Drug-Resistant AIDS Strains

Drug-resistant strains of the AIDS virus are on the rise, appearing in as many as 4.5 percent of newly infected patients tested in two new studies.

The studies, published in today's Journal of the American Medical Association, involve mostly gay white men. Resistance, however, could be more prevalent in other groups, such as drug users and their sex partners, researchers said.

About 40,000 new HIV infections occur yearly in the United States. In recent years, powerful drug cocktails have subdued the virus to undetectable levels in many patients. But studies have found that the virus persists or returns in 10 to 50 percent of cases.

The complicated drug regimen has proven difficult to follow, and many patients who missed doses or quit taking their medicines developed drug-resistant infections that are passed to others.

HIV is still so new that scientists even disagree on how to define resistance. And since both studies used laboratory tests, no one is sure about how the definitions will translate into patient care. Giving high doses of a drug may be enough to overwhelm a virus's resistance.

In one study, researchers at the University of California at San Diego defined resistance as a tenfold increase in HIV's ability to withstand a drug in comparison to a laboratory strain. That study, led by Susan J. Little, tested 141 patients and found that three--or 2 percent--had HIV with at least tenfold greater resistance to one or more drugs. An additional 36 patients--or 26 percent--had HIV that was 2.5 to 10 times more resistant. The participants were tested in San Diego, Los Angeles, Dallas, Denver and Boston.

In the other study, researchers at Rockefeller University in New York defined resistance as a threefold increase in HIV's ability to withstand a drug. That study, led by Daniel Boden of the Aaron Diamond AIDS Research Center, tested 80 subjects in New York and Los Angeles.

Of the 67 who could be tested for resistance, three had HIV that was highly resistant--or fivefold resistant--to multiple drugs. The subjects were among the 18 who had HIV that was at least threefold resistant to at least one drug.

Newborns and Hospital Stays

Discharging full-term babies and their mothers from the hospital more quickly may not endanger the newborns' health, a study found.

The study examined the rates of infants returned to an Ohio hospital soon after birth. However, the authors of the test said babies discharged earlier were not necessarily healthier.

From 1991 to 1995, the median length of hospital stays for 102,678 babies born to mothers on Medicaid, the health insurance program for the poor, declined from 2.2 days to 1.6 days. Yet the percentage of those newborns who returned to the hospital within a week of birth declined to 1 percent in 1995 from 1.3 percent in 1991. The rehospitalization rate within 14 days of birth declined to 1.7 percent in 1995 from 2.1 percent in 1991.

The two most common causes of rehospitalization were jaundice and respiratory problems, said the report in today's Journal of the American Medical Association.