From the perspective of Medicare claims, hospitalizations for pneumonia and influenza overwhelmingly reflect the incidence of bacterial pneumonia, as the dominant ICD-9-CM diagnosis code that hospitals list is 486, “Pneumonia due to unspecified organism.” Whether all of these cases are truly bacterial in etiology is uncertain, as accumulating epidemiologic studies suggest that our historical assumption that pneumonia in adults is most often bacterial, rather than viral, is incorrect. Adenoviruses, coronaviruses, and enteroviruses likely all contribute to the milieu of pathogens that engender pneumonia. On the other hand, because viral pneumonia tends to be less severe than bacterial pneumonia, it is reasonable to hypothesize that hospitalized cases of pneumonia are more likely to be bacterial in etiology. Regardless of etiology, the seasonality of admission rates for pneumonia and influenza among prevalent dialysis patients is tremendously clear. This seasonality is intuitive, but has not been reported in the past. The implications are substantial.
The dialysis patient population is known to be immunosuppressed, with poor white cell function and bacterial killing. Poor response to hepatitis B vaccination is common, thus requiring multiple administrations to elicit a clinically significant response in the antibody titer. Because pneumonia and influenza are important sources of morbidity and mortality in their own rights, and because their occurrence is associated with increased risk of subsequent cardiovascular events, both preventive and interventional approaches demand consideration.
While the Centers for Disease Control and Prevention has recommended influenza vaccinations for high-risk populations, including those with kidney disease, and providers have responded by increasing vaccination rates, little is known about short-run and long-run immune system responsiveness to single vaccinations. There have been suggestions that dialysis patients should receive high-dose influenza vaccinations, as well as more frequent pneumococcal vaccines. There has also been debate over the use of polyvalent pneumococcal vaccines. At a minimum, pragmatic clinical trials are needed to guide the use of these therapies.
In addition, greater attention could be afforded to the transmission of respiratory diseases among in-center dialysis patients, including vaccination of all staff and required masking of infectious patients. Cleaning procedures to prevent blood borne disease transmission in dialysis facilities could be adapted, with surface cleaning on a more frequent basis, and, as is done in acute care settings, cleaning of all surfaces, not only chairs and machines. Pragmatic clinical trials could test these approaches. Regional variation in admission rates for pneumonia and influenza suggest that conducting these trials in cold-weather states may be particularly illustrative.