Internal validity of the Swedish Maternal Health Care Register
- Equal contributors
1 Department of Clinical Sciences, Obstetrics and Gynecology, Umeå University, Umeå, Sweden
2 Dalarna University, School of Health and Social Studies, Falun, Sweden
3 Umeå School of Business and Economics, Department of Statistics, Umeå University, Umeå, Sweden
4 Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
5 Department of Research and Development, Västernorrland County Council, Västernorrland, Sweden
6 Primary Health Care, Parental and Child Health Care, Östersund, Sweden
7 Primary Health Care, Maternal Health Care Unit, Örebro, Sweden
BMC Health Services Research 2014, 14:364 doi:10.1186/1472-6963-14-364Published: 30 August 2014
The Swedish Maternal Health Care Register (MHCR) is a national quality register that has been collecting pregnancy, delivery, and postpartum data since 1999. A substantial revision of the MHCR resulted in a Web-based version of the register in 2010. Although MHCR provides data for health care services and research, the validity of the MHCR data has not been evaluated. This study investigated degree of coverage and internal validity of specific variables in the MHCR and identified possible systematic errors.
This cross-sectional observational study compared pregnancy and delivery data in medical records with corresponding data in the MHCR. The medical record was considered the gold standard. The medical records from nine Swedish hospitals were selected for data extraction. This study compared data from 878 women registered in both medical records and in the MHCR. To evaluate the quality of the initial data extraction, a second data extraction of 150 medical records was performed. Statistical analyses were performed for degree of coverage, agreement and correlation of data, and sensitivity and specificity.
Degree of coverage of specified variables in the MHCR varied from 90.0% to 100%. Identical information in both medical records and the MHCR ranged from 71.4% to 99.7%. For more than half of the investigated variables, 95% or more of the information was identical. Sensitivity and specificity were analysed for binary variables. Probable systematic errors were identified for two variables.
When comparing data from medical records and data registered in the MHCR, most variables in the MHCR demonstrated good to very good degree of coverage, agreement, and internal validity. Hence, data from the MHCR may be regarded as reliable for research as well as for evaluating, planning, and decision-making with respect to Swedish maternal health care services.