Uninsured patients with a variety of common medical diagnoses are significantly less likely to be transferred between hospitals for treatment, according to researchers at the University of Pittsburgh School of Medicine in collaboration with the University of Iowa and University of Toronto.

The findings, which were published in the Annals of Internal Medicine, suggest that non-medical factors, including a patient’s sex and insurance coverage, may influence care decisions and lead to potential health disparities. They also found that women, insured or not, are less likely to be transferred between hospitals.

“Federal law requires hospitals and physicians to care for and stabilize any patient with an emergency medical condition, regardless of the patient’s ability to pay,” explained Janel Hanmer, MD, PhD, assistant professor of medicine at Pitt’s School of Medicine and lead author of the study. “While there’s been persistent concern about patients being transferred between hospital emergency rooms for non-medical reasons, our study is one of the first to look at inter-hospital transfers among patients who have already been admitted to the hospital.”

The researchers used data from the 2010 Nationwide Inpatient Sample (NIS), the largest all-payer inpatient care database in the United States, to examine the relationship between a patient’s insurance coverage and the hospital transfers for five common medical diagnoses: biliary tract disease, chest pain, pneumonia, sepsis, and skin infection.

The data covered 315,748 hospitalized patients, ages 18 to 64, who were discharged from 1,051 hospitals across the country.

A close look at the data revealed that uninsured hospitalized patients were 20% to 40% percent less likely to be transferred to another hospital for four of the five diagnoses when compared with privately insured patients, even after adjusting for demographic factors and severity of illness. Additionally, women were significantly less likely to be transferred than men for all five diagnoses, with transfer rates of women occurring from 35% to 40% less often than for men. The transfer rate for all patients between hospitals ranged from 2% to 5%, depending on the diagnosis.

“We hypothesized that uninsured patients would be more likely to be transferred as hospitals tried to punt these unprofitable cases to other hospitals in the area. Our study showed this did not happen,” Hanmer explains. “Instead, we found that uninsured patients – and women – were substantially less likely to be transferred, suggesting that perhaps both the uninsured and women are not being transferred when they should be.”

The study notes that the data used in the research lacked the details necessary to determine if the differences seen were due to clinical differences, patient preference, physician referral patterns, or receiving hospital screening practices.

According to Hanmer, the study is cause for concern and future investigation into the outcomes of transferred patients. “If we presume that transfer between hospitals results in greater access to advanced treatments, then it’s evident that the uninsured and women face a serious health care disparity,” she noted. “Alternatively, privately insured patients and men may be at risk of greater exposure to more costly procedures and excessive treatments.”