Epidemiology of hospital-treated Salmonella infection; data from a national cohort over a ten-year period.

OBJECTIVE

The aim of this study was to describe the clinical and economic burden of hospital admissions related to Salmonella infections amongst the population of Spain over the course of 10 years (1997-2006).

METHODS

Data provided by the National Epidemiology Surveillance System for Hospital Data (Conjunto Mínimo Básico de Datos; CMBD) were analysed. This database included information about Salmonella infection-related hospital incidence rates, patient demographics, length of stay, mortality, case-fatality rates and associated costs.

RESULTS

During the period 1997-2006, 65,100 infections due to Salmonella were recorded, indicating an annual incidence rate of 16.18 cases/100,000 people/year (95% confidence interval [CI] 16.05-16.30). The average length of hospital stay for patients with Salmonella infection was of 7.6 days (SD 8.9), and the average patient age was 31 years old (SD 29). The mortality rate was 0.23/100,000 people (95% CI 0.22-0.24 per 100,000 people), and the case-fatality rate was 1.40% (95% CI 1.33-1.51%). The incidence rate was significantly higher in those <14 and >65 years old (maximum of 89.12 cases/100,000 people <4 years old; 95% CI 87.80-90.45 cases/100,000). The mortality and case-fatality rates increased significantly with age, reaching 2.05 deaths per 100,000 people (95% CI 1.70-2.37 cases/100,000) or 7.53% (95% CI 6.34-8.73%) in people >85 years old. The total cost of Salmonella infection was 124 million Euros during the study period, with children up to 4 years of age being the most prominent consumers of resources.

CONCLUSIONS

Salmonella infection remains an important cause of hospitalization of children up to 4 years old, but the main mortality and case-fatality rates are observed in persons older than 65 years.