How reliable are health registers? Registration of induced abortions and sterilizations in Finland.

Finland's population-based health registers are widely used in health-monitoring and research. We assessed the quality of the Finnish Register on Induced Abortions and Sterilisations and compared it to the Hospital Discharge Register. Ten hospitals out of 67 public hospitals performing induced abortions and sterilizations and three randomly selected months in 2011 were included. This data was compared to the data in the Register on Induced Abortions and Sterilisations. The sample presented 43.1% of all induced abortions and sterilizations during the study months. The coverage on data on induced abortions was excellent: 97.0% of induced abortions were found in the register. Coverage on data on sterilizations was good: 89.4% of sterilizations performed were found in the register. More detailed comparisons of the variable data showed good to very good validity. The coverage of the Hospital Discharge Register was found also to be good. The validity of Finland's Register on Induced Abortions and Sterilisations makes it a good base for research and health-monitoring. The Hospital Discharge Register was a good source in measuring volumes of hospital use as well as the main diagnoses or procedures, but the registration of single diagnoses or procedures may be less ideal for research.