Should everyone start HIV therapy
when their CD4 count drops below 250? Or is it different strokes for different
folks?
Words Jeffrey Williams
Images Raffaele Teo
All
of us living with HIV in the developed world face the big question at some
point: when should I start taking HIV therapy? For some, this question may
be: should I even start at all?
One of the main considerations is that once we start therapy, we have to stick
to it for life. As the doctors like to put it, we will need to take the ‘medicine
as prescribed’. Many fear the constraints such a regimen will place
on their lifestyle or worry the long-term side effects of the meds will adversely
affect their lives.
‘When should I start?’ or ‘How late can I leave it?’
are both questions we need to think about. HIV doctors follow national treatment
guidelines from the British HIV Association (BHIVA) when deciding when and
how to treat us. But how much notice should we take of these guidelines?
One size not for all
An important consideration is that no two people will respond to an illness
or medication in exactly the same way. If you gave ten randomly chosen HIV
positive adults the same dose of an HIV drug and asked for their experience
of side effects, you will get ten quite distinct responses. Some will feel
nauseous and some may get diarrhoea, but not all will get all the potential
side effects. The picture becomes even more complicated when you consider
not all of us are the same size or weight. Despite these differences, adult
dosing of medication is always the same for all adults.
We are all unique
The way we respond to HIV medication is not only due to our differences but
also the way our bodies respond to the progression of the virus. We are each
unique and not just cloned copies of each other; which is what makes living
so much fun. Our uniqueness arises from our genes. Each of us (including supposedly
identical twins) receives a unique combination of genes from our parents,
and those genes, and their interaction with our environment, makes us who
we are.
Fast and slow progressors
It is unfortunate but true that for some, HIV infection progresses more rapidly
than for others. Certain people have a natural defence against HIV invading
their cells. This inherited defence (seen in a small
percentage of the general population) slows down the progression of the infection.
In individuals who have not inherited this inbuilt defence, HIV progression
is more rapid. Only a fraction of those who become HIV positive will either
be slow or rapid progressors. People who progress more
rapidly are likely to need therapy sooner.
Different strokes
For most people with HIV not on treatments, infection progresses more or less
at the same rate. It’s our genes and the type of virus we were infected
with that primarily determine this rate. The higher our viral load, the more
CD4 cells we are likely to lose each year. A group of adults of the same age
who seroconvert on the same date will not all progress to the point where
they need to begin medication at the same time. Some will take many more years
to arrive at the same low level CD4 cell count as the others.
Clinical trials that look at the effectiveness of a new treatment or a drug’s
optimum dosing level take account of this. Trials recruit thousands of patients
to obtain an average that is appropriate for the vast majority of people.
The magic number
So, when guidelines for treatment say people living with HIV should begin
treatment when their CD4 falls to about 250, this is guidance for the majority
of the population. Because people respond differently to their illness, there
will be some who need to start therapy well before their CD4 drops below 250.
Similarly, there will be a few who can live relatively safely with a low CD4
count. But most doctors agree that starting before the CD4 drops below 200
makes most sense.
Other infections
The time someone should begin therapy also depends upon whether they have
a serious opportunistic infection. The way people respond to an opportunistic
infection is also largely a function of genes. This means some people (though
not many) who have CD4 cell counts well above 250 and a
serious opportunistic infection, like Kaposi’s sarcoma, may have no
choice but to start therapy. Equally, there are some, but again not many,
who may have CD4 counts below 250 who need not begin therapy to boost their
immune systems because they have some inherited protection against some infections.
The few
This range of responses to HIV infection can be seen in any population or
country. It’s a distribution which results from our genes and our lifestyles:
smoking, heavy drinking and unhealthy diet can stress the immune systems of
HIV negative people. National guidelines are just what the name says: guidelines,
to be used by clinicians to finetune their treatment to each individual living
with HIV. All these guidelines say is that the majority of people living with
HIV will need to begin therapy by the time their CD4 counts fall to about
250, but this is not the case for a small minority. Within this minority there
will be a large fraction that will have already started therapy before their
immune systems were stressed to a level of about 250 CD4 cells. Few, indeed,
will be able to live without therapy below the level of 250 CD4 cells. Regular
CD4 testing shows how your immune system is coping with HIV infection. If
your CD4 count falls rapidly and is heading to the 200-250 level, your doctor
is likely to suggest thinking about treatment. At the very least they will
suggest a more regular, monthly monitoring of your CD4 count.
And finally…
It’s worth remembering a large proportion of people living with HIV
in the UK are not diagnosed until their CD4 count is at this critical level.
So many of us will have to think about beginning treatment quite soon after
we have received our HIV diagnosis.
• UKC have just published a new booklet entitled Starting, Switching
and Stopping HIV Therapy. Look out for it at your clinic
• Visit www.bhiva.org for BHIVA’s full guidelines on starting
HIV therapy
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