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Recombinant hepatitis B vaccine use in chronic hemodialysis patients |
Fabrizi F, Di Filippo S, Marcelli D, Guarnori I, Raffaele L, Crepaldi M, Erba G, Locatelli F |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology Recombinant Hepatitis B Vaccine for chronic hemodialysis patients.
Economic study type Cost-effectiveness analysis.
Study population Chronic hemodialysis patients.
Setting Hospital. The economic study was carried out in Lecco, Italy.
Dates to which data relate The dates associated with the effectiveness and resource use data collection were not clearly stated (January 1991 was stated to be the beginning of the vaccination programme, whilst data for the pre-vaccination programme period corresponded to the period 1985-1990). The price date was not explicitly reported.
Source of effectiveness data Effectiveness data were derived from a single study.
Link between effectiveness and cost data The costing was undertaken retrospectively on the same patient sample as that used in the effectiveness study.
Study sample From a total of 190 hemodialysed patients who were tested for HBV markers, 118 patients (58 males and 60 females, age range 18-91 years) completed a vaccination programme with recombinant vaccine with a median duration of HD treatment of 21 months. No power calculations to determine the sample size were given.
Study design Non-randomised study with historical controls from a single centre. The follow up period was 24 months. Seventy-two patients did not complete a vaccination programme and were excluded from the study as were another 28 patients who did not complete the follow-up period.
Analysis of effectiveness The analysis of the clinical study was based on treatment completers only. The primary health outcomes used in the analysis were the response rate of HD patients to recombinant hepatitis B vaccine with a reinforced schedule, and the number of HBV infection episodes among responder HD patients during the follow-up period. This figure was compared with the corresponding figure for HD patients at the beginning of the vaccination programme. HBV-infection was defined as a given patient having 2 consecutive serum specimens that were positive for HBsAg, anti-HBc, or both. Clinical significance (type I) was established if the sample was positive for HBsAg or the level of alanine aminotransferase was more than 2 times the upper limit of normal. Those infections with development of anti-HBc only, elevated transaminase levels, or symptoms were defined as clinically unimportant (type II).
Effectiveness results Recombinant hepatitis B vaccine was administered at 0, 1 and 2 months, obtaining a seroprotection rate of 67% (79/118), with 57% (45/79) being high responders. Of those responder patients with a complete follow-up, 40 showed declining but persistently protective anti-HBs levels, whilst 11 lost the seroprotection within 15-18 months after the first vaccine dose. There were 7 episodes of HBV infection among HD patients at the institution during the 1985-1990 (pre-intervention) period (one type I infection, and 6 type II infections), whilst there were no infections observed in the between responder vaccinees during the 2-year follow-up.
Measure of benefits used in the economic analysis The measure of benefits was persistence of anti-HBs antibodies in HD responder vaccinees after 24 months of follow-up, and HBV infections avoided.
Direct costs Costs of vaccination were included. The costs associated with morbidity due to hepatitis B infection, and annual vaccination of HD staff members and new patients were excluded. Quantities of resource use were not analysed separately, except for the number of patients undergoing surveillance testing (non responders) and those requiring revaccination. Costs were not discounted. The quantity/cost boundary adopted was the hospital. The price date was not stated.
Sensitivity analysis A sensitivity analysis was not carried out.
Estimated benefits used in the economic analysis At month 24, 78% maintained protective levels of anti-HBs, and 45% of those were high responders. Seven infectionswere observed during the 5-year pre-intervention period as opposed to none in the group of responders during the 2-year follow-up.
Cost results The total cost of vaccinating 118 HD patients was $9,440. The additional costs of continued serologic screening for 118 patients over the corresponding cost figure for the vaccination option was $3,272 ($5,192 - $1,920) per year. Therefore, the authors argued, within less than three years, the initial costs of vaccination are paid off.
Synthesis of costs and benefits Costs and benefits were not combined since the vaccination option was considered to be the dominant strategy.
Authors' conclusions The relatively low response to recombinant B vaccine in HD patients stressed the need to combine the use of vaccine with infection control strategies such as serological surveillance, isolation practices, compliance with "universal precautions", routine cleaning and disinfection in order to eradicate hepatitis B in this clinical setting.
CRD COMMENTARY - Selection of comparators A justification was given for the comparator used.
Validity of estimate of measure of benefit The validity of the estimate of measure of benefit may be weakened by the study design used (historical control) and the principle used to analyse the results.
Validity of estimate of costs Adequate details about the costs were not given (e.g. price date) and some cost items were omitted (e.g. staffvaccination and costs of morbidity from vaccination). Note also that no allowance was made for the effect of time on the valuation of costs (i.e. no discounting was present in the estimates).
Other issues Appropriate comparisons were made with other studies. The issue of generalisability to other countries was partly addressed.
Implications of the study Further studies may be needed in order to validate the results of this study on the cost-effectiveness of hepatitis B vaccination strategy for chronic hemodialysis patients.
Bibliographic details Fabrizi F, Di Filippo S, Marcelli D, Guarnori I, Raffaele L, Crepaldi M, Erba G, Locatelli F. Recombinant hepatitis B vaccine use in chronic hemodialysis patients. Nephron 1996; 72(4): 536-543 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Aged; Aged, 80 and over; Blood Transfusion; Chronic Disease; Cost-Benefit Analysis; Evaluation Studies as Topic; Female; Hepatitis Antibodies /biosynthesis; Hepatitis B /economics /immunology /prevention & Hepatitis B Core Antigens /immunology; Hepatitis B Vaccines /adverse effects /economics /therapeutic use; Humans; Immunization Schedule; Immunoenzyme Techniques; Male; Middle Aged; Renal Dialysis; Vaccines, Synthetic /adverse effects /economics /therapeutic use; control AccessionNumber 21996000474 Date bibliographic record published 31/03/1999 Date abstract record published 31/03/1999 |
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