Table 3 Data in medical records and the Sweedish Maternal Health Care Register (MHCR); comparison between the two data-sets using correlation analysis, and analysis of sensitivity and specificity for binary variables
From: Internal validity of the Swedish Maternal Health Care Register
Variable | Data source: Medical records | Data source: MHCR | Data available in both data sources | Identical information in both data sources | Correlationa | Sensitivity | Specificity | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
n | % | n | % | n | % | n | % | ||||
Variables collected at first antenatal care (ANC) visit | |||||||||||
Date of first visit in ANC (numerical) | 877 | 99.9 | 868 | 98.9 | 867 | 98.7 | 685 | 79.0 | 0.878 (S) | ||
No of previous deliveries (numerical) | 878 | 100 | 867 | 98.7 | 867 | 98.7 | 840 | 96.8 | 0.971 (P) | ||
Maternal weight at first ANC visit (numerical) | 862 | 98.1 | 855 | 97.4 | 847 | 96.4 | 798 | 94.2 | 0.990 (P) | ||
Maternal height (numerical) | 872 | 99.3 | 862 | 98.2 | 860 | 97.9 | 834 | 97.0 | 0.982 (P) | ||
Smoking at first ANC visit (Yes/No) | 875 | 99.7 | 872 | 99.2 | 868 | 98.9 | 843 | 97.1 | 0.742 (C) | 0.650 | 0.995 |
Use of Snuff at first ANC visit (Yes/No) | 878 | 100 | 871 | 99.2 | 871 | 99.2 | 861 | 98.9 | 0.540 (C) | 0.429 | 0.998 |
Assessment of alcohol screening prior to pregnancy (AUDIT) (Yes/No) | 802 | 91.3 | 859 | 97.8 | 788 | 89.7 | 691 | 87.7 | 0.480 (C) | 0.986 | 0.393 |
If Yes, AUDIT score (numerical)b | 650/643 | 98.9 | 777/771 | 99.2 | 621 | 95.5 | 600 | 96.6 | 0.989 (P) | ||
Variables collected at 4 to 16 weeks postpartum | |||||||||||
Prenatal diagnostics | |||||||||||
Amniocentesis (AC) (Yes/No) | 875 | 99.7 | 791 | 90.1 | 788 | 89.7 | 772 | 98.0 | 0.754 (C) | 0.743 | 0.991 |
Chorion Villus Sampling (CVS) (Yes/No) | 875 | 99.7 | 790 | 90.0 | 787 | 89.6 | 778 | 98.9 | 0.176 (C) | 0.167 | 0.995 |
Combined Ultrasound and Biochemical screening (CUB) (Yes/No) | 780 | 88.8 | 791 | 90.1 | 700 | 89.7 | 665 | 95.1 | 0.888 (C) | 0.936 | 0.957 |
Second trimester Serum Screening (Yes/No) | 849 | 96.7 | 790 | 90.0 | 767 | 87.4 | 671 | 87.4 | 0.002 (C) | 0.043 | 0.958 |
Ultrasound examination at 16 – 21 gestational weeks (Yes/No) | 862 | 98.2 | 791 | 90.1 | 779 | 88.6 | 755 | 96.9 | 0.064 (C) | 0.979 | 0.800 |
Estimated date of delivery (ultrasound) (numerical)c | 871 | 99.2 | 874 | 99.5 | 868 | 98.9 | 781 | 90.0 | 0.946 (S) | ||
Oral Glucose Tolerance Test (OGTT) performed (Yes/No) | 869 | 98.9 | 877 | 99.9 | 868 | 98.9 | 842 | 97.0 | 0.854 (C) | 0.880 | 0.982 |
If Yes, 2-hour value of plasma glucose at OGTT (numerical)d | 100/48 | 48.0 | 104/97 | 93.3 | 46 | 46.0 | 34 | 73.9 | 0.902 (P) | ||
Smoking at 32 gestational weeks (Yes/No) | 858 | 97.7 | 876 | 99.8 | 856 | 97.5 | 849 | 99.1 | 0.864 (C) | 0.821 | 0.998 |
Use of Snuff at 32 gestational weeks (Yes/No) | 832 | 94.8 | 876 | 99.8 | 830 | 94.5 | 826 | 99.5 | 0.712 (C) | 0.625 | 0.999 |
Maternal weight, last data entry after 35 gestational weeks (numerical) | 777 | 88.5 | 843 | 96.0 | 760 | 86.6 | 706 | 92.9 | 0.989 (P) | ||
No. of ANC visits until estimated date of delivery (numerical) | 877 | 99.9 | 868 | 98.9 | 867 | 98.7 | 627 | 72.3 | 0.915 (P) | ||
Date of delivery (numerical) | 878 | 100 | 878 | 100 | 878 | 100 | 842 | 95.9 | 0.989 (S) | ||
Live born child (Yes/No) | 878 | 100 | 878 | 100 | 878 | 100 | 874 | 99,5 | 0.598 (C) | 0.999 | 0.500 |
Birth weight (numerical) | 876 | 99.8 | 869 | 99.0 | 868 | 98.9 | 813 | 93.7 | 0.989 (P) | ||
Gender of infant (Boy/Girl/Sex unknown) | 878 | 100 | 874 | 99.5 | 874 | 99.5 | 862 | 99.2 | 0.973 (C) | ||
Singleton birth/multiple births | 877 | 99.9 | 878 | 100 | 877 | 99.8 | 875 | 99.7 | 0.908 (C) | ||
Mode of delivery (vaginal/instrumental vaginal/caesarean section) | 876 | 99.8 | 876 | 99.8 | 874 | 99.5 | 857 | 98.0 | 0.946 (C) | ||
If caesarean section, elective CS/emergency CSe | 130/115 | 88.5 | 129/128 | 99.2 | 110 | 84.6 | 102 | 92.7 | 0.841 (C) | ||