The ratio of physical activity during the 12-h night period to the number of steps in the daytime as new predictive indicator of fall risk

Abstract

We analyzed the changes in 24-h physical activity and number of steps of patients hospitalized at Kawanishi City General Hospital to obtain reliable information on fall risk in hospitalized patients. Twenty-four inpatients (male 14, female 10；median age, 64.5 (39-92)) were studied. Major disorders were as follows：hepatic disorder 5, cataract 4, cancer 3, diabetes 2, and infection 2. Patients wore a physical activity monitor at their waist. Physical activity (METS：metabolic equivalents) and number of steps in 24 hours were monitored continuously until the day before discharge. The number of steps and the physically active ⊿METS during the 12-h night period (18:00-06:00) were about half those during the 12-h daytime period (6:00-18:00). The ratio of physically active ⊿METS at night to the number of steps in the daytime of patients with low risk assessment for falls was lower than that of patients with high risk assessment for falls, which suggests a relationship between physical activity at night and fall risk. The ratio of physically active ⊿METS at night to the number of steps in the daytime in 3 patients who experienced falls was significantly higher than that of patients who did not experience falls. These results indicate that the ratio of physically active ⊿METS at night to the number of steps in the daytime might be one of the indicators of fall risk.