[Overdiagnosis and defensive medicine in occupational medicine].

In clinical medicine since some years overdiagnosis is giving rise to growing attention and concern. Overdiagnosis is the diagnosis of a "disease" that will never cause symptoms or death during a patient's lifetime. It is a side effect of testing for early forms of disease which may turn people into patients unnecessarily and may lead to treatments that do no good and perhaps do harm. Overdiagnosis occurs when a disease is diagnosed correctly, but the diagnosis is irrelevant. A correct diagnosis may be irrelevant because treatment for the disease is not available, not needed, or not wanted. Four drivers engender overdiagnosis: 1) screening in non symptomatic subjects; 2) raised sensitivity of diagnostic tests; 3) incidental overdiagnosis; 4) broadening of diagnostic criteria for diseases. "Defensive medicine" can play a role. It begs the question of whether even in the context of Occupational Medicine overdiagnosis is possible. In relation to the double diagnostic evaluation peculiar to Occupational Medicine, the clinical and the causal, a dual phenomenon is possible: that of overdiagnosis properly said and what we could define the overattribution, in relation to the assessment of a causal relationship with work. Examples of occupational "diseases" that can represent cases of overdiagnosis, with the possible consequences of overtreatment, consisting of unnecessary and socially harmful limitations to fitness for work, are taken into consideration: pleural plaques, alterations of the intervertebral discs, "small airways disease", sub-clinical hearing impairment. In Italy the National Insurance for occupational diseases (INAIL) regularly recognizes less than 50% of the notified diseases; this might suggest overdiagnosis and possibly overattribution in reporting. Physicians dealing with the diagnosis of occupational diseases are obviously requested to perform a careful, up-to-date and active investigation. When applying to the diagnosis of occupational diseases, proper logical criteria should be even antecedent to a good diagnostic technique, due to social outcome for the worker.