World Health Organization Adverse Reaction Terminology Dictionary

Abstract

The World Health Organization Adverse Reaction Terminology (WHO ART) Dictionary was developed in 1968 and is hierarchical in nature. At the top of the hierarchy are 30 system organ classes, followed by high-level terms, preferred terms, and included terms. Some preferred terms are also high-level terms.

The WHO ART Dictionary is used at Schering Corporation for standardized coding of adverse drug events occurring in clinical trials, postmarketing, and in published literature. Automatic encoding is primarily used in the data entry process for clinical trials, whereby literal terms are keypunched into the computer and are electronically matched to the corresponding WHO preferred term. Common terms not automatically matched to a WHO term may be added to the dictionary as “lexicon terms” to increase the automatic matching rate to at least 75%. Terms are stored as the literal term, the preferred term, the system organ class, and sometimes the included term. In the postmarketing setting, coding of adverse drug events is performed manually or by automatic encoding. Terms are stored as the preferred term and corresponding system organ class. The Director of Medical Services is responsible for making decisions regarding the addition of new terms. Schering has found the WHO ART Dictionary to be flexible enough to be useful for report preparation, labeling development, storage of published literature, and at all phases of clinical development.