Influenza-Like Illnesses Cause Excess Deaths Among People with Kidney Failure

David T. Gilbertson, PhD

Over 1000 patients with end-stage renal disease likely die each year as a result of flu-like illness.

That’s the top-line finding of a new study that looked at mortality among patients with end-stage renal disease (ESRD) and compared it to seasonal trends in rates of influenza-like illnesses (ILI).

It is already known that patients in vulnerable health categories, such as those with kidney failure, face a higher risk of death and illness during flu season. What was not previously known, however, was whether lines could be drawn between mortality and seasonal fluctuations in ILI, a category that includes a range of respiratory tract infections.

In search of an answer, a team of investigators from several universities teamed up to examine data from the Centers for Disease Control and Prevention’s Outpatient ILI Surveillance Network and from Centers for Medicare and Medicaid Services’ ESRD database. They pulled statistics from 2000 through 2013, focusing specifically on influenza seasons, which for this study were defined as the fourth quarter of one year and the first quarter of the following year.

The investigators found that an absolute 1% increase in influenza-like illness in the fourth quarter of a year was correlated with a 1.5% increase in mortality among patients with ESRD in the same quarter. In the first quarter of the following year, a 1% ILI increase was linked to an 2% increase in mortality.

They estimated that around 1100 deaths among patients with ESRD each year were likely attributable to influenza-like illnesses.

Corresponding author David T. Gilbertson, PhD, an associate professor of medicine at the University of Minnesota, told MD Magazine® that while the number is high, it fits with other research about the impacts of ILI.

“In terms of the number of deaths, we considered it an important, but also plausible number,” he said. “Since there are roughly 100,000 deaths per year among ESRD patients, the contribution of influenza and influenza-like illness to mortality seems in line with other studies in non-ESRD populations.”

Gilbertson said the data also showed that deaths in the ESRD population correlated with intra-season trends in ILI. In years when influenza and ILI peaked early, the number of deaths among patients with ESRD peaked earlier, too. When the flu/ILI season peaked later than normal, the height of ESRD mortality was also late.

The findings suggest that physicians treating patients with ESRD need to take extra care to try and prevent the spread of flu and ILI, Gilbertson said, calling prevention “the first order.” He said patients with ESRD should make sure to get the flu vaccine each year, and he also suggested hospitals and clinics increase their dialysis machine disinfection efforts in the winter months. If a patient does get sick, Gilbertson said antivirals could be considered, with dose adjustments for patients with ESRD, though he noted that interventions were not a part of the data analyzed in the study.

The study, “Excess Deaths Attributable to Influenza-Like Illness in the ESRD Population,” was published in the Journal of the American Society of Nephrology.