Excess of all-cause mortality after a fracture in type 2 diabetic patients: a population-based cohort study

Post-fracture mortality in type 2 diabetes mellitus (T2DM) patients has been poorly studied. We report an absolute and relative excess all-cause mortality following a fracture in these patients compared to non-diabetic patients.

Introduction: T2DM and osteoporotic fractures are independently associated with a reduced lifespan, but it is unknown if T2DM confers an excess post-fracture mortality compared to non-diabetic fracture patients. We report post-fracture all-cause mortality according to T2DM status.

Methods: This is a population-based cohort study using data from the SIDIAP database. All ≥50 years old T2DM patients registered in SIDIAP in 2006-2013 and two diabetes-free controls matched on age, gender, and primary care center were selected. Study outcome was all-cause mortality following incident fractures. Participants were followed from date of any fracture (AF), hip fracture (HF), and clinical vertebral fracture (VF) until the earliest of death or censoring. Cox regression was used to calculate mortality according to T2DM status after adjustment for age, gender, body mass index, smoking, alcohol intake, and previous ischemic heart and cerebrovascular disease.

Results: We identified 166,106 T2DM patients and 332,212 non-diabetic, of which 11,066 and 21,564, respectively, sustained a fracture and were then included. Post-fracture mortality rates (1000 person-years) were (in T2DM vs non-diabetics) 62.7 vs 49.5 after AF, 130.7 vs 112.7 after HF, and 54.9 vs 46.2 after VF. Adjusted HR (95% CI) for post-AF, post-HF, and post-VF mortality was 1.30 (1.23-1.37), 1.28 (1.20-1.38), and 1.20 (1.06-1.35), respectively, for T2DM compared to non-diabetics.

Conclusions: T2DM patients have a 30% increased post-fracture mortality compared to non-diabetics and a remarkable excess in absolute mortality risk. More research is needed on the causes underlying such excess risk, and on the effectiveness of measures to reduce post-fracture morbi-mortality in T2DM subjects.