A recent meta-analysis in this journal showed incidences between 3.4 and 33.9%. 
Studies performed by pharmacists and epidemiologists produced lower incidences 
than internists' studies. We reassessed the prevalence of iatrogenic admissions 
in a study of internists. Iatrogenic disease was defined as adverse drug 
reactions according to the World Health Organization Definition and 
complications induced by non-drug medical interventions. Subsequent admissions 
at the Departments of Medicine/Cardiology/Pulmonology in a 1,250 bed general 
hospital in the Netherlands from May 2007 to August 2007 were studied. 2,000 
consecutive admissions were studied: 576 (29%, 26-32%) were classified as 
possibly iatrogenic; out of these 380 (19%, 17-22%) as definitely iatrogenic, 
out of whom 229 (12%, 10-14%) had already been classified as iatrogenic by the 
admitting physicians. Patients with cardiac disease, hypertension, 
gastrointestinal conditions, anticoagulant treatment and use of NSAIDs were, 
particularly, at risk of iatrogenic admission with percentages of 22 (16-24), 13 
(11-18), 12 (9-15), and 7 (5-11) %. An independent predictor of iatrogenic 
admissions was age with an odds ratio of 1.27 per 10 years (p = 0.0001). 1. At 
least 19% of admissions to the Departments of Internal 
Medicine/Cardiology/Pulmonology, and, maybe, even percentages up to 29% were due 
to adverse drug effects. 2. A large difference between the numbers of iatrogenic 
admission according to the physicians in charge of admission and the 
investigators, 229 versus 380 patients, was observed. 3. Most often iatrogenic 
admissions were observed with cardiac disease, hypertension, gastrointestinal 
conditions, anticoagulant treatment, and use of NSAIDs.