Effect of age and HAART regimen on clinical response in an urban cohort of HIV-infected individuals

Objectives: The prevalence of HIV infection in older patients (≥50 years) is increasing due to HAART, and new HIV infections in older patients. Some earlier studies suggest that older patients respond differently to HAART than younger patients. The objective of this study is to compare the effectiveness of HAART in older and younger HIV patients. Design: Retrospective analysis of an observational clinical cohort. Methods: Virologic and immunologic response, progression to AIDS and mortality were compared between 670 younger patients (<40 years) and 149 older patients (≥50 years) by t-test, Kaplan-Meier methods, and multivariate Cox proportional hazards analysis. Results: Compared with younger patients, older patients were more likely to be on nonnucleoside reverse transcriptase inhibitors based versus protease inhibitor based regimens (42 vs. 29%, P < 0.01). Time to HIV-1 RNA virologic suppression was less in older than in younger patients (3.2 vs. 4.4 months, P < 0.01). Immunologic response did not differ by age. Older patients had fewer AIDS-defining opportunistic infections (22 vs. 31%, P < 0.01 ), but higher mortality (36 vs. 27%, P = 0.04) and shorter survival (25th percentile survivor function 36.2 vs. 58.5 months, P = 0.02) than younger patients. Older age was associated with more rapid virologic suppression [adjusted hazard ratio = 1.33 (1.09-1.63)] and earlier mortality [adjusted hazard ratio = 1.56 (1.14-2.14)]. Nonnucleoside reverse transcriptase inhibitors based regimens were associated with more rapid virologic suppression [adjusted hazard ratio = 1.22 (1.03-1.44)]. Conclusion: Time to virologic suppression after HAART initiation was shorter in older patients, although CD4 response did not differ by age. Older patients had fewer opportunistic infections, but survival was shorter. Our data suggest a need to better understand causes of mortality in older patients.