Relevance of Prevalence Values

Abstract

Regarding the healthcare delivered to patients with euthyroid goiter in general practice, and on the basis of our own research experience in developing a guideline on thyroid disorders in general practice for the German College for General Practitioners and Family Physicians (Deutsche Gesellschaft fur Allgemeinmedizin, DEGAM), we wish to draw attention to the following. We have noticed with some surprise that, for some years now, authors of German scientific articles have been citing the Papillon study when reporting the prevalence rates of goiter and thyroid nodules for the German population. What remains completely unconsidered is the question of the relevance of these prevalence values for the German population. When looking at the selection of the study participants, for example (voluntary participation of “people in work,” who themselves (!) reported no prior thyroid-related findings), one may assume a high selection bias. These prevalence rates are not representative for the German population. Most cases of goiter are asymptomatic. Do all persons with asymptomatic changes of the thyroid (mostly incidental findings) have to be referred for further diagnostic/therapeutic measures? Or is watchful waiting sufficient, provided the patients have received comprehensive information? It is worth mentioning that thyroid cancer is rare. Estimated, age-standardized incidence rates of thyroid cancer according to the Robert Koch-Institute are 3.1/100 000 in men and 6.3/100 000 in women (1). Most thyroid changes are of benign origin (23). Against the background of very low incidence rates, the question arises of how effective further diagnostic measures are, especially in cases of asymptomatic euthyroid goiter. Their predictive value is too low due to the very low prevalence rates, especially in general practice. On the basis of the current state of knowledge, the DEGAM guideline for thyroid disorders will appeal to general practitioners to adopt an approach of watchful waiting in patients with asymptomatic thyroid changes (always depending on the clinical symptoms, in accordance with patients’ own wishes, and provided comprehensive information has been given).