Primary care utilization and mental health diagnoses among adult patients requiring interpreters: a retrospective cohort study.

Background: Patients requiring interpreters may utilize the health care system differently or more frequently than patients not requiring interpreters; those with mental health issues may be particularly difficult to diagnose.
Objective: To determine whether adult patients requiring interpreters exhibit different health care utilization patterns and rates of mental health diagnoses than their counterparts.
Design: Retrospective cohort study examining patient visits to primary care (PC), express care (EC), or the emergency department (ED) of a large group practice within 1 year.
Patients: Adult outpatients (n = 63,525) with at least one visit within the study interval and information regarding interpreter need.
Main Measures: Mean visit counts, counts of mental disorders, and somatic symptom diagnoses between patients requiring interpreters (IS patients) and not requiring interpreters (non-IS patients).
Key Results: IS patients (n = 1,566) had a higher mean number of visits overall (3.10 vs. 2.52), in PC (2.54 vs. 1.95), and in ED (0.53 vs. 0.44) than non-IS patients (all p < 0.01). IS patients had a lower mean number of visits in EC than non-IS patients (0.03 vs. 0.13; p < 0.01). Interpreter need remained a significant predictor of visit count in multivariate analyses including age, sex, insurance, and clinical complexity. A greater proportion of IS patients were high utilizers (10+ visits) than non-IS patients (3.6 % vs. 1.7 %; p < 0.01). IS patients had a lower frequency of mental health diagnoses (13.9 % vs. 16.7 %), but a higher frequency of diagnoses recognized as potential somatic symptoms including diseases of the nervous (29.3 % vs. 24.2 %), digestive (22.6 % vs. 14.5 %), and musculoskeletal systems (43.2 % vs. 34.5 %), and ill-defined conditions (61 % vs. 49.9 %), all p < 0.01.
Conclusions: IS patients visited PC more often than their counterparts and were more often high utilizers of care. Two sources of high utilization, mental health diagnoses and somatic symptoms, differed appreciably between our populations and may be contributing factors.