Twenty-four-hour, weekly and annual patterns in serious falls of non-institutionalized independent Spanish seniors

OBJECTIVE: The study aimed to explore clock hour, day-of-week, and month-of-year patterns of serious falls experienced by non-institutionalized Spanish seniors (age ≥65 years) in relation to associated conventional intrinsic and extrinsic factors. PATIENTS AND METHODS: Intake emergency department records from January 1 to December 31, 2013 of a tertiary hospital of southern Spain were abstracted for particulars of falls, including the time of occurrence, experienced specifically by non-institutionalized seniors. Chi-squares and Single and Multiple-Component Cosinor (time series) Analyses were applied to determine the statistical significance of observed 24-hour, 7-day, and annual variation. RESULTS: Falls were ~2.5-fold more numerous in older women than older men and ~7-fold more frequent between 12:00 and 14:00 hours than ~02:00 hours, respectively, the time spans corresponding to the absolute peak and trough of the 24-hour pattern in falls. The midday/early afternoon peak primarily represented incidents of women ≥75 years of age that occurred inside the home while walking, standing, or moving on stairs. A late evening less prominent excess of mostly inside-the-home incidents of women ≥75 years of age, largely due to fragility, slipping, stumbling, or tripping, was additionally detected. Cosinor Analysis substantiates statistical significance of the 24-hour patterning of falls of men and women (both p<0.001). Day-of-week differences, with prominent Thursday peak and Sunday minimum, were additionally detected, but only for falls of women occurring outside the home (Cosinor Analysis: p=0.007). Day-of-week discrepancy in female/male sex ratio (SR) of fallers was demonstrated, arising from day-of-week disparity in the SR of inside-the-home incidents, with ~4.5-fold more elderly women than elderly men falling Thursday than any other day of the week (p=0.005). Non-statistically significant month-of-year difference in falls, lowest in autumn and highest (~60% more) in winter, was observed and explained by prominent seasonal difference in incidents by elderly women. CONCLUSIONS: Serious falls of non-institutionalized independent seniors are characterized according to intrinsic and extrinsic factors by prominent 24-hour and 7-day patterning. These findings complement the understanding of the epidemiology of falls of the elderly and further inform fall prevention programs.