Hospital incidence, in-hospital mortality and medical costs of pneumococcal disease in Spain (2008-2017): a retrospective multicentre study.

Objective: The aim of this study was to analyze the characteristics of the patients attended with a pneumococcal disease in Spanish hospitals, to evaluate trends in hospital incidence and in-hospital mortality and to quantify patients' use of resources and medical costs.

Methods: Medical admission records of patients admitted due to pneumococcal disease between 1 January 2008 and 31 December 2017 were obtained from a Spanish hospital discharge database. Records were identified with the International Statistical Classification of Diseases and Related Health Problems, 9th and 10th version codes corresponding to pneumococcal pneumonia, bacteraemia, pyogenic arthritis, endocarditis, meningitis, peritonitis and unspecified pneumococcal infections.

Results: Admissions of 168,074 patients were analyzed, with a mean age of 63.5 years (median = 72; interquartile range = 28). Pneumococcal pneumonia was responsible for 64.1% of all admissions, with a hospital incidence of 31.1 per 10,000 patients that decreased significantly over the study period ( = .002). Hospital incidence of meningitis also displayed a decreasing trend over the study period ( = .003), whereas incidence of bacteraemia and pyogenic arthritis increased significantly ( = .001;  = .004). Mean Charlson Comorbidity Index was 3.3 (standard deviation = 2.2). In-hospital mortality was 7.0% over the study period, being the highest in patients admitted with endocarditis (17.2%). Sepsis, acute renal failure, disorders of fluid electrolyte and acid-base balance, heart failure and acute respiratory failure were strongly associated with in-hospital mortality. Mean length of hospital stay was of 11.1 days (median = 22; interquartile range = 26) and there was a majority of urgent admissions (95.0%); the most extended stays were registered in patients with endocarditis, meningitis and pyogenic arthritis. The mean hospital admission cost was €5676, €104.2 million annually for all registered patients; 50.3% of all costs were associated with pneumonia, whereas the highest admission costs were registered in patients with endocarditis (€15,991) and meningitis (€11,934). Mean admission costs increased significantly over the study period for pneumonia and bacteraemia and decreased for endocarditis.

Conclusions: The incidence of pneumococcal pneumonia and meningitis decreased over the study period after the introduction of vaccination in Spain. The advanced age of patients and presence of chronic comorbid conditions that are associated to in-hospital mortality must be taken into account when improving care protocols and upcoming vaccination plans.