Hospital Admission due to Adverse Drug Events (ADE): An Analysis of German Routine Hospital Data of 2006

Background: In developed countries 1-5% of all hospital admissions are due to adverse drug events (ADE). An ADE is defined as an injury resulting from medical intervention related to a drug. The established reporting systems and study designs only capture selective data. The objective of the current analysis was to evaluate the rate, distribution and correlations of ADE related admissions by using German routine data. Methods: ADEs were identified by an array of 502 specified codes of the ICD-10-GM. The evaluation included only verified codes and was carried out by remote queries of the German DRG-Statistics 2006. Hospital admission due to an ADE was identified via the primary diagnosis. Results: Of all hospital admissions 0.92% were revealed to be certainly caused by an adverse drug event. The average age between affected and non-affected was nearly identical for women 53.48 vs. 53.67 years, for men it was reduced by 4 years (48.38 years). The average hospital stay was lower for cases with an ADE, being reduced by 1.3 days for women (6.26 days vs. 7.55 days) and 1.5 days for men (5.91 days vs. 7.42 days). While mortality with an odds ratio (OR) of 0.59 (95% CI 0.57-0.62) was lower in ADE cases, the rate of emergency admissions due to ADE was increased, the OR being 3.10 (95% CI 3.07-3.13). The wards with excess rates of ADE cases were internal medicine, paediatrics, dermatology, intensive care and neurology. Conclusions: Younger age, reduced hospital stay and lower mortality of ADE cases are contrary to findings in the relevant literature. The DRG-Statistics also comprise populations which often are excluded in established study designs, in particular, children and cases due to medication errors, overdose, poisoning and allergic reactions. As these cases respond easily to prevention and are of significant interest to pharmacovigilance, the use of routine data is valuable for more intense research of ADE.