Prevalence of CMV
retinitis remains high among people living with HIV in resource-limited settings,
results of a systematic review of 65 studies published in the online edition of
Clinical Infectious Diseases show.
Prevalence of this AIDS-defining condition was 14% in Asia and 2% in Africa.
Approximately three-quarters of cases involved people with a CD4 cell count
below 50 cells/mm3.
“This review found
that the prevalence of CMV retinitis in resource-limited settings, notably
Asian countries, remains high,” write the authors. “Part of the explanation for
the enduring high prevalence of CMV retinitis in Asia can be found in the fact
that, despite considerable progress in scaling up access to ART [antiretroviral
therapy], the proportion of patients who present late for HIV care remains
(CMV) is a late-stage opportunistic infection in people with HIV, typically
occurring when CD4 cell count falls below 100 cells/mm3. The most
frequent manifestation of CMV disease in people living with HIV is CMV
retinitis, which is responsible for over 90% of cases of HIV-related blindness.
Largely thanks to
antiretroviral therapy, new cases of CMV retinitis are very rare in richer
There is also an
assumption that CMV retinitis is no longer a major concern in resource-limited
settings, especially as access to antiretroviral therapy is increasing.
international team of investigators was concerned that access to CMV
diagnostic and treatment services is limited in many low- and middle-income
countries. Moreover, the researchers noted that studies have reported widely
varying rates of the condition.
conducted a systematic review and meta-analysis of research published between
1996 and early 2013 that reported on the prevalence of CMV retinitis among people living with HIV in resource-limited countries. Studies were included if
they assessed the occurrence of CMV retinitis by fundoscopic examination and
had a cohort of at least ten adults living with HIV.
A total of 65
studies involving 20,280 people met the investigators’ inclusion criteria.
Most of these studies were conducted in Asia (39 studies, 12,931 participants),
followed by Africa (18 studies, 4325 participants) and Latin America (five studies,
2836 participants). The age of participants at the time of screening ranged from 21 to
41 years. The majority of studies (50) were conducted in hospital settings.
Just under a fifth (18%) were carried out between 1993 and 2002; a third
between 2003 and 2005; 24% between 2006 and 2008; and 26% between 2009 and
quality of the studies was rated as low to moderate. The majority (52) had a
prospective design and reported using indirect ophthalmoscopy with dilation of
the pupils. In 30 studies an ophthalmologist conducted the screening. Only 30
studies stratified outcomes according to CD4 cell count.
Prevalence of CMV
retinitis ranged from a low of 0.2% in a study conducted in Nigeria, to 72% in a
Thai study. Prevalence exceeded 5% in four countries: Thailand, 24% (five
studies, 1397 patients); Myanmar, 25% (five studies, 2928 patients); China,
15% (nine studies, 2357 patients); and India, 7% (13 studies, 4305 patients).
By region, the
highest prevalence was in Asia (14%) and lowest in Africa (2%). Only 19 studies
reported whether disease affected one or both eyes. Their findings showed that 43%
of patients had CMV retinitis in both eyes. Almost a third (32%) of patients
had lost vision in one or both eyes.
three-quarters (73%) of cases involved people with a CD4 cell count below 50
cells/mm3. A further 16% of patients had a CD4 cell count between
50-100 cells/mm3 at the time of diagnosis.
indicates the important clinical burden of CMV retinitis, predominantly in
patients with CD4<100 cells/mm3, and that the disease is commonly
bilateral and commonly associated with vision loss,” comment the investigators.
Prevalence did not
differ over time, and was similar in studies conducted between 1993 and 2002
(12%) and between 2009 and 2013 (17%).
There was no
difference in prevalence according to whether screening was conducted by an
ophthalmologist or an HIV clinician trained in retinal examination. “From an
operational perspective, this is encouraging, and points towards the potential
for integrating routine retinal examination as part of basic care for all late
presenters,” the researchers suggest.
They believe their
findings have important clinical implications, especially the need to improve
the detection of people with CMV retinitis: “routine retinal screening by
indirect ophthalmoscopy of all late presenters with CD4 below 100 cells should
be considered.” The investigators also suggest that CMV prophylaxis may be
beneficial for some patients and that pressure needs to be exerted to make oral
therapies for CMV retinitis affordable for resource-limited countries.
The Medicines Patent Pool and Roche announced an agreement to provide valganciclovir to treat CMV retinitis at low cost in 138 countries earlier this month.