NEW YORK (Reuters Health) - Up to one third of patients who have a heart or liver transplant could suffer a vertebral fracture in the years following their surgery, results of a study suggest.

A team of German researchers found that 21% of heart transplant patients and 14% of liver transplant patients had experienced a vertebral fracture caused by bone thinning one year after the operation. By the second year, 27% of heart patients and 21% of liver patients reported a fracture, and by the third and fourth years, one third of patients in each group had sustained a fracture.

The study included 105 patients who had undergone a heart transplant and 130 patients who had a liver transplant.

The bone-building nutrients calcium and vitamin D did not lower patients' risk of fracture, according to the report in the February 3rd issue of The Lancet.

``Our data confirmed a high risk of osteoporotic fractures...which may markedly influence the quality of life of these patients along with the survival rate,'' Dr. Gudrun Leidig-Bruckner, from the University of Heidelberg in Germany, told Reuters Health.

Preventive therapies to reduce the rate of osteoporosis-linked fractures after transplantation are needed, she said. Specifically, new immunosuppressive drugs need to be evaluated.

These drugs suppress the immune system and are routinely given to patients following a transplant so that the new organ is not targeted as a foreign invader and attacked by the immune system. But immunosuppressive drugs also inhibit bone growth by preventing the absorption of calcium.

In an accompanying editorial, Dr. Pierre Delmas from Claude Bernard University in Lyon, France, suggests that hormone replacement therapy could be given to postmenopausal women who undergo transplants, since these women do not produce much estrogen, a hormone that protects bones.

Drugs such as alendronate and risedronate may also lower the risk of fracture in these women, although more research is needed, he adds. These compounds have been shown to reduce the risk of other types of fractures in some women with the bone-thinning disease.

SOURCE: The Lancet 2001;357:325, 342-347.