What constitutes a thorough osteoporosis diagnostic work up?
A recent article shows how the authors evaluated 377 consecutive subjects who had been diagnosed with osteoporosis to try to determine the cause of their osteoporosis. See J Int Med 2002 Nov;252(5):389-97, Search for occult secondary osteoporosis: impact of identified possible risk factors on bone mineral density. Deutschmann HA and others, PMID: 12528756. Their goal was to, "Determine whether the use of more elaborate diagnostic tests can identify possible risk factors for secondary osteoporosis and to evaluate the impact of these possible risk factors on the severity of bone disease in the study population." Using dual-energy X-ray absorptiometry (DXA) to determine bone mineral density (BMD), and a battery of clinical tests to diagnose possible risk factors for osteoporosis, the authors found the following: "Osteoporosis without attributable risk factors was diagnosed in 106 women (37%) and 30 men (33%). In 241 patients (179 women, 62 men) one or more possible risk factors for osteoporosis (in this paper also called subclinical disease) were revealed." They concluded, "All the identified subclinical diseases would have remained undetected if the currently accepted guidelines for the investigation of patients with osteoporosis were applied. The statistically significant correlation between the number of identified possible risk factors and the severity of bone disease in the individual patient strongly suggests the pathogenic significance of the identified subclinical diseases. It is yet to be shown whether specific treatment of these subclinical diseases yields additional improvement of bone mass as compared with standard treatment of osteoporosis."
Editor's comments: (Note: There are references on this Web site that suggest the minimal diagnostic tests that should be done to properly diagnosis osteoporosis: See this page for more information). I won't go into all the details of this study since the diagnostic testing methods are complex and would be mainly directed to the physician doing the tests. There are, however, several aspects of the study that are worthy of comment, mainly in that it provides a plan of attack to someone who wants an extremely thorough diagnostic workup to determine anything that could be causing his/her osteoporosis. This particularly might be someone who has had a diagnosis of idiopathic osteoporosis or who has been on approved osteoporosis therapy without a significant positive response. These people might want to look for some occult cause of the osteoporosis that might also respond to some other therapy. Here are the identifiable risk factors that the authors looked for:
Short reproductive period/hypogonadism, lactose malabsorption, past history of hyperthyroidism, hypercalciuria, borderline hyperparathyroidism, renal tubular acidosis type I (RTA I), interstitial nephritis other than analgesic, analgesic abuse nephropathy, exocrine pancreatic insufficiency, other malabsorption syndrome, mild phosphate diabetes, myeloma/lymphoma, osteogenesis imperfecta, vitamin d(3) deficiency.
This study found that as diagnostic tests detected one or more of these subclinical disease risk factors in subjects, subjects had decreased BMD. And, as the number of risk factors per individual increased, the BMD decreased, too. Some of the risk factors they considered are not generally deemed as such for osteoporosis. In particular, they associated lactose malabsorption with osteoporosis, and apparently not just because these people consume less calcium, but as an independent risk factor. They point out that as many as 30% of people with this problem are asymptomatic, thus requiring a special H2-breathing test, a personal history, and possibly analysis of the rise of blood glucose after lactose ingestion. They also noted that seventeen subjects were diagnosed with reduced excretory pancreatic function, with no symptoms of steatorrhea (an excess of fat in the stools) seen. To detect this condition physicians measure the elastase in the stool, and this is not a current test done when osteoporosis is detected. Twenty-two females and 19 males exhibited idiopathic hypercalciuria without kidney stones. This was combined with disturbed intestinal calcium absorption in 6% of the individuals tested, apparently compounding the effect on BMD. Incomplete RTA was found in 27 patients, with a possible cause for this renal acidification defect being found in 10 of these people. The authors describe how the incomplete acidification affects BMD to support the importance of doing RTA diagnostic tests after osteoporosis is diagnosed. (See the article for full details and references to their other articles on this topic).
The authors rightly question how important it is to do all these diagnostic tests since additional therapy might not be beneficial to increase BMD beyond other approved osteoporosis medications. But, in the absence of clinical trials to show otherwise, it would probably be wise to treat whatever condition are diagnosed along with, e.g., Fosamax or Actonel hoping for an added effect. The findings of this study would apply and be most useful to individuals that are not responding to accepted osteoporosis medications or who have a diagnosis of idiopathic osteoporosis. These people should mention this article to their physician to see if additional diagnostic testing is warranted.