The bisphosphonate alendronate has an acceptable balance between benefit and risk in terms of fracture outcomes, even for over 10 years of continuous use, new research concludes.

Writing in a study in The BMJ the Danish authors said previous research had highlighted concerns that antiresorptive treatment could lead to atypical femur fractures that could offset the benefits of long-term use.

“It is vitally important to recognise and verify safety alerts and, if verified, scale them appropriately so that clinical practice—including duration of osteoporosis treatment—is driven by absolute rates of benefit and absolute measures of harm so that treatments with good safety records are not inappropriately withdrawn or changed to less cost effective or less safe alternatives,” they wrote.

The Danish prescription registry held almost 20 years of drug exposure data that could be linked to all fracture outcomes treated in hospital in the same period.

Using data from the registry as well as two case-control studies the researchers analysed data from almost 62,000 men and women aged between 50 and 94 who had not previously taken alendronate.

They found use of alendronate in excess of 10 years was associated with an adjusted 30% lower risk of hip fracture and no increase in the risk of fractures of the subtrochanteric femur or femoral shaft.

“Even if all subtrochanteric and femoral shaft fractures observed in alendronate users were atypical, the number remains too low to offset the benefits on hip fracture with long term alendronate treatment for up to 10 years,” the researchers wrote in the BMJ.

“Our study provides reassurance that the total risk of subtrochanteric and femoral shaft fractures does not increase over the first 10 years of high adherence to alendronate…implying that increases in atypical femur fractures are offset by decreases of at least the same size in the risk of non-atypical subtrochanteric and femoral shaft fractures,” they concluded