USE OF THE INTERNATIONAL CLASSIFICATION O F DISEASES FOR THE DISABILITY INSURANCE IN SWITZERLAND - A RELIABILITY STUDY

The International Classification of Diseases (ICD-10) was introduced i n a pilot phase for coding of diagnoses in a sample of cases encounter ed in the Swiss Disability Insurance (SDI), as a substitute for the SD I codes, judged unsuitable for the description of disability. The goal of this study is to evaluate the reliability of use of these codes, b y studying the coding reproductibility between the Medical Observation Centers (MOC) and the Evaluation and Coordination Center. A second go al was to evaluate the feasibility of coding by non-physicians. Reliab ility of diagnoses was examined by level of precision: chapters, group s categories and sub-categories. The agreement between the two coding Centers varies from 78%, at the chapter level, to 29% at the most deta iled level. This agreement is improved if taking into account the thre e main diagnoses for the comparison, reaching 91%. The results of the physician coder, concerning the precision and reliability of coding, a re significantly superior to those of an economist coder and a medical secretary coder. To improve coding agreement, it is proposed to train coding professionals, provide coding tools, clarify which diagnosis i s the main one, and seek a consensus for cases of systematic disagreem ent. The ideal level of precision should not be so high as to produce diagnostic codes with low reliability. It should, however, be precise enough to give a satisfactory description of the problems encountered.