Has the spectrum of AIDS-defining illnesses been changing since the introduction of new treatments and combination of treatments?

Immune reconstitution in HIV-1-infected individuals treated with potent antiretroviral therapy

Potent combination antiretroviral therapy that was introduced in the mid-1990s for treatment of HIV-1 infection has resulted in unprecedented decreases in HIV-1 replication and increases in CD4+ T cell counts in many individuals. Coincident with the introduction of potent combination antiretroviral therapy, substantial declines in AIDS-related morbidity and mortality have been observed. Although these declines strongly suggest that significant immune reconstitution is occurring, increasing evidence suggests that immune reconstitution is neither uniform nor complete in all treated individuals. Clinical data suggest that some HIV-1-associated malignancies have not declined despite the new therapies, and that not all treated individuals reconstitute CD4+ T cell numbers to normal values. Laboratory studies reveal that immune responses to ubiquitous antigens are reconstituted, but that responses to rarely encountered antigens, such as tetanus, are not reconstituted without repeat vaccination. Many questions remain concerning the extent and clinical significance of the immune reconstitution that occurs in the setting of antiretroviral drug therapy. A better understanding of the nature of the immune reconstitution that results from potent antiretroviral therapy is critical to the optimal clinical management of HIV-1-infected individuals, and may provide important insights into the immunopathogenesis of HIV-1 infection as well.

Epidemiology of AIDS-related tumours in developed and developing countries

AIDS-associated illnesses include Kaposi's sarcoma (KS), non-Hodgkin's lymphoma (NHL), and, since 1993, invasive cervical cancer (ICC). Between 1988 and 1998, among AIDS cases reported in western Europe, 9.6% had KS and 3.9% had NHL as AIDS-defining illnesses. Between 1988 and 1998, the frequency of KS decreased from 13.4 to 6.4%, while NHL increased from 3.8 to 5.3%. Estimates of the relative risk (RR) of neoplasms in HIV-seropositive populations came from population-based cancer and AIDS registries linkage studies conducted in the United States, Italy and Australia and from a few cohort and case-control studies. In adults with HIV/AIDS, the RR was over 1000 for KS and ranged between 14 for low-grade NHL and over 300 for high-grade NHL. For Hodgkin's disease (HD), a consistent 10-fold higher RR was observed. For cervical and other anogenital tumours associated with human papilloma virus, risk increases were 2- and 12-fold, depending upon location. In Africa, the AIDS epidemic led to KS becoming the most common cancer type in men in several areas. The RR of AIDS-associated tumours were lower in Africa than those reported in western countries.

Impact of HAART on the clinical management of AIDS-related cancers

The development of HIV-related disease has changed dramatically since the introduction of highly active antiretroviral therapy (HAART) into clinical practice. Since the use of protease inhibitors became widespread, a 30-50% reduction in Kaposi's sarcoma (KS) has been observed. The results of recent studies indicate that HAART may be a useful alternative both to immune response modifiers during less aggressive stages of KS disease and to systemic cytotoxic drugs in the long-term maintenance therapy of advanced KS. The impact of HAART regimens on the incidence of systemic lymphoma (NHL-HIV) remains unclear, but it can be hypothesised that patients treated with HAART may survive longer with continued B cell stimulation and dysregulation resulting in an increased incidence of lymphoma over time. The impact of HAART on survival in patients affected by NHL-HIV has recently been evaluated and a positive correlation between HAART and outcome in these patients has been found. The spectrum of cancers in patients with HIV infection may develop further since these patients survive longer with HAART and with a better control of opportunistic infections. With the increasing use of HAART, the dilemma is whether to institute or continue protease inhibitors use during chemotherapy. Based on the advances in our understanding of HIV-related disease and the availability of new antiretroviral therapies, the choice for anti-HIV agents in patients receiving chemotherapy is important.

AIDS across Europe, 1994-98: the EuroSIDA study

BACKGROUND

The clinical presentation of HIV-1 related diseases could have changed after the introduction of highly active antiretroviral treatment (HAART). We aimed to assess changes over time in the incidence of ADIs overall and within CD4 lymphocyte count strata, the relationship with treatment and degree of immunodeficiency at diagnosis of ADIs.

METHODS

We did a prospective observational multicentre study of over 7300 patients in 52 European HIV-1 outpatient clinics. Incidence rates per 100 patient-years of observation were calculated.

FINDINGS

In total, we recorded 1667 new ADIs; the incidence of ADIs declined from 30.7 per 100 patient-years of observation during 1994 (95% CI 28.0-33.4) to 2.5 per 100 patient-years of observation during 1998 (95% CI 2.0-3.0, p<0.0001, test for trend). Median CD4 lymphocyte count at diagnosis of a new ADI increased from 28 cells/microL to 125 cells/microL between 1994 and 1998 (p<0.0001), yet a steep decline in the rate of ADIs was seen after stratification by latest CD4 lymphocyte count within each year (< or = 50, 51-200, and > 200 cells/microL). Patients on HAART had a lower rate of ADIs than patients not on this treatment within each CD4 lymphocyte count strata. The proportion of ADIs attributable to cytomegalovirus retinitis and Mycobacterium avium complex declined over time (p=0.0058 and 0.0022, respectively), whereas the proportion of diagnoses attributable to non-Hodgkin lymphoma has increased (p<0.0001). In 1994, less than 4% of ADIs were non-Hodgkin lymphoma, in 1998 the proportion was almost 16%. This condition has become one of the most common ADIs in patients on HAART.

INTERPRETATION

Our findings lend support to the idea that treatment regimens can lower the incidence of ADIs. The immediate risk of an ADI for a given CD4 lymphocyte count has declined over time and is lower among patients on HAART. Long-term follow-up of patients on combination treatment is essential to monitor the incidence of new and emerging diagnoses.

Impact of HAART on causes of death of persons with late-stage AIDS

CONTEXT

The increasing use of highly active antiretroviral therapies (HAARTs) has changed the course of AIDS-related illnesses and enhanced the quality of life of patients infected with human immunodeficiency virus (HIV) and may have changed the causes of deaths in patients with acquired immunodeficiency syndrome (AIDS).

OBJECTIVE

The aim of the present study was to investigate causes of deaths in long-term care hospital patients with late-stage AIDS who expired at the Coler-Goldwater Memorial Hospital in New York City in 1995, and in 1998 and 1999, that is, immediately before and the two most recent years after the advent of HAART.

METHODS

Analysis of causes of deaths as recorded on the death certificates of 232 AIDS patients.

RESULTS

The overall mortality rate declined from 75.6 deaths per 100 person-years in 1995 to 33.2 deaths per 100 person-years in 1998-1999 (P < .001). The number of AIDS patients who expired because of sepsis and opportunistic infections, which included Pneumocystis carinii pneumonia (PCP), decreased significantly from 30 (26.1%) and 24 (20.9%) in 1995 to 15 (12.8%) and 10 (8.5%) in 1998-1999, respectively (P < .05). In contrast, deaths from hepatic failure increased from 0 (0%) in 1995 to 7 (6%) in 1998-1999 (P < .05). Increases, although not significant statistically, were associated with pneumonias excluding PCP, end-stage AIDS, renal failure, and malignancies. Analysis of cause-specific mortality by gender between 1995 and 1998-1999 revealed very little difference between men and women. This analysis showed, however, that the infectious processes taken together (pneumonias excluding PCP, sepsis, and opportunistic infections including PCP) were significantly less frequent causes of death in 1998-1999 than in 1995 (P < .01).

CONCLUSION

These findings indicate that HAART affected the causes of deaths in patients with AIDS, with "traditional" opportunistic infections diminishing in importance relative to chronic medical conditions and malignancies.

Impact of zidovudine-based triple combination therapy on an AIDS drug assistance program

A static deterministic model was used to estimate the effect of the shift to a triple combination therapeutic standard on the annual AIDS Drug Assistance Program (ADAP) budget, total medical care expenditures, and population health outcomes for New York (NY) state ADAP enrollees. The model used opportunistic disease incidence data from the Multicenter AIDS Cohort Study (MACS) and other studies. Costs of treating opportunistic infections (OIs) and other HIV complications with each type of therapy were derived from treatment algorithms and standard unit costs. CD4+ cell counts were used as an index of need for OI prophylaxis and for determining OI incidence. Treatment with zidovudine-based combination therapy has been shown to increase CD4+ cell counts and reduce OI incidence. The model estimated that a change from monotherapy to triple therapy would have increased NY ADAP budget expenditures per enrollee by 115%. However, total medical system costs per ADAP enrollee (including ADAP costs) would decrease by 0.4% in the base case as a result of reduction in OIs and other HIV sequelae and associated costs. Results are sensitive to the assumed percentage of people taking combination therapy as well as to the assumptions made about the impact of the combination therapy on CD4+ cell count. Total ADAP budget impacts will depend on the growth in ADAP enrollment as a result of the availability of more effective therapies. In conclusion, this model demonstrates how access to newer, more effective HIV drug treatments can reduce the costs of treating OIs and provide major health benefits for ADAP enrollees.

Advances in the epidemiology of HIV-associated non-Hodgkin's lymphoma and other lymphoid neoplasms

The spectrum of HIV-related lymphoid malignancies certainly includes non-Hodgkin's lymphoma (NHL; i.e., chiefly large-cell lymphoma and Burkitt's lymphoma), primary lymphoma of the brain (PBL) and, possibly, Hodgkin's disease (HD). Since the mid-1990s, several epidemiological studies have led to better quantification of the burden of lymphomas in HIV-infected populations. AIDS surveillance data from 17 western European countries show that between 1988 and 1997 a total of 7,148 AIDS cases had NHL as the AIDS-defining illness. The yearly number of cases rose steadily from 1988 to 1995 but declined thereafter. As a percentage of AIDS-defining illnesses, NHL increased from 3.6% in 1994 to 4.9% in 1997. Percent increases were observed in different strata by area, age group, sex and HIV-transmission group. To estimate relative risk (RR) of NHL and other lymphoid neoplasms in unselected HIV-seropositive populations, records of population-based cancer registries and AIDS registries were linked in the United States, Italy and Australia. RRs for NHL in adults with HIV/AIDS ranged between 14 (for low-grade NHL) to over 300 (for high-grade NHL). For HD, the RR was approximately 10. Limited findings from studies based on death certificates and cohorts of HIV-seropositive persons were consistent with those from registry linkage studies. In developing countries, the risk of HIV-associated NHL appears to be much lower than in developed countries, but under-ascertainment and earlier death from other AIDS manifestations may explain the lack of HIV-associated lymphomas in Africa.