Low serum osteocalcin levels are associated with diabetes mellitus in glucocorticoid treated patients

Bone turnover markers are decreased in GC-treated subjects with DM. Decreased OC levels in GC-treated patients were associated with an increased risk of DM. These results suggest the involvement of OC in glucose homeostasis regulation in DM.

INTRODUCTION

Osteocalcin (OC) is involved in the regulation of glucose homeostasis. Glucocorticoid (GC) treatment is associated with impaired osteoblast function, decreased OC levels, and the development and/or worsening of pre-existing diabetes mellitus (DM). Whether decreased OC levels in GC-treated subjects contribute to DM is not well known. The aim of this study was to analyse whether OC levels in GC-treated patients are associated with the presence of DM.

METHODS

One hundred twenty-seven patients (aged 61.5 ± 17.9 years) on GC treatment were included. GC dose, treatment duration, presence of DM and bone formation (OC, bone ALP, PINP) and resorption markers (urinary NTX, serum CTX) were analysed. The cut-offs of each bone turnover marker (BTM) for the presence of DM were evaluated and optimised with the Youden index and included in the logistic regression analysis.

RESULTS

Among the patients, 17.3% presented DM. No differences were observed in GC dose or duration or the presence of fractures. Diabetics showed lower levels of OC (7.57 ± 1.01 vs. 11.56 ± 1; p < 0.001), PINP (21.48 ± 1.01 vs. 28.39 ± 1; p = 0.0048), NTX (24.91 ± 1.01 vs. 31.7 ± 1; p = 0.036) and CTX (0.2 ± 1.01 vs. 0.3 ± 1; p = 0.0016). The discriminating BTM cut-offs for DM presence were < 9.25 ng/mL for OC, < 24 ng/mL for PINP, < 27.5 nMol/mM for NTX and < 0.25 ng/mL for CTX. In a multivariate logistic regression model adjusted for GC dose, BMI, age and the above four BTMs, only OC remained independently associated with DM presence. Thus, in a model adjusted for GC dose, BMI and age, OC was significantly associated with DM (OR: 6.1; 95%CI 1.87-19.89; p = 0.001).

CONCLUSION

Decreased OC levels in GC-treated patients are associated with increased odds of DM, and only OC was independently associated with DM in a model including four BTMs.

Risk factors for the development of glucocorticoid-induced diabetes mellitus

AIMS

To evaluate the incidence of glucocorticoid-induced diabetes mellitus (GC-DM) by repeated measurements of the postprandial glucose and detect predictors for the development of GC-DM.

METHODS

Inpatients with rheumatic or renal disease who received glucocorticoid therapy were enrolled in this study. We compared the clinical and laboratory parameters of the GC-DM group with the non-GC-DM group and performed a multivariate analysis to identify risk factors.

RESULTS

During a four-week period, 84 of the 128 patients (65.6%) developed GC-DM. All patients were diagnosed based on the detection of postprandial hyperglycemia. The GC-DM group had an older age (65.2 vs. 50.4 years, p<0.0001), higher levels of fasting plasma glucose (93.3 vs. 89.0mg/dl, p=0.027) and HbA1c (5.78 vs. 5.50%, 39.7 vs. 36.6 mmol/mol, p=0.001) and lower eGFR values (54.0 vs. 77.1 ml/min/1.73 m(2), p=0.0003) than the non-GC-DM group. According to the multivariate analysis, an older age (more than or equal to 65 years), higher HbA1c level (more than or equal to 6.0%) and lower eGFR (<40 ml/min/1.73m(2)) were identified as independent risk factors for GC-DM (OR 2.95, 95% CI 1.15-7.92, OR: 3.05, 95% CI 1.11-9.21, OR: 3.42, 95% CI: 1.22-10.8, respectively). The risk ratio for the development of GC-DM in the patients with at least one of these three risk factors was 2.28. The dose of glucocorticoids was not statistically related to the development of GC-DM.

CONCLUSIONS

Patients with an older age, higher HbA1c level and lower eGFR require close monitoring for the development of GC-DM, regardless of the dose of glucocorticoids being administered.