Patients at for-profit hospitals face higher death and readmission rates, and thin nurse staffing explains much of the gap, according to a major new study.

The research from Penn Nursing’s Center for Health Outcomes and Policy Research and the Leonard Davis Institute, published open access in Medical Care, covered more than 1.17 million patients across 143 for-profit and 798 nonprofit hospitals in ten states.

Seventy-one percent of nurses at for-profit hospitals said their assigned workloads were unsafe, compared with 54 percent at nonprofits. Burnout ran at 53 percent versus 44 percent.

For-profit hospitals saw roughly 11 additional deaths per 1,000 medical admissions and 5 per 1,000 surgical admissions. Staffing differences were a main explanation for the higher mortality.

Thirty-day readmissions were 2.04 percentage points higher for medical patients and 1.76 points higher for surgical patients.

The authors say investment in nursing and state safe-staffing rules are actionable fixes that could save lives regardless of who owns the hospital.