Table 2.
Agreement of Data From Birth Certificate Checkboxes With ICD-9-CM Codes in Hospital Discharge Records for Checkboxes That Correspond Directly to Items in the Centers for Disease Control and Prevention’s Severe Maternal Morbidity Index, California, 2007–2012
| Concordance Metric | ||||||||
|---|---|---|---|---|---|---|---|---|
| Complication | Prevalence Based on Birth Certificates, % | Prevalence Based on ICD-9-CM Codes in Discharge Records, % | κ | Sensitivity, % | Specificity, % | PPV, % | NPV, % | Accuracy, % |
| Transfusion | 0.10 | 0.91 | 0.143 | 8.1 | 99.9 | 70.1 | 99.2 | 99.1 |
| Eclampsia | 0.00 | 0.07 | —a | 0.0 | 100.0 | — | 99.9 | 99.9 |
| Anesthetic complications | 0.00 | 0.01 | — | 0.0 | 100.0 | — | 99.9 | 99.9 |
| Unplanned hysterectomy | 0.03 | 0.09 | 0.392 | 25.1 | 100.0 | 89.9 | 99.9 | 99.9 |
| Sepsis | 0.35 | 0.04 | 0.013 | 6.7 | 99.7 | 0.8 | 100.0 | 99.6 |
| Any complication | 0.47 | 1.04 | 0.123 | 9.4 | 99.6 | 20.8 | 99.1 | 98.7 |
Abbreviations: ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; NPV, negative predictive value; PPV, positive predictive value.
a The κ value and PPV could not be calculated because no cases were identified on the basis of the birth certificate.