FRAX tool in type 2 diabetic subjects: the use of HbA1c in estimating fracture risk

Alessia Valentini; Maria Assunta Cianfarani; Livia De Meo; Pasquale Morabito; Daniele Romanello; Umberto Tarantino; Massimo Federici; Aldo Bertoli

doi:10.1007/s00592-018-1187-y

FRAX tool in type 2 diabetic subjects: the use of HbA_1c in estimating fracture risk

Acta Diabetol. 2018 Oct;55(10):1043-1050. doi: 10.1007/s00592-018-1187-y. Epub 2018 Jul 6.

Authors

Alessia Valentini¹, Maria Assunta Cianfarani¹, Livia De Meo¹, Pasquale Morabito¹, Daniele Romanello¹, Umberto Tarantino², Massimo Federici¹, Aldo Bertoli³

Affiliations

¹ Department of Systems' Medicine, University of Roma "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy.
² Department of Orthopaedics and Traumatology, University of Roma "Tor Vergata", Rome, Italy.
³ Department of Systems' Medicine, University of Roma "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy. aldo.bertoli@uniroma2.it.

PMID: 29980834
DOI: 10.1007/s00592-018-1187-y

Abstract

Aims: Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fractures, despite having greater bone mineral density (BMD) than non-diabetic subjects. This has led to the hypothesis that the presence of impaired bone quality among diabetics reduces bone strength. The Fracture Risk Assessment Score (FRAX) algorithm, introduced to facilitate the evaluation of fracture risk, underestimates the risk of fracture in diabetic patients. The purpose of this study is to confirm the relationship between the degree of metabolic compensation and the 10-year probability of a major fracture or a hip osteoporotic fracture observed in our previous study and to ascertain whether glycosylated hemoglobin (HbA_1c) can improve the predictive value of FRAX in patients with T2DM.

Methods: Our data derive from a retrospective clinical study conducted at the "Tor Vergata" Polyclinic in Rome on 6355 subjects over 50 years of age evaluated for osteoporosis. All available clinical records were examined. HbA_1c was available for 242 of these subjects and all had had a Dual-energy X-ray Absorption (DXA) scan of the lumbar spine and femoral neck. The risk of fracture was estimated using the Italian version of the FRAX algorithm.

Result: Patients with T2DM had BMD and T-scores higher than those of non-diabetic subjects, while FRAX average values were higher in the non-diabetic group. HbA_1c and FRAX are inversely correlated with each other: for each incremental percentage point of HbA_1c growth, the FRAX major osteoporotic fracture probability is reduced by 0.915 points and the FRAX hip osteoporotic fracture probability by 1.438 points. The introduction of a correction factor derived from HbA_1c, resulted in mean FRAX values of diabetic patients equivalent to those of non-diabetic subjects.

Conclusions: We propose a correction factor derived from HbA_1c that could enhance the predictive ability of fracture risk estimated by the FRAX algorithm in subjects with T2DM.

Keywords: BMD; Elderly; FRAX; Fracture risk; HbA1c; Osteoporosis; T-score; Type 2 diabetes mellitus.

Publication types

Evaluation Study

MeSH terms

Absorptiometry, Photon / methods
Aged
Aged, 80 and over
Algorithms*
Bone Density
Diabetes Mellitus, Type 2 / blood
Diabetes Mellitus, Type 2 / complications*
Diabetes Mellitus, Type 2 / diagnosis
Diagnostic Techniques, Endocrine*
Female
Glycated Hemoglobin / analysis*
Humans
Lumbar Vertebrae
Male
Middle Aged
Osteoporosis / blood
Osteoporosis / diagnosis*
Osteoporosis / etiology
Osteoporotic Fractures / blood
Osteoporotic Fractures / diagnosis*
Osteoporotic Fractures / etiology
Retrospective Studies
Risk Assessment / methods
Risk Factors

Substances

Glycated Hemoglobin A

Grants and funding

PRIN2015/MIUR