Utility of the National Cooperative Growth Study database for safety reporting

The National Cooperative Growth Study (NCGS) maintains the largest database in the world, collecting information on patients with growth disorders treated with growth hormone (GH). More than 24,000 children have been monitored during its first decade (1985 through 1995). The database provides unique opportunities to learn about effectiveness of GH therapy in a real-world context. Its size also makes it possible to investigate rare adverse reactions, which is not reasonable in a randomized controlled trial (RCT). The frequency of adverse experiences reported in an observational study like the NCGS is lower than in an RCT, because the investigators in an observational study typically do not report events that they believe are clearly unrelated to the study drug. Nevertheless the NCGS has greatly facilitated collecting adverse-event data; approximately 75% of all adverse-event reports for GH received by the manufacturer are through NCGS data-collection forms. The NCGS has thus amassed a repository of GH safety data that is unparalleled. Furthermore, in contrast to an RCT, the NCGS database reflects real-world experience with long-term GH therapy in North America. Although the advantages of an observational study such as the NCGS must be recognized, such a study does differ from an RCT in important ways. For example, because the NCGS protocol allows customized patient treatment and individualization of GH therapy, it may be difficult to use the database to address questions (e. g., estimation of dose-response relationships, true incidence of adverse events) that require RCT designs.