Validation study of obstetric hospitalization data held on the Brazilian National Health System Hospital Information System for maternal morbidity surveillance: Brazil, 2021-2022

Objective: To validate the Brazilian National Health System Hospital Information System (SIH/ SUS) for maternal morbidity surveillance. Methods: This was a cross-sectional study conducted in 2021/2022, taking as its reference a national study on maternal morbidity (MMG) conducted in 50 public and 28 private hospitals; we compared SIH/SUS and MMG data for hospitalization frequency, reason and type of discharge and calculated sensitivity, specificity, positive and negative likelihood ratios for seven diagnoses and four procedures. Results: Hospitalizations identified on SIH/SUS (32,212) corresponded to 95.1% of hospitalizations assessed by MMG (33,867), with lower recording on SIH/SUS (85.5%) for private hospitals [10,036 (SIH/SUS)]; 11,742 (MMG)]; compared to MMG, SIH/ SUS had a lower proportion of hospitalizations due to "complications during pregnancy" (9.7% versus 16.5%) as well as under-recording of all diagnoses and procedures assessed, except "ectopic pregnancy". Conclusion: Better recording of diagnoses and procedures on SIH/SUS is essential for its use in maternal morbidity surveillance.