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JAC Advance Access originally published online on November 11, 2005
Journal of Antimicrobial Chemotherapy 2006 57(1):4-7; doi:10.1093/jac/dki411
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© The Author 2005. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org

Leading article

HIV infection in older patients in the HAART era

Sophie Grabar1,2,*, Laurence Weiss3 and Dominique Costagliola2

1 Service de Biostatistique et Informatique Médicale, Université Paris-Descartes, Faculté de Médecine, Hôpital Cochin, Paris, France; 2 Unité 720 INSERM et Université Pierre et Marie Curie, Paris, France; 3 Department of Clinical Immunology, Université Paris-Descartes, Faculté de Médecine, Hôpital Européen Georges Pompidou, Paris, France


* Correspondence address. Hôpital Cochin, Service de Biostatistique et Informatique Médicale, 27 Rue du Fg St Jacques, 75 679 Paris CEDEX 14, France. Tel: +33-1-58-41-20-24 (direct)/+33-1-58-41-31-54 (secretary); Fax: +33-1-58-41-19-61; E-mail: grabar{at}cochin.univ-paris5.fr


    Abstract
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 Abstract
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 Epidemiology
 Treatment and prognosis
 Immune reconstitution during...
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An increasing number of patients over 50 years of age are now living with HIV, owing to highly active antiretroviral therapy (HAART) that prolongs survival on the one hand and to late diagnosis of patients living with occult HIV infection on the other hand. Most studies have shown that compared with younger patients, patients over 50 generally have a slower immunological response to HAART and experience more rapid clinical progression, despite a better virological response. Low thymic output probably plays a role in the poorer CD4 cell response in patients initiating HAART over 50 years. Management of HIV infection in older patients is particularly complex, mainly because they are more likely to have co-morbidities necessitating specific medications that may interact with antiretroviral drugs. More controlled studies of HAART efficacy and tolerability in such patients are needed to establish specific management guidelines. Information campaigns targeting older patients and their doctors are also needed to ensure timely diagnosis of HIV infection and antiretroviral treatment initiation.

Keywords: antiretroviral treatment , elderly , HIV/AIDS


    Introduction
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 Abstract
 Introduction
 Epidemiology
 Treatment and prognosis
 Immune reconstitution during...
 Comorbidity and toxicity
 Conclusions
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HIV-infected elderly subjects are an emerging patient category in industrialized countries. Based on recent studies, including a paper we have published in AIDS,1 the following article addresses specific management issues relating to HIV infection in patients over 50 years of age, focusing on epidemiological data and the response to HAART.


    Epidemiology
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 Abstract
 Introduction
 Epidemiology
 Treatment and prognosis
 Immune reconstitution during...
 Comorbidity and toxicity
 Conclusions
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Clinicians will encounter increasing numbers of older HIV-infected patients in coming years. Epidemiological data from rich countries show that the HIV-infected population is ageing in parallel with the use of potent treatments, and that the number of older patients who are newly infected or newly diagnosed is increasing. The age cut-off of 50 years often adopted to define ‘elderly’ patients with HIV/AIDS is younger than that usually used in most other settings. Recent data from the CDC2 show that the cumulative number of AIDS cases among American adults over 50 years of age quintupled during the last decade; in 2000, patients over 50 accounted for ~15% of all AIDS cases recorded in the United States.3 The figures are similar in France: in 2003, ~19% of patients enrolled in the French Hospital Database on HIV (FHDH), a nationwide hospital-based cohort of >100 000 HIV-infected patients, were over 50 (21% of men, 13% of women).4

In contrast to younger patients, the main documented risk factor for HIV infection among patients over 50 is heterosexual intercourse. Injection drug use is rare, and the route of HIV infection is often unknown. Early in the HIV/AIDS pandemic, older subjects represented a large proportion of patients who were infected by blood products or whose exposure group was unknown, but these rates have fallen markedly in recent years: ~15% of American patients aged over 50 years contracted HIV through blood transfusion in the 1980s, compared with only 1.1% in 1999. This decline is of course related to transfusion risk-reduction policies.

In addition to the ‘ageing cohort effect’, most studies have shown that HIV infection tends to be diagnosed at a later stage in elderly patients than in younger patients.5,6 This implies that antiretroviral treatments tend to be started later, possibly compromising their efficacy. Our team (FHDH) has examined factors associated with late assess to care, as defined by recruitment to our hospital cohort when the CD4 cell count is <200 cells/mm3 or when AIDS has already occurred.7 Age at recruitment was independently associated with late access to care. After age 30 years, the risk increased gradually with age at recruitment: relative to patients under 30, the risk of late access to care was increased 1.8-fold (95% CI; 1.6–1.9) between 30 and 40 years, 2.5-fold (95% CI = 2.3–2.8) between 40 and 50 years, 2.9-fold (95% CI = 2.6–3.3) between 50 and 60 years and 3.4-fold (95% CI = 2.9–4.0) among patients aged 60 or more.

Factors potentially explaining the late diagnosis of HIV infection in older patients include less common routine screening; poor awareness of the risk of HIV infection or of safer sex practices in this age group; failure of physicians to consider the possibility of HIV infection in these patients; and confusion between symptoms of opportunistic infections and those of frequent co-morbid conditions associated with ageing. In particular, HIV infection itself may mimic neurological disorders such as Alzheimer's disease, Parkinson's disease and cerebrovascular dementia. Internists, general practitioners, geriatricians and neurologists should thus be more aware of the possibility of occult HIV infection among their patients.


    Treatment and prognosis
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 Abstract
 Introduction
 Epidemiology
 Treatment and prognosis
 Immune reconstitution during...
 Comorbidity and toxicity
 Conclusions
 Transparency declarations
 References
 
As in many other diseases, age is an important prognostic factor in HIV infection.8 Age at seroconversion5,9 and age at a given CD4 cell count10 were shown to be important determinants of progression and survival before the widespread introduction of HAART, starting in 1996. Since this date, many studies, including the ART Cohort Collaboration (ART-CC), which includes 13 cohort studies conducted in Europe and North America,11 have shown that age remains an independent predictor of clinical progression on HAART. The impact of age in the ART-CC study seemed to be less marked than in the pre-HAART era, but a threshold effect was noted at 50 years.

Because older patients are usually excluded from clinical trials, controlled data are lacking on this age group. Studies of the response to HAART in elderly patients have mostly involved small populations and relatively short follow-up.1218

In a recently published study,1 we examined immunological and clinical responses to first-line HAART according to age at treatment outset in a cohort of 3015 HIV-infected patients, 401 of whom were over 50. This analysis, based on the FHDH, showed that patients over 50 had significantly slower CD4 cell reconstitution than younger patients, despite a better virological response. Among patients with baseline HIV RNA levels >5 log copies/mL (see Figure 1), the mean CD4 cell increase during the first 6 months of HAART was 42.9 cells/mm3/month in patients under 50, compared with 36.9 cells/mm3/month in older subjects. CD4 cell response slowed after 6 months of treatment, counts rising by 17.9 cells/mm3/month in patients under 50, and by 15.6 cells/mm3/month in older patients. This impaired immunological response was associated with a more rapid clinical progression in patients over 50. During the first year of HAART, 10.2% of patients over 50 died or had a new AIDS-defining event, compared with 5% of younger patients. After 5 years the respective figures were 21.9% and 12.4%. In contrast, viral suppression, defined by an HIV RNA level <500 copies/mL, was more frequent in patients over 50 than in younger patients [HR (hazard ratio) = 1.23, 95% CI = 1.11–11.38]. In most studies,19,20 viral suppression was less frequently achieved in younger subjects, a phenomenon usually attributed to poorer adherence to treatment.21



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Figure 1.. Mean CD4 cell count increase during HAART according to age at treatment initiation and the baseline HIV RNA level in 3015 HIV-infected patients. Adapted with permission from Grabar et al.1

 

    Immune reconstitution during HAART: impact of age
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 Abstract
 Introduction
 Epidemiology
 Treatment and prognosis
 Immune reconstitution during...
 Comorbidity and toxicity
 Conclusions
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HIV infection is associated with a gradual decline in circulating naive and memory CD4 T cell counts. Immune restoration following HAART can be divided into two phases: an initial rapid increase in the CD4 T-cell count during the first 8 weeks of therapy, resulting mainly from a redistribution of memory T lymphocytes sequestered in lymph nodes; and a slower phase mainly involving accrual of naive T cells. This increase in naive CD4 T-cell numbers could be due to peripheral expansion of existing naive T cells and/or to thymic production of new naive T cells. Douek et al.22 quantified peripheral TCR-excision circle (TREC)-bearing recent thymic emigrants and obtained evidence that the adult thymus could contribute to CD4 T-cell reconstitution during HAART. This was subsequently confirmed by other groups.23 Thymic involution during ageing would thus have a negative impact on HAART-induced CD4 T-cell reconstitution. Indeed, CD4 TREC levels correlate negatively with age, both in healthy individuals22 and during immune reconstitution in cancer patients undergoing autologous bone marrow transplantation.24 Thymic output has been found to reach a minimum after the age of 55 years.25 Accordingly, low thymic output probably plays a role in the lesser CD4 cell response observed in patients initiating HAART over 50 years of age.

In our study1 the risk of clinical progression during HAART was 1.5 times higher (95% CI = 1.2–2.0) among patients over 50 than among younger patients. Overall, three-quarters of clinical events occurred in patients with <200 CD4 cells/mm3. Interestingly, the nature of AIDS-defining events differed between the two age groups. Older patients had a significantly higher risk of CMV disease (HR = 5.0), HIV encephalopathy (HR = 2.8) and Kaposi's sarcoma (HR = 2.3), while the risk of PCP (HR = 1.9), recurrent bacterial pneumonia (HR = 2.0) and progressive multifocal leucoencephalopathy (HR = 3) also tended to be higher, although not significantly, probably owing to a lack of statistical power in our analyses. The mean CD4 cell count at which each disease occurred did not differ between the two age groups, indicating that it is the CD4 cell count reached while on HAART rather than age itself that determines the risk of onset of a particular disease.

Since low CD4 cell counts are associated with a higher risk of disease progression, interleukin-2 (IL-2) administration has been investigated and found to lead to a substantial and sustained increase in circulating CD4 T-cell counts in HIV-infected patients26,27 including patients over 50 who are virological responders/immunological low-responders.28 However, younger age was an independent predictor of a better CD4 cell response to intermittent IL-2 therapy in the ESPRIT trial.29 Anyway, whether the increase in CD4 cell count following IL-2 administration will be associated with a clinical benefit is currently being assessed in two large Phase III international trials (ESPRIT and SILCAAT).

Whether or not the slower CD4 cell response in older patients has implications for the optimal timing of HAART initiation remains to be determined. Such studies must take into account the relative contributions of the age-related impairment of CD4 cell responses on the one hand, and of late diagnosis and treatment on the other hand. However, HIV infection must be diagnosed rapidly in older patients if treatment is to be started before major CD4 cell depletion occurs, thereby preserving the chances of clinical and immunological success.


    Comorbidity and toxicity
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 Abstract
 Introduction
 Epidemiology
 Treatment and prognosis
 Immune reconstitution during...
 Comorbidity and toxicity
 Conclusions
 Transparency declarations
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Older patients are more likely to have comorbid conditions such as metabolic disorders (diabetes mellitus), malignancies and renal, hepatic or cardiac dysfunctions. In addition, the overall risk of cancer is ~2-fold higher among HIV-infected patients than in the general population.30,31 Moreover, HIV-infected patients treated with antiretroviral drugs are at higher risk of cardiovascular disease and of metabolic complications. The risk of myocardial infarction has been shown to increase significantly both with age and with the duration of exposure to HAART.32,33 Whether or not older patients are at higher risk of severe toxicities as a result of hepatic or renal dysfunctions remains to be explored but is likely. Such conditions can interfere with the drug metabolism and/or can require treatments that may interact with antiretroviral drugs and be responsible for higher blood concentrations of the drugs. As a consequence, management of antiretroviral therapy in elderly patients is particularly complex,34 and must take into account together with HIV infection multiple factors, including co-morbidity, concomitant treatments, and age-specific pharmacokinetics. There are currently no specific management guidelines for this age group. In addition, controlled data on efficacy and tolerability are sparse or nonexistent, as older patients and patients with co-morbidities are usually excluded from clinical trials. These data are needed to establish specific recommendations.


    Conclusions
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 Abstract
 Introduction
 Epidemiology
 Treatment and prognosis
 Immune reconstitution during...
 Comorbidity and toxicity
 Conclusions
 Transparency declarations
 References
 
The HIV-infected population is ageing in industrialized countries, as a result of both prolonged survival due to effective antiretroviral treatment and the increasing proportion of diagnoses made among patients over 50 years of age. Older patients are at a higher risk of HIV disease progression, for at least three reasons: first, they tend to be diagnosed at a more advanced stage; second, they have a slower immunological response to HAART; and third, they are at a higher risk of complications, such as cancer and cardiovascular disease because of the combined effect of ageing, HIV infection and antiretroviral treatment. More studies of this age group are needed to establish specific management guidelines. Information campaigns targeting older patients and their doctors are required, both to prevent HIV transmission and to diagnose and treat HIV infection in a timely manner.


    Transparency declarations
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No declarations were made by the authors of this paper.


    References
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 Conclusions
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1. Grabar S, Kousignian I, Sobel A et al. Immunologic and clinical responses to highly active antiretroviral therapy over 50 years of age. Results from the French Hospital Database on HIV. AIDS 2004; 18: 2029–38.[CrossRef][ISI][Medline]

2. Mack K, Ory M. AIDS and older Americans at the end of the twentieth century. J Acquir Immune Defic Syndr 2003; 33: S68–75.

3. Centers for Disease Control and Prevention. AIDS cases in adolescents and adults,by age—United States, 1994–2000. HIV/AIDS Surveill Suppl Rep 2003; 9: 1–24.

4. Delfraissy J. Prise en charge thérapeutique des personnes infectées par le VIH. Recommandations du groupe d'experts. Rapport 2004, p. 284. Paris: Flammarion Médecine-Sciences, 2004.

5. Castilla J, Sobrino P, De La Fuente L et al. Late diagnosis of HIV infection in the era of highly active antiretroviral therapy: consequences for AIDS incidence. AIDS 2002; 16: 1945–51.[CrossRef][ISI][Medline]

6. Skiest DJ, Rubinstien E, Carley N et al. The importance of comorbidity in HIV-infected patients over 55: a retrospective case-control study. Am J Med 1996; 101: 605–11.[CrossRef][ISI][Medline]

7. Lanoy E, Mary-Krause M, Tattevin P et al. How does delayed access to care influence the survival of HIV patients during the HAART era? In: XV International AIDS Conference, Bangkok, Thailand, 2004. Abstract ThPeB7138.

8. Babiker AG, Peto T, Porter K et al. Age as a determinant of survival in HIV infection. J Clin Epidemiol 2001; 54 Suppl 1: S16–21.

9. Carre N, Deveau C, Belanger F et al. Effect of age and exposure group on the onset of AIDS in heterosexual and homosexual HIV-infected patients. SEROCO Study Group. AIDS 1994; 8: 797–802.[ISI][Medline]

10. Phillips AN, Lee CA, Elford J et al. More rapid progression to AIDS in older HIV-infected people: the role of CD4+ T-cell counts. J Acquir Immune Defic Syndr 1991; 4: 970–5.

11. Egger M, May M, Chene G et al. Prognosis of HIV-1-infected patients starting highly active antiretroviral therapy: a collaborative analysis of prospective studies. Lancet 2002; 360: 119–29.[CrossRef][ISI][Medline]

12. Perez JL, Moore RD. Greater effect of highly active antiretroviral therapy on survival in people aged > or = 50 years compared with younger people in an urban observational cohort. Clin Infect Dis 2003; 36: 212–18.[CrossRef][ISI][Medline]

13. Grimes RM, Otiniano ME, Rodriguez-Barradas MC et al. Clinical experience with human immunodeficiency virus-infected older patients in the era of effective antiretroviral therapy. Clin Infect Dis 2002; 34: 1530–3.[CrossRef][ISI][Medline]

14. Tumbarello M, Rabagliati R, De Gaetano Donati K et al. Older HIV-positive patients in the era of highly active antiretroviral therapy: changing of a scenario. AIDS 2003; 17: 128–31.[CrossRef][ISI][Medline]

15. Manfredi R, Chiodo F. A case-control study of virological and immunological effects of highly active antiretroviral therapy in HIV-infected patients with advanced age. AIDS 2000; 14: 1475–7.[CrossRef][ISI][Medline]

16. Viard JP, Mocroft A, Chiesi A et al. Influence of age on CD4 cell recovery in human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy: evidence from the EuroSIDA study. J Infect Dis 2001; 183: 1290–4.[CrossRef][ISI][Medline]

17. Knobel H, Guelar A, Valldecillo G et al. Response to highly active antiretroviral therapy in HIV-infected patients aged 60 years or older after 24 months follow-up. AIDS 2001; 15: 1591–3.[CrossRef][ISI][Medline]

18. Goetz MB, Boscardin WJ, Wiley D et al. Decreased recovery of CD4 lymphocytes in older HIV-infected patients beginning highly active antiretroviral therapy. AIDS 2001; 15: 1576–9.[CrossRef][ISI][Medline]

19. Duran S, Saves M, Spire B et al. Failure to maintain long-term adherence to highly active antiretroviral therapy: the role of lipodystrophy. AIDS 2001; 15: 2441–4.[CrossRef][ISI][Medline]

20. Lucas GM, Chaisson RE, Moore RD. Highly active antiretroviral therapy in a large urban clinic: risk factors for virologic failure and adverse drug reactions. Ann Intern Med 1999; 131: 81–7.[Abstract/Free Full Text]

21. Hinkin CH, Hardy DJ, Mason KI et al. Medication adherence in HIV-infected adults: effect of patient age, cognitive status, and substance abuse. AIDS 2004; 18 Suppl 1: S19–25.

22. Douek DC, McFarland RD, Keiser PH et al. Changes in thymic function with age and during the treatment of HIV infection. Nature 1998; 396: 690–5.[CrossRef][Medline]

23. Franco JM, Rubio A, Martinez-Moya M et al. T-cell repopulation and thymic volume in HIV-1-infected adult patients after highly active antiretroviral therapy. Blood 2002; 99: 3702–6.[Abstract/Free Full Text]

24. Hakim FT, Memon SA, Cepeda R et al. Age-dependent incidence, time course, and consequences of thymic renewal in adults. J Clin Invest 2005; 115: 930–9.[CrossRef][ISI][Medline]

25. Naylor K, Li G, Vallejo AN et al. The influence of age on T cell generation and TCR diversity. J Immunol 2005; 174: 7446–52.[Abstract/Free Full Text]

26. Kovacs JA, Vogel S, Albert JM et al. Controlled trial of interleukin-2 infusions in patients infected with the human immunodeficiency virus. N Engl J Med 1996; 335: 1350–6.[Abstract/Free Full Text]

27. Levy Y, Durier C, Krzysiek R et al. Effects of interleukin-2 therapy combined with highly active antiretroviral therapy on immune restoration in HIV-1 infection: a randomized controlled trial. AIDS 2003; 17: 343–51.[CrossRef][ISI][Medline]

28. Katlama C, Carcelain G, Duvivier C et al. Interleukin-2 accelerates CD4 cell reconstitution in HIV-infected patients with severe immunosuppression despite highly active antiretroviral therapy: the ILSTIM study—ANRS 082. AIDS 2002; 16: 2027–34.[CrossRef][ISI][Medline]

29. Weiss L, Aboulhab J, Babiker G et al. Preliminary results of ESPRIT (evaluation of subcutaneous proleukin in a randomised international trial): baseline predictors of CD4 T-cell response to interleukin-2. Antiviral Ther 2003; 8: S188.

30. Herida M, Mary-Krause M, Kaphan R et al. Incidence of non-AIDS-defining cancers before and during the highly active antiretroviral therapy era in a cohort of human immunodeficiency virus-infected patients. J Clin Oncol 2003; 21: 3447–53.[Abstract/Free Full Text]

31. Clifford GM, Polesel J, Rickenbach M et al. Cancer risk in the Swiss HIV Cohort Study: associations with immunodeficiency, smoking, and highly active antiretroviral therapy. J Natl Cancer Inst 2005; 97: 425–32.[Abstract/Free Full Text]

32. Friis-Moller N, Sabin CA, Weber R et al. Combination antiretroviral therapy and the risk of myocardial infarction. N Engl J Med 2003; 349: 1993–2003.[Abstract/Free Full Text]

33. Mary-Krause M, Cotte L, Simon A et al. Increased risk of myocardial infarction with duration of protease inhibitor therapy in HIV-infected men. AIDS 2003; 17: 2479–86.[CrossRef][ISI][Medline]

34. Manfredi R. HIV disease and advanced age: an increasing therapeutic challenge. Drugs Aging 2002; 19: 647–69.[CrossRef][ISI][Medline]


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