Medical Interpretation Affects Quality of Health Care

Medical College of Wisconsin researcher Glenn Flores, MD, has found striking evidence that the type of language interpretation provided to patients who speak limited or no English can affect the outcomes of medical care. He has done the most extensive review to date of studies on medical interpreter services for such patients.

Dr. Flores is Associate Professor of Pediatrics, Epidemiology, and Health Policy at the Medical College and Director of the Center for Advancement of Underserved Children at the Medical College and Children's Hospital of Wisconsin, a major affiliate of the Medical College. His work appeared in Medical Care Research and Review.

The number of people speaking a language other than English in the US has increased from 31 million to 47 million in the last decade, while the number of those with limited English has grown from 14 million to 21 million. As a result, medical providers are seeing many more patients who do not speak English at all or well enough to understand medical instruction without an interpreter.

In some cases, this type of patient is provided with a medically trained interpreter. In other cases, a family member or staff person who speaks the language may be pressed into service. (These are referred to as ad hoc interpreters). Often, no interpreter is provided.

Many individual studies have been done on how these differences in interpretation affect medical care. Dr. Flores' meta-analysis is the first to look at, and draw conclusions from, all of them.

In order to organize the vast amount of data, Dr. Flores grouped the studies into three categories: Communication Issues; Patient Satisfaction with Care; and Processes, Outcomes, Complications and Use of Health Services. The conclusions were slightly different for each category.

Communication Issues: The large number of studies on this aspect of medical interpretation led to several conclusions.

• People who need interpretation but don't get it report a poor understanding of their diagnosis and treatment and often wish their provider had "explained things better."
• Untrained interpreters, including family members, misinterpret or omit up to half of all doctors' questions, are more likely to make errors that have clinical consequences, have higher risk of not mentioning side effects and may ignore "embarrassing" medical issues.

"These findings indicate that having an ad hoc interpreter or none at all can impair communication quality in health care," Dr. Flores said. "They suggest that bilingual providers and trained medical interpreters may be the best option for communication with limited English proficiency patients."

Patient Satisfaction: Studies that dealt with how patients felt after their medical encounters again demonstrated the value of medical interpretation. The study review found that bilingual providers resulted in the highest level of patient satisfaction. Ad hoc interpreters resulted in significantly lower satisfaction. Patients who needed, but didn't receive, interpretation at all had the lowest satisfaction rate.

Health Processes, Outcomes, Complications and Use of Health Services: These types of studies provided important information.

• Interpreter services improve the rates at which limited English proficient people use preventative screenings.
• Some studies showed that medical visits lasted longer when interpreters were provided; other studies, however, did not demonstrate this effect.
• Trained interpreters resulted in more office visits and more prescriptions being written and filled.
• Limited English proficient patients without interpretation or with ad hoc interpreters have more medical tests, higher test costs and a higher rate of hospitalization.

"These findings indicate that trained interpreters generally result in better health processes, outcomes and use of services," Dr. Flores said, but, he added, "additional research in this area is warranted."

Reflecting on his analysis of many individual studies, Dr. Flores noted the lack of randomized controlled studies, the gold standard of research. He also pointed out the need for more research to compare cost and effectiveness of various types of interpreter services.

Most of the studies focused on Spanish-speaking populations; he felt more research was needed on people who speak languages other than Spanish. Since several studies confirmed that interpretation errors can be a root cause of medical errors, he urged more research on the association between medical errors and lack of interpreter services.

"This systematic review of the literature indicates that additional studies employing rigorous methods are needed on the most effective and least costly ways to provide interpreter services to patients with limited English proficiency," Dr. Flores said. "Available evidence suggests that optimal communication, the highest patient satisfaction, the best outcomes and the fewest errors of clinical consequence occur when patients with limited English proficiency have access to trained professional interpreters or bilingual health care providers."

The study was supported by a grant from the US Department of Health and Human Services Office of Minority Health.

This article previously appeared in Medical College of Wisconsin World.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.