Analysis of the risk factors of mortality in elderly patients with hip fracture using a combined database of medical and long-term care insurance claims data

Abstract

BackgroundThe present study evaluated the risk of mortality in elderly hip fracture, focusing on comorbidities and nursing care levels. MethodsThe present study was an observational cohort study that used a combined database of medical and long-term care insurance (LTCI) claims data from one prefecture in Japan between 2011 and 2016. In total, 6125 patients aged 65 years and older were selected from acute care hospitals with a diagnosis of “hip fracture” between March 2011 and March 2012. The impact of long-term care insurance claim evaluation levels and comorbidities at recruitment time was investigated using this dataset. These patients were followed up monthly until March 2016. Based on this person-month dataset, survival analysis was performed with death as the endpoint. Cases in which receipt data were missing during the middle of the observation period and cases in which the patient survived at the end of the observation period were censored. ResultsThe number of deaths during the observation period was 635 (10.4%). The impact of comorbidities and nursing care level on mortality were both significant as follows: high nursing care level before the fracture (hazard ratio: 1.09, P < 0.001), comorbidities of malignant diseases (HR: 1.45, P < 0.001), heart disease (hazard ratio: 1.20, P = 0.037), pneumonia (hazard ratio: 1.27, P < 0.001), chronic obstructive pulmonary disease (hazard ratio: 1.28, P = 0.026), renal failure (hazard ratio: 1.44, P < 0.001), and dementia (hazard ratio: 1.27, P = 0.013). ConclusionThe results of this study showed that a high level of nursing care and presence of comorbidities such as malignant diseases, heart diseases, pneumonia, chronic obstructive pulmonary disease, renal failure, and dementia increased mortality in elderly patients with hip fracture. Furthermore, this study showed the usefulness of a combined database of medical and LTCI claims data for clinical and health service-related research in the field of orthopedics.