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Oral bisphosphonates reduced risk for jaw degradation
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Oral bisphosphonates decreased the risk for adverse bone outcomes in patients with osteoporosis and/or cancer, whereas intravenous therapy increased the risk.
The researchers analyzed the medical claims of 714,217 individuals with osteoporosis and/or cancer. Those who received IV bisphosphonates had a fourfold increased risk for inflammatory jaw conditions. In addition, these patients also had a sixfold increased risk for having major surgical resection in the jaw.
These increases were not seen in patients who received oral bisphosphonates.
The researchers concluded that the mode of therapy, IV or oral, led to different risk profiles. They recommended that physicians and dentists understand the higher frequency of adverse jaw effects in patients who received IV bisphosphonates, particularly osteonecrosis of the jaw. – by Katie Kalvaitis
J Am Dent Assoc. 2008;139:23-30.
The researchers’ implication that oral bisphosphonate use is protective or associated with a reduced risk for adverse bone outcomes is difficult to defend due to many limitations. They did refrain from including this statement in the summary conclusions within their abstract. For this, the researchers are to be commended. But overall, their data merely support previous work that IV bisphosphonate use is associated with a higher level of risk for osteonecrosis of the jaw than with oral bisphosphonate use.
The results of this study are very difficult to interpret for several reasons. One, as stated by the researchers, the ICD-9 code used to represent osteonecrosis (526.4) is quite nonspecific and includes osteitis of the jaw. A common term for this condition, used by dentists and laypeople alike, is “dry socket.” To my knowledge, no other paper has suggested that dry socket is a manifestation of jaw osteonecrosis or that it is more or less common in people who use bisphosphonates. Two, since one of the major risk factors for jaw osteonecrosis is previous surgery of the jaw, including tooth extraction, it is unclear why the researchers chose to present data from patients who had “surgery for a necrotic process” only. For the total osteoporotic population of 263,352, there were only 108 such surgeries. We are left to guess how many extractions were performed in osteoporotic patients not on bisphosphonates vs. those on oral or IV drug. Although the implication is that the relative number of extractions per patient/per group would be similar, it is dangerous to assume such normality. Given the small number of cases (43 of 179,784) of subsequent osteitis, osteomyelitis or sequestrum in this group, the reported “protective effect” could easily disappear if examined as a percentage of total surgical procedures of the jaw.
Of course, a big problem is that there are no CPT codes for tooth extractions. The researchers touch on this issue in their discussion but do not fully explain the potential significance of this limitation.
The third major outcomes subgroup, “Surgery for cancerous process of jaw,” adds nothing to this manuscript. As a pathologist, I can guarantee that most of the surgeries will have been for squamous cell carcinoma arising from the surface oral mucosa, not metastatic disease. In addition, surgery is not the treatment of choice for multiple myeloma. Since the researchers do not mention this data subset in their written results section nor in their discussion, maybe they could not figure out why they included these numbers, either. The only way they could be viewed as relevant would be whether the reported surgeries were subsequently associated (or not) with a necrotic bone process. This connection was not pursued or at least not presented.
Finally, it is well known that osteonecrosis in patients using oral bisphosphonates tends to be milder (lower-stage) than in patients using IV bisphosphonates. As such, many of these patients are never treated surgically (no CPT code and probably no ICD-9 code) but managed by prescription of chlorhexidine mouth rinse. Simple removal of small loose sequestra in these patients, if needed at all, may or may not receive a CPT code beyond office visit or examination.
– John R. Kalmar, DMD, PhD
Professor, Graduate Program Director, Oral and Maxillofacial Pathology, Ohio State University