Many elderly in the United States undergo surgery in their last year before death, with rates varying substantially by age and region, according to a study published Thursday.

Authors of a study published in the Lancet Journal say their findings “suggest discretion in health-care providers’ decisions to intervene surgically at the end of life.”

Researchers looked for patters in elderly fee-for-service Medicare patients ages 65 and older who died in 2008.

Of 1.8 million seniors, nearly 32 percent underwent an inpatient surgical procedure during their last year. However the rate of surgery fell to 23.6 percent between the ages of 80 and 90.

The study also found differences by region.

Munster, Indiana had the highest intensity while the lowest intensity region was in Honolulu, Hawaii, according to End-of-life surgical intensity (EOLSI) scores for various hospital referral regions.