The Danish National Patient Register (DNPR)is widely used for research and administrative purposes. However, its usability is highly dependent of the validity of the registered data. We therefore aimed to determine the positive predictive value (PPV) of angina pectoris and acute coronary syndrome (ACS) in the DNPR.
We selected a random sample of 500 patients registered with angina pectoris and a random sample of 500 patients registered with ACS among all hospitalisations at any department in Northern Denmark between 1 January 2007 and 31 December 2007. We reviewed the medical records of the sample patients and recorded whether the angina pectoris and the ACS diagnoses were valid, based on the European Society of Cardiology criteria.
The PPV of definite and probable angina pectoris was 45.9% (95% confidence interval (CI): 41.3-50.6%), whereas the PPV of verified ACS was 86.6% (95% CI: 83.3-89.5%). Stratification by hospital department revealed significantly higher PPVs for diagnoses received in a cardiology unit for both angina pectoris (61.7%; 95% CI: 53.4-69.6%) and ACS (95.5%; 95% CI: 91.3-98.0%). Stratification by gender showed a significantly higher PPV among men registered with angina pectoris (51.2%; 95% CI: 45.3-57.1%).
The angina pectoris and ACS data contained in the DNPR should be used with caution in register studies if validation is not possible. Restricting analyses of ACS data to patients discharged from cardiology wards may be a useful option in register-based studies.
The quality of the data recorded by the British Columbia Cancer Registry for 521 new cases of invasive cervical cancer was evaluated. The registry's pathological diagnosis in all new registrations of invasive cervical cancer diagnosed in British Columbia between 1977 and 1979 was compared with a best estimate of the true diagnosis, which was determined from the results of the provincial cervical cytology screening program and the clinical charts at the Cancer Control Agency of British Columbia. The registry's data overestimated the true incidence of invasive cervical cancer by approximately 55%, since 184 (35%) of the cases were incorrectly registered. Of the 184, 141 (77%) were cases of preinvasive cervical cancer, 26 (14%) did not meet the criteria for a true case (i.e., they were not newly diagnosed in British Columbia between 1977 and 1979) and 17 (9%) were cases of invasive cancer of another primary site. In addition, 28 cases of invasive cervical cancer diagnosed in the province during the study period had not been reported to the registry. Thus, both over-reporting and under-reporting occurred. There is a need for constant evaluation of registry data if cancer registries are to fulfil their potential contribution to cancer control programs and research.
The acute myocardial infarction (AMI) register of the FINMONICA study, the Finnish part of the WHO-coordinated multinational MONICA project, operates in the provinces of North Karelia and Kuopio in eastern Finland and in Turku, Loimaa and in communities around Loimaa in southwestern Finland. The AMI register serves as an instrument for the assessment of trends in mortality from coronary heart disease (CHD) and of the incidence and attack rates of AMI among 25-64-year-old residents of the study areas. This report describes the methods used in the FINMONICA AMI register and the findings during the first 3 years of the study, in 1983-1985. The criteria of the multinational WHO MONICA project were used in the classification of fatal events and in the diagnosis of non-fatal definite AMI, but based on the experience within the FINMONICA study, stricter diagnostic criteria than those originally described in the WHO MONICA protocol were used for non-fatal possible AMI. This led to a marked improvement in the comparability of the data from the three study areas with regard to the incidence and attack rates of non-fatal AMI. During the 3-year period the total number of registered events was 6266 among men and 2092 among women. Among men the incidence and attack rates of AMI and mortality from CHD were higher in eastern than in southwestern Finland. Also among women the incidence and attack rates of AMI were higher in eastern than in southwestern Finland, whereas there was no regional difference in mortality from CHD among women. The mortality findings of the FINMONICA AMI Register were in good agreement with the official CHD mortality statistics of Finland.