The analysis compared incident HIV by age among the VACS, the Nathan Smith Clinic, and CDC data, and HIV severity by age in the VACS vs. Nathan Smith.
In the VACS, Nathan Smith, and CDC data sets, respectively, the percentages of individuals aged 50 years and older with newly diagnosed HIV were 48%, 24%, and 18%.
An analysis of severity of HIV at diagnosis showed that among individuals aged 60 years and older in the VACS cohort, 20% had an AIDS-defining illness, 43% had CD4 counts below 200/mL, and 49% were diagnosed with AIDS. In the Nathan Smith cohort, 33% had an AIDS-defining illness, 58% had CD counts below 200/mL, and 67% received an AIDS diagnosis.
Looking at non-AIDS–associated conditions, they found that the absolute risk for bacterial pneumonia for HIV-positive patients increased from 6.6% among those aged 40 years and younger to 13.7% for those aged 60 years and older. In contrast, the risk for pneumonia was just 1.2% among HIV-negative controls aged 40 years and younger, and grew only slightly to 2.1% for those aged 60 years and older. The relative risk for pneumonia among HIV-positive vs. negative individuals ranged from 5.3 among those younger than 40 years, to 6.4 among those aged 60 years and and older.