BACKGROUND. Health care databases provide a widely used source of data for health care research, but their accuracy remains uncertain. We analyzed data from the 1985 National DRG Validation Study, which carefully reabstracted and reassigned ICD-9-CM diagnosis and procedure codes from a national sample of 7050 medical records, to determine whether coding accuracy had improved since the Institute of Medicine studies of the 1970s and to assess the current coding accuracy of specific diagnoses and procedures. METHODS. We defined agreement as the proportion of all reabstracted records that had the same principal diagnosis or procedure coded on both the original (hospital) record and on the reabstracted record. We also evaluated coding accuracy in 1985 using the concepts of diagnostic test evaluation. RESULTS. Overall, the percentage of agreement between the principal diagnosis on the reabstracted record and the original hospital record, when analyzed at the third digit, improved from 73.2% in 1977 to 78.2% in 1985. However, analysis of the 1985 data demonstrated that the accuracy of diagnosis and procedure coding varies substantially across conditions. CONCLUSIONS. Although some diagnoses and all major surgical procedures that we examined were accurately coded, the variability in the accuracy of diagnosis coding poses a problem that must be overcome if claims-based research is to achieve its full potential.

Oculodentodigital dysplasia (ODDD) is an autosomal dominant disorder characterized by pleiotropic developmental anomalies of the limbs, teeth, face and eyes that was shown recently to be caused by mutations in the gap junction protein alpha 1 gene (GJA1), encoding connexin 43 (Cx43). In the course of performing an Nethyl-N-nitrosourea mutagenesis screen, we identified a dominant mouse mutation that exhibits many classic symptoms of ODDD, including syndactyly, enamel hypoplasia, craniofacial anomalies and cardiac dysfunction. Positional cloning revealed that these mice carry a point mutation in Gja1 leading to the substitution of a highly conserved amino acid (G60S) in Cx43. In vivo and in vitro studies revealed that the mutant Cx43 protein acts in a dominant-negative fashion to disrupt gap junction assembly and function. In addition to the classic features of ODDD, these mutant mice also showed decreased bone mass and mechanical strength, as well as altered hematopoietic stem cell and progenitor populations. Thus, these mice represent an experimental model with which to explore the clinical manifestations of ODDD and to evaluate potential intervention strategies.

The current evidence does not support the routine use of any of the 9 risk factors for further risk stratification of intermediate-risk persons.