Interobserver reliability of the International Classification of Primary Care

OBJECTIVE: The International Classification of Primary Care was developed as an attempt to overcome the limitations of the International Statistical Classification of Diseases and Related Health Problems, 10th revision, when used for primary health care. The aim of the study was to evaluate the interobserver reliability of the International Classification for Primary Care when coding reasons for health-related interruption of daily activities. METHODS: Data analyzed pertained to 801 subjects from Phase 2 of the Pro-Saude Study, involving the employees of a Rio de Janeiro university who reported having been prevented from carrying out any of their usual activities (work, study, or leisure) for health-related reasons in the two weeks prior to data collection. Health problems reported in response to an open question were separately coded by two classifiers. Interobserver reliability with respect to number of health problems was calculated by weighted kappa; for the remaining analyses (chapters and full codes), crude kappa coefficients were used. RESULTS: A total of 1,641 health problems were coded by the first classifier, and 1,629 by the second. Interobserver reliability with respect to the number of health problems coded was substantial (weighted kappa=0.94; 95% CI: 0.93;0.94). Chapter and full codes showed substantial (kappa=0.89; 95% CI: 0.88;0.90) and moderate (0.76; 95% CI: 0.76;0.78) reliability, respectively. CONCLUSIONS: The results suggest that the International Classification of Primary Care is adequate for the coding of health-related reasons for interruption of daily activities.