Emorragia post partum in Umbria: accuratezza del sistema informativo sanitario regionale per il codice ICD-9-CM 666.x

INTRODUCTION: Postpartum haemorrhage (PPH) is the main cause of morbidity and mortality for pregnant women. Administrative databases are useful sources of information for the assessment of PPH and related outcomes, once the corresponding ICD-9-CM code is validated. The objective of the present study is to evaluate the accuracy of the ICD-9-CM code related to PPH. MATERIAL AND METHODS: Source of the data was the Regional Healthcare Database of the Umbria Region. The population of interest were women with at least 20 weeks of gestation that delivered in any hospital in the Umbria Region during 2012-2016. Cases of interest were identified using the ICD-9-CM 666.x code. For validation purposes, both cases (women who delivered and developed PPH) and non-cases (women who delivered without occurrence of PPH) were considered and algorithms proposed. The basic criterion used for the validity of ICD-9-CM codes was the presence of bleeding ≥500 ml. Additional criteria based on values of haemoglobin or transfusion of red blood cells were considered. Sensitivity, specificity and predictive values were calculated. RESULTS: Medical charts of 422 cases and 200 non-cases were examined. Accuracy results for code 666.x related to the presence of bleeding ≥500 ml were: sensitivity 97% (95% CI, 96-99%), specificity 70% (65-76%), positive predictive value (PPV) 79% (76-82%) and negative predictive value (NPV) 95% (91-97%). The best algorithm was the one that, in addition to the basic criterion, considered both the haemoglobin values and red blood cell transfusion: sensitivity 93% (90-95%), specificity 85% (80-90%), PPV 92% (89-94%) and NPV 86% (81-90%). ICD-9 subcodes showed a higher specificity and PPV for immediate bleeding (666.0, 666.1) than delayed or secondary haemorrhage (666.2). CONCLUSIONS: The accuracy data from the present study confirm that the Regional Healthcare Database of the Umbria Region can be used as a reliable source for the evaluation of epidemiological studies relating to PPHs, in order to improve the quality of maternity care.