The impact of language barriers & interpreters on critical care patient outcomes.

Background: In a multicultural society, the impact of language proficiency and interpreter use on critical care patient outcomes is unknown.

Objective: To investigate the relationship between English language preference, requirement for an interpreter and in-hospital mortality amongst non-elective intensive care unit (ICU) patients.

Method: Adult patients admitted to all 23 public ICUs within the state of Victoria, Australia from July 2007 to June 2018, were extracted from The Australian New Zealand Intensive Care Society Adult Patient Database. De-identified patient data was matched using probabilistic methods and statistical linkage keys to the Victorian Admitted Episodes Database. Patients were classified into one of three groups: 'English preferred', 'English not preferred' and 'Interpreter required'.

Results: 126,891 ICU admissions were analysed, of whom 3394 (3%) were in the 'English not preferred' group and 6355 (5%) in the 'Interpreter required' group. Compared to the 'English preferred', both the 'English not preferred' and 'Interpreter required' groups were older, had more co-morbidities and higher severity of illness scores. In-hospital mortality was 13.1% in the 'English preferred' group, 19.6% in the 'English not preferred' group and 16.7% in the 'Interpreter required' group. However, after adjusting for sex, severity of illness and socio-economic status, the 'English not preferred' group remained with a higher risk adjusted mortality (OR 1.21, 95%CI 1.07-1.36, P = 0.002), whereas the 'Interpreter required' group had a lower adjusted risk of mortality (OR 0.81, 95%CI 0.74-0.89, P < 0.001).

Conclusion: Being identified as having a requirement for an interpreter was associated with improved outcomes for adults admitted to public hospital ICUs in Victoria. Interpreter services should be more readily available in the hospital setting. It is recommended that patients, family members and clinicians actively use interpreter services when English is not the preferred language of an ICU patient.