Nearly 1 in 5 wait-listed patients who remain hospitalized in Hawaii after the need for acute care ends suffer from an infectious disease, a report shows.

The report by Hawaii Health Information Corp., which collects statewide health care data, said that wait-listed patients with infectious diseases significantly drive up costs and are the most difficult to place, resulting in patients being kept in hospitals for an extended period.

"Meeting the complex medical and behavioral needs of waitlisted patients is a key challenge in reducing the hospital waitlist," Peter Sybinsky, president and CEO of HHIC, said in a press release issued Tuesday. "Solutions will require development of appropriate community and institutional resources and the funding sources to maintain them. As a community, we need to take aggressive efforts."

"Medicare needs to seriously look at what it pays nursing homes in Hawaii to provide for the special needs that these infectious patients constitute," Sybinsky said. The government also must put additional resources into mental health services, the homeless and other affected populations, he said.

The most common disease among wait-listed patients was septicemia — a severe blood infection that can lead to organ failure or death and which costs isle hospitals $4.7 million annually, the report said. The number of wait-listed patients with the dangerous condition more than doubled between 2006 and 2011.

Other top conditions among these patients include parasitic diseases and cellulitis, a bacterial skin infection.

Wait-listed patients do not require inpatient care, but stay in hospitals because of a lack of long-term care and other community services, such as nursing homes with higher-skilled staff to meet the needs of those with complex conditions. Other barriers include a lack of specialty equipment, the cost of multiple or high-cost antibiotics and limited resources to support patients with mental illness, HHIC said.

The priciest conditions among these patients include cerebrovascular atherosclerosis (hardening of the arteries and the leading cause of heart attacks), amputation of lower limbs, hip and femur procedures for trauma, major respiratory infections and renal failure, according to the report. Combined, the top wait-listed conditions totaled $25.6 million, or 37 percent of the $69.9 million annual cost to hospitals.

HHIC found mental illness — drug and alcohol abuse, schizophrenia, bipolar disorders and depression — to be a common underlying condition, affecting 49 percent of wait-listed patients.

The report is based on 2011 discharge data from all Hawaii hospitals except Tripler Army Medical Center.