AEGiS-14IAC: Lead-time adjustment in cohort studies evaluating when to initiate therapy.

14th International AIDS Conference


Barcelona, Spain - July 7-12, 2002

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Lead-time adjustment in cohort studies evaluating when to initiate therapy.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. TuOrB1143)

Cole SR, Li R, Anastos K, Detels R, Young M, Phair JP, Munoz A
Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States

BACKGROUND: To estimate the impact of deferring highly active antiretroviral therapy (HAART) initiation on time to AIDS using a novel method that adjusts for unobserved lead-time in higher CD4 cell counts categories by HIV+ persons who initiate HAART at lower levels of CD4.

METHODS: 739 men and women from the Multicenter AIDS Cohort and Women's Interagency HIV Studies, who initiated HAART between 1996 and 2000 while AIDS-free and with CD4 counts ≤ 500 cells/ é L, were followed for onset of clinical AIDS for up to 3 1/2 years. Lead-time and the number of unseen fast-progressors were quantified using data from the MACS in the pre-HAART era under a missing at random assumption, conditional on CD4. Lead-time- and fast-progressor-adjusted AIDS hazard ratios were estimated using Cox proportional hazards models and multiple imputation.

RESULTS: 312 men and 427 women each had median CD4 cell counts of 269 cells/ é L at HAART initiation; 12% of the men (n=36) and women (n=52) developed AIDS during follow up. For the comparison of initiating HAART with CD4 ≤ 200 (n=237) vs. 201-350 (n=278) the median lead-time was 1.7 years, the estimated number of unseen fast-progressors was 24, and the adjusted hazard ratio was 2.32 (95% CI: 1.33, 4.05). For the comparison of initiating HAART with CD4 between 201-350 vs. 351-500 (n=224) the median lead-time was 1 year, the estimated number of unseen fast-progressors was 9, and the adjusted hazard ratio was 0.86 (95% CI: 0.35, 2.14).

CONCLUSION: Data from two large, comprehensive cohorts indicate that deferring HAART initiation until CD4 is below 201 cells/ é L is detrimental. Furthermore, initiating HAART with CD4 between 201-350 cells/ é L seemed preferable to initiating with CD4 between 351-500 cells/ é L.

Keywords: AEGIS, Antiretroviral Therapy, Highly Active, CD4 Lymphocyte Count, Cohort Studies, Acquired Immunodeficiency Syndrome, HIV Infections, HIV Seropositivity, Human, Female, Male, therapy, prevention & control, drug therapyKWDaegis,antiretroviraltherapy,highlyactive,cd4lymphocytecount,cohortstudies,acquiredimmunodeficiencysyndrome,hivinfections,hivseropositivity,human,female,male,therapy,prevention&control,drugtherapy

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TuOrB1143

Copyright © 2002 - International AIDS Society (IAS). Reproduction of this abstract (other than one copy for personal reference) must be cleared through the IAS.