Heart failure is associated with an increased risk for osteoporosis and fractures. In one recent study, heart failure patients were found to have six times as many hip fractures as other heart patients.
Lasix and other drugs in the class known as loop diuretics are commonly used to treat heart failure. But these drugs also promote elimination of calcium by the kidneys, which could promote bone loss and fracture.
But in the largest study ever to examine the issue, researchers found little evidence linking the use of loop diuretics to changes in bone mineral density, falls, and fractures in postmenopausal women.
Only a small increase in risk was seen in women who took the drugs for more than three years.
"I would characterize these findings as very reassuring," says lead researcher Laura D. Carbone, MD, MS, of the University of Tennessee Health Science Center.
"When these drugs were used for short periods, there was no increase in the fracture rate. When they were used for longer periods, the fracture risk was just slightly increased."
Heart Failure, Falls, and Fractures
Carbone and colleagues analyzed data on the use of loop diuretics and outcomes in nearly 135,000 women enrolled in the national health study known as the Women's Health Initiative in the 1990s.
The researchers compared the rate of fractures and falls among the 3,411 study participants who used loop diuretics and those who did not over eight years of follow-up. They also analyzed bone mineral density measurements for 300 diuretic users and 9,124 nonusers throughout the observation period.
They found no significant differences between the two groups in bone mineral density at study entry and after three years of observation.
Likewise, no significant difference was seen in total fractures, hip fractures, vertebral fractures in the back, or falls when loop diuretics were used for three years or less.
Use of the drugs for more than three years was associated with a 16% increase in risk for total fractures.
But in women with heart failure, loop diuretics were associated with a slight reduction in fracture risk. This finding, however, could have been due to chance.
Carbone points out that most of the women in the study were getting adequate amounts of calcium in their diets, either through the foods they ate or through supplementation.
"We don't know if these findings apply to women who are not getting enough calcium," she says.
It is also not clear if the findings apply to men, who tend to eliminate more calcium in their urine than women do, she says.
At least one recent study in men suggested that loop diuretics may accelerate bone loss at the hip.
"Patients on loop diuretics do have a higher risk for fractures, but this study suggests that it is because they are in poorer health and not because of the drugs they take," she says.
Loop Diuretics Protective?
Mayo Clinic endocrinologist Robert Wermers, MD, says the study is encouraging, especially the finding in women with heart failure.
"Women with heart failure who took loop diuretics actually had a lower risk for fractures," he says. "This shows the importance of treating the disease."
He adds that clinicians treating heart failure patients and other frail, older populations need to recognize that they are at increased risk for falls and fractures.
"People who are medically frail are certainly at risk for falling and breaking a bone," he says. "In addition to giving medication, we really need to focus on fall prevention."