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J C Jager

Publications and source records attributed to J C Jager.

At least 37 records · Page 2Linked to original sources
PubMed1998

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.

Acquired Immunodeficiency Syndrome↗
PubMed1998

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.

Adolescent↗
PubMed1997

Hospital care for persons with AIDS in the European Union.

This study estimates the current and future hospital resources for AIDS patients in the European Union (EU), using multinational scenario analysis (EU Concerted Action BMH1-CT-941723). In collaboration with another EU-project ('Managing the Costs of HIV Infection'), six national European studies on the utilization of hospital care for AIDS have been selected to provide the data for our analysis. The selection criteria involve recentness, quality, comparability, accessibility and representativeness. Baseline hospital resource utilization is estimated for hospital inpatient days and outpatient contracts, using a standardized approach controlling for two severity stages of AIDS (chronic stage and late stage). The epidemiological part of the study is based on standard models for backcalculating HIV incidence and projecting AIDS incidence, prevalence and mortality. In the next step, baseline resource utilization is linked to epidemiological information in a mixed prevalence and mortality-based approach. Several scenarios render different future epidemiological developments and hospital resource needs. For the year 1999, hospital bed needs of 10,000-12,700 in the EU are indicated, representing an increase of 20-60% compared to the estimated current (1995) level. The projected range for 1999 corresponds to a maximum of 0.65% of all hospital beds available in the EU. The growth in the number of outpatient hospital contacts is projected to possibly exceed that of inpatient days up to 1.82 million in 1999. Our methodology illustrates that estimation of current and future hospital care for AIDS has to be controlled for severity stages, to prevent biases. Further application of the multinational approach is demonstrated through a 'what-if' analysis of the potential impact of combination triple therapy for HIV/AIDS. Estimation of the economic impact of other diseases could as well benefit from the severity-stages approach.

Acquired Immunodeficiency Syndrome↗
PubMed1997

European contribution to the science, prevention and management of HIV infection.

The objectives of the European Commission Biomed AIDS Programme are to enable Europe to pool its intellectual and financial resources in the control, treatment and prevention of HIV infection and AIDS. In order to facilitate this aim the Commission has allocated 40 to 50 million ECU over the past 6 years for concerted action of the Biomed projects on AIDS by the countries of the European Union. This is only a small proportion of the real cost spent by the member countries on this epidemic.

AIDS Vaccines↗
PubMed1996

Lifetime hospitalization profiles for symptomatic, HIV-infected persons.

We explored the relationship between the incidence of hospitalization and disease progression in a group of 140 symptomatic, HIV infected patients by linking hospitalizations to the time of diagnosis, the time of death, or both. The relationship could best be described by positively skewed U-patterns or (weak) J-patterns with a high use of resources immediately following diagnosis and preceding death. The lifetime hospitalization profiles differed according to the type of insurance, age, the initial diagnosis in the CDC-IV stage and the length of survival. The results not only confirm general hypotheses posed by other research groups, but also demonstrate the existence of variations among subgroups of patients. The results can be used to improve economic assessments of the impact of AIDS in The Netherlands and the European Union. The method used has the advantage of being based on a bottom-up approach to resource utilization, involving the use pf prospective data for the patients' full lifespans, and can easily be applied to other areas of health services research.

Adult↗
PubMed1995

AIDS scenarios for The Netherlands; the economic impact on hospitals.

OBJECTIVE: To assess the economic impact of HIV/AIDS on the health care system in The Netherlands. DATA AND METHODS: Two types of data are used: (i) routine surveillance data on AIDS incidence and (ii) information on hospital resource utilisation and corresponding monetary costs. Progression of disease is modelled using a multi-stage model, with stages corresponding to clinical classifications and to different phases of health care need. Economic impact is analysed for all stages in three scenarios: the reference and two alternative scenarios. RESULTS: In the year 2000 hospital bed need would reach 220 beds if yearly new HIV infections in the 1990s remain at the level estimated for the end of the 1980s, and if the intensity of hospital care remains constant. A minimum need of 125 beds is projected if no new HIV infections occur in the 1990s. Hospital costs in 1993 are estimated to amount to 33.8 million ECUs. Scenarios indicate a range of 26.7-50.7 million ECUs for the year 2000 (price level: 1993). The proportion of the costs of hospital inpatient care and cure in total hospital costs increases, whereas the proportion for outpatient services decreases. CONCLUSIONS: Projected hospital bed need of 125-220 for HIV/AIDS in the year 2000 is limited compared to the projections for coronary heart disease and stroke, but approaches that for lung cancer, pneumonia and diabetes. We estimate hospital costs to have been 85% of total health care costs for HIV/AIDS in 1993. In 1993, the estimated proportions in hospital costs are 41% for inpatient care, 20% for inpatient cure and 39% for outpatient facilities. Our scenarios indicate a decreasing share of outpatient costs--possibly to 30% of total hospital costs for HIV/AIDS in 2000--illustrating the growing relative importance of the AIDS stage for the hospital costs. We project hospital costs for HIV/AIDS in 2000 to reach up to 0.53% of projected hospital costs for all diseases. A present value of 38 million ECUs (23%) of hospital costs projected in the reference scenario might be avoidable, during the period 1994-2000. However, with unchanged treatment patterns a present value of 127 million ECUs for hospital costs during the same period is projected to represent unavoidable costs (discount rate: 5%). In The Netherlands, data needs in the field of economic impact assessment of HIV/AIDS especially refer to registrations of non-hospital outpatient resource utilisation and costs.

Acquired Immunodeficiency Syndrome↗
PubMed1995

In-patient care for symptomatic, HIV-infected persons: a longitudinal study of hospitalizations, in-patient drug use, and related costs.

Patterns in the costs of hospital in-patient care and in-patient drug treatment of 121 symptomatic, HIV-infected patients are described for a university hospital between 1987 and 1991. Trend analyses have been performed on quarterly and yearly data using parametric and non-parametric statistical techniques. During the 5-year study period the demand for hospital beds almost quadrupled despite a constant number of admissions per person-year and a 40% decrease in the average length of stay. The demand for beds was highest in the autumn and winter months. The impact of female and/or heterosexual subgroups on the yearly utilization of resources increased and reasons for hospitalization became more diverse; there were fewer hospitalizations for Pneumocystis carinii pneumonia infection. Antimicrobial drug treatment accounted for the increased drug treatment costs. The implications for AIDS-treating specialists, hospital managers, and scenario analysts are discussed.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Analysis of the AIDS epidemic in The Netherlands, 1982-1993].

OBJECTIVE: Description of the epidemiology and transmission categories of AIDS in the Netherlands. DESIGN: Descriptive. SETTING: The Netherlands. METHOD: Analysis of all registered AIDS patients until 31 December 1993. Trends in the composition of this population were studied with respect to age and sex, risk groups, geographic distribution across the country, heterosexual transmission, AIDS-defining diseases and reporting pattern. RESULTS: From the first patient in 1982 until December 31, 1993, a cumulative total of 2912 patients was diagnosed and reported in the Netherlands (2995 when corrected for reporting delay). The numbers of reported AIDS cases in the Netherlands are smaller than previously predicted by mathematical models. The proportion of homosexual men in the incidence of AIDS dropped from 89 to 73 per cent, the proportions of intravenous drug users and heterosexual transmission rose to 11 per cent each. Patients in the category of heterosexual transmission are mainly individuals from countries where heterosexual contact is the dominant mode of transmission and their sex partners, and to a lesser extent the sex partners of intravenous drug users (whether or not in relation to prostitution). The proportion of women is rising (229 patients or 8 per cent by December 1993), with most cases transmitted initially by intravenous drug use but later by heterosexual contact. CONCLUSION: The number of AIDS cases in all risk groups combined is levelling off. However, more detailed analysis shows that the numbers of cases of heterosexual transmission and those in young homosexual men are still rising. For a better quantitation of the quality of the AIDS data, specific research into underreporting and non-diagnosis of AIDS cases in the Netherlands is warranted.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The basic reproduction ratio R0 for a sexually transmitted disease in a pair formation model with two types of pairs.

We study a model for pair formation and separation with two types of pairs which differ in average duration. A fraction f of all newly formed pairs have a long duration (denoted by "steady"), the remaining fraction 1-f have a short duration ("casual"). This distinction is motivated by data about the survival times of partnerships in a sociological survey. In this population we consider a sexually transmitted disease, which can have different transmission rates in steady and in causal partnerships. We investigate under which conditions an epidemic can occur after introduction of the disease into a population where the process of pair formation and separation is at equilibrium. If there is no recovery we can compute an explicit expression for the basic reproduction ratio R0; if we take recovery into account we can derive a condition for the stability of the disease-free equilibrium which is equivalent to R0 < 1. We discuss how R0 depends on various model parameters.

Epidemiologic Methods↗
PubMed1994

Trends in hospital resource utilization by HIV-infected persons, January 1987-June 1990.

Trends in the utilization of various hospital resources by HIV-infected persons between January 1987 and June 1990 have been studied to support health care planning. Data on 126 asymptomatic and symptomatic HIV-infected persons have been recorded at a patient level and analyzed at half-yearly intervals. At a hospital level, increasing utilization trends were observed. At the patient level, a decreasing utilization intensity was measured for admissions, inpatient days, inpatient diagnostic examinations, and outpatient consultations. Increasing utilization intensity was measured for care during admissions. A constant utilization intensity was observed for outpatient diagnostic examinations and inpatient medication days. Use of interventions tended to increase at the end of the study period. Discriminating between trends in the utilization of different hospital resources can improve the management of hospital health care demands of HIV-infected people.

Adult↗
PubMed1994

Social transmission routes of HIV. A combined sexual network and life course perspective.

A combined sexual network and lifecourse perspective is proposed as a basis for reconstructing the sexological infrastructure of HIV dissemination. Necessary data are drawn from a representative sample survey of 1001 adults (age range 18-50 years) in the Netherlands. Heterosexual respondents' behavioural risk level, expressed in the number of unprotected sexual interconnections with primary and secondary partners, is found to be related to both age and relational status, though these variables cannot fully predict risk. While those under 24 years of age are over-represented in the larger components of sexual networks, above 32 years of age there is a small group who follow a lifestyle of regularly changing sexual partners.

Adolescent↗
PubMed1993

Economic impact of the AIDS epidemic in the European Community: towards multinational scenarios on hospital care and costs.

OBJECTIVE: To underpin multinational public-health HIV/AIDS strategy planning in the European Community (EC) by integrating national studies on HIV/AIDS in scenario analysis. METHOD: Three types of data are used: routine surveillance data, information on disease progression and observational studies on the economic impact. The HIV/AIDS epidemic is simulated using two models (MIDAS and PC-Based AIDS Scenarios). Selected simulations, consistent with surveillance data, are connected to economic impact (hospital-bed needs and annual hospital costs for AIDS patients). Parameter values expressing per person-year economic impacts are derived from a structured review of publications on economic aspects of AIDS. RESULTS: Evaluation of published studies on hospital resource use and costs in EC countries shows that there are significant differences between both countries and studies, even after conversion to similar measures (for example, using purchasing power parities). These differences are partly due to factors such as the composition of the patient population. Differences in methodology may also have influenced the results. Economic impact is analysed for combinations of three factors; survival time after AIDS diagnosis, hospital inpatient days needed per person-year and corresponding hospital costs per person-year. All scenarios indicate 1995 hospital-bed needs above the 1990 level of 5400 beds. Hospital cost projections for 1995 vary (up to US$1050 million). CONCLUSIONS: (1) For economic impact assessment, there are important gaps in epidemiological and economic data, and in the methods for linking these. (2) Standardization of studies on the resource use and costs of HIV/AIDS is necessary to provide a sound basis for multinational scenarios. (3) Preliminary multinational scenarios show that by 1995 hospital-bed needs for AIDS might reach 0.45% of all hospital beds available in the EC, and that hospital cost projections for AIDS in that year will range from 0.15% to 0.30% of EC health-care expenditure.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Quality of life of persons with HIV infection in an academic hospital].

OBJECTIVE: Comparison of the quality of life of asymptomatic (n = 24) and symptomatic (n = 20) HIV-infected patients and description of the changes in quality of life during the symptomatic stage. DESIGN: Prospective study. SETTING: University Hospital Utrecht. METHOD: Every four months questionnaires on quality of life were completed by 44 of 55 consecutive HIV-infected patients. RESULTS: Physically, asymptomatic HIV-infected patients were better off than symptomatic HIV-infected patients; psychologically, however, both groups of patients showed similar responses. During the symptomatic stage the patients' physical functioning diminished further, but feelings of anxiety or depression showed no marked change; self-evaluations of health conditions became slightly more negative with time.

Academic Medical Centers↗
PubMed1992

Short and medium term projections of the AIDS/HIV epidemic by a dynamic model with an application to the risk group of homo/bisexual men in Amsterdam.

Several methods exist for short term projection of the numbers of AIDS cases. Some use extrapolation of empirical curves fitted to data up to a given time, whereas others such as the popular method of 'back projection' or actuarial methods also use information about the process. In this paper we describe a dynamic model based on a distributed modelling technique allowing for variability both in infectiousness and in age distribution of the population at risk. Some model parameters are taken from the literature, others are estimated from AIDS incidence data from the homo/bisexual population in Amsterdam. The model described here simulates prevalence and incidence of HIV infection. We present prediction intervals for two years from January 1990 onwards. We discuss three scenarios based on the estimated model, two of which consider early treatment with anti-viral drugs. Given the model and the state of the epidemic in Amsterdam, early treatment intervention must be combined with very drastic measures for reducing infectivity in order to have any serious impact on the course of the epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Prognosis concerning HIV-infection and AIDS epidemic in The Netherlands based on mathematical analysis].

In the Netherlands by the 1st of January 1990 1074 AIDS patients have been reported to the Department of the Chief Medical Officer. In the last few years the proportion of intravenous drug users increased and the proportion of homo/bisexual men decreased. After adjustment for the effect of delay in reporting the total number of AIDS patients by 1st January 1990 is estimated to be 1173. It appears that the reporting delay outside Amsterdam is longer than in this city. The time required for doubling of the half-yearly incidence of new AIDS patients (doubling time, dt) increased from 9 months in the beginning of the epidemic to 34 months. It is expected on the assumption of constant dt that 1120 new AIDS patients will be diagnosed in 1990 and 1991 together. The present growth among the homo/bisexual men (dt 34 months) is smaller than the one among the intravenous drug users (dt 23 months). The growth in Amsterdam (dt 36 months) is less than that in the rest of the Netherlands (dt 32 months). Based on the course of the AIDS epidemic the number of HIV infected (including the AIDS patients) is estimated as 9,000-12,000 by the 1st of January 1990.

Acquired Immunodeficiency Syndrome↗