Bone Abstracts

Purpose: To describe the timing and whereabouts of the hip fracture patient at the time of fracture in a population-based setting and to relate these factors with residential and health status, seasonal variation and snow-covered ground.

Methods: We consecutively included 486 hip fracture cases (age ≥50 years) admitted to a Swedish Orthopedic Department during a 1-year period. Data concerning socio-demographic details, fall location, time of fracture, comorbidity and medications were collected from in-patient medical records and through patient or caregiver interviews.

Results: Patients living in residential care showed no daytime peak in fracture occurrence and were more likely to fracture during evening and nighttime hours than community-dwellers who fractured indoors (OR: 1.43, 95% CI .90–2.27). Results showed that, when controlled for the effects of age and number of comorbidities, subjects using psychotropic drugs, with or without dementia, were more than twice as likely to fracture during nighttime hours (adj. OR: 2.36, 95% CI 1.17–4.77) compared to those without dementia or psychotropic drug use. Even subjects without dementia but taking psychotropic drugs showed a greater likelihood to fracture at night (adj. OR: 2.60, 95% CI 1.24–5.44). We observed an increased hip fracture incidence on snow-covered days, which occurred both indoors (incidence rate ratio (IRR): 1.34, 95% CI 1.02–1.74) and outdoors (IRR: 1.27, 95% CI .82–1.97), among community-dwelling subjects, whereas only a weak seasonal trend was seen, based on month, in hip fracture incidence among community-dwelling subjects fracturing indoors.

Conclusions: Special attention and possibly fall-preventive efforts should be directed not only towards those living in residential care facilities but also towards community-dwelling subjects taking psychotropic drugs since these groups have a higher incidence of nighttime hip fracture. Further research aiming to explain the seasonal variation of indoor fracture incidence among community dwellers is warranted.