Trends in Hospitalization for Infective Endocarditis as a Reason for Admission or a Secondary Diagnosis

We postulate that the trends for infective endocarditis (IE) are different for patients admitted for this condition compared with those admitted for a different reason with IE as a secondary diagnosis. Using the Myocardial Infarction Data Acquisition System (MIDAS) database, we analyzed 21,443 records of patients hospitalized with diagnosis of IE from 1994 to 2015. There were 9,191 patients hospitalized with IE as the primary diagnosis, and 12,252 patients with IE as a secondary diagnosis. Piecewise linear models were used to detect changes in trends. A bootstrap method was used to assess the statistical significance of the slopes and break point of each model. Differences in co-morbidities and microbiological patterns were analyzed. Trend analysis showed a significant decrease in IE as the primary diagnosis starting in the year 2004 (p <0.01). Hospitalizations with IE as a secondary diagnosis showed a linear increase in incidence (p <0.001), without any change points. In primary diagnosis IE, the proportion of streptococci as a causative microorganism was higher compared with staphylococci (p <0.001). On the contrary, in secondary diagnosis IE, the proportion of staphylococci was higher than streptococci (p <0.001). The proportion of gram-negative and other organism IE was similar in both groups. In conclusion, this study showed 2 divergent temporal trends in hospitalizations for IE as a primary or secondary diagnosis starting in 2004. The profile of the microorganisms reveals a steady higher proportion of staphylococcal infection in secondary diagnosis IE compared with streptococcal infection. Different strategies are needed for the prevention of IE.