HIV treatment has come a long way since the first reported case of AIDS in 1981. In the early days of AIDS, there were no drugs available to fight the immune deficiency that caused AIDS-related opportunistic infections.
Today there are a number of therapies available to people living with HIV. Many HIV drug therapies require carefully timed dosing schedules and multiple medications, and efficacy often depends on exacting adherence to these protocols. One concern among doctors and patients alike is drug resistance, which can be the result of poor adherence.
Below, Dr. Jason Leider, Director of the Adult HIV Program for Jacoby Hospital and North Central Bronx Hospital and the Health Center at Tremont, discusses the danger of drug resistance.
Could you give us a sense of the numbers of new HIV diagnoses per year, and the numbers of people currently being treated for HIV?
About 40,000 people are newly infected each year with HIV in the United States, and this number has actually stayed the same for the last few years.
There are about 900,000 people with HIV in the United States altogether right now. The majority are aware of their HIV status, but only perhaps 250,000 of these people are on consistent medications to help fight HIV.
What is drug-resistant HIV?
Drug-resistant HIV is HIV virus in a person that has partial to complete resistance to medications that are currently available for HIV treatment. In other words, the medications are no longer as effective or effective at all in treating the virus.
Health
How does drug resistance happen?
The most common way it happens is when people miss medicine doses consistently. Often the virus will actually become resistant to the medicine, just the same way that, if you were given a treatment for an ear infection and didn't take the antibiotic consistently, missing a lot of doses, then often the infection doesn't respond as well to the antibiotic. You would then have to go on much more potent antibiotics and longer courses of treatment to cure the infection.
How many people who are currently in treatment are experiencing drug resistance?
In the study that we're doing up here at our hospitals, we're seeing about 30 percent of people with resistant virus. There's a report that's just coming out from UCLA. Their estimates are that in San Francisco, according to different analyses that they've used, by the year 2005, forty-two percent of all of the people in San Francisco who are HIV positive will not respond to current therapy.
How many treatments do you have to miss before you become resistant to the treatments?
Current HIV treatment requires a high level of adherence. And the estimates are that you need to take around 95 percent of the doses correctly to get full effect of the medications. What that means is that if you're on a medicine twice a day, and you're going to take it for an entire week, proper adherance would be 14 doses. You would probably be okay if, in a week, you missed one or two doses or took them incorrectly. So you have to really work at this and really try to achieve 100 percent adherence to the medications if you're going to have an optimal outcome and prevent resistance development.
And proper adherence requires proper timing of medication as well?
Yes. Adherence is not just swallowing the pills, but swallowing them at the correct times. It's swallowing them with the appropriate dietary requirements. Some medicines have no dietary requirements. Some actually require food in order to be absorbed better. Some medications require that you take them without foods because the stomach acid actually destroys the medicines. Sometimes if you take medicines too far apart or too close together, there could be periods in the day when you may have too much medication in your body and may experience side effects. And then if there is too long an interval between doses, the drug level may be so low that you can actually have resistant virus develop.
A doctor should go over with you what the dietary requirements are for each medication. Also, you should ask the pharmacist to give you any kind of information about requirements of medications. Should they be taken with food, without food? Are there dietary requirements? What are the proper times of the day to take the medicines?
Is it possible to reverse resistance to a drug?
Yes, but it becomes much harder to treat people who have some level of resistance than those who don't.
Are those subsequent medications usually more toxic?
Sometimes they are. Often the drug regimens end up being more difficult in terms of number of pills or number of doses.
We try to tailor a person's first regimen to their lifestyle as closely as possible so that it is as few pills as possible, as few number of requirements in terms of food or restrictions, and as few doses as possible.
But we still only have fifteen medications out there. If you become resistant to the medicines you're on, you may also be developing resistance to medicines you aren't taking because some of the medicines are somewhat related to each other. So it's harder sometimes to tailor the second or third regimens to someone's lifestyle than the first time you pick a regimen.
Do you think that drug resistance is going to be a major problem in coming years?
Oh, yes. I think it's one of the biggest problems we're going to face in terms of HIV treatment. We're seeing our own patients coming in who have never been on medications, who already have resistant virus.
What percentage of people who have never taken medication are infected with drug resistant HIV?
Right now it's low. It's under five percent. But I would say that the way things are going, that probably in the next five years-if the trends continue-it may be all the way up to fifteen percent of people coming into care will already have significant resistance to some of the medications.
Why?
When a person's on medication, and they have resistant virus, often it's hard to lower their viral load, and we know that the risk of transmission of virus from one person to another becomes higher as the viral load goes up. So if you have a higher viral load, and you're positive, and you have resistant virus, you're more likely to spread the virus to someone else. And when you do, it's often the resistant virus that you're spreading.
What should be done to slow the development of drug resistant strains of the virus?
In the past, efforts in HIV risk reduction have been targeted by decreasing risky sexual practices or intravenous drug use. And people who are positive were not really included in trying to decrease transmission, which has been called "AIDS exceptionalism". Now, there's a huge project by the CDC to include people who are HIV positive in educational programs about decreasing transmission of virus to their partners, whether they be sexual partners or drug-using partners. Often, people who are positive know where other positive people may be better than the health communities, and can encourage them to get tested.
We would like to see people get tested much earlier. And we know one thing is that we see the virus being transmitted higher in heterosexual communities, especially communities of color. And this has also been a national trend.
So come in earlier.
Come in earlier. Be tested. There are free testing sites all over. And some tests don't even require drawing blood. They can use an oral test. There are a lot of free sites in New York City and throughout the country.
And if you do test positive, don't delay treatment. Some people test positive but it takes them a long time to come to grips with going in for treatment. If you're coming in for care when you're already sick, you may not only need to be treated for HIV, but you may end up needing treatment for other illnesses related to a weakened immune system, and the treatment becomes more complicated.
To locate an HIV test site near you, log on to: http://www.hivtest.org/locate/index.htm.
Jason Leider, MD, PhD, North Bronx Health Care Network of Jacobi & North Central Bronx Hospitals
