What’s new in osteoporosis: report of the 8th International Symposium on Osteoporosis

The 8th International Symposium on Osteoporosis (ISO) sponsored by the National Osteoporosis Foundation (www.nof.org) was held in Washington, D.C. last week and had a full program of updates and “forecasts." The target audience was physicians and other health care professionals for whom osteoporosis was not a major area of interest or expertise. Judging by the Q&A periods, the intended audience was there, and the presenters for the most part did what was expected of them.

The Fracture Risk Assessment Tool (FRAX) is in play and can be found on the NOF website. It is a tool to be used to assess a patient’s 10-year probability of sustaining a hip or other major osteoporosis-related fracture. The program asks for demographic and vital statistics data and medical history and has the option to include bone density in the model. It should only be used for untreated patients and then only in patients where there is some uncertainty as to whether intervention with FDA-approved therapies for osteoporosis are indicated. FRAX is a work in progress by which I mean that the data contributing to the model will be continually updated, and it may not become an integrated program on the DXA report for a while. The tool on the web is very user friendly (it even automatically converts pounds and inches to kilos and meters if you let the model know you are in the United States). Try it on a few patients before you know their DXA result and again when that result is available.

There was not much new about diagnostic modalities, but there was a great deal of discussion concerning the inadequate recognition of osteoporosis being a likely diagnosis in patients presenting with a minimal trauma fracture (trauma resulting from a fall from a standing height or less). Most distal forearm/wrist (Colles’) fractures, the earliest clinical manifestation of osteoporosis in a postmenopausal woman, present to an Emergency Department, and because a woman fell before fracture, osteoporosis is not considered. There is a very active movement to include the ED in the diagnostic chain for osteoporosis.

New classes of drugs are being evaluated in clinical trials, and the results look very promising. Right behind this advance is a burgeoning body of basic science that is completely unraveling the inner workings of osteoblasts (bone-forming cells) and osteoclasts (bone-resorbing cells). I must have heard of at least 15 different chemicals involved in the bone-remodeling process and even more pathways that control their production and action. To get a feel for the list, do a search for the Wnt signaling pathway and also the LRP5 gene but don’t try and memorize what you read. I’m just happy when I think I can understand at least some parts of it. The potential drug pipeline for osteoporosis seems large.

Possible side effects of bisphosphonates generated much discussion that clarified the extent of the issue — the local upper gastrointestinal distress is not uncommon (yes, that is a double negative, but I can’t quantitate “common”), but the others (osteonecrosis of the jaw, femur fractures, atrial fibrillation, carcinoma of the esophagus) are rare at the doses used for osteoporosis. The dental issue has received most unfavorable and unwarranted attention. Dental emergencies require urgent attention whether the patient is on bisphosphonate or not, but the risk of ONJ seems restricted to invasive dental procedures that extend beyond the tooth, and even then the occurrence is <1 in 10,000 and likely much less than that. My dentist (used to be my senior lab assistant so is not worried about holding things back from me) tells me that non-emergent dental care can safely be postponed for six months in most cases, and I assure him that most patients on bisphosphonate for prevention or treatment of osteoporosis can safely be off therapy for six months. “Bad news” sells, and I am obviously biased, but the worrying side effects of bisphosphonates are overstated.

Perhaps the most important topics discussed at the symposium were the growing numbers of common conditions and medications associated with bone loss and increased risk of osteoporosis. Add to your list diabetes, depression, rheumatoid arthritis and their therapies (thiazolidinediones, selective serotonin reuptake inhibitors, proton pump inhibitors), to name a few.

The session on skeletal health from the first trimester through to pregnancy and lactation had good news and bad news. We have learned a lot about the calcium and vitamin D requirements of pregnancy needed to optimize skeletal development in utero and also how to best care for the nutritional requirements for premature babies in the neonatal ICU. On the downside, teenage depression is not going away and neither are the eating disorders or the female athlete triad. These disorders are also on the upswing in males, and there are no magic bullets for therapy for either sex.

On a much more positive note, pregnancy and lactation result in substantial negative bone balance in mother, but it all appears to come back, possibly even with overshoot, and that includes multiple pregnancies with breast feeding. Just make sure that nursing and pregnant mothers are getting appropriate calcium and vitamin D in their diet and supplement — biology and physiology cannot overcome nutritional deficiency, and these nutrients and supplements can be bought inexpensively (one can pay much more for fancy labels and astonishing claims but “caveat emptor”). Medroxyprogesterone acetate (Depo-Provera, DMPA; Pharmacia & Upjohn) is also associated with bone loss and carries an FDA “black box” warning label to that effect, but here too the skeleton gets replenished if the drug is discontinued, even after years of use.