk. Presence of the infectious agent, hepatitis C virus (HCV), appears to be a much more sensitive criterion. Stored serum samples from transfusion blood as well as recipients of transfusion were tested by ELISA, RIBA and PCR for the presence of HCV. The results show that RIBA and PCR are about equally sensitive and are able to detect HCV positivity in many sera that might have been otherwise transfused. Routine screening for the presence of virus will dramatically reduce the danger of hepatitis infection to transfusion patients.

[Infection with T-lymphotropic virus in Dutch blood donors, 1993-1996]. / Infectie met humaan T-lymfotroop virus bij Nederlandse bloeddonoren, 1993-1996.

Infection with human T-lymphotrophic virus (HTLV) type 1 causes a neurological disorder or leukaemia in a minority of infected persons. Since January 1993 the Dutch blood banks screen each donation for presence of HTLV-1 infection. Approximately 4,000,000 donations from 700,000 donors have been tested. The numbers of confirmed HTLV-1 positive donors were: 1993: 15; 1994: 6; 1995: 8; 1996: 3. In 1995 one case of HTLV-2 infection was detected as well. In 26/32 (81%) of the HTLV-1 positive cases either the donor or his/her partner originated from HTLV-1 endemic areas. The introduction of HTLV screening prevents the silent spread of HTLV via blood transfusion.

[Leukodepletion of blood products: a requirement for improvement of quality and safety]. / Leukodepletie van bloedproducten: een maatregel ten behoeve van kwaliteit en veiligheid.

The presence of leukocytes in blood products has no beneficial effect on the recipient, except in special situations such as for patients being prepared to receive an organ transplantation. On the other hand the leukocytes have a number of untoward side effects such as HLA immunisation, non haemolytic febrile transfusion reactions, virus transmission and postoperative infections. In response to a request of the Minister of Health, Welfare and Sports, the Health Council of the Netherlands prepared a recommendation on the need of routine leukodepletion by filtration of blood. Although the introduction of leukodepletion of blood products is favoured, it is emphasized that only data from selected patient groups are available while the costs of leukodepletion are considerable. Therefore, an evaluation of the benefits and cost effectiveness of blood filtration is recommended. It is argued that leukodepletion, already introduced in a number of countries, is now considered to be 'state of the art'. Furthermore product liability, public opinion about blood safety and the precaution duty of manufacturers should be taken into account.

[Aids caused by HIV-2 in The Netherlands]. / AIDS door HIV-2 in Nederland.

In four patients in Rotterdam AIDS was diagnosed, and it was subsequently demonstrated that they were infected with HIV type 2. One of the patients was an immigrant from the Cape Verde islands, two of the others had heterosexual contacts with persons of this area, and the fourth patient was a male homosexual without known contacts with Africans. The Cape Verde islands are one of the areas in which HIV-2 infection occurs, and because of immigration into The Netherlands and in particular to Rotterdam, the possibility of HIV-2 infection should be considered in persons of this population group and their sexual contacts. Furthermore, problems with serologic investigations should be avoided by the application of HIV-2 specific confirmatory assays.

[Optimal versus maximal safety of the blood transfusion chain in The Netherlands; results of a conference. College for Blood Transfusion of the Dutch Red Cross]. / Optimale versus maximale veiligheid van de bloedtransfusieketen in Nederland; resultaten van een conferentie. College voor de Bloedtransfusie van het Nederlandse Rode Kruis.

An invitational conference was held on September 11, 1996 by the Medical Advisory Commission to the Blood Transfusion Council of the Netherlands Red Cross, addressing the issues of 'maximal' versus 'optimal' safety measures for the blood supply. Invited were blood transfusion specialists, clinicians, representatives of patient interest groups, the Ministry and Inspectorate of Health and members of parliament. Transfusion experts and clinicians were found to advocate an optimal course, following strategies of evidence-based medicine, cost-benefit analyses and medical technology assessment. Patient groups depending on blood products, such as haemophilia patients would rather opt for maximal safety. Insurance companies would choose likewise, to exclude any risk if possible. Health care juridical advisers would advise to choose for optimal safety, but to reserve funds covering the differences with 'maximal safety' in case of litigation. Politicians and the general public would sooner choose for maximal rather than optimal security. The overall impression persists that however small the statistical risk may be, in the eyes of many it is unacceptable. This view is very stubborn.

New developments in hepatitis C.

Since the detection of hepatitis B virus (HBV) in the 1960s and hepatitis A virus in the 1970s, a considerable proportion of infections of (probably viral) hepatitis could not be classified. About 90% of transfusion-related hepatitis was identified as non-A/non-B. In 1988 investigators from the Chiron Company (USA) detected the non-A, non-B agent and named it hepatitis C virus (HCV). An anti-HCV antibody assay (ELISA) and subsequently confirmation tests (immunoblot and polymerase chain reaction) were developed. HCV infection results in a chronic carrier state of the virus in about 80%. Almost all HCV carriers have, irrespective of their liver function tests, histologic signs of chronic hepatitis and/or liver cirrhosis. Chronic HCV infection is, like HBV, also associated with the development of hepatocellular carcinoma. Most HCV carriers are infected by parenteral routes (intravenous drug use, blood transfusion, tattooing). Intravenous drug users and haemophilia patients have the highest risk (80-90%) of becoming infected. Sexual and perinatal transmission does not play an important role in spreading the infection. Antiviral therapy (alpha-interferon) in patients with chronic hepatitis C will normalize liver function tests in about 25% of the cases, but it is unclear if the HCV carrier state will disappear and if liver cirrhosis will be prevented. At present no specific immunoglobulin or vaccine preparations are available to prevent the HCV infection.

Hepatitis C virus and blood transfusion: past and present risks.

The risk of HCV transmission by blood and blood products has been greatly reduced since the early 1980's. Selection of non-remunerated donors, donor selection to prevent HIV transmission, initial surrogate testing in some regions, and introduction of anti-HCV testing have all contributed to this. ALT surrogate testing has become obsolete since the introduction of anti-HCV testing. The residual risk of HCV transmission due to donations in the anti-HCV window period at present is about 1 in 100 000 transfusions of cellular products, and transmission of HCV by plasma products treated with modern inactivation methods such as solvent-detergent treatment, has not been reported. Hemovigilance programmes, which are presently being installed, will provide more data on the safety of blood transfusion. Introduction of HCV nucleic amplification technology (NAT) as a quality control of manufacturing pools for plasma products or as a form of blood donor screening by minipools is anticipated in many European countries for the coming year. Given industrial developments, NAT testing of individual blood donations may become available within the next 2 years. HCV NAT testing will further annihilate the residual risk, and the cost-effectiveness will become relatively low in comparison with other public health measures.

Blood transfusion and hepatitis: still a threat?

The incidence of post-transfusion hepatitis (PTH) in recipients of blood products is reviewed. PTH was observed in 10%-12% of recipients of blood products in the United States, 2%-4% in northern Europe and 15%-20% in southern Europe. All studies indicate that 80%-90% of all PTH cases are attributed to non-A/non-B. At least 40% of the patients with PTH non-A/non-B will develop chronic hepatitis or cirrhosis. No specific tests for the detection of the non-A/non-B agent(s) exist. However, several independent studies indicate that part of the donors carrying the infectious non-A/non-B agent have increased levels of alanine amino transferase (ALT). When donors are excluded with elevated ALT values, it is estimated that about 30% of the PTH non-A/non-B cases would be prevented. Some studies indicate that anti-hepatitis B core (anti-HBc) positive donors may carry an increased risk to transmit the non-A/non-B agent, but more recent studies do not confirm this. There is hope that a specific non-A/non-B test will be developed soon.

Enhanced detection of HIV-1 sequences using polymerase chain reaction and a liquid hybridization technique. Application for individuals with questionable HIV-1 infection.

In this report we describe a sensitive HIV-1 detection method which is applicable for confirmation testing of donors whose blood sample gives indeterminate viral-serology results. The method involves performing a polymerase chain reaction (PCR) and detecting the generated fragments using liquid hybridization and gel retardation. We found that it is as specific as blotting on a filter and hybridization with an internal probe but at least tenfold more sensitive. After applying it on DNA samples of a panel of 11 persistent indeterminate anti-p24gag-reactive donors, none was found to be PCR positive. Considering other negative virological and biochemical test results and case-historical data, these donors are not likely to be HIV-1 infected.

Paying for blood donations: still a risk?

It is presently disputed whether studies indicating a higher risk of infectious diseases among paid blood donors are lessons of the past, or still hold relevance. Comparative studies published between 1968 and 2001 were assessed for a possible trend of change in the relative risk for infectious disease markers between paid and unpaid blood or plasma donors. Studies reporting that paid donors had lower risk were found, but most studies, including recent ones, continued to report that paid donors have higher rates of infectious disease markers than unpaid donors. By log-linear regression analysis of the relative risk estimates for infectious disease markers among paid and unpaid donors from 28 published data sets, evidence was not found to indicate that the difference in risk for infectious disease markers between paid donors and unpaid donors had diminished over time (P = 0.128, not significant). Paid donors are still more likely than unpaid donors to donate blood in the period during which infectious donations escape detection by blood-screening tests (the "window-period"). Therefore, paid donations have a higher risk that labile blood components (such as red blood cells and platelets) are infected. Additional safety measures for handling plasma donations, and the preparation, purification and viral-inactivation steps employed for the production of plasma derivatives, may render the difference in infectious disease marker rates in donors irrelevant for plasma products. However, not all viruses are inactivated and paid donors were repeatedly found to have higher frequencies of markers for emerging agents. In a quality system, critical steps of the process should be addressed, and selection of the donor population is one of the first steps in this process. It is advised that blood establishments present yearly reports (with complete and raw data) to authorities on the incidence and prevalence of infectious disease markers among their donors as an ongoing surveillance on the "quality" of their donor populations. Paid blood or plasma donors still have higher rates for infectious disease markers than unpaid donors.

Comparison of two anti-hepatitis C virus enzyme-linked immunosorbent assays: Wellcozyme VK45 and Ortho 2.0.

BACKGROUND: The aim of the present study was to compare 2 anti-HCV ELISA tests with respect to sensitivity and specificity in detecting Hepatitis C antigen. MATERIALS AND METHODS: A 3rd-generation anti-HCV ELISA (Wellcozyme anti-HCV VK45) was compared with a 2nd-generation anti-HCV ELISA (Ortho HCV 2.0) in various serum panels: A) anti-HCV ELISA-positive samples of blood donations (n = 536), B) non-A, non-B hepatitis patients (n = 188), C) multi-transfused patients (n = 79), D) hemodialysis patients (n = 473), and E) random blood donors (n = 1,080). RESULTS: Of 248 cDNA polymerase chain reaction (cDNA-PCR) positive samples in panels A, B, and C, ELISA-VK45 detected 247 (99.6%) and Ortho-2 248 (100%). The cDNA-PCR-positive sample missed by ELISA-VK45 showed isolated anti-C33c reactivity in a 2nd-generation recombinant immunoblot (RIBA-2). Of 281 RIBA-2-positive samples, ELISA-VK45 detected 274 (97.5%) and Ortho-2 279 (99.3%). ELISA-VK45-negative, RIBA-2-positive samples showed combined anti-C100/5-1-1 reactivity in RIBA-2 in 6/7 cases and anti-C22 and C33c reactivity in one. Ortho-2-negative, RIBA-2-positive samples showed combined anti-C100/5-1-1 reactivity in RIBA-2 in 2/2 cases. The specificities of ELISA-VK45 and Ortho-2 were not significantly different in 1,080 blood donors. CONCLUSION: It is concluded that the ELISA-VK45 lacks sensitivity because a cDNA-PCR-confirmed positive sample was missed in the assay. The specificity of both ELISAs was comparable.

A simple strategy to look back on posttransfusion hepatitis B in a multitransfused patient.

BACKGROUND AND OBJECTIVES: In January 1996, a case of hepatitis B virus (HBV) seroconversion in a multitransfused patient was reported to the blood bank From March through October 1995, the patient had received 23 units of red cells and 30 units of pooled platelet concentrates, encompassing an exposure to a total of 200 whole blood donations. MATERIALS AND METHODS: In order to trace hepatitis B surface antigen (HBsAg)-negative but HBV-infectious blood donation(s), we tested samples of the donors obtained > or = 3 months after the implicated donations for anti-HBc (Corezyme EIA, Abbott). From 172/200 donors, archived samples of subsequent donations were available for this purpose. The remaining 28 donors were reinvited to the blood bank to obtain an additional blood sample for anti-HBc testing. RESULTS: 1/200 follow-up donor samples was anti-HBc-positive. Retrospective testing of the implicated HBsAg-negative blood donation of this donor revealed anti-HBc-negative and HBV-DNA-positive results. The patient was transfused with the platelets of the HBV-infectious donation. On looking back, the other blood products prepared from this HBV-infectious donation caused posttransfusion HBV infection (PT-HBV) in 2 additional patients. CONCLUSION: Anti-HBc testing on mainly archived follow-up samples of 200 donors implicated in PT-HBV was a rapid, simple cost-effective and donor-friendly method to identify an infectious but HBsAg-negative, anti-HBc-negative and HBV-DNA PCR-positive blood donation. Routine anti-HBc screening would not have prevented this HBV transmission.