HIV testing and treatment
programmes in sub-Saharan Africa need to prioritise older individuals,
according to research published in PLOS
ONE
. Investigators in Uganda found that after starting antiretroviral
therapy (ART) people aged 50 years and older had higher mortality and poorer
immune reconstitution compared to younger people.

“Older age is associated with poorer
response to ART and excess mortality compared to the younger,” comment the
authors. “Our data show that older persons retain a significantly higher risk
for mortality and this is not modified over time.”

The prevalence of HIV among the
over-50s is increasing. Almost 60% of older HIV-positive individuals live in sub-Saharan
Africa. Studies conducted in richer settings have shown that older age at ART
initiation is associated with poorer outcomes, such as impaired CD4 response
and higher mortality risk.

Investigators in Uganda wanted to
see if this was also the case in sub-Saharan Africa. They therefore designed a
retrospective study involving 8500 adults who started ART between 2006
and 2012 at the HIV clinic at Mbarara Hospital. Data collected during routine
follow-up were analysed to see if age was associated with mortality risk and
immune reconstitution. Participants were stratified into three age groups at the time they started ART: younger
(18-34 years); middle (35-49 years) and older (50 years and older). Information
was also gathered on key baseline characteristics associated with outcomes
after starting ART, including HIV disease stage, CD4 cell count and body mass
index (BMI).

Approximately two-thirds of
participants were female. Median age was 32 years. Over half (56%) were in the younger age group, 37% in middle age and 7% in the older age group.

Individuals were followed for a median
of 1.5 years and contributed over 66,000 person-years of follow-up.

Older people were less likely
than other age groups to have a baseline CD4 cell count above 350 cells/mm3.
A significantly higher proportion of the over-50s had low BMI. 

During follow-up, 2% of people
died. After adjusting for potential
confounders, older age was associated with a
63% increase in mortality compared to younger people (adjusted RR = 1.63; 95%
CI 1.26-2.11). Men had a higher mortality risk than women, and more advanced
HIV disease at baseline was also associated with an increase in mortality risk.

“After adjustment for gender, CD4
count, education and duration of ART, age at ART initiation remained an
important predictor of mortality and older patients had a poorer prognosis
compared to the young age group,” comment the authors.

There was also some evidence that
older age was associated with a fall in CD4 cell count after ART initiation,
but this finding fell just short of significance (RR = 1.79; 95% CI 0.89-3.58).

The poorer immunological response
in older people could be due to impaired thymus function, as this gland plays
an important role in CD4 cell reconstitution.

The investigators believe their
findings have clear implications for ART treatment programmes in sub-Saharan
African settings – older people should be a priority group for eligibility to initiate ART very early. 

“Older patients showed poorer
immunological response and higher risk for mortality following ART initiation compared
to the young adults,” conclude the authors “Further studies should be conducted
to further understanding the biological mechanisms for the poorer immunological
response and the excess mortality in the older patients. Interventions such as
adjuvant therapy to antiviral therapy may be necessary to improve immunological
recovery.”