Methods for estimating HIV prevalence: A comparison of extrapolation from surveys on infection rate and risk behaviour with back-calculation for the Netherlands

Objectives: To compare HIV prevalence estimates (total number infected) by using extrapolation from surveys on infection rate and risk behaviour (EIR) in specific segments of the population and back-calculation (BC) on reported AIDS cases. To discuss potential sources of bias and error, and to identify areas for improvement of the methodology. Design: Systematic comparison and epidemiological assessment of data input, underlying assumptions, and output. Methods: Low, possibly unbiased and high estimates of HIV prevalence as of January 1996 for homo/bisexual men, injecting drug users, heterosexual men and women with multiple partners, and blood transfusion recipients and haemophiliacs were derived from surveys and continuous data collections on HIV infection rate and risk behaviour in the Netherlands between 1992 and 1996. These were compared with estimates (point and 95% CI) by empirical Bayesian BC on AIDS cases 1982–1995. Results and conclusions: The estimate of HIV prevalence by EIR was 13,806 with low and high estimates of 9619 and 17,700, respectively. The HIV prevalence estimate by BC was 8812 (95% CI: 7759–9867). The available data from EIR are too limited for accurate estimates of HIV prevalence. EIR estimates could be improved considerably with more precise data on prevalence of risk behaviours and HIV prevalence rate for homosexual men. More confidence can be put in the BC estimates, but these could be underestimates because of the age effect on incubation time, pre-AIDS treatment and relapse of risk behaviour. BC estimates could be improved by a better representation of the incubation time distribution (including the effect of age thereupon), better data on the effectiveness and uptake of pre-AIDS antiretroviral treatment and prophylaxis of opportunistic infections, and on the level of underreporting.

[1]  J. Goudsmit,et al.  Prevalence and risk factors of HIV infections among drug users and drug-using prostitutes in Amsterdam. , 1988, AIDS.

[2]  M. Segal,et al.  Different AIDS incubation periods and their impacts on reconstructing human immunodeficiency virus epidemics and projecting AIDS incidence. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[3]  I M Longini,et al.  Use of immunological markers and continuous‐time Markov models to estimate progression of HIV infection in homosexual men , 1996, AIDS.

[4]  A M Downs,et al.  Reconstruction and prediction of the HIV/AIDS epidemic among adults in the European Union and in the low prevalence countries of central and eastern Europe , 1997, AIDS.

[5]  Y. V. van Duynhoven,et al.  Laboratory-based HIV surveillance with information on exposure: importance of discriminating person-based from test-based results , 1996, International journal of STD & AIDS.

[6]  O. Gill,et al.  A birth cohort analysis of AIDS in Europe: high incidence among young persons at risk , 1998, AIDS.

[7]  Mitchell H. Gail,et al.  AIDS Epidemiology: A Quantitative Approach , 1994 .

[8]  T. Sandfort,et al.  Increase in unprotected anogenital intercourse among homosexual men. , 1993, American journal of public health.

[9]  J. Goudsmit,et al.  Changes in sexual behaviour and the fall in incidence of HIV infection among homosexual men. , 1989, BMJ.

[10]  S H Heisterkamp,et al.  Correcting reported AIDS incidence: a statistical approach. , 1989, Statistics in medicine.

[11]  P. Hutto,et al.  HIV Seroprevalence and Reasons for Refusing and Accepting HIV Testing , 1991, Sexually transmitted diseases.

[12]  J C Jager,et al.  AIDS surveillance and prediction of the HIV and AIDS epidemic: methodological developments. , 1993, AIDS (London).

[13]  J. Margolick,et al.  Estimating the 1978-1990 and future spread of human immunodeficiency virus type 1 in subgroups of homosexual men. , 1991, American journal of epidemiology.

[14]  H. Hull,et al.  Comparison of HIV-antibody prevalence in patients consenting to and declining HIV-antibody testing in an STD clinic. , 1988, JAMA.

[15]  M. D. de Ridder,et al.  Comparison of patients refusing with patients accepting unlinked anonymous HIV testing in an outpatient STD department in The Netherlands. , 1997, International journal of STD & AIDS.

[16]  T. Quinn,et al.  Characterization of Patients Accepting and Refusing Routine, Voluntary HIV Antibody Testing in Public Sexually Transmitted Disease Clinics , 1994, Sexually transmitted diseases.

[17]  R. Coutinho,et al.  High mortality among HIV‐infected injecting drug users without AIDS diagnosis: implications for HIV infection epidemic modellers? , 1994, AIDS.

[18]  D. Gibbs,et al.  Populations at Increased Risk of HIV Infection: Current Knowledge and Limitations , 1991, Journal of Acquired Immune Deficiency Syndromes.

[19]  R. Geskus,et al.  Differences in Progression to AIDS between Injection Drug Users and Homosexual Men with Documented Dates of Seroconversion , 1996, Epidemiology.

[20]  C. Henquet,et al.  [HIV surveillance in an outpatient clinic for sexually transmissible diseases in Amsterdam, 1991-1994; low and stable prevalence among heterosexual clients]. , 1995, Nederlands tijdschrift voor geneeskunde.

[21]  Kaye Wellings,et al.  An Estimate of the Prevalence of Human Immunodeficiency Virus Infection in England and Wales by Using a Direct Method , 1994 .

[22]  G. Raab,et al.  Immunologic markers of AIDS progression: consistency across five HIV‐infected cohorts Multicohort Analysis Project Workshop. Part I , 1994, AIDS (London).

[23]  D. Vlahov,et al.  Category of exposure to HIV and age in the progression to AIDS: longitudinal study of 1199 people with known dates of seroconversion , 1996, BMJ.

[24]  J. Hendriks,et al.  Estimation of the magnitude of the HIV epidemic among homosexual men: Utilization of survey data in predictive models , 1993, European Journal of Epidemiology.

[25]  G. Satten,et al.  The incubation period to AIDS in injecting drug users estimated from prevalent cohort data, accounting for death prior to an AIDS diagnosis , 1998, AIDS.