Co-existing psychiatric illness should be considered in assessing hospital readmissions for three common medical conditions used by Medicare and Medicaid to penalize hospitals with "excessive" readmission rates.

That was the conclusion of a newly published collaborative study by 11 major U.S. healthcare providers - including Henry Ford Health System - affiliated with the nationwide Mental Health Research Network (MHRN).

The study is published in Psychiatric Services.

The subject of readmission rates has been of increasing concern to U.S. hospitals since October 2012, when the Centers for Medicare and Medicaid Services (CMS) tied readmissions to reimbursement as part of the Affordable Care Act, informally known as Obamacare.

"CMS chose three general medical conditions - heart failure, acute myocardial infarction and pneumonia - as a way of assessing excessive re-hospitalizations and penalizing providers by reducing payment for healthcare services," says Henry Ford researcher Brian K. Ahmedani, Ph.D., lead author of the new study. Dr. Ahmedani is a researcher at the Center for Health Policy and Health Services Research.

"The policy was adopted as a way to curb rising healthcare costs and improve quality of care, and CMS chose those three conditions because they're common, expensive to treat, and often result in readmission."

Hospital readmissions account for a large share of healthcare spending in the U.S., including more than $17 billion of Medicare costs each year. In attempting to reduce excessive readmissions - those occurring within 30 days of a patient's original hospitalization - CMS is expected to add other medical conditions to the three already used as standards.

"So to avoid reimbursement penalties, it is very important for healthcare providers across the U.S. to develop effective interventions to reduce 30-day readmissions," Ahmedani explains. "The question is, where to start to provide the most reductions in readmissions at the lowest cost?

"Our current study chose to focus on psychiatric conditions."

Psychiatric illness was already known to be highly comorbid - existing at the same time as another medical condition - with heart failure, acute myocardial infarction (AMI) and pneumonia.

Two smaller previous studies were conducted at a single healthcare site and produced conflicting results: one showed higher rates of 30-day readmissions, and the other found lower rates.

The new study identified more than 160,000 patients who had been admitted to the 11 MHRN-affiliated healthcare centers between January 2009 and December 2011 for any of the three medical conditions targeted by CMS. It was the largest and most geographically diverse investigation of its kind.

Analysis of the data found that patients with psychiatric comorbidities in the previous year were readmitted to the hospital 3 to 5 percent more often within 30 days than those without a psychiatric diagnosis.

Perhaps even more troubling, the researchers noted, is that nearly 30 percent of those admitted to the hospital with heart failure, AMI or pneumonia were diagnosed in the previous year as having a mental health condition.

Most important, the study concluded, individuals with a psychiatric concern probably accounted for an even larger proportion of admissions for heart failure, AMI or pneumonia, but because mental health conditions are often not diagnosed, these illnesses weren't captured in medical records.

"These findings suggest that psychiatric comorbidities influence 30-day all-cause readmission rates for individuals with heart failure, AMI and pneumonia," Ahmedani says.

"Because depression, anxiety and substance abuse appeared to be the most common diagnoses among the patients we studied, and because each was associated with increased readmission rates, these disorders may be the most appropriate for healthcare systems to focus their primary screening efforts."

Using this knowledge to target patients at higher risk of readmission, the study concluded, it may be possible to make progress toward the long-term goal of improving the quality and cost of healthcare and easing the risk to hospitals of CMS penalties for excessive readmissions.