["Primum non nocere". Prospective study of 115 cases of iatrogenic diseases collected over one year in 106 patients].

One hundred and fifteen cases of iatrogenic disorders were observed in 106 patients during a one-year prospective study. Each case was included after informed agreement of two investigators. Each case was classified into 4 groups, according to duration time between iatrogenic disorder and hospitalization, and into 3 sections according to responsibility of causative agent. A control group of 200 patients matched for age and sex was studied. Patients represented 8% of the hospitalisations. Mean age (69.2 years) was higher than other patients hospitalized during the same period (61.6 years). Principal causative agents were diuretics (30), physchotrops (13) and technic examinations (12). Main pathologies were electrolytes disorders (28), orthostatic hypotension (19), confusion and/or alteration of mental functions (13), and cutaneous or allergic disorders (12). Mean induced hospitalization duration time was of 8 days. Mean estimate cost was 18,808 francs per patient. Associated factors were elderly, and an elevated number of drugs. A negligency could participate to iatrogenic disorders in 50% of cases. Half part of iatrogenic disorders could be avoided by using simple precautions: respect of contra-indications, restriction on self-therapy and of number of associated drugs.