Table 4 Comparison between primary collection and re-collection of data from medical records using correlation analysis, and analysis of sensitivity and specificity for binary variables
From: Internal validity of the Swedish Maternal Health Care Register
Variable | Medical recordsa | Medical records re-collectionb | Data available in both data sources | Identical information in both data sources | Correlationc | Sensitivity | Specificity | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
n | % | n | % | n | % | n | % | ||||
Variables collected at first antenatal care (ANC) visit | |||||||||||
Date of first visit in ANC (numerical) | 150 | 100 | 150 | 100 | 150 | 100 | 116 | 77.3 | 0.773 (S) | ||
No of previous deliveries (numerical) | 150 | 100 | 150 | 100 | 150 | 100 | 149 | 99.3 | 0.988 (P) | ||
Maternal weight at first ANC visit (numerical) | 147 | 98.0 | 148 | 98.7 | 147 | 99.3 | 146 | 99.3 | 0.995 (P) | ||
Maternal height (numerical) | 149 | 99.3 | 149 | 99.3 | 149 | 100 | 148 | 99.3 | 1.000 (P) | ||
Smoking at first ANC visit (Yes/No) | 149 | 99.3 | 149 | 99.3 | 149 | 100 | 148 | 99.3 | 0.794 (C) | d | 1.000 |
Use of Snuff at first ANC visit (Yes/No) | 150 | 100 | 150 | 100 | 150 | 100 | 146 | 97.3 | 0.793 (C) | 0.667 | 1.000 |
Assessment of alcohol screening prior to pregnancy (AUDIT) (Yes/No) | 130 | 86.7 | 130 | 86.7 | 130 | 86.7 | 121 | 93.1 | 0.729 (C) | 0.972 | 0.136 |
If Yes, AUDIT score (numerical)e | 113/109 | 96.5 | 108/106 | 98.1 | 102 | 90.3 | 100 | 98.0 | 0.987 (P) | ||
Variables collected at 4 to 16 weeks postpartum | |||||||||||
Prenatal diagnostics | |||||||||||
Amniocentesis (AC) (Yes/No) | 150 | 100 | 150 | 100 | 150 | 100 | 150 | 100 | 1.000 (C) | 1.000 | 0.983 |
Chorion Villus Sampling (CVS) (Yes/No) | 150 | 100 | 150 | 100 | 150 | 100 | 150 | 100 | 1.000 (C) | d | 0.992 |
Combined Ultrasound and Biochemical screening (CUB) (Yes/No) | 147 | 98.0 | 149 | 99.3 | 147 | 98.6 | 142 | 96.6 | 0.912 (C) | 0.919 | 0.941 |
Second trimester Serum Screening (Yes/No) | 148 | 98.7 | 150 | 100 | 148 | 98.7 | 148 | 100 | f | ||
Ultrasound examination at 16 – 21 gestational weeks (Yes/No) | 147 | 98.0 | 147 | 98.0 | 147 | 98.0 | 145 | 99.0 | 0.246 (C) | 0.975 | d |
Estimated date of delivery (ultrasound) (numerical)g | 147 | 100 | 147 | 100 | 147 | 100 | 145 | 98.7 | 0.955 (S) | ||
Oral Glucose Tolerance Test (OGTT) performed (Yes/No) | 149 | 99.3 | 149 | 99.3 | 148 | 98.0 | 144 | 98.0 | 0.819 (C) | 1.000 | 0.986 |
If Yes, 2-hour value of plasma glucose at OGTT (numerical)h | 13/10 | 77.0 | 10/9 | 90.0 | 9 | 69.2 | 9 | 100 | 1.000 (P) | ||
Smoking at 32 gestational weeks (Yes/No) | 145 | 96.7 | 145 | 96.7 | 145 | 100 | 145 | 100 | 1.000 (C) | 1.000 | 1.000 |
Use of Snuff at 32 gestational weeks (Yes/No) | 145 | 96.7 | 145 | 96.7 | 145 | 100 | 144 | 99.3 | 0.797 (C) | 1.000 | 1.000 |
Maternal weight, last data entry after 35 gestational weeks (numerical) | 142 | 94.7 | 141 | 94.0 | 141 | 99.3 | 137 | 97.2 | 1.000 (P) | ||
No. of ANC visits until estimated date of delivery (numerical) | 150 | 100 | 150 | 100 | 150 | 100 | 96 | 64.0 | 0.890 (P) | ||
Date of delivery (numerical) | 150 | 100 | 150 | 100 | 150 | 100 | 149 | 99.3 | 0.975 (S) | ||
Live born child (Yes/No) | 150 | 100 | 150 | 100 | 150 | 100 | 150 | 100 | f | 1.000 | 1.000 |
Birth weight (numerical) | 150 | 100 | 150 | 100 | 150 | 100 | 140 | 93.3 | 0.997 (P) | ||
Gender of infant (Boy/Girl/Sex unknown) | 150 | 100 | 150 | 100 | 150 | 100 | 149 | 99.3 | 0.987 (C) | ||
Singleton birth/multiple births | 150 | 100 | 150 | 100 | 150 | 100 | 150 | 100 | 1.000 (C) | ||
Mode of delivery (vaginal/instrumental vaginal/caesarean section) | 150 | 100 | 150 | 100 | 150 | 100 | 149 | 99.3 | 0.983 (C) | ||
If caesarean section, elective CS/emergency CSi | 23/22 | 95.7 | 23/23 | 100 | 22 | 95.7 | 22 | 100 | 1.000 (C) | ||