Objective: Hospital data are a useful resource for studying pregnancy complications, including bleeding-related conditions, however, the reliability of these data is unclear. This study aims to examine reliability of reporting of bleeding-related conditions, including anaemia, obstetric haemorrhage and blood disorders, and procedures, such as blood transfusion and hysterectomy, in coded hospital records compared with obstetric data from two large tertiary hospitals in New South Wales.
Results: There were 36,051 births between 2011 and 2015 included in the analysis. Anaemia and blood disorders were poorly reported in the hospital data, with sensitivity ranging from 2.5% to 24.8% (positive predictive value (PPV) 12.0-82.6%). Reporting of postpartum haemorrhage, transfusion and hysterectomy showed high sensitivity (82.8-96.0%, PPV 78.0-89.6%) while moderate consistency with the obstetric data was observed for other types of obstetric haemorrhage (sensitivity: 41.9-65.1%, PPV: 50.0-56.8%) and placental complications (sensitivity: 68.2-81.3%, PPV: 20.3-72.3%). Our findings suggest that hospital data may be a reliable source of information on postpartum haemorrhage, transfusion and hysterectomy. However, they highlight the need for caution for studies of anaemia and blood disorders, given high rates of uncoded and 'false' cases, and suggest that other sources of data should be sought where possible.
Keywords: Anaemia; Blood disorders; Coagulation disorders; Haemorrhage; Hysterectomy; Platelet disorders; Transfusion; Validity.