Risk factors affecting inhospital mortality after hip fracture: retrospective analysis using the Japanese Diagnosis Procedure Combination Database

Abstract

Objective: To identify risk factors for inhospital mortality in patients with hip fractures using the Japanese Diagnosis Procedure Combination (DPC) nationwide administrative claims database.

Design: Retrospective observational study.

Setting: Hospitals adopting the DPC system during 2007-2009.

Participants: The authors analysed a total of 80 800 eligible patients aged ≥60 years with a single hip fracture (International Classification of Diseases, 10th Revision codes: S72.0 and S72.1). The DPC database includes patients treated between July and December each year.

Main outcome measures: Inhospital mortality after hip fracture.

Results: The overall inhospital mortality rate after hip fractures was 3.3%. Multivariate analysis indicated that inhospital mortality was significantly associated with male gender (OR 2.12, 95% CI 1.94 to 2.31), advancing age and number of comorbidities. Significantly higher mortality was observed in those treated conservatively (OR 4.25, 95% CI 3.92 to 4.61). Surgical delays of 5 days or more were significantly associated with higher rates of inhospital mortality (OR 1.34, 95% CI 1.20 to 1.50).

Conclusions: In patients with hip fractures, male gender, advancing age, high number of comorbidities, conservative treatment and the surgical delay of 5 days or more were associated with higher rates of inhospital mortality.

Figure 1

ORs of inhospital mortality and 95% CIs in conservatively treated patients with hip fracture. (A) Patients were stratified into three groups according to the number of comorbidities. (B) Patients were stratified into four groups according to age.