Monitoring the rate of hospitalization before rotavirus immunization in Italy utilizing ICD9-CM regional databases

Recently, two Rotavirus (RV) vaccines were licensed in Italy, rendering RV illness a vaccine preventable disease. To assess the RV hospitalization rate in Italy, a study focused on the Regional hospital discharge forms (HDD) databases was carried out.

Regional HDD databases from Piemonte, Veneto, Friuli-Venezia-Giulia and Marche were analyzed. A total of 434,335 hospitalizations were counted in the study timeframe and 13,234 VE diagnoses (3% of hospitalizations) were collected. A total of 8546 RVE cases (2% of hospitalizations, 64% of all VE) were observed, of which 1.2% were primary diagnoses (PD) and 0.8% secondary diagnosis (SD). The RVE hospitalization peak (4.9%) was observed at the age of 1 year (4.5% in 7-12 months of age) with a median hospital stay of 4.4 days (s.d +/- 4.2). Two deaths (out of 8546 RVE cases) were identified.

Regional HDD databases with the diagnosis of viral enteritis (VE) and RV enteritis (RVE) (ICD9-CM code 00861-69 and 008.8) in any position of the first 20 discharge diagnoses in children aged less or equal to 5 years between 2001 and 2005 were requested.

Despite some limitations due to the HDD synthetic contents and low potential for clinical interpretation, the Regional HDD databases, including PD and SD, may be a useful tool for monitoring the clinical impact of RV vaccination introduction in Italy.