[AIDS-free time and survival of an injecting drug users HIV seroconvertors cohort]

The shifting pattern of cause-specific mortality in a cohort of human immunodeficiency virus-infected and non-infected injecting drug users

AIMS

To monitor changes in cause-specific mortality before and after 1997 according to human immunodeficiency virus (HIV) serological status in a cohort of injecting drug users (IDUs) observed for a 17-year period (1987--2004).

DESIGN

Community-based prospective cohort study of IDUs recruited in three acquired immunodeficiency virus (AIDS) prevention centres (1987--96) and followed-up until to 2004.

METHODS

We obtained annual overall mortality rates and mortality rates by specific causes according to HIV status. Poisson regression models were adjusted to compare mortality rates between calendar periods. Significant changes in slope trends were evaluated by join-point regression. Disease-specific mortality rates were estimated using competing risk models.

FINDINGS

From 7186 IDUs recruited (80677.218 person-years), 1589 deaths were observed with an overall mortality rate of 19.7 per 1000 person-years (95% CI, 18.8-20.7). This rate decreased from 22.9 per 1000 (95% CI, 21.4-24.7) before 1997 to 17.4 per 1000 (95% CI, 16.3-18.6) after 1997 [relative risk (RR) 0.83; 95% confidence interval (CI), 0.75-0.92]. Risk of death for HIV-positive was four times higher than for HIV-negative (RR 4.08; 95% CI, 3.63-4.58). Among HIV-positive individuals a significantly decreased change point in trend was found in 1997 for both total and AIDS mortality. HIV-negative individuals showed a similar pattern for drug overdose, suicide and accident mortality. Both groups showed an increase in proportional mortality by liver-related causes, cardiovascular diseases and cancer. Furthermore, a progressively increasing trend was observed for the three causes. However, there were no significant differences according to serological groups.

CONCLUSIONS

Cardiovascular and cancer mortality are increasing among IDUs, but the increases are not related to HIV infection. We have not found a link between highly active antiretroviral therapy (HAART) introduction and increases in mortality for specific causes.

Effectiveness of highly active antiretroviral therapy in Spanish cohorts of HIV seroconverters: differences by transmission category

OBJECTIVE

To evaluate the population effectiveness of highly active antiretroviral therapy (HAART) in HIV progression and determine the heterogeneity of the effect of HAART in GEMES (Spanish multicenter study of seroconverters).

DESIGN

Multicenter cohort study.

METHODS

Data from 1091 persons with well-documented HIV seroconversion dates from 1980s to January 2000 were analysed. Risk of AIDS and death in subjects with same duration of HIV infection were compared in different calendar periods; before 1992, 1992-1995 (reference), 1996-1997, 1998 and 1999 with Kaplan-Meier methods and Cox proportional hazards models, allowing for late entry, fitting calendar period as time-dependent covariate and adjusting for transmission category, age and gender.

RESULTS

Statistically significant reductions in the risk of AIDS were first observed in 1998 [hazard ratio (HR), 0.59; 95% confidence interval (CI), 0.35-1.01] becoming more pronounced in 1999 (HR, 0.45; 95% CI, 0.24-0.84). Reduction in the risk of death was seen in 1997, though only reached borderline significance in 1999 (HR, 0.53; 95% CI, 0.26-1.07). Progression to AIDS and death was slower in women (HR, 0.68; 95% CI, 0.46-0.99 and HR, 0.53; 95% CI, 0.33-0.87, respectively). Compared with men who have sex with men (MSM), intravenous drug users (IDU) had lower reductions in the risk of AIDS and death.

CONCLUSIONS

Reductions in incidence of AIDS and death in GEMES are seen after 1998 and 1999, respectively, compared with 1992-1995, being more pronounced in MSM compared with IDU, the commonest category in Spain.

Factors influencing HIV progression in a seroconverter cohort in Madrid from 1985 to 1999

OBJECTIVE

To study HIV progression from seroconversion over a 15 year period and measure the population effectiveness of highly active antiretroviral therapy (HAART).

METHODS

A cohort study of people with well documented dates of seroconversion. Cumulative risk of AIDS and death were calculated by extended Kaplan-Meier allowing for late entry. Cox proportional hazards models were used to study variables associated with HIV progression. To assess the impact of HAART, calendar time was divided in three periods; before 1992, 1992-6, and 1997-9.

RESULTS

From January 1985 to May 2000, 226 seroconverters were identified. The median seroconversion interval was 11 months, median seroconversion date was March 1993. 202 (89%) were men, 76% of whom were homo/bisexual. A 66% reduction in progression to AIDS was observed in 1997-9 compared to 1992-96 (HR 0.34 95% CI: 0.16 to 0.70). People with primary education appeared to have faster progression to AIDS compared to those with university studies (HR 2.69 95%CI: 1.17 to 6.16). An 82% reduction in mortality from HIV seroconversion was observed in 1997-9 (HR 0.18 95% CI: 0.05 to 0.68) compared to 1992-6. Progression to death for people with primary education was twice as fast as for those with university education (p 0.0007). People without confirmation of an HIV negative test had faster progression (HR 4.47 95% CI: 1.18 to 16.92).

CONCLUSIONS

The reduction in progression to AIDS and death from seroconversion from 1992-6 to 1997-9 in Madrid is likely to be attributable to HAART. HIV progression was faster in subjects with primary education; better educational level may be associated with better adherence to medication.

Changes in the uptake of antiretroviral therapy and survival in people with known duration of HIV infection in Europe: results from CASCADE

OBJECTIVES

To estimate the times from HIV seroconversion to death, and to the initiation of therapy and the mean CD4 cell count at initiation.

DESIGN AND METHODS

Using Kaplan-Meier methods, allowing for late entry, we analysed CASCADE (Concerted Action on SeroConversion to AIDS and Death in Europe) data from HIV-infected individuals with known dates of seroconversion. We tested the association of time to initiation of therapy and of survival with: exposure category, age, sex, presentation during acute infection and calendar year at risk (as time-dependent) in Cox proportional hazards models, stratifying by study. We estimated the mean CD4 cell count at the initiation of therapy using interval regression.

RESULTS

Of 5893 seroconverters, 1613 (27.4%) died. The risk of death was 65% lower (95% CI = 57-72%) in 1997-99 compared to previous years. Being at risk in earlier calendar years, older age and a short interval between negative and positive test dates were associated with shorter survival. At the same time from seroconversion, people at risk in 1997-99, older individuals and people with a short test interval were more likely to initiate therapy. Injecting drug users (IDUs) were less likely to initiate therapy compared to those exposed through sex between men (RR = 0.79, 95% CI = 0.69-0.89). The mean CD4 cell count at therapy initiation was 205 cells/mL, which increased significantly over time. Although the earlier initiation of therapy was consistent with longer survival in the 1997-99 period, we found no evidence of this in other calendar periods.

CONCLUSIONS

We found a significant and substantial reduction in the risk of death and a significant trend of earlier initiation of antiretroviral therapy (ART) in the 1997-99 period. Although IDUs were less likely to initiate therapy their overall survival did not appear to differ from others. The increasing tendency to initiate ART closer to seroconversion has unknown long-term consequences which require monitoring.

Effect of ignoring the time of HIV seroconversion in estimating changes in survival over calendar time in observational studies: results from CASCADE

OBJECTIVE

To compare estimates of changes in HIV survival over time derived from seroconverter and prevalent cohorts.

DESIGN AND METHODS

Using pooled data from 19 seroconverter cohorts (CASCADE), the relative risk of death from HIV seroconversion by calendar time at risk from 1 January 1991 was examined. The analyses were repeated, ignoring knowledge of the time of seroconversion, but adjusting for the CD4 cell count at the time the participant came under observation, thus mimicking a prevalent cohort. Estimates from the 'prevalent' cohort approach were compared with those obtained from the seroconverter cohort.

RESULTS

Of 5428 subjects at risk on 1 January 1991 or later, 1312 (24.2%) had died. In the analysis based on time from seroconversion, estimates of the effect of calendar year showed marked reductions in mortality in 1997-1999 only, with no evidence of a linear trend over the period 1991-1996 (P-trend = 0.85). Using the prevalent cohort approach a decrease in the relative risk of death was observed from 1991 to 1998-1999, with a statistically significant trend of a decrease in risk from 1991 to 1996 (P-trend = 0.002). Similar findings were observed when the analyses was repeated taking the start date of the cohort as 1 January 1988.

CONCLUSION

Lack of knowledge of HIV infection duration may lead to biased and exaggerated estimates of survival improvements over time. The adjustment for duration of infection in prevalent HIV cohorts through laboratory markers may compensate inadequately for this.

[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.