The Diagnosis and Treatment of Primary Osteoporosis According to Current Guidelines: Unreliable in the Individual Case

by Prof. Dr. med. Klaus M. Peters, Prof. Dr. med. Erika Baum in volume 33/2008

The interesting update provided by Baum and Peters is opposed by a more timely paradigm for defining osteoporosis: the consequence of the civilization related mechanical disuse of the skeleton by loads (1). The "gold standard" DXA is therefore not suitable for evaluating the risk of fractures because the deficiency is not primarily pathological. This also applies synonymously to the surplus of body fat which we carry with us. Systematic errors in DXA scanning can result in substantial over- or underestimation of the measured bone mineral content (2). The WHO definition was interpreted incorrectly. A pioneer of densitometry said in this regard (3): "But let it be clear that the World Health Organization T score criteria were proposed for use in epidemiological studies, for comparison between populations ... They were not intended for diagnosis or treatment decisions in individual cases."

Slim or anorexic individuals are often found to have a high "fracture risk" referring to DXA scans, whereas quantitative computed tomography (QCT) shows that the same vertebra shows normal resistance to fracture. Therefore, the T score is a doubtful basis for therapeutic decisions. Even an overwhelming wealth of data can not justify a "high level of evidence", since this evidence basis was misleadingly established and interpreted.

The pharmaceutical industry has almost exclusively used DXA scanning over the past 20 years to evaluate its osteoporosis drugs. The method is undoubtedly representative and valid in large sample sizes, but it is unreliable in the individual case scenario. The DVO guidelines acknowledge this fact only partly, provided that the method is used accordingly and the user is able to distinguish hidden individual measurement errors. In diabetes mellitus, a method to measure blood glucose level with a comparatively high inaccuracy would be dangerous. DOI: 10.3238/arztebl.2009.0039b


Prof. Dr. med. Dipl.-Min. Peter Schneider
Universitätsklinikum
Klinik und Polokilinik für Nuklearmedizin
Josef-Schneider-Str. 2
97080 Würzburg, Germany

Conflict of interest statement
The author is a member of the organization REKO(Regionaler Expertenkreis Osteoporose; regional expert circle for osteoporosis).

References

1. Frost HM, Schneider P, Schneider R: Osteoporosis a disease requiring treatment or osteopenia a physiologic state? – Behandlungsbedürftige Osteoporose oder physiologische Osteopenie? – WHO Definition im Gegensatz zum Utah Paradigma. Dtsch Med Wochenschr 2002; 127: 2570–4

2. Schneider P, Reiners Chr: Quantitative Bestimmung der Knochenmasse: heutiger Stand und Fallstricke der Methoden. Med Welt 1998; 49: 157–63.

3. Dequeker J: Bone densitometry is not a good predictor of hip fracture. BMJ 2001; 323: 795–9.