Expanded European AIDS case definition

[Estimating the completeness of AIDS reporting in Spain]

OBJECTIVE

To evaluate AIDS case reporting in the Spanish regions as compared with the AIDS deaths registered in mortality statistics, in order to identify possible deviations indicative of underreporting.

METHODS

We carried out an ecological analysis taking each region as a unit. We compared incidence and mortality obtained from the AIDS reporting system with the HIV/AIDS deaths obtained from the mortality statistics of the Spanish Institute for Statistics. The 1986-1998 period was analysed globally, then the analysis was repeated for the 1995-1998 period.

RESULTS

In the 1986-1998 period there was a good correlation (r = 0.93) between the AIDS incidence rates and HIV/AIDS mortality rates obtained from death statistics. Some regions presented an AIDS incidence lower than expected according to their mortality rate when it was compared with the national average, with Asturias (27%), Comunidad Valenciana (26%), Andalucia (20%), Ceuta (18%) and Cantabria (13%) standing out. Taking as a reference the five regions with the highest completeness, the underreporting in Spain was of 13%. In the 1995-1998 period these deviations increased moderately. In the 1986-1998 period, 18.9% less deaths were notified to the AIDS reporting system in comparison with death statistics, showing a great variability between regions.

CONCLUSIONS

In Spain the reporting level of AIDS cases is acceptable for the aims of surveillance, although in some regions measures to improve it should be taken. The notification of deaths to the AIDS reporting system presents great deficiencies.

Is the time from HIV seroconversion a determinant of the risk of AIDS after adjustment for updated CD4 cell counts?

OBJECTIVE

To evaluate the effect of time from seroconversion to a given CD4 cell count on progression to AIDS after that count after adjusting for updated CD4 cell counts.

METHODS

Using pooled data from 19 seroconverter cohorts, we examined the association between the time from a CD4 <500 cells/mm 3, (<350, <200) to the first AIDS-defining event and time from seroconversion to that CD4 threshold. We adjusted for age, gender, exposure category, and HIV test interval in Cox models stratified by cohort. We estimated the residual effect of time from seroconversion, adjusting for updated CD4 cell counts. A cause-specific competing-risks model was then used to evaluate this residual effect on progression to each AIDS-defining disease. Analyses were censored on December 31, 1995.

RESULTS

Of 3825, 3006, and 1804 individuals reaching CD4 thresholds of 500, 350, and 200, respectively, 1274, 1192, and 985, respectively, developed AIDS. We found a significant effect of time from seroconversion on the risk of AIDS even after adjusting for updated CD4 counts. For individuals reaching a CD4 threshold of 350 cells/mm 3, a 1-year increase from seroconversion was associated with an increase in risk of AIDS of 6% (3%-9%) ( p =.01). This effect appeared to be nonlinear. In the first 4 years, a 1-year increase from seroconversion was associated with an 11% increase in the risk of AIDS, but there was no apparent increase in risk after 4 years. The residual effect of time from seroconversion was significantly heterogeneous ( p =.002), with respect to the risk of individual AIDS-defining diseases. Findings were similar for CD4 thresholds of 500 and 200 cells/mm 3, respectively.

CONCLUSIONS

We found a small, statistically significant, residual effect of time from seroconversion on the risk of AIDS. In practical terms, when considering an infected individual's risk of AIDS from a given CD4 cell count, there is little to be gained from knowing the time of seroconversion. However, this effect differs significantly among specific AIDS-defining diseases.

A change-point model for reporting delays under change of AIDS case definition

Accurate monitoring of disease incidence is of major public health concern. The time delay between diagnosis and the date of reporting creates bias in estimating disease incidence. Changes in case definition are expected to have an impact on the time lag of case reporting. We propose a change-point model for reporting delays in AIDS that takes into account recent changes in the AIDS definition in US and European countries. The model was applied to California AIDS surveillance data and the distribution of reporting delays before and after the recent change of definition in 1993 were analyzed in terms of contributing factors. The overall significance of the model with change-point as compared to the model without change-point indicates that the effect of the 1993 change in definition on the distribution of reporting delays was highly significant (p < 0.0001). Overall, reporting delay of cases initially diagnosed with AIDS-defining diseases before 1993 was shorter compared to after 1993; reporting delay of cases initially diagnosed meeting the 1993 immunologic case definition was shorter than of those initially diagnosed with AIDS-defining diseases. Region of residence, mode of exposure, race/ethnicity and time of diagnosis emerged as the main covariates in the models. The method introduced here applies to current and possible future changes of the AIDS case definition as well as changes in diagnostic criteria or case definition in diseases other than AIDS. We demonstrate that such changes may be accompanied by sizeable changes in the distribution of reporting delays, and thus adjustment for reporting delays must be recalibrated after a change in definition.

HIV surveillance among men who have sex with men

OBJECTIVES

To review current approaches to HIV surveillance among men who have sex with men (MSM), identify illustrative best practices and lessons learned, and outline ways to enhance surveillance systems.

METHODS

Review of the literature and institutional guidelines for HIV/AIDS, sexually transmitted infection (STI), and behavioral surveillance and summary of results of an international workshop.

RESULTS

On-going formative research, HIV/AIDS and STI case reporting, HIV prevalence and incidence studies, and behavioral surveys are essential components of an effective HIV surveillance system for MSM. Alliances with key organizations and actors in MSM communities provide points of access, assist in the development of measures, and guide appropriate use of data. Sampling techniques (convenience, snowball, quota, microsite, time-location, and population-based) offering a range of methods, complexity, and cost have been successfully implemented in MSM communities. Plausible estimates of the size of MSM populations, which are ultimately crucial to the interpretation of surveillance data, can be improved upon using primary and secondary data.

CONCLUSIONS

The purpose of HIV surveillance among MSM is not only to monitor disease occurrence and its antecedents, but to regularly use data to plan and evaluate prevention and care programs, advocate for prevention resources, and improve the health, social welfare and human rights of MSM. Practical, incremental steps can be taken to improve HIV surveillance among MSM in all regions of the world in all stages of the epidemic.

Incidence of invasive cervical cancer in a cohort of HIV-seropositive women before and after the introduction of highly active antiretroviral therapy

To assess whether the incidence of invasive cervical cancer (ICC) has changed as a result of highly active antiretroviral therapy (HAART), we conducted a prospective cohort study on the incidence of ICC before and after the introduction of HAART among Italian women with a known duration of HIV infection. We estimated the incidence per 1000 person years of ICC as a first AIDS-defining disease for the periods 1981 through 1991, 1992 through 1995, and 1996 through 1998. We also estimated the incidence of other first AIDS-defining diseases. Kaplan-Meier and Cox models were applied to compare the periods 1981 through 1995 and 1996 through 1998 in terms of cumulative incidence and relative hazards (RHs). The analysis included 483 women (median follow-up: 7 years). In the period 1981 through 1995, a trend of increase was observed in the incidence of ICC and other AIDS-defining diseases; this trend has continued only for ICC, whereas the incidence of other AIDS-defining diseases has decreased since 1996. Compared with 1981 through 1995, the RH of ICC for 1996 through 1998 was 7.41 (95% confidence interval [CI]: 1.21--45.44); when adjusting for age at HIV seroconversion, the RH decreased to 4.75 (95% CI: 0.80--28.24). It remains to be determined whether the continued increase in ICC incidence after the introduction of HAART is attributable to a decreasing competitive mortality from other AIDS-defining diseases among HIV-infected women.

The evolving mode of presentation of HIV-infected patients to health services of northern Spain: 1985 through December 1999

To evaluate the mode in which human immunodeficiency virus (HIV)-infected patients have had their first contact with the health services throughout time as well as their demographic and immunologic features, all 1,076 adult HIV-infected patients seen at our institution were grouped by the year of presentation. The patients' age and gender, the mode of presentation (admitted through the emergency department or seen at the outpatient clinic), and the presence of acquired immune deficiency syndrome (AIDS)-defining conditions and CD4 counts at the time of presentation were analyzed. The patients' age at presentation and the rate of female patients increased throughout time (p < 0.001, and p = 0.01, respectively). There was a progressive decline in the proportion of patients who were hospitalized until the mid-1990s (p < 0.0001), followed by a rise during the subsequent years (p = 0.04). This U-shaped curve was opposite to that of CD4 counts, which was ascending until 1994 (p = 0.04), to decline progressively later (p = 0.1). Patients whose first contact with the hospital was through admission had lower CD4 counts (p = 0.007), and higher rates of AIDS diagnosis throughout time (p < 0.0001). We conclude that some features of HIV-infected patients at the time of their first contact with the health services are changing over time, such as older age, increasing numbers of women, and higher degrees of immunosuppression. These findings seem to reflect the increasing number of patients unaware of their past risk factors, and should be considered for the development of strategies targeted to this population in order to allow earlier detection of their infection.

Concomitant cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy plus highly active antiretroviral therapy in patients with human immunodeficiency virus-related, non-Hodgkin lymphoma

BACKGROUND

The feasibility and efficacy of concomitant chemotherapy and highly active antiretroviral therapy (HAART) is still unknown in patients with human immunodeficiency virus (HIV)-related malignancies. To evaluate the impact of chemotherapy plus HAART on the clinical course of patients with HIV-related, systemic, non-Hodgkin lymphoma (HIV-NHL), the authors compared retrospectively a group of 24 patients with HIV-NHL who were treated with the cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy regimen plus HAART with a group of 80 patients who were treated with CHOP chemotherapy or a CHOP-like regimen (i.e., cyclophosphamide, doxorubicin, teniposide, and prednisone with vincristine plus bleomycin) without receiving antiretroviral therapy.

METHODS

All patients were enrolled in two sequential trials performed at the Aviano Cancer Center, Italy, from April 1988 to December 1998. HAART was included with combination therapy from January 1997. Antiretroviral regimens consisted of two reverse transcriptase inhibitors and one protease inhibitor.

RESULTS

The two treatment groups were well matched with regard to patient demographics, NHL characteristics, HIV status, and treatment, i.e., the number of cycles and chemotherapy dose. The response rates were similar between the two groups. Severe anemia (Grade 3-4 according to the World Health Organization criteria) was significantly greater in the patients who received CHOP-HAART compared with the patients who received CHOP alone (33% vs. 7%, respectively; P = 0.001). Leukopenia was similar between the two groups, but colony stimulating factor support was significantly greater in the CHOP-HAART group than in the control group (92% vs. 66%, respectively; P = 0.03). Seventeen percent of CHOP-HAART patients developed severe autonomic neurotoxicity, whereas none of the CHOP patients developed neurotoxicity (P = 0.002). At similar median follow-up, opportunistic infection (OI) rates and mortality were significantly lower in the CHOP-HAART patients than in the CHOP patients (18% vs. 52%, respectively; P = 0.05; and 38% vs. 85%, respectively; P = 0.001). The median survival for CHOP-HAART patients was not reached, whereas the medial survival of CHOP patients was 7 months (P = 0.03).

CONCLUSIONS

The combination of CHOP plus HAART is feasible and may reduce the morbidity from OIs in HIV-NHL patients. However, careful attention must be directed to cross toxicity and possible pharmacokinetic interactions between antiretroviral and antineoplastic drugs. The impact of the combined chemotherapy plus HAART treatment on patient survival needs urgently to be evaluated in prospective studies.

How complete is AIDS surveillance in Europe? An eagle eye comparison with mortality data

OBJECTIVES

Preliminary assessment of the adequacy of AIDS surveillance efforts in Europe by comparing data from two official sources-AIDS surveillance and mortality statistics.

METHODS

The study used ENAADS (European Non-Aggregate AIDS Data Set) data compiled by the European Centre for the Epidemiological Monitoring of AIDS in St Maurice, France, and mortality statistics from WHO. As ENAADS provides information about AIDS incidence as well as AIDS mortality, both series were compared with WHO mortality data. Western European countries with more than 1000 adult AIDS cases as of July 1997 were included in the cross country comparative analyses.

RESULTS

AIDS surveillance and mortality statistics in Europe depict four different patterns: (1) high overall concordance (Austria, Italy, Switzerland); (2) concordance between incidence by ENAADS and mortality by WHO, but a delay in mortality reporting in ENAADS (France, Spain); (3) more cases in WHO mortality data than in ENAADS data (Germany, Portugal); (4) more cases in ENAADS data than in WHO mortality data (Sweden, United Kingdom, Greece, Belgium).

CONCLUSIONS

National AIDS surveillance systems in Europe exhibit important differences in terms of completeness and functionality. New challenges such as the introduction of effective but expensive and complex treatments will exert demands on surveillance efforts. Countries with discrepant AIDS and mortality data should try to improve and update their surveillance systems.

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.

Increasing proportion of late diagnosis of HIV infection among patients with AIDS in Italy following introduction of combination antiretroviral therapy

We analyzed trends over time and determinants of late diagnosis of HIV infection among people diagnosed with AIDS in 1986 to 1998 in a tertiary care center in Rome, Italy. Information on the date of a first HIV test was collected prospectively, in addition to data routinely collected for AIDS reporting. Patients with AIDS were defined as "late testers" if the time interval between first positive HIV test result and AIDS diagnosis was < or = 3 months. Overall, 503 people with AIDS of 1977 included in the analysis (25.4%) were late testers. the proportion of late testers decreased from 62.5% in 1986 to 16% in 1995. Thereafter, this proportion increased to 20.5% in 1996, 33.7% in 1997, and 36.6% in 1998. In multivariate analysis, the following variables were significantly associated with late testing: AIDS diagnosis in years 1986 to 1993 or 1997 to 1998 compared with 1995, male gender, age > or = 45 years, men who have sex with men, heterosexual contacts, or having unknown transmission mode compared with intravenous drug users, and being born outside Italy. Since 1996, the overall number of AIDS cases diagnosed at our center began to decrease whereas the number of late-testing AIDS patients did not decrease, resulting in an increasing proportion of late testers during the last 3 years of the study. This findings may reflect the effect of combination antiretroviral therapy in slowing progression to AIDS of HIV-infected persons aware of their status. A relevant number of people still discover their HIV infection late and may therefore miss treatment opportunities. New testing strategies are needed to reach more people who engage in high-risk behaviors, especially those at risk for sexual transmission, and those born outside Italy.

Pre-AIDS mortality and its association with HIV disease progression in haemophilic men, injecting drug users and homosexual men

OBJECTIVE

To study pre-AIDS mortality and its association with HIV disease progression in different exposure groups with known intervals of HIV seroconversion.

DESIGN AND METHODS

The type and rate of pre-AIDS deaths were assessed in 111 HIV-infected haemophilic men followed in London, and 118 injecting drug users and 158 homosexual men followed in Amsterdam. In each group, the association between CD4+ T-cell count, HIV RNA and pre-AIDS mortality was studied using proportional hazards analysis.

RESULTS

By 10 years after seroconversion 7.3% of the haemophilic men had died without AIDS and 38.2% had developed AIDS. These figures were 20.2 and 30.5% for injecting drug users, and 8.0 and 55.0% for homosexual men. The major causes of pre-AIDS mortality appear to differ in the three exposure groups. The risk of pre-AIDS death tended to increase with decreasing CD4 cell count and increasing HIV RNA levels in injecting drug users and homosexual men. In men with haemophilia the associations were less obvious, although the log-transformed CD4 cell count was predictive for pre-AIDS death.

CONCLUSIONS

Pre-AIDS deaths occur and are at least partially related to HIV disease progression irrespective of how individuals became infected. Because of the longer life expectancy due to highly active antiretroviral therapy (HAART), pre-AIDS deaths are likely to show a further increase. Methods to incorporate these intermediate outcomes should be considered in the estimation of the size of the HIV epidemic and in the survival analysis of HIV-infected individuals. Prevention and treatment of non-AIDS infections, especially hepatitis C virus infection, and cancers will become increasingly important in HIV-infected individuals. The interaction between these therapies and HAART should be closely monitored.

[Trends in the number of human immunodeficiency virus infected persons and AIDS cases in Spain: 1980-1998]

BACKGROUND

To describe the trend in the number of HIV-infected persons and the number of AIDS cases in Spain between 1980 and 1998.

SUBJECTS AND METHODS

The following information was used: annual incidence of AIDS taken from the National Registry, AIDS deaths taken from the same registry and from the Registry of Vital Statistics, HIV seroprevalence in studies in sentinel populations, HIV incidence in cohorts of exposed persons, and reports of HIV infections in the registries existing in the autonomous communities. We considered three events of interest--HIV infection, AIDS and death--which were related using back-projection and compartmental models.

RESULTS

HIV spread rapidly in Spain during the years 1980. Transmission subsequently declined by more than 50% to figures that probably do not exceed 6,000 new infections in 1998. The incidence of AIDS increased to more than 7,000 new cases in 1994 and has since declined to some 4,000 cases in 1998. The level of AIDS mortality has always been lower than the incidence; it increased up to 1995 and then dropped to less than half in subsequent years. The number of living persons infected with HIV, including AIDS cases, arose until the early years 1990 and has since remained steady at about 125,000 persons. The number of cases of living persons with AIDS has increased continuously, and is estimated at about 19,000 through the end of 1998.

CONCLUSIONS

The recent trend in new infections, AIDS cases and deaths is favourable, while the number of infected living persons remains very high.

Human herpesvirus 8 seropositivity and risk of Kaposi's sarcoma and other acquired immunodeficiency syndrome-related diseases

BACKGROUND

The incidence of Kaposi's sarcoma (KS) is increased severalfold in individuals infected with human immunodeficiency virus-1 (HIV). Human herpesvirus 8 (HHV8) has also been implicated in KS. We investigated several factors that may determine the onset of KS, particularly HHV8 infection in individuals after becoming seropositive for HIV.

METHODS

We studied 366 individuals belonging to different HIV-exposure categories (i.e., homosexual activity, intravenous drug use, and heterosexual contact) for whom a negative HIV serologic test and then a positive HIV serologic test were available within a 2-year period. HHV8 antibody testing was performed by use of an immunofluorescence assay on the first serum sample available after the first positive HIV test. Actuarial rates of progression of KS and of other acquired immunodeficiency syndrome (AIDS)-defining diseases were estimated by use of time-to-event statistical methods. All statistical tests were two-sided.

RESULTS

Twenty-one of the 366 study participants developed AIDS-related KS, and 83 developed AIDS without KS. One hundred forty (38.3%) participants had detectable anti-HHV8 antibodies. The actuarial progression rate to KS among persons co-infected with HIV/HHV8 was nearly 30% by 10 years after HIV seroconversion. Increasing HHV8 antibody titers increased the risk of developing KS (for seronegative versus highest titer [1:125 serum dilution], adjusted relative hazard [RH] = 51.82; 95% confidence interval [CI] = 6.08-441.33) but not of other AIDS-defining diseases (adjusted RH = 1.14; 95% CI = 0.72-1.80). HHV8-seropositive homosexual men compared with HHV8-seropositive participants from other HIV-exposure categories showed an increased risk of KS that approached statistical significance (adjusted RH = 6.93; 95% CI = 0.88-54.84).

CONCLUSIONS

Approximately one third of individuals co-infected with HIV/HHV8 developed KS within 10 years after HIV seroconversion. Progression to KS increased with time after HIV seroconversion. Higher antibody titers to HHV8 appear to be related to faster progression to KS but not to other AIDS-defining diseases.

Temporal changes in the rate of progression to death among Italians with known date of HIV seroconversion: estimates of the population effect of treatment. Italian HIV Seroconversion Study (ISS)

OBJECTIVE

To evaluate changes in survival among HIV-positive individuals with known date of seroconversion (SC).

DESIGN

Prospective cohort study.

METHODS

Follow-up lasted from SC to death or to the end of 1997. A multivariate Cox model was applied to estimate relative hazards (RH) of death. The year of SC (as a categoric fixed variable) and calendar year (as a time-dependent variable) were considered to evaluate, respectively, cohort and prevalent changes in the rate of death. A separate Cox model was used to assess the association between survival and new combination therapies, using an "intention to treat" approach.

RESULTS

The study included 1535 individuals (53.9% injecting drug users, 25.3% homosexuals, 19.5% heterosexuals); 75.8% seroconverted between 1980 and 1991, and 24.2% seroconverted between 1992 and 1997. When adjusting for year of SC, the RH of death (and that of AIDS) was significantly lower in 1997, compared with before 1991 (RH = 0.54; 95% confidence interval, 0.30-0.98). Adjusted RHs of death were significantly lower for combination antiretroviral therapy, compared with no therapy. When combining the two Cox models, the 1997 reduction in risk of death was largely due to antiretroviral therapies; similar results were obtained when the endpoint was AIDS.

CONCLUSIONS

A reduction in the risk of death, probably due to combination antiretroviral therapy, was observed in 1997 after having adjusted for age at SC and year of SC.

ICU admission in patients infected with the human immunodeficiency virus - a multicentre survey

We conducted a retrospective study to assess the reasons for admission to the intensive care unit, and subsequent outcome, in patients infected with the human immunodeficiency virus (HIV). Four hospitals in the south of England participated, all with specialist HIV units. Data were collected on 127 patients admitted to ICU on 133 separate occasions between June 1993 and October 1997. The mean age on admission was 38 years (range 23-60 years). Ninety-four patients (70.7%) were documented HIV-positive before admission and 36 (27%) were diagnosed HIV-positive for the first time during admission; 36.1% were admitted with Pneumocystis carinii pneumonia. Overall ICU mortality was 33%, in-hospital mortality was 56% and the eventual mortality at the end of follow-up (March 1998) was 72%. Survival was highest in those admitted with respiratory HIV-related disease or HIV-unrelated illness. Associations with poor outcome included a prior AIDS-defining illness, a CD4 cell count of less than 100 cells.ml-1 and admission secondary to sepsis.

Changing spectrum of HIV infection and its associated conditions in Spain: the end of the beginning?

To evaluate the natural history and the impact that different strategies have had on HIV infection and its associated conditions, a cohort of 970 patients (432 had AIDS) who had been seen over a period of 13 years were studied. The incidence of new HIV-infected patients had increased steadily since 1985, peaking in 1993 (52.9 cases/100,000 population), to significantly decrease in the subsequent years. The most common AIDS-defining illnesses (ADIs) were tuberculosis (52.3% of the patients), Pneumocystis carinii pneumonia (30%), and candidal esophagitis (28.6%). The frequency of new cases of tuberculosis per patient with ADI clearly decreased over this period (p < 0.0001), whereas that of P. carinii pneumonia decreased slowly until 1994, to fall thereafter to about half the previous levels (p = 0.005). Candidal esophagitis showed a biphasic pattern, the second peak probably due to the emergence of fluconazole resistance. The number of ADIs per patient increased from the beginning of the observation period, peaking in 1995 (1.67 ADI/patient), followed by a statistically significant decrease that, in 1997, reached the 1987 levels (1.22 ADI/patient). We conclude that the clinical spectrum of HIV infection is improving in the last years. Except for tuberculosis, prophylaxis for other ADIs, although effective, does not seem to have had a dramatic impact on occurrence. The most impressive reductions have been observed only after the introduction of antiretroviral combination therapy.

Serum IgG antibodies to human herpesvirus-6 (HHV-6) do not predict the progression of HIV disease to AIDS. Italian Seroconversion Study group

OBJECTIVES

To evaluate if different levels of human herpesvirus 6 (HHV-6) antibodies can predict HIV disease progression.

DESIGN

Longitudinal study of individuals with a documented date of HIV seroconversion.

SETTING

Clinical centers located throughout Italy.

PATIENTS

Individuals who serconverted for HIV between 1983 and 1995 in Italy.

METHODS

Sera were tested for IgG antibodies to HHV-6 using a commercial enzyme immunoassay. A serum sample with an optical density (OD) > or =242 (i.e. the mean value of 10 negative controls +4x standard deviation) was considered as HHV-6 positive; the progression of HIV disease was evaluated estimating the relative hazards (RH) of AIDS (by Cox models) for individuals with higher levels vs. lower levels of HHV-6 antibodies or considering levels of antibodies based on 10% increase of the distribution (deciles). Rates of CD4 decline fitting linear regression were also estimated.

RESULTS

A total of 381 persons were followed for a median time of 4 years (range: 0.15-9 years) following the date of collection of the serum sample. The median OD value of HHV-6 antibodies was 306, with an interquartile range of 241-440 and a range of 48-2330. A slight inverse correlation was found between HHV-6 antibody levels and age of the individual at the time of serum collection (Spearman rank correlation coefficient, -0.16; p = 0.0013). No association was found between HHV-6 and CD4 level or between HHV-6 and CD8 level at the date of serum collection. The unadjusted RH of progression to AIDS was 0.63 (95% CI: 0.42-0.96) for HHV-6 positive individuals vs. HHV-6 negative; when adjusting for possible confounders (CD4, age, pre-AIDS HIV-related pathologies at the date of sera collection, and previous anti-herpes treatment), the RH of AIDS increased to 0.80 (95% CI: 0.51-1.23). No particular association with HIV disease progression was found when using the deciles of the distribution of HHV-6 antibodies. The median CD4 cell loss was 5.0x10(6) cells/l per month among HHV-6 positive individuals and 5.7x10(6) cells/l per month among the others.

CONCLUSIONS

The presence of high levels of HHV-6 antibodies does not seem to predict the clinical or immunologic progression of HIV disease.

CD4+ and CD8+ lymphocytes and HIV RNA in HIV infection: high baseline counts and in particular rapid decrease of CD8+ lymphocytes predict AIDS

OBJECTIVE

To study the progression of HIV infection in relation to immunological and virological variables with emphasis on the role of CD8+ lymphocytes.

DESIGN

Prospective follow-up from October 1991 of patients observed for at least 18 months allowing nucleoside analogue monotherapy. Peripheral CD4+ and CD8+ lymphocyte counts, HIV RNA, and soluble CD8 were analysed by statistics allowing the evaluation of serial data, avoiding time points with concurrent infections.

SETTING

Tertiary university clinic.

PATIENTS

Forty-nine patients were followed for 52.6 months, baseline CD4+ count of 300 x 10(6)/l, sample interval of 5.9 months (medians).

MAIN OUTCOME MEASURES

AIDS, death, and CDC groups B- or C-related events.

RESULTS

AIDS developed in 28% of patients. Baseline CD8+ counts above the median were significantly associated with AIDS development; the best Cox model included CD8+ cells and the log10RNA/CD4 ratio. A decline in CD8+ counts relative to baseline most significantly predicted AIDS, along with higher baseline RNA and actual CD4+ counts of less than 200 x 10(6)/l. Levels of soluble CD8 in the blood relative to total CD8+ cells significantly increased in patients developing AIDS. Death occurred in 16% of the patients, and was only predicted by high CD8+ cell counts at baseline. CDC B- and C-related events occurred in 35% of the patients and were best predicted by high baseline CD8+ counts and high RNA levels.

CONCLUSIONS

The serial quantitation of CD8+ lymphocytes gave highly significant predictive information on the natural progression of HIV infection in patients with moderate to severe immune deficiency. Our data suggest that the hyperactivation of CD8+ lymphocytes is an important factor leading to a numerical decrease of CD8+ lymphocytes in progressive HIV infection.

Increasing survival time after AIDS in Italy: the role of new combination antiretroviral therapies. Tuscany AIDS Study Group

BACKGROUND

In Italy, antiretroviral combination therapy was adopted in mid-1995 and protease inhibitors in mid-1996.

OBJECTIVE

To conduct a prospective, population-based, observational study to evaluate the effect of these therapies on the survival of persons with AIDS (PWA).

METHODS

PWA living in the Tuscany region diagnosed between 1985 and 31 March 1997 (National AIDS Registry) were studied. Information on antiretroviral drugs, prophylactic treatment, CD4 cell count, and AIDS-defining illnesses was collected for PWA still alive at 1 January 1996 and those diagnosed thereafter (analysis cut-off date, 30 November 1997). Kaplan-Meier curves were calculated by year of diagnosis. A Cox model was then used to estimate the adjusted (by sex, age, HIV exposure category, CD4 cell count, type and number of AIDS-defining illnesses) relative hazard (RH) of death by year of diagnosis and calendar date (considered as a time-dependent variable). Similar analyses were repeated for PWA diagnosed after 1989, having been stratified by disease-specific AIDS condition. A final analysis was performed for PWA still alive at 1 January 1996 or diagnosed thereafter for estimating the effect of single, double and triple combination therapy (time-dependent variables), having adjusted for the above variables and for prophylactic treatment.

RESULTS

A total of 1683 (79.5%) out of 2118 PWA died before 1 December 1997. Use of more potent combination therapies, including protease inhibitors, greatly increased during 1997. Median survival was 2.9, 12.3, 13.4, 11.4 and 17.6 months for diagnoses before 1987, in 1987-1990, 1991-1993, 1994 and 1995, respectively; an estimated 62% of those diagnosed in 1996-1997 had survived 15 months after diagnosis. The Cox model showed a trend of decrease of RH for calendar time starting in the first half of 1996, compared with 1994. When stratifying by specific AIDS-defining disease there was no statistically significant evidence that the improved overall survival was due to increased survival only for certain diseases. The final multivariate analysis for the 771 PWA still alive at 1 January 1996 or diagnosed thereafter estimated significant RH < 1.0 for double and triple therapy (RH, 0.61 and 0.36, respectively) compared with no therapy.

CONCLUSIONS

A significant reduction in risk of death after AIDS was observed from the second half of 1996, apparently due to the widespread use of antiretroviral combination therapies.

Risk of cancer in patients with HIV disease. London African HIV/AIDS Study Group

The aim of this study was to compare cancer incidence in a cohort of HIV-infected patients with the incidence rates in the population of South East England. Data collected for a retrospective cohort study of 2048 HIV-infected patients were analysed to examine the incidence of cancer. Cases of cancer occurring in South East England from 1985-1995 were obtained from the Thames Cancer Registry. Standardized incidence ratios were calculated by comparison of the observed number of cases for each cancer type in HIV-infected non-Africans with the numbers expected, calculated from the age and sex specific registration rates for the South East England population using person-years of observation. The crude incidence rates of cancer were calculated for HIV-infected Africans. The incidence of non-AIDS defining cancers such as Hodgkin's disease (standardized incidence ratio 22; 95% CI: 3-80) and anal cancer (standardized incidence ratio 125; 95% CI: 3-697) were significantly increased for non-African males with HIV disease. Anal cancer was also significantly increased for non-African females (standardized incidence ratio 1667; 95% CI: 43-9287). Kaposi's sarcoma (KS) was the commonest cancer among HIV-infected Africans and males had an incidence which was nearly 3 times that of females. There is evidence to suggest that the risks for other non-AIDS defining cancers were significantly increased in persons with HIV disease which may have implications for HIV/AIDS surveillance.

The estimated impact of the CCR-5 delta32 gene deletion on HIV disease progression varies with study design. Oslo HIV Cohort Study Group

OBJECTIVES

To study the impact of the genotype CCR-5 wild-type +/A32 on the progression rate to AIDS and death, and to discuss sources of bias according to study design.

METHODS

A prospective study of 310 HIV-positive subjects with follow-up time from study entry (prevalent cohort), and a prospective study of 105 HIV-positive subjects with well-defined time of HIV seroconversion, with follow-up time from the retrospectively assessed date of HIV seroconversion (retrospective incident cohort).

RESULTS

Slower progression to AIDS among subjects with CCR-5 +/delta32 than those with CCR-5 +/+ genotype was estimated in the prevalent cohort (P=0.07, log-rank test). Slower progression to death from any cause was also estimated for subjects with CCR-5 +/delta32 (P < 0.05, log-rank test). No differences in survival after AIDS diagnosis were seen (P=0.89, log-rank test). No differences in the progression rate to AIDS (P=0.82, log-rank test) or death (P=0.78, log-rank test) were estimated in the retrospective incident cohort.

CONCLUSIONS

The varying estimates of the impact of CCR-5 genotype on progression to AIDS in this and other studies, may be real and reflect differences in the dependence of HIV on the CCR-5 receptor, or may be due to systematic errors caused by study design. Several methodological difficulties occur when the factor studied, such as CCR-5 genotype, is associated both with the risk of being HIV-infected and the progression of disease.

Hospitalization parameters in patients infected with HIV: an analysis of the period 1992-1997

The course of several hospitalization parameters of HIV-infected patients in a general hospital during the past 6 years was analyzed. There was a decrease observed in the number of non-AIDS diagnosed patients admitted during the observation period, but this decrement was noted only in the past 2 years in AIDS patients. This decline was not accounted for by a decrease in the incidence of AIDS patients seen each year, and was very probably due to the efficacy of antiretroviral combination therapy. The average length of stay of both AIDS and non-AIDS diagnosed patients decreased markedly during the first 3 years to stabilize during the remaining observation period. An analysis of the mode in which the patients were seen for the first time in the hospital (admitted from the emergency department because of complications of advanced HIV infection or attended in the outpatient clinic) revealed that, after a steady decrease from 1985 to 1995 in the relative proportion of patients hospitalized (p < 0.0001), there was an inversion of the downward trend in the past two years (p = 0.04). Most of the patients admitted during these 2 years were persons who did not know that they were infected with HIV. This observation reinforces the need for education campaigns and voluntary HIV testing which are particularly directed toward persons with high risk factors for the infection, in order to provide medical care before complications of advanced HIV infection appear.

Adenoidal and tonsillar lymphocyte subsets in AIDS children

Tonsils and adenoids are secondary lymphoid organs exposed to the environment. The most important classifications of AIDS include the lymphocyte subsets of peripheral blood. We have studied the lymphocyte subsets in peripheral blood and secondary lymphoid organs in a control group of children suffering adenotonsillar pathology and in five children with AIDS and the same adenotonsillar pathology. The antigen surface markers were determined by flow cytometry in lymphocytes isolated from peripheral blood, and from tonsils and adenoids after tonsillectomy and adenoidectomy, in the control group and in children diagnosed with AIDS. The most important findings in tonsils and adenoids were a decrease of the total T lymphocytes, helper T lymphocytes and CD4/CD8 ratio; an increase of cytotoxic T lymphocytes and B lymphocytes, as well as a 200% increase in monocytes of AIDS-affected children. These observations show the value of analyzing the lymphocyte subsets of the tonsils and adenoids of AIDS-affected children, and establishing an earlier relation to clinical symptoms.

Disease progression and survival in HIV-1-infected Africans in London

OBJECTIVE

To examine differences in progression to AIDS and death between HIV-1-positive Africans (most infected in sub-Saharan Africa and therefore with non-B subtypes) and HIV-1-positive non-Africans in London.

DESIGN

Retrospective cohort study of 2048 HIV-1-positive individuals.

SETTING

HIV-1-infected individuals attending 11 of the largest HIV/AIDS units in London.

PATIENTS

Subjects were 1056 Africans and 992 non-Africans seen between 1982-1995.

RESULTS

There were no differences in crude survival from presentation to death between Africans and non-Africans (median 82 and 78 months, respectively; P = 0.22). Africans progressed more rapidly to AIDS [hazard ratio (HR), 1.21; 95% confidence interval (CI), 1.02-1.45] but after adjustment for age, sex, Centers for Disease Control and Prevention category B symptoms and CD4+ lymphocyte count at presentation, year of HIV diagnosis and hospital attended, this difference was no longer significant (adjusted HR, 1.15; 95% CI, 0.93-1.43). Africans with AIDS had a reduced risk of death compared with non-Africans (HR, 0.78; 95% CI, 0.63-0.96) but not after adjustment for age, CD4+ lymphocyte count at AIDS, initial AIDS-defining conditions (ADC) and hospital attended (HR, 0.98; 95% CI, 0.76-1.27). Tuberculosis as the first ADC was associated with a 64% reduction in the risk of death. CD4+ lymphocyte decline was not significantly different between Africans and non-Africans (P = 0.18).

CONCLUSIONS

Differences in progression to AIDS and death and CD4+ lymphocyte decline between HIV-1-infected Africans and non-Africans in London could not be attributed to ethnicity or different viral subtypes. Age and the clinical and immunological stage at presentation, or AIDS, were the major determinants of outcome. Compared with other diagnoses, tuberculosis as the initial ADC was associated with increased survival. Lack of access to health care and exposure to environmental pathogens are the most likely causes of reduced survival with AIDS in Africa, rather than inherently different rates of progression of immune deficiency due to racial differences or viral subtypes.

Determinants of delayed diagnosis of HIV infection in France, 1993-1995

OBJECTIVE

To describe the circumstances of the first HIV-positive test and to study the determinants of a delayed diagnosis of HIV infection.

METHODS

In a retrospective study among adult AIDS patients diagnosed between July 1993 and May 1995 in two French districts, data on socioeconomic characteristics, circumstances of first HIV-positive test and attitudes and behaviours regarding medical care were collected in a confidential interview and analysed for potential association with a late test, defined as a first HIV-positive test within 6 months of AIDS diagnosis.

RESULTS

Of the 359 AIDS patients studied, 69 (19.2%) had a late test. Late testers were more likely than other patients to have had an HIV-positive test because of clinical symptoms (89.7 versus 38.9%, P < 0.001) and not to perceive themselves as being at risk of infection with HIV (53.6 versus 39.3%, P < 0.05). The proportion of late testers was 34.6% among heterosexually infected patients, 12.7% among homo-/ bisexual men and 9.6% among injecting drug users. Factors independently associated with a late test were male gender [adjusted odds ratio (aOR), 5.6; 95% confidence interval (CI), 1.7-18.9] and absence of earned income (aOR, 5.2; 95% CI, 1.4-19) among heterosexually infected patients; high education (aOR, 3.1; 95% CI, 1.0-9.6) and having consulted a person practising alternative medicine (aOR, 3.4; 95% CI, 1.2-10) in homo-/bisexual men.

CONCLUSIONS

Despite incentives to be tested for HIV, many individuals in France are still tested too late, even if they are in known high-risk groups. Efforts to test HIV-infected people as early as possible should be made by increasing the perception of HIV risk and decreasing the level of missed opportunities for testing. Current case management approaches make this recommendation critically important from both public health and an individual perspective.

Frequency and determinants of use of antiretroviral and prophylactic therapies against Pneumocystis carinii Pneumonia (PCP) before AIDS diagnosis in Italy

To determine the frequency and the determinants of use of antiretroviral drugs and prophylaxis for Pneumocystis carinii Pneumonia (PCP) among HIV-infected individuals before AIDS diagnosis, a questionnaire was sent to all physicians reporting at least one AIDS case during the first six months of 1994 to the Italian National AIDS Registry. Information on cases diagnosed between 1 January and 31 March 1995 was collected. Information was obtained for 878 (66.4%) of the 1323 persons with AIDS: 447 (50.9%) had received antiretroviral drugs and 343 (39.1%) PCP prophylaxis, whereas 303 cases (34.5%) had received both. Individuals who became aware of being HIV-positive shortly before AIDS diagnosis were less likely to have started antiretroviral therapy (adjusted odds ratio (AOR): 0.05, 95% CI: 0.03-0.09). Homosexual men and heterosexuals were more likely to begin therapy (AOR: 1.40, 95% CI: 0.83-2.37 and AOR: 1.79, 95% CI: 1.05-3.05, respectively) compared to injecting drug users. Individuals living in Southern Italy and foreigners were less likely to start therapy (AOR: 0.75, 95% CI: 0.49-1.16 and AOR: 0.40, 95% CI: 0.15-1.09, respectively) compared to those living in Northern Italy. Results were similar for PCP prophylaxis. Lack of awareness of HIV infection, HIV exposure category, and geographical area were the most important factors associated with treatment before AIDS diagnosis.

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.

Geography of AIDS-associated Kaposi's sarcoma in Europe

BACKGROUND

Classical Kaposi's sarcoma (KS) is about four times more common in southern Europeans than in northern Europeans.

OBJECTIVE

To describe the epidemiology of AIDS-associated KS (AIDS-KS) in Europe and to determine whether it occurs with increased frequency in southern Europe.

METHODS

Analysis of the 'European non-aggregate AIDS data set', as of September 1995. Countries with a cumulative total of > or = 50 KS cases as the presenting manifestation of AIDS were included. Homosexual men were excluded from south versus non-south comparisons because of possible confounding effects due to their route of HIV transmission.

RESULTS

KS was the presenting manifestation of AIDS for 13.3% (16,367 out of 122,679) of men and 2% (491 out of 24,826) of women. In all countries, the risk for KS was higher in individuals who acquired HIV infection via sexual rather than parenteral transmission. Among AIDS patients, there is little difference by sex in the risk of KS in injecting drug users (IDU) or transfusion recipients. The percentage with KS increased with age among homosexual and bisexual men, from 10% in the age group 15-19 years to 23% in the age group 30-39 years. In all countries, the percentage with KS declined over time. The risk of KS was not significantly higher in southern Europe. The percentage with KS in southern Europe was slightly lower than in northern Europe (P > 0.1) in male IDU (1.8% versus 2.1%), and only slightly higher (P > 0.1) in female IDU (1.5% versus 1.1%), in male transfusion recipients (3.5% versus 3.0%), in female transfusion recipients (2.4% versus 2.3%), and in both heterosexual men (7.5% versus 6.2%) and women (2.0% versus 1.6%) excluding those originating from countries where heterosexual HIV transmission is frequent.

CONCLUSIONS

The strong geographic predilection described for classical KS in southern Europe was not seen for AIDS-KS. If KS is caused by a viral infection in an immunodeficient host, our findings suggest the geographical variations in classical KS are not due to variation in prevalence of the causative virus but may be due to geographical variations in the prevalence of a form of mild immunodeficiency.

Pulmonary and extrapulmonary tuberculosis at AIDS diagnosis in Spain: epidemiological differences and implications for control

OBJECTIVE

To ascertain the differential factors associated with pulmonary versus extrapulmonary tuberculosis (TB) at AIDS diagnosis in Spain.

DESIGN

Analysis of AIDS surveillance data.

METHODS

Data about AIDS patients, aged 12 years and over, diagnosed in 1995 were taken from the Spanish AIDS Register. The respective proportions of cases presenting with pulmonary and extrapulmonary TB at AIDS diagnosis were analysed by gender, age, HIV transmission category, prison record, province, country of origin and CD4+ lymphocyte count. A multivariate analysis was carried out using logistic regression analysis.

RESULTS

Of 6161 AIDS cases analysed, 20.1% presented with pulmonary TB and 20.4% with extrapulmonary TB. Overall, TB showed association with men, age under 30 years, injecting drug users (IDU), cases of heterosexual HIV transmission, and concurrent or past stay in prison. Frequency of TB proved no different among foreign-born patients. Pulmonary and extrapulmonary TB showed a similar distribution for most of the variables. Current prison inmates registered a high risk of pulmonary TB [adjusted odds ratio (OR), 4.2; 99% confidence interval (CI), 3.1-5.8] compared with patients without prison record, and ex-prison inmates registered an intermediate risk (OR, 2.3; 99% CI, 1.8-3.0). Among patients with TB at AIDS diagnosis, pulmonary TB was associated with subjects currently in prison (OR, 2.1; 99% CI, 1.5-3.0) and injecting drug use (OR, 1.5; 99% CI, 1.0-2.4). Pulmonary TB presented with higher CD4+ lymphocyte counts than extrapulmonary TB (P < 0.001).

CONCLUSIONS

The results suggest the importance that recent transmission of TB may be having among young adults, IDU and prison inmates in particular, and calls for a review of control strategies.

The AIDS epidemic among Spanish drug users: a birth cohort-associated phenomenon

OBJECTIVES

In Spain the number of new acquired immunodeficiency syndrome (AIDS) cases among injection drug users continues to rise. The time trend up to 1994 has been analyzed, with special attention paid to the different generations.

METHODS

The source for injection drug use-related cases was the Spanish AIDS Register. Independent analyses of annual specific rates were run for each sex with the use of an age-period-cohort log-linear model.

RESULTS

After adjustment for age and year of diagnosis, AIDS incidence related to injection drug use is associated with specific birth cohorts. Rising values are observed in the successive generations born during the 1950s, peaking in men born in 1962 and women born in 1964. In subsequent cohorts, there is a marked falloff in incidence for both sexes, but this decline is seen to halt in men from the 1972 birth cohort onwards. The overall period effect is upward, yet the trend flattens in the last years. There is a pronounced age effect with maximum values in men and women at ages 29 and 27, respectively.

CONCLUSIONS

It is essential to urge avoidance of risk behaviors in new generations.

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

OBJECTIVES

To reconstruct the HIV epidemic and to provide forecasts of AIDS incidence among adults in the European Union (EU) and in a group of low prevalence (LP) countries of central and eastern Europe (including the Asian republics of the former Soviet Union).

METHODS

An empirical Bayesian back-calculation method was applied to AIDS incidence data reported by 31 March 1994. The HIV-infection curve was modelled as a yearly step function and a seven-stage Markov model of disease progression, incorporating effects of pre-AIDS treatment, was used. Estimation was by penalized maximum likelihood with empirical Bayesian smoothing. Data were analysed by transmission group and, within the EU, by country. Predictions of AIDS cases to 1998 were made assuming constant annual HIV incidence from 1993 onwards.

RESULTS

Estimated HIV prevalences per 100,000 population aged 15-59 years were, at 31 December 1993, 198 (n = 447,800) in the EU and 2.7 (n = 6840) in the 22 LP countries, with increases of 41% (EU) and 71% (LP) between 1989 and 1993. Among homo/bisexual men in the EU, prevalence appears to have stabilized since 1989 and AIDS incidence appears to be reaching a peak. Among all prevalent HIV infections in the EU, 42% were estimated to be among injecting drug users, 25% among homo-/bisexual men and 18% among persons infected heterosexually, compared with 29%, 35% and 19%, respectively, in the LP countries. Without allowing for the 1993 revision of the case definition, annual AIDS incidence is predicted to increase, between 1994 and 1998, by 24% in the EU and by 48% in the LP countries, with the largest percentage increases among heterosexually-infected persons.

CONCLUSION

The overall HIV prevalence rate is estimated to have been about 70-fold lower in the LP countries than in the EU in the early 1990s, but to be increasing much more rapidly in the former. Moreover, recent reports of rapidly increasing HIV infection rates suggest that back-calculation may seriously underestimate the size of the epidemic in the LP countries. Implementation of effective preventive measures is urgent if large-scale epidemics are to be avoided in the presently LP countries of the European region.

The natural history of human immunodeficiency virus infection among women as compared with men

There has been growing interest in the issue of human immunodeficiency virus infection among women, both because of the increasing number of women worldwide infected in recent years (and consequently a higher number of infected children) and because of the higher efficacy of male-to-female transmission of human immunodeficiency virus, which leads to higher risk for women of acquiring the infection compared with men. The present reviews is an attempt to outline the main results obtained from the most recent longitudinal studies conducted among cohorts of human immunodeficiency virus-positive individuals that include analyses of the differences between males and females in the progression of the infection. No evidence of major gender differences between males and females in progression to acquired immune deficiency syndrome or to death is shown by any o the reviewed articles.

Low doses of zidovudine plus didanosine are less effective than higher doses of didanosine monotherapy: a randomized trial in patients pretreated with zidovudine

OBJECTIVE: To compare the clinical efficacy and tolerance of didanosine (ddl) monotherapy with low-dose zidovudine/didanosine (AZT/ddl) therapy among HIV-infected patients previously treated with AZT. METHODS: A randomized controlled trial was carried out of ddl 400 mg daily versus AZT/ddl 300/200 mg daily among patients with CD4 cell counts </=350 mm3 and prior AZT treatment for at least 16 weeks. Fifty eight patients received ddl monotherapy and 66 combined treatment. RESULTS: Patients were similar with respect to demographic, clinical and laboratory characteristics, and prior AZT treatment. Median duration of follow-up was 17.3 months. In the ddl group, 20 patients (34%) discontinued treatment because of toxicity, compared to 19 (29%) in the AZT/ddl group (p=0.38). There was no statistically significant difference in CD4 change between the two groups. In the ddl group, 16 patients (28%) developed a clinical endpoint (death or AIDS-defining opportunistic infection), compared to 33 (50%) in the combined therapy group (relative risk 1.8; 95% confidence interval 1.1-2.9; p=0.01). CONCLUSIONS: For fairly advanced AZT-pretreated patients, monotherapy with ddl was clinically and statistically superior to the low-dose AZT/ddl combination in preventing AIDS-defining illness and death. When access to drugs is limited, e.g. in under-resourced countries, combining available drugs and reducing dosage may be less effective than a single drug at the conventional dosage.

The effect of the 1993 European revision of the AIDS case definition in Italy: implications for modelling the HIV epidemic

OBJECTIVES

To evaluate the effect of the 1993 European AIDS definition on reducing pre-AIDS mortality and to what degree an earlier diagnosis can be made.

DESIGN

Prospective observational study.

METHODS

All patients diagnosed between January 1993 and December 1994 and reported to the National AIDS Registry from four Italian regions, who met only the new criteria for the 1993 case definition (AIDS-1993) were studied. Follow-up of patients who did not eventually meet the 1987 definition (AIDS-1987), or had not died from other causes (pre-AIDS-1987 death), was censored at the last available clinical visit before 1 April 1996. We analysed the data using Kaplan-Meier non-parametric survival analysis and Cox proportional hazards model.

RESULTS

A total of 74 (4.1%) individuals met only the new criteria. Of these, 49 (62.2%) were men, 42 (56.8%) had pulmonary tuberculosis, 22 (29.7%) had recurrent bacterial pneumonia, and 10 (13.5%) had cervical cancer. During follow-up, 35 (45.3%) individuals developed an AIDS-1987 disease, and 10 (13.5%) died without fulfilling the AIDS-1987 definition. Pre-AIDS-1987 death accounted for 22.2% (10 out of 45) of the subsequent outcomes observed prior to 1 April 1996. Using Kaplan-Meier technique, we estimated that after 9.8 months 50% of these individuals were diagnosed with AIDS-1987 disease, or died without such a diagnosis. Individuals with lower CD4+ count at the time of the AIDS-1993 diagnosis progressed more rapidly to AIDS-1987 than those with a higher count. In contrast, pre-AIDS-1987 mortality was strongly associated with injecting drug use, whereas no association was found with CD4+ count.

CONCLUSIONS

Approximately 50% of individuals with one of the three new AIDS-defining diseases will develop an AIDS-1987 disease or will die within 1 year. Time from AIDS-1993 to AIDS-1987 disease is strongly associated with CD4+ count at diagnosis. AIDS_1993 diagnosis reduced the pre-AIDS-1987 mortality in injecting drug users. Furthermore, approximately 20% of individuals diagnosed with AIDS-1993 disease are expected to die without developing an AIDS-1987 disease. These data should be useful for correcting the AIDS incidence curve in Europe for the effect of the changes in the AIDS definition.

Category of exposure to HIV and age in the progression to AIDS: longitudinal study of 1199 people with known dates of seroconversion. HIV Italian Seroconversion Study Group

OBJECTIVES

To determine whether rate of development of AIDS is affected by category of exposure to HIV and whether the more rapid development found in older subjects persists for each exposure category.

DESIGN

Longitudinal study of people with known date of seroconversion to HIV.

SETTING

16 HIV treatment centres throughout Italy.

SUBJECTS

1199 people infected with HIV through use of injected drugs, homosexual sex, or heterosexual sex.

MAIN OUTCOME MEASURES

AIDS as defined by 1987 definition of Centers for Disease Control (including and excluding neoplasms) and by 1993 European definition.

RESULTS

225 subjects (18.8%) progressed to AIDS (Centers for Disease Control 1987 definition) during median follow up of 5.8 years. Univariate analyses showed more rapid progression to AIDS for older subjects compared with younger subjects and for homosexual men compared with other exposure categories. The age effect was of similar size in each exposure category and in men and women. In a bivariate model with age and exposure categories simultaneously included as covariates, differences by exposure category disappeared for use of injected drugs and heterosexual sex compared with homosexual sex (relative hazards 1.02 (95% confidence interval 0.71 to 1.45) and 1.07 (0.70 to 1.64) respectively), while the age effect remained (relative hazard 1.55 (1.32 to 1.83) for 10 year increase in age). Analyses using the other definitions for AIDS did not appreciably change these results.

CONCLUSIONS

There was no evidence of differences in rate of development of AIDS by exposure category, while there was a strong tendency for more rapid development in older subjects for all three groups. This supports the view that external cofactors do not play major role in AIDS pathogenesis but that age is of fundamental importance.

HIV disease progression in 854 women and men infected through injecting drug use and heterosexual sex and followed for up to nine years from seroconversion. Italian Seroconversion Study

OBJECTIVE

To compare the progression of HIV-1 infection in men and women followed up for up to nine years after an accurately estimated date of seroconversion.

DESIGN

Prospective observational study.

SETTING

16 HIV outpatient clinics across Italy.

SUBJECTS

321 women and 533 men infected with HIV through injecting drug use or heterosexual sex and with accurately estimated dates of seroconversion.

MAIN OUTCOME MEASURES

Progression to severe CD4 lymphocytopenia (CD4 lymphocyte count < 200 x 10(6)/l), development of AIDS defining diseases, and death from AIDS.

RESULTS

Thirty two women and 67 men developed AIDS at Kaplan-Meier progression rates of 25% (95% confidence interval 13.8% to 35.5%) and 23% (15.6% to 30.4%), respectively, 7 years after seroconversion. In a Cox proportional hazards model the relative hazard was 0.93 (that is, a slightly lower hazard in women) before and 1.10 (0.70 to 1.72) after adjusting for age, HIV exposure group, and year of seroconversion. When CD4 lymphocytopenia and death from AIDS were used as end points the results were similar, with adjusted relative hazards of 0.95 (0.63 to 1.42) and 0.72 (0.48 to 1.79) respectively. In both women and men the risk of developing AIDS before the CD4 lymphocyte count had declined below 200 x 10(6)/l was small (3% in women, 6% in men). The estimated median count at which AIDS developed in women (34 x 10(6)/l; 10 x 10(6) to 44 x 10(6)) was similar to that for men (44 x 10(6)/l; 22 x 10(6) to 60 x 10(6)).

CONCLUSION

There seems to be little evidence for appreciable differences in the natural course of HIV infection between men and women followed up from the time of seroconversion.