[Pharmaco-economic aspects of vaccination against invasive pneumococcal infections in persons over 65 years of age; review of the literature on cost effectiveness analysis]. / Farmaco-economische aspecten van vaccinatie tegen invasieve pneumokokkeninfecties bij 65-plussers; literatuuroverzicht van kosteneffectiviteitsanalysen.

OBJECTIVE: To assess the cost-effectiveness of vaccination to prevent invasive pneumococcal disease in the elderly. DESIGN: Review of the literature. METHODS: Articles in Dutch or English reporting studies into the cost-effectiveness of vaccination for the prevention of invasive pneumococcal infection in persons over 65 years of age were retrieved from Medline (1980-2000; search terms: 'pneumococcal' and 'vaccine' in combination with 'costs' or 'economics') and on the basis of the reference lists in the articles found. The following aspects of the selected studies were assessed: the net costs per year of life gained, the incidence of invasive pneumococcal disease in the elderly, the mortality due to invasive pneumococcal infections, the effectiveness of the vaccine in the prevention of invasive pneumococcal infections, and the costs of the vaccine and its administration. Attention was also given to specific age categories and to the effects of varying certain crucial assumptions. RESULTS: We retrieved a total of five studies: one each for the USA, Canada, the Netherlands and Spain and a multinational study for five European countries. The cost-effectiveness of vaccination of the elderly against invasive pneumococcal infections varied from cost savings to [symbol: see text] 33,000,-per life-year gained. The Dutch study estimated the cost-effectiveness at [symbol: see text] 10,100,-per life-year gained (price level 1995). Almost all the studies selected based their estimate of the effectiveness of vaccination on the same case-control study from the USA. The potential effects on cost-effectiveness of more extensive influenza vaccination and of the inclusion of re-vaccination against pneumococci were not included in the analyses. CONCLUSION: The cost-effectiveness of vaccination against invasive pneumococcal infections in persons over 65 years of age (in the Netherlands as well as in several other countries) was below the previously accepted threshold of [symbol: see text] 20,000,-.

Health economics of a hexavalent meningococcal outer-membrane vesicle vaccine in children: potential impact of introduction in the Dutch vaccination program.

The cost-effectiveness of universal vaccination of infants with a new hexavalent meningococcal B outer-membrane vesicle vaccine is projected for The Netherlands by applying decision analysis. The societal perspective is taken and direct and productivity costs (friction costs method) are considered. Future costs and effects are discounted at 4% (base year 1998). In this simulation model, vaccination would prevent 19 deaths and eight cases with severe long-term sequelae per year, rendering 526 additional quality adjusted life years (QALYs) per year. Yearly costs of acute phase of illness due to meningococcal infections in children are estimated at 1,426,634, while the future costs due to sequelae are estimated at 3,801,121 per year. Of all these costs, the vaccination program could prevent 3,334,052 per year. The program costs of meningococcal vaccination are estimated at 11,601,356, resulting in a cost-effectiveness ratio (CER) of 15,721 per QALY. These results are sensitive to the vaccine dose price (conservatively estimated at 10), efficacy, and coverage of meningococcal sero-subtypes.

Cost-effectiveness analysis of pneumococcal vaccination for elderly individuals in The Netherlands.

OBJECTIVE: To assess the cost effectiveness (net costs per life year gained) of pneumococcal vaccination of elderly individuals aged 65 years and over in The Netherlands. DESIGN AND SETTING: A pharmacoeconomic analysis was conducted from the healthcare perspective in The Netherlands. The gender- and age-specific modelling framework linked epidemiological aspects of invasive pneumococcal disease (e.g. incidence, mortality, life years lost) to vaccination and hospital resource use. To derive 90% confidence limits for net costs per life year gained a stochastic analysis was performed. INTERVENTION: Pneumococcal vaccination in the elderly with the 23-valent vaccine. Effectiveness of the vaccine in preventing invasive pneumococcal disease was derived from international studies. MAIN OUTCOME MEASURES AND RESULTS: Pneumococcal vaccination in the elderly was not found to be cost saving. At baseline, stochastic and univariate sensitivity analysis net costs per life year gained were estimated to be between 6000 and 16,000 euro (EUR) [EUR1 = 1.1 US dollars; cost level 1995]. A scenario analysis on alternative age-dependent vaccination strategies indicated even higher net costs per life year gained, up to EUR28,000 for vaccinating only those elderly aged 85 years and over. CONCLUSIONS: Pneumococcal vaccination is associated with net costs per life year gained of EUR10,100 (at baseline assumptions). These costs are higher than those for influenza vaccination (EUR5500). Our pharmacoeconomic approach, which needs to be considered in conjunction with social, psychological and budgetary issues, is intended to contribute to rational decision-making in healthcare policy.

[Screening for asymptomatic Chlamydia trachomatis infection in pregnancy; cost-effectiveness favorable at a minimum prevalence rate of 3% or more]. / Screening op asymptomatische infectie met Chlamydia trachomatis in de zwangerschap; gunstige kosteneffectiviteit bij een prevalentie van tenminste 3%.

OBJECTIVE: To estimate the cost-effectiveness of antenatal screening for Chlamydia trachomatis. DESIGN: Pharmaco-economic model analysis. METHOD: The risks of C. trachomatis infection during pregnancy and of complications of the infection as well as the cost of screening for complications (pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy, infertility and neonatal pneumonia) and of treatment were estimated. Assumed were a ligase chain reaction on urine and treatment of identified infected cases with erythromycin or amoxicillin (second choice). Cost-effectiveness was calculated and presented in net direct and indirect costs per major complication averted. RESULTS: For C. trachomatis prevalences in pregnancy above 4% benefits exceed the costs. For prevalences between 2.82% and 4.00% net costs are positive, but a major complication averted costs less than f 1000.-. Considering sensitivity analysis as well, screening for C. trachomatis at prevalences above 3% costs less than f 1000.-per major complication averted and might even save costs. No recent Dutch data on C. trachomatis prevalence in pregnancy are published however. CONCLUSION: Given the current information, antenatal C. trachomatis screening can be recommended from a pharmaco-economic perspective if C. trachomatis prevalence in pregnancy is 3% or more.

Cost effectiveness of expanded antenatal HIV testing in London.

BACKGROUND: Recently the Department of Health announced the introduction in England of voluntary universal HIV screening in early pregnancy to prevent vertical transmission. New data have shown the importance of HIV infection in infants born to mothers who were HIV-negative in early pregnancy and who acquired HIV later in pregnancy or during lactation. This requires consideration of repeat testing in late pregnancy and testing of partners of pregnant women (expanded antenatal HIV testing). OBJECTIVE: To estimate cost effectiveness of expanded antenatal HIV testing in London (England) within the framework of universal voluntary HIV screening in early pregnancy. DESIGN: Incremental cost-effectiveness analysis. METHODS: Cost estimates of service provision for HIV-positive children and adults by stage of HIV infection were combined with estimates of health benefits for infants and parents and with costs of counselling and testing (testing costs). In a pharmacoeconomic model cost effectiveness was estimated for expanded antenatal HIV testing in London for universal and selective strategies. RESULTS: Testing costs in the plausible range of pounds sterling 4 to pounds sterling 40 translate into favourable incremental cost-effectiveness estimates for expanded antenatal HIV testing in London which is already at low numbers of vertical transmissions averted per 100000 pregnant women who test HIV-negative in early pregnancy. Favourable cost effectiveness for universal expanded testing would require testing costs in the lower range, whereas selective expanded testing may produce favourable cost effectiveness at testing costs close to pounds sterling 40. CONCLUSION: Based on pharmaco-economic considerations, the authors believe that implementation of expanded HIV testing in London should be considered.

Back-calculation by birth cohort, incorporating age- specific disease progression, pre-AIDS mortality and change in European AIDS case definition. European Union Concerted Action on Multinational AIDS Scenarios.

OBJECTIVES: To adapt and improve methodology for back-calculation of AIDS in Europe and to examine the feasibility of estimating past HIV incidence by birth cohort. METHODS: Empirical Bayesian back-calculation (EBBC) used Markov disease progression models, modified to allow for three diseases added to the AIDS case definition in 1993 and for pre-AIDS mortality, and estimation by penalized maximum likelihood with a neighbour prior. EBBC by 5-year birth cohort assumed a minimum age at infection and age-dependent progression rates; three versions, with varying age effects, were investigated using AIDS cases diagnosed prior to the introduction of highly active antiretroviral therapies (HAART). RESULTS: Compared with the no age-effect version, EBBC by birth cohort tended to produce flattened HIV incidence curves in country-exposure groups with < 1000 AIDS cases, reflecting effects of the neighbour prior when data become sparse. Otherwise, birth cohort analysis, with moderate effects of age on progression, gave initially increasing incidence curves and consistent patterns across countries, with the 1960-1964 cohort most affected. In the European Union, incidence is estimated to have peaked in 1983 among homosexual men and in 1988 among injecting drug users; 460000 persons were estimated to be living with HIV/AIDS at the end of 1995. CONCLUSIONS: Our improved methodology deals effectively with the change in AIDS case definition and has allowed quantitative assessments of the HIV epidemic by birth cohort using all AIDS cases diagnosed before 1996, thus providing a sound basis for public health policy at a time when estimation of more recent prevalence is compromised by the effects of HAART.

Cost-effectiveness of screening programs for Chlamydia trachomatis: a population-based dynamic approach.

BACKGROUND: Models commonly used for the economic assessment of chlamydial screening programs do not consider population effects. GOAL: To develop a novel dynamic approach for the economic evaluation of chlamydial prevention measures and to determine the cost-effectiveness of a general practitioner-based screening program. STUDY DESIGN: The dynamic approach was used to estimate the cost-effectiveness of a screening program for the first 10 years of screening in The Netherlands. Screening involved a ligase chain reaction test on urine followed by standardized therapies and partner referral. Eligible persons were sexually active, 15 to 24 years, visited a general practitioner, and had no symptoms of sexually transmitted diseases. The heterosexual model population, which consisted of persons 15 to 64 years, had a total chlamydial prevalence of 4.1% before screening. Screening effects on chlamydial incidence were computed by using a population-based stochastic simulation model. Incidence data were connected with a decision analysis model to determine the health effects of the program. The net costs of the program were calculated (investment costs minus averted costs, in 1997 US$) from a societal perspective and expressed per major outcome averted (symptomatic pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy, infertility, neonatal pneumonia). RESULTS: Unlike the standard static approach, our model adequately addresses dynamic processes such as chlamydial transmission and the impact of screening programs on chlamydial incidence in the population. During the first 10 years of screening, the investigated program yields savings of US $492 or US $1,086 per major outcome averted, excluding or including indirect costs, respectively. These results depend on chlamydial prevalence and partner referral. CONCLUSIONS: The cost-effectiveness of chlamydial screening programs seems best to be determined by using dynamic modeling on a population basis. In addition to preventing negative health outcomes, the investigated screening program may save costs.

Pharmacoeconomics of influenza vaccination in the elderly: reviewing the available evidence.

Most western countries have influenza vaccination programmes for citizens aged > or = 65 years. This paper reviews the available evidence on whether elderly influenza vaccination is worthwhile from a pharmacoeconomic point of view. A search on Medline and EMBASE resulted in a primary selection of approximately 100 studies on the pharmacoeconomics of influenza vaccination in the elderly. Further selection of studies to be included in the review was based on several criteria such as original research paper, cost-benefit or cost-effectiveness analysis. influenza vaccination in the elderly, and publication between 1980 and 1999. The 10 studies included in the final selection were evaluated regarding 3 main aspects: benefit-cost ratio and cost-effectiveness ratio; vaccine effectiveness; and relative costing of the vaccine. In general, differences in benefit-cost ratios could be explained by differences in effectiveness and relative costing of the vaccine. Considering the available pharmacoeconomic evidence, influenza vaccination of the elderly in western countries is an intervention with favourable cost-effectiveness in terms of net costs per life-year gained and even has cost-saving potential. In particular, influenza vaccination among elderly people at higher risk, such as the chronically ill elderly, is generally found to be cost saving. Relatively favourable cost-effectiveness among non-high-risk elderly justifies universal influenza vaccination of the elderly from a pharmacoeconomic point of view.

Hospital care for persons with AIDS in European-Union countries; a cross-country comparison.

This paper compares AIDS hospital care in several European-Union countries. For this purpose hospital-care utilisation studies on inpatient days and outpatient contacts were analysed in a generic approach controlling for severity stages of AIDS. Lifetime hospital-care needs for AIDS are derived, providing useful information for health-care policy makers. In a next step, lifetime estimates are linked to estimated annual new cases of AIDS, resulting from standardised epidemiological modelling. These results on AIDS impact at the population level are reported including statistical confidence limits. Both lifetime hospital-care needs at the patient level and AIDS impact at the population level are compared between countries and related to characteristics of the national AIDS epidemics and health-care systems. A person with AIDS has a contact--either inpatient day or outpatient visit--with the hospital in 14% (UK) to 24% (France) of the days spent in the AIDS stage. Related to the national AIDS epidemics (epidemiological impact), Italy and Greece have high levels of outpatient contacts per million population. Estimated hospital-bed needs for AIDS in 1995 are up to 2.13% (in Spain) of total national acute-care hospital beds available. Estimated per-capita needs for outpatient visits in 1995 are highest in Italy, corresponding to 108 doctor full-time equivalents. In a case-study for Greece and The Netherlands, differences in hospital-care utilisation patterns were assessed to correspond with differences in their health-care systems (number of hospital beds, doctors and nurses per capita and some qualitative characteristics of medical care in both countries). International comparison of AIDS hospital care is possible using standardised analysis of national hospital-care utilisation data and standardised epidemiological modelling. Estimates of lifetime hospital-care needs are an essential input for cost-effectiveness analyses used to aid health-care policy decision-making.

[Pharmaco-economic evaluation of mandatory HIV-screening in pregnancy; a cost-efficacy analysis in Amsterdam]. / Farmaco-economische evaluatie van universele HIV-screening in de zwangerschap; een kosteneffectiviteitsanalyse voor Amsterdam.

OBJECTIVE: To estimate the cost effectiveness of universal screening for HIV of pregnant women in Amsterdam. DESIGN: Pharmaco-economic model calculation. METHOD: An estimate was made of the minimal and maximal prevalences of undiagnosed HIV infection during pregnancy for the whole of Amsterdam, based on epidemiological data from observation among pregnant women in two Amsterdam hospitals and one obstetrical practice. The calculation was based on universal screening with an ELISA test. The interventions after screening comprised pharmacotherapy during pregnancy, delivery by caesarean section and breast-milk substitution. The issues of pharmaco-economic analysis were whether or not costs were reduced and net costs per year of life gained; the question was also studied at what lifetime costs of care for HIV infected children the net costs would be nil (costs equal benefits). RESULTS: Universal HIV screening in Amsterdam required a total investment of about Dfl 300,000.-per annum. In many of the analysed options for HIV screening the financial profits exceeded the investment. Variation of assumptions showed that the net costs of HIV screening under all conditions investigated would remain below Dfl 1,200.-per life year gained. CONCLUSION: Universal HIV screening of pregnant women in Amsterdam showed a favourable cost effectiveness. The calculations indicated a possibility of reducing costs.

Socio-economic aspects of extended STD screening in pregnancy.

Screening for sexually transmitted diseases (STDs) in early pregnancy is included in routine antenatal care for several infectious agents in many western European countries. Pharmaco-economics of these interventions have been evaluated. Currently, reconsideration of antenatal screening is ongoing, with explicit attention given to extending the STD testing to some other infectious agents, such as HIV and Chlamydia trachomatis (CT). This paper examines the socio-economics of such extensions for the Netherlands and the UK. Based on pharmaco-economic investigations in the UK and the Netherlands, we argue that serious consideration should be given to expanding antenatal STD screening to include universal testing for HIV and CT. Further research should be directed to the economic aspects of paediatric HIV infection and the epidemiology of CT in pregnancy.

Current and future medical costs of asthma and chronic obstructive pulmonary disease in The Netherlands.

The aim of this study was to estimate the healthcare costs of asthma and chronic obstructive pulmonary disease (COPD), in the Netherlands, in 1993. Also studied was the future development of these costs, as a result of ageing and possible changes in smoking behavior. A prevalence-based cost-of-illness approach was used to estimate direct medical costs. Age- and gender-specific data were obtained from representative national registries and large, representative surveys. To model future costs, cost estimates were linked to an epidemiological model based on a dynamic multi-state lifetable. It describes 1 yr changes, from one state to another, that result from ageing, birth, migration, incidence, recovery from asthma and death due to asthma, COPD or other causes, and starting or quitting smoking. Three different scenarios were modelled: 1) a reference scenario which primarily predicts the impact of ageing. 2) an 'attainable' smoking reduction scenario and 3) an 'extreme' smoking reduction scenario. Direct medical costs were estimated to be $US 346 million in 1993. With increasing age, the relative importance of asthma in total asthma and COPD costs decreased from 91% to less than 4%. Annual costs per patient were estimated to be $US 499 for asthma and $US 876 for COPD. The breakdown of costs differed considerably between asthma and COPD. The reference scenario predicted the costs to increase by 60% to reach $US 555 million by 2010, COPD prevention as modelled in the second and the third scenario reduced the projected cost increase from 60%, to 57% and 48%, respectively. Together, the direct costs of asthma and COPD represent 1.3% of the Dutch health care budget. The breakdown of the costs shows different patterns for asthma and COPD. The costs of these diseases are expected to increase by 60% in the near future. In the short run the impact of smoking reduction on reducing this increase is relatively small, but it will be greater in the long run.

[Opportunistic screening for genital infections with Chlamydia trachomatis among the sexually active population in Amsterdam. III. Cost-effectiveness analysis of screening women and the role of reinfection and partner treatment]. / Opportunistische screening op genitale infecties met Chlamydia trachomatis onder de seksueel actieve bevolking in Amsterdam. III. Kosteneffectiviteitsanalyse van screening bij vrouwen uitgebreid met de rol van herinfectie en partnermeebehandeling.

The role of reinfection and the importance of partner treatment were added to a pharmacoeconomic model for the analysis of a GP-based opportunistic screening programme for Chlamydia trachomatis (CT) in sexually active women in Amsterdam. A favourable cost-effectiveness was found for partner treatment. Partner treatment was cost saving and overall net costs per major outcome averted by the screening programme were reduced by 40% or more due to partner treatment. From a pharmacoeconomic point of view partner treatment should be routinely provided in the framework of a CT screening programme for Amsterdam women.

Universal HIV screening of pregnant women in England: cost effectiveness analysis.

OBJECTIVE: To estimate the cost effectiveness of universal, voluntary HIV screening of pregnant women in England. DESIGN: Cost effectiveness analysis. Cost estimates of caring for HIV positive children were based on the stage of HIV infection and calculated using data obtained from a London hospital between 1986 and 1996. These were combined with estimates of the health benefits and costs of antenatal screening so that the cost effectiveness of universal, voluntary antenatal screening for HIV infection in England could be estimated. MAIN OUTCOME MEASURES: Lifetime, direct costs of medical care of childhood HIV infection; life years gained as a result of the screening programme; net cost per life year gained for different pretest counselling costs; and different prevalence rates of pregnant women who were unaware that they were HIV positive. RESULTS: Estimated direct lifetime medical and social care costs of childhood HIV infection were pound178 300 using a 5% discount rate for time preference (1995-6 prices). In high prevalence areas screening pregnant women for HIV is estimated to be a cost effective intervention with a net cost of less than pound4000 for each life year gained. For areas with comparatively low prevalence rates, cost effectiveness could be less than pound20 000 per life year gained, depending on the number of pregnant women who are unaware that they are infected and local screening costs. CONCLUSIONS: Our results confirm recent recommendations that universal, voluntary antenatal HIV screening should be implemented in the London area. Serious consideration of the policy should be given for other areas in England depending on local prevalence and screening costs.

[Opportunistic screening for genital infections with Chlamydia trachomatis in sexually active population of Amsterdam. II. Cost-effectiveness analysis of screening women]. / Opportunistische screening op genitale infecties met Chlamydia trachomatis onder de seksueel actieve bevolking in Amsterdam. II. Kosteneffectiviteitsanalyse van screening bij vrouwen.

OBJECTIVE: To estimate the cost effectiveness of Chlamydia trachomatis (CT) screening of young women visiting general practitioners. DESIGN: Economic model analysis. METHODS: Data on the health care needs for CT complications were derived from various sources; costing was done using estimated cost prices, charges and the friction cost method; epidemiological data were derived from a pilot study among 22 general practices in Amsterdam, the Netherlands. The analyses were carried out assuming screening with ligase chain reaction test of a urine sample and treatment of identified cases of infection with single-dose azitromycin. The model intervention consisted of screening all heterosexually active women aged 15-19, 15-24, 15-29, or 15-34 years (strategies 1, 2, 3 and 4, respectively). Cost effectiveness was presented in net direct and indirect costs per woman cured and per major outcome averted (pelvic inflammatory disease (PID), chronic pelvic pain, ectopic pregnancy, infertility and pneumonia of newborns). RESULTS: The first two strategies were cost saving. For the third strategy net costs per woman cured and per major outcome averted were almost 110.- Dutch guilders (DFL) and over DFL 300, respectively. The last strategy costs over DFL 320 per woman cured and over DFL 910 per major outcome averted. The cost effectiveness was sensitive to the assumed probability of progression of CT infection to PID. CONCLUSION: Universal implementation of the screening programme investigated in Amsterdam for women aged 15-24 years would result in approximately equal savings and costs. Screening of all 15-29-year-old women would require a net investment of DFL 350,000.

Economic evaluation of influenza vaccination. Assessment for The Netherlands.

OBJECTIVE: The objective of this study was to determine the costs associated with influenza and the cost effectiveness (net costs per life-year gained) of influenza vaccination in The Netherlands. DESIGN AND SETTING: The economic evaluation comprised a cost-of-illness assessment and a cost-effectiveness analysis, both of which were conducted from the healthcare perspective in The Netherlands. The modelling framework for the economic evaluation linked epidemiological aspects of influenza (e.g. incidence, mortality, years of life lost) to vaccination coverage and healthcare resource use. Healthcare resource use was specified for hospitalisations, general practitioner visits and drugs. INTERVENTION: The intervention assessed in the cost-effectiveness analysis was influenza vaccination. MAIN OUTCOME MEASURES AND RESULTS: The costs of influenza were estimated to be 31 million euros (EUR) for the influenza season 1995/96 in The Netherlands (EUR1 approximately $US1.1). For the extended programme in 1997/98, i.e. all elderly people, the cost-effectiveness ratio was estimated at EUR1820 per life-year gained. Sub-group analysis demonstrated that the programme had a more favourable cost effectiveness among the chronically ill elderly population (cost saving) than among the rest of the elderly population (EUR6900 per life-year gained). CONCLUSION: Influenza vaccination has a cost-effectiveness ratio that is better than or comparable to that of other implemented Dutch programmes in the prevention of infectious diseases.

Estimating influenza-related hospitalization in The Netherlands.

The purpose of this study was to examine the impact of influenza on hospitalization in The Netherlands. Two methods were applied to estimate this effect: (a) regression analysis and (b) comparison of hospitalization in epidemic years with non-epidemic years. Hospital discharge rates in 1984-93 have been considered. The study shows that, during the period studied, on average, almost 2700 people were hospitalized for influenza per annum, and that influenza was diagnosed as the main cause for hospitalization in only a fraction of these hospitalizations (326: 12%). From an economic perspective, these results imply that the cost-effectiveness of vaccination against influenza may be severely underestimated when looking only at changes achieved in the number of hospitalizations attributed to influenza.

A birth cohort analysis of AIDS in Europe: high incidence among young persons at risk.

OBJECTIVES: To study trends in AIDS incidence in Europe by age and year of birth. DESIGN: Age-period-cohort analyses were adopted to distinguish the different time factors of calendar year, age and year of birth. METHODS: Non-aggregate AIDS incidence data from 12 European countries (1978-1994) were adjusted for reporting delay and expressed per unit of population (per 100000 persons or 100000 person-years). Age-specific incidence patterns (absolute level and rate of increase) were compared between 5-year birth cohorts for homo-/bisexual men, injecting drug users (IDU) and heterosexual contact cases. RESULTS: Mean age at diagnosis increased strongly amongst IDU, but less so among homo-/bisexual men and heterosexual contact cases. Of a total 110646 reported cases (116311 after adjustment for reporting delay), 87167 (78.8%) were among people born in 1950-1974 [91951 (79.1%) after adjustment for reporting delay]. The relative impact on specific birth cohorts differed strongly by exposure group. Incidences at age ranges of 20-24 and 25-29 years among cohorts born in 1965 and after were about the same level (homo-/bisexual men, IDU) or higher (heterosexual contact cases) than older birth cohorts when these were in the same age range; rates of increase were less among homo-/bisexual men and IDU, but higher among heterosexuals. There were large differences between counties. CONCLUSIONS: Overall, AIDS incidence among cohorts born in 1965 and after is about the same level (homo-/bisexual men, IDU) or higher (heterosexual contact cases) than older cohorts when these were in the same age range. Rates of increase of AIDS incidence curves suggest reduced HIV transmission amongst the most recent cohorts of homo-/bisexual men and IDU, but among young heterosexuals the epidemic is still expanding.

Disease-staging for modelling current and future health-care impact of disease: illustrations for diabetes mellitus and AIDS.

This paper addresses the economic relevance of appropriately staging progression of disease for cost assessment and projection. Illustrations are drawn from two Dutch cost-of-illness studies for Diabetes Mellitus (DM) and AIDS. Our disease-staging specifies a separate late stage to capture terminal high-intensity care for end-stage complications. Data are used from a registration of national hospital resource utilization for DM and from a detailed database on AIDS hospital care and costs. In particular, differences in average length of hospital stay for several potential DM end-stage complications are compared with non-DM patients. Neglecting the separation of a specific late stage is estimated to possibly miscalculate 15-20% of the hospital bed needs for DM and AIDS in the Netherlands. In particular, confidence intervals of future projections for AIDS hospital beds--using respectively staged and non-staged models--do not overlap. AIDS hospital costs are overprojected by almost 11% in the non-staged model. Our estimation of DM hospital bed needs raises the percentage in total Dutch hospital beds from 1.7% (neglecting a specific late stage) to 2.0%. For DM and AIDS an appropriate disease-staging averts structural biases in estimations of bed needs and costs, and therefore benefits the planning of hospital care facilities. Obviously, gathering comparable information and developing similar methodology on other diseases, such as respiratory disease, cardiovascular disease and cancer, is needed and could benefit planning in these fields.