Wednesday, February 23, 2011

Study confirms long-term bone drug use and atypical fractures

Older women who used bisphosphonates (medications that prevent loss of bone mass) for five years or more were more likely to experience "atypical" fractures involving the femoral shaft (bone in the leg that extends from the hip to the knee) or subtrochanteric (fractures in the bone just below the hip joint), compared to women with less usage, according to a study in JAMA.

In the primary analysis, the researchers found that use of bisphosphonates for 5 years or longer was associated with a 2.7 times higher odds of hospitalization for subtrochanteric or femoral shaft fracture compared with transient use (less than 100 days in total) of bisphosphonates. The secondary analysis examining the risk of typical osteoporotic fractures included 9,723 women with fractures of the femoral neck or intertrochanteric region (a section of the femur) during bisphosphonate therapy. Extended bisphosphonate use (greater than 5 years) was associated with a 24 percent reduced risk of fracture compared with transient use. Women with intermediate bisphosphonate use (3-5 years) demonstrated a similarly low risk, while a shorter duration of bisphosphonate use (100 days to 3 years) was associated with a nonsignificant reduction in the risk of such fractures. Further analysis suggested that more than half of subtrochanteric or femoral shaft fractures among women taking bisphosphonates for greater than 5 years were attributable to extended bisphosphonate use; and that approximately 1 of every 10 subtrochanteric or femoral shaft fractures cases in the population might be prevented if no patient received more than 5 years of exposure. Among 52,595 women with at least 5 years of bisphosphonate therapy, a subtrochanteric or femoral shaft fracture occurred in 71 (0.13 percent) during the subsequent year and 117 (0.22 percent) within 2 years.

"In summary, our findings provide strong evidence that prolonged bisphosphonate therapy is associated with an increased risk of subtrochanteric or femoral shaft fracture, although the absolute risk of these fractures is low. These findings also highlight the need for a thoughtful assessment of individual risk of fracture when considering extended bisphosphonate therapy and that long-term use of these drugs may warrant reconsideration, especially in patients at relatively low risk of fracture. It may be appropriate to consider a drug holiday for selected patients, particularly as the cumulative duration of bisphosphonate therapy surpasses 5 years. Additional research is needed to better understand the prognosis of subtrochanteric or femoral shaft fractures among frail older adults, identify the specific subgroups of long-term users at the highest risk for these adverse effects, and explore whether interruptions in therapy reduce the risk of subtrochanteric or femoral shaft fractures over the long term," the authors write.

Bonnie - yet more evidence that we are not "one size fits all." And in the case of long-term bisphosphonate use, you are playing with fire.

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