Let me start with the scary and necessary-to-know statistics: Osteoporosis affects 10 to 12 million people in the US and forty million have low bone density (osteopenia). In 2005, over 2 million fractures were diagnosed. One in three Caucasian women over 50 will experience an osteoporotic fracture in her lifetime. (Whites and Asian women tend to have a lower bone mass than women of other ethnicities.) We also “out fracture” men (who have thicker bones) by a factor of 1.6. And if a woman fractures her hip, she has a 20% chance of dying within a year. Osteoporosis is a very disabling, costly, and yes, mortal disease.
There has been a welcomed increase (both medically and financially) in pharmaceutical therapies that help avoid and/or treat osteoporosis. By now, you have all seen the ads and articles for the various bisphosphonates including oral alendronate (Fosomax), risedronate (Actonel) and ibandronate (Boniva) which can be used daily, weekly or monthly. There are also intravenous bisphosphonates that can be administered every 3 months or just once a year.
Then came the media outcry about potential side effects that these medications could cause….jaw necrosis, perhaps atrial fibrillation and more recently “atypical” fracture of the femoral shaft (long, upper leg bone), especially after long term use. I want to address the latter concern in this article.
Remember, these medications work by binding to the bone, preventing cells called osteoclasts from drilling minute cavities that make the bone porous. Cells called osteoblasts then do “their thing” and fill the cavities up. When stable, the drilling and filling are equal and thus maintain bone structure and strength. However if the drilling outpaces the filling, there is bone loss. This occurs with age (unfortunately after 30), and is accelerated by lack of estrogen (menopause) certain medications, especially steroids, diseases and the “wrong” genes. It is also aided and abetted by lack of proper nutrition.
Just to reiterate, bisphosphonates help stop the drilling and with time those minute cavities that made the bone porous get filled, diminishing the risk of fracture. We now know that these bisphosphonates attach and remain in the bone performing this job for years after being discontinued.
Recent cases have appeared in medical journals in which the femoral bone fractured in a horizontal fashion without prior significant trauma. In most instances, the patients were taking long term bisphosphonates. How concerned should we be about this newly media reported “atypical” femur fracture?
An article in the May issue of The New England Medical Journal may help allay physician and patient concerns. It concludes that this type of fracture is truly rare. The authors used data from 3 randomized and placebo-controlled, prospective studies involving 14,195 women and 55,000 person years of observation. The risedronate data that they reviewed provided up to 10 years of study. All together, they found a total of 12 fractures in 10 patients that were classified as possible “atypical” femur fractures. (To be accurate, they were called subtrochanteric or diaphyseal fractures). The incidence came out to just 2.3 per 10,000 patient years. The authors also calculated that treating 1,000 women who had osteoporosis for 3 years would prevent about 100 fractures (including 11 hip fractures), a benefit that way exceeded the risk of “atypical” fracture, if indeed it was caused by the bisphosphonates.
So what does this mean? Well according to an editorial that followed the article, “physicians should not rush to judgment and stop prescribing bisphosphonates because of concern about atypical femoral fractures.” They should, however, reevaluate patients who have received long term therapy in the context of contemporary guidelines. (And for these please see my previous website article that discusses the use of FRAX to determine for whom and when to start therapy.)
I now review the FRAX indications for each patient who is at risk for osteoporosis. If she is a candidate for medication I will prescribe it, but carefully follow her with tests to check for bone loss. If she is stable for a number of years (usually 5 years) I suggest stopping the medication or at least taking a drug holiday. The good of the bisphosphonates still outweighs a possible bad, at least for those who need it.
Now, although I usually end my weekly newsletter with just one article, I have to mention another that just came out in JAMA. It also dealt with bone fractures. As we now all know, Vitamin D has become the vitamin “De jour”. The amount of D found in up to 70% of American is inadequate; low levels have been associated with osteoporosis, heart disease and a number of cancers. I ask all my patients about their Vitamin D intake (and exposure, remember you can get it though sun rays) and repeatedly advise them to take at least 1,000 international units (IU’s) daily. I often check Vitamin D levels with a blood test, especially if there is a history of low bone density. For those whose level is found to be extremely low, I prescribe 50,000 units of Vitamin D-2 a week or every other week for several months, and then recheck their levels. If they have achieved a D level that is sufficiently high, I have them continue with an OTC supplement of up to 2,000 units daily.
Researches in Melbourne, Australia tried to maximize Vit D administration by giving elderly women considered to be at high risk of fracture a dose of 500,000 IU of Vitamin D orally once a year. They carried out a double-blind, placebo-controlled trial in 2256 women aged 70 or older. Half were given this very high yearly dose for 3 to 5 years; the others were given a placebo. There was no difference between the 2 groups with regard to calcium intake (indeed it increased for both). But contrary to expectations the group that received the high dose Vitamin D experienced 15% more falls and 26% more fractures than the placebo group. And the increase in falls was most apparent in the 3 months after they were given high dose Vit D! Frankly, the authors couldn’t explain this but went on to suggest that dosing should be more frequent and at lower doses. So far I (and most of my colleagues) will probably stick to advising daily 1,000 units or more of D and if your levels are low that you increase the dose (with a prescription) on a weekly or biweekly schedule. But I doubt we will prescribe that single oral dose once a year. So please continue to use D and calcium on a regular basis for better bones. And if necessary, go ahead and take that bisphosphonate that I or another doctor may have prescribed. The bones you strengthen will be there to stand you in good stead!