Maternal morbidity profile in hospitalizations in the Unified Health System in São Paulo, Brazil: analysis using data mining, 2014 to 2019

Abstract In Brazil, approximately 80% of births are registered in the Hospital Information System of the Unified Health System (SIH/SUS), which has several fields for recording morbidities. SIH/SUS is the only Brazilian information system that has morbidity data, but its use for maternal morbidity surveillance is still limited. The objective of this study was to identify a set of diagnoses that alone or together increase the risk of maternal death, via data mining technique. Obstetric hospitalizations at SIH/SUS of women aged 10-49 years from the largest state in Brazil (São Paulo) from 2014 to 2019 were analysed. Diagnoses were classified into 12 groups, adapting the World Health Organization’s classification proposal of maternal deaths. Groups of diagnoses that were related to maternal death were identified using association rules with the Apriori algorithm. Of the 2,742,467 hospitalizations, 831 (0.03%) resulted in death. The most frequent diagnoses associated with death, alone or in combination, were nonobstetric complications (62.0%). Pregnancy-specific hypertensive complications (20.1%), pregnancy-related infections (19.9%) and haemorrhages (13.6%) were also present in hospitalizations resulting in death. The risk of death was more significant for nonobstetric complications, unknown causes and external causes, with lifts above 10. The risk of death was at least three times greater for groups of diagnoses related to the most frequent causes of maternal death in the country (complications of hypertension, infections, and haemorrhages). Uncomplicated abortion, gestational diabetes and other causes of nonobstetric hospitalization were only associated with maternal death when together with other diagnoses. The results of this study reaffirm the importance of hypertensive, haemorrhagic and infectious causes for maternal death and highlight the relevance of nonobstetric causes for the surveillance of maternal morbidity since women with these diagnoses, alone or associated with other complications, yield to a higher risk of death. Competing Interest Statement The authors have declared no competing interest. Funding Statement Yes Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: We analysed databases that are deidentified and made publicly available (open access). According to the Brazilian National Health Council ethics resolution n° 510/2016 (April 7, 2016), research ethics committee approval was waived. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable Data Availability https://datasus.saude.gov.br/transferencia-de-arquivos/ https://drive.google.com/drive/folders/1eceyf0uN6l4u-pAQpRgzSy9uvZeK3qHZ?usp=sharing