Characteristics of the use of cold combination products among older ambulatory patients at the National Hospital Organization Tochigi Medical Center in Japan: a retrospective single-center observational study

OBJECTIVE: This study aimed to determine the frequency and characteristics of prescriptions of cold combination products among older ambulatory patients. A retrospective observational study was conducted using electronic medical records. All patients aged 65 years or older who continued visiting internal medicine physicians for at least 1 year were included. The primary outcome was the prescription of cold combination products by any physicians in National Hospital Organization Tochigi Medical Center during a 1-year follow-up. RESULTS: Seven hundred fifty-six patients were included. The mean age was 75.4 years, 392 (51.9%) were men, the mean Charlson Comorbidity Index was 1.8, and the mean number of medications was 4.9. The proportion of patients who were prescribed cold combination products during the 1-year follow-up was 6.1% (95% confidence interval 4.4–7.8%). The prescription of cold combination products was not significantly associated with age (p = 0.11) or Charlson Comorbidity Index (p = 0.93) but was associated with an increasing number of medications (p < 0.001). A substantial proportion of older ambulatory patients were exposed to cold combination products during a 1-year follow-up.