Only a tenth of patients admitted to the hospital have sepsis, but the condition contributes to half of all hospital-related deaths.

The reason behind the phenomenon has been unclear, a University of Michigan Health System news release reported.

"Our study was designed to quantify the national impact of sepsis on hospitalized patients and to highlight the importance of sepsis care on mortality at a population level," study lead author Vincent Liu, M.D., M.S, of the Kaiser Permanente Northern California Division of Research, said in the news release.

Sepsis occurs when chemicals are released into the bloodstream to fight-off infections, but also trigger inflammation. This condition can lead to organ damage and even death, Mayo Clinic reported.

The researcher performed an analysis that encompassed. 6.5 million past patients; the information was mostly taken from discharge records provide by the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS), the news release reported.

"Although patients may have been weakened by heart disease or cancer or other chronic diseases, it is often sepsis that leads to their death.  Preventing death from sepsis is a core strategy for improving care for many, many conditions -- conditions that people might think are not related to acute infections," Dr. Liu said.

After the analysis the researchers determined that sepsis patients had a hospital mortality rate of 10.4 percent , compared with 1.1 percent of patients who did not have sepsis. They also determined that about 52 percent of hospital deaths occurred in patients diagnosed with sepsis.

"We were surprised to find that as many as 1 in 2 patients dying in US hospitals had sepsis. Teasing apart these findings in a similar regional study of sepsis mortality at Kaiser Permanente Northern California, we found that most patients already had sepsis at the time of hospital admission. There was also a large number of patients with less severe sepsis, a group for whom treatment guidelines are less well-defined," Dr. Liu said. "The results of our study suggest that improved care for sepsis patients of all severity levels and in all hospital settings could result in many future lives saved."