RARE BONE DISORDER FOUND IN H.I.V. PATIENTS

By Lawrence Altman

The New York Times 9 Sept. 2000

An uncommon disorder that destroys bone is turning up with surprising frequency among people infected with the AIDS virus, federal researchers reported yesterday.

The researchers, from the National Institutes of Health, said they did not know precisely what was causing the bone destruction among individuals infected with H.I.V., the virus that causes AIDS. Nor do they know why the disorder, which has led to hip replacement for some patients, is being detected only now.

The disorder is known as osteo necrosis, or avascular necrosis, because the death of bone results from a lack of blood supply. The disorder can be painful and affect bones in many areas. The type found among people infected with H.I.V. involves the hip and affected 4 percent of such people in a study conducted at the clinical center of the health institutes, Dr. Joseph Kovacs, one of the researchers, said in an interview.

"We're very concerned about this," Dr. Kovacs said, "because it is potentially a very debilitating problem and we think its prevalence will increase."

The problem was at first thought to be related to anti-H.I.V. drugs like the protease inhibitors that were first marketed about four years ago, but the researchers say that so far this link has not been proved. They presented their report at a meeting of the Infectious Diseases Society of America in New Orleans.

Also under investigation as possible causes are the use of hormones like testosterone and short-term steroids, as well as cholesterol-lowering drugs, the researchers said.

The bone problem is not related to the degree of immune deficiency from AIDS or any particular pattern in the use of anti-H.I.V. drugs. Those affected were more likely than others in the study to have been involved in weight training and body building.

Osteonecrosis is a different condition from osteoporosis, or thinning of the bones. Last February, scientists reported that many infected people had developed osteoporosis as a complication of anti-H.I.V. therapy.

Osteonecrosis is also different from another recently detected problem known as lipodystrophy, in which fat is redistributed so that H.I.V.-infected people develop disfiguring cosmetic problems.

The institutes' researchers first noted the osteonecrosis problem during a four-day period in May 1999 when two H.I.V. patients complained of pain deep in the groin. One, a bicycle rider, said that he felt as if he had pulled something, but that the condition did not get better with time the way a pulled muscle would. Other patients limped from pain in the hip and groin.

Dr. Kovacs, one of those who detected the first cases, said his team performed magnetic resonance imaging tests that confirmed the pain was due to avascular necrosis.

"The two cases focused our attention," he said, "because until then we had never detected a case" in the 17 years the institutes' clinical center has cared for H.I.V. patients.

The institutes' doctors then found two more cases. All four patients needed hip replacement surgery.

At about the same time, Dr. Kovacs said, his team learned that doctors in Washington, San Francisco and elsewhere were detecting the bone disorder in a small but increasing number of people with H.I.V.

The team checked with the Food and Drug Administration and learned it had also noted a small but increasing number of reported cases of osteonecrosis, Dr. Kovacs said. The cases reported to the F.D.A. were not linked to any product.

Dr. Kovacs's team then conducted a study of about two-thirds of the H.I.V.-infected patients cared for at the health institutes. Of the 339 who volunteered for the study, 15, or 4.4 percent, were found to have avascular necrosis of one or both hips. None of the 15 had symptoms, but many had large areas of bone destruction, raising the possibility that the condition had been detected in an early stage, Dr. Kovacs said.

For purposes of scientific comparison, the team did M.R.I. scans on 118 noninfected volunteers. None had the bone disorder.

The health institutes is conducting larger studies to determine how many H.I.V.-infected people will develop osteonecrosis and how many will need surgery for a total hip replacement. The studies also seek to find what is causing people with H.I.V. to develop osteonecrosis, with the hope that the answer will lead to prevention and treatment.

"Our concern is that this is going to be getting worse with time," Dr. Kovacs said. "But we're hopeful that it won't be as bad as we think."