Obesity Impact in the Economic Burden of Invasive Pneumococcal Disease in Hospitalised Adults in Portugal: The Sphere Study

OBJECTIVES: Invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae is associated with a significant morbidity and mortality, posing a considerable burden for healthcare systems worldwide. Vaccines are the primary and most cost-effective primary prevention intervention.

This real-world study aimed to estimate the economic burden and healthcare resource utilisation (HCRU) of IPD hospitalisations in Portuguese adult patients, with a particular focus on the impact of obesity on outcomes due to its association with an increased risk of IPD.

METHODS: Patient-level data from seven Portuguese hospitals were retrospectively analysed. Adult patients (≥18 years) hospitalised with confirmed IPD between 2017-2018 were included. Patients were stratified into four classes according to their baseline body-mass index: Underweight (<18.5); Normal (18.5-24.9); Preobese (25.0-29.9); Obese (≥30). Cost data was derived from the Portuguese diagnosis-related groups database.

RESULTS: The study analysed 395 IPD hospitalisations, with 44 (11.1%) occurring in obese patients. Most patients were male (61.8%) and aged ≥65 (55.4%). Most individuals (72.2%) had at least one relevant comorbidity; chronic cardiac disease (27.1%), diabetes mellitus (25.6%) and chronic respiratory disease (20.5%) were the most prevalent. Only 4.8% had confirmed vaccination prior to admission. IPD-related hospitalisations in obese patients were associated with a higher HCRU compared to non-obese patients. Intensive care unit (ICU) admission was required in 27.3% of obese patients versus 13.5%-23.7% of non-obese patients’ groups. Median overall length of hospital stay was significantly longer in obese patients (18.0 days) versus non-obese groups (7.0-12.0 days; p<0.05). Furthermore, the median cost per IPD-related hospitalisation episode was significantly higher in obese patients (5,928.60€) than in non-obese groups (2,506.40€-3,733.50€).

CONCLUSIONS: The results of this real-world study highlight the substantial economic impact IPD has on healthcare systems. Understanding the impact of obesity on the severity of disease and economic burden of IPD can assist health policymakers to prioritise this group as a target for prevention measures.