Do citation trends reflect epidemiologic patterns? Assessing MRSA, emerging and re-emerging pathogens, 1963–2014

BACKGROUND: A rapid rise in PubMed citations on methicillin-resistant Staphylococcus aureus (MRSA) occurred after 2000, but the relationship of trends in citation to epidemiologic trends for infectious disease is not known. METHODS: We queried PubMed(R), for citations to the following: MRSA, HIV/AIDS, Staphylococcus aureus, severe acute respiratory syndrome, Lyme disease, avian influenza, West Nile virus, Chikungunya, Ebola virus and Middle Eastern respiratory syndrome. Incidence or mortality data were tabulated. RESULTS: We identified 560,225 citations in 1963–2014. There were two distinct qualitative citation patterns. Type I pathogens showed a decade of initial exponential growth. Type II pathogens showed a sudden spike in citations in a year or two, followed by a relative decline. MRSA most closely resembled a Type I pathogen. CONCLUSIONS: The Type I pattern pathogens had varied trends in disease incidence in the years following the exponential growth and subsequent decline in the number of citations. Their differing epidemiologic patterns did not correlate with their pattern of citations. We conclude that citation trends on MRSA cannot be used to determine past epidemiologic trends and also that the citation trend for MRSA in 1995–2011 most closely resembled that for HIV in 1981–1998.