SATURDAY, Nov. 19, 2016 (HealthDay News) -- For people with chronic kidney disease, poor sleep may boost the chances that their illness will worsen, new research suggests.

"Short sleep and fragmented sleep are significant yet unappreciated risk factors for chronic kidney disease progression," said study author Dr. Ana Ricardo, of the University of Illinois at Chicago.

"Our research adds to the accumulating knowledge regarding the importance of sleep on kidney function, and underscores the need to design and test clinical interventions to improve sleep habits in individuals with chronic kidney disease," she said in a news release from the American Society of Nephrology.

However, it's not clear from the study that a lack of sleep is what caused the worsening kidney failure. The study was only able to find an association between these factors.

The research included 432 adults with chronic kidney disease. The researchers monitored their sleep habits for five to seven days via wrist monitors. Then the researchers tracked their health for a median of five years.

The participants slept an average of 6.5 hours a night; 70 of them developed kidney failure and 48 died, the study found.

After adjusting the statistics so they wouldn't be thrown off by other risk factors such as weight or heart disease, the researchers linked each hour of additional nighttime sleep to a nearly 19 percent lower risk of kidney failure.

Quality of sleep also appeared to be important: Those with worse sleep were also more likely to develop kidney failure.

The researchers also found that people who reported being sleepy during the day were 10 percent more likely to die during the follow-up period.

The research was scheduled to be presented Saturday at the American Society of Nephrology Kidney Week conference in Chicago. Studies released at conferences are considered preliminary until published in a peer-reviewed medical journal.

More information

For more about kidney disease, try the National Kidney Foundation.