272. CD4 Nadir at HAART Initiation Is Not Associated with the Development of Community Acquired Pneumonia
Session: Poster Abstract Session: HIV-Associated Infections and Malignancies
Thursday, October 18, 2012
Room: SDCC Poster Hall F-H
Background: Compared to non-HIV infected patients, HIV-infected patients have an increased incidence of bacterial pneumonia despite being on HAART.  This study examined whether CD4 nadir at the time of HAART initiation impacted the time to community acquired pneumonia (CAP) in patients on HAART enrolled in the U.S. Military HIV Natural History Study (NHS) from 1994-2011.

Methods: NHS participants ≥ 18 years at documented HIV diagnosis date with at least one follow-up visit after HAART initiation (HI) and CD4 count between HIV diagnosis and HI were followed from HI until first CAP diagnosis or last medical history.  CD4 nadir at HI was defined as the lowest CD4 value between HIV diagnosis and HI.  CAP was determined from medical record review using predefined NHS diagnostic criteria.  The Cox proportional hazards models were used to assess adjusted risk factors for CAP.

Results: 2514 participants initiating HAART (median [IQR] age 34 [29, 40] years, 93% male, 43% Caucasian, 43% African American, median [IQR] follow-up of 5.2 [1.9, 11.0] years) were divided into CD4 nadir classes of 0-200, 201-350, and >350 cells/mm3 with 735, 998, and 781participants in each class, respectively.  There were a total 291 first CAP diagnoses after HAART during 14787.27 person-years (PY) of follow-up for a rate of 1.97/100 PY (95% CI 1.75-2.21).  CD4 nadir was associated with both CAP and AIDS prior to HI at baseline (p-value=0.008 and <0.001, respectively).  Although significantly associated with CAP in an unadjusted model, CD4 nadir was not associated with time to CAP in the adjusted model (CD4 nadir 0-200 cells/mm3: HR 1.18, 95% CI 0.86-1.62; CD4 nadir 201-350 cells/mm3: HR 0.98, 95% CI 0.73-1.33).  However, prior CAP diagnosis (HR 12.24, 95% CI 8.72-17.18) or AIDS-defining illness (1.67, 95% CI 1.2-2.34) was strongly associated with risk of CAP after HI.

Conclusion: Prior CAP or AIDS-defining illness, but not CD4 nadir, was associated with the development of CAP while on HAART.  These findings suggest that there may be a subset of HIV patients immunologically more susceptible to CAP despite HAART.

Pamela Ward-Demo, DVM, MD1, Octavio Mesner, MS2, Ionut Bebu, PhD2, Michael Landrum, MD1,2, Brian Agan, MD2, Nancy Crum-Cianflone, MD MPH2,3 and Erica Johnson, MD1,2, (1)San Antonio Military Med. Ctr., Fort Sam Houston, TX, (2)Infectious Disease Clinical Research Program, Uniformed Services University, Bethesda, MD, (3)Naval Health Research Center, San Diego, CA

Disclosures:

P. Ward-Demo, None

O. Mesner, None

I. Bebu, None

M. Landrum, None

B. Agan, None

N. Crum-Cianflone, None

E. Johnson, None

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