Insulin Hyposecretion in Nondiabetic, Tacrolimus-Treated Renal Transplant Recipients More Than 6 months Posttransplantation

Role of insulin resistance indices in predicting new-onset diabetes after kidney transplantation

New-onset diabetes mellitus (NODAT) is a serious complication following renal transplantation. In this cohort study, we studied 118 nondiabetic renal transplant recipients to examine whether indices of insulin resistance and secretion calculated before transplantation and at 3 months post-transplantation are associated with the development of NODAT within 1 year. We also analysed the long-term impact of early diagnosed NODAT. Insulin indices were calculated using homeostasis model assessment (HOMA) and McAuley's Index. NODAT was diagnosed using fasting plasma glucose. Median follow-up was 11 years. The cumulative incidence of NODAT at 1 year was 37%. By logistic regression, recipient age (per year) was the only significant pretransplant predictor of NODAT (OR 1.04, CI 1.009-1.072), while age (OR 1.04, CI 1.005-1.084) and impaired fasting glucose (OR 2.97, CI 1.009-8.733) were significant predictors at 3 months. Pretransplant and 3-month insulin resistance and secretion indices did not predict NODAT. All-cause mortality was significantly higher in recipients developing NODAT within 1 year compared with those remaining nondiabetic (44% vs. 22%, log-rank P = 0.008). By Cox's regression analysis, age (HR 1.075, CI 1.042-1.110), 1-year creatinine (HR 1.007, CI 1.004-1.010) and NODAT within 3 months (HR 2.4, CI 1.2-4.9) were independent predictors of death. In conclusion, NODAT developing early after renal transplantation was associated with poor long-term patient survival. Insulin indices calculated pretransplantation using HOMA and McAuley's Index did not predict NODAT.

Diabetes mellitus after hematopoietic stem cell transplantation

OBJECTIVE

To review the current literature on posttransplant diabetes mellitus after hematopoietic stem cell transplantation, including its epidemiologic features, transplant-related risk factors, and treatment.

METHODS

A literature search was conducted in PubMed for articles on diabetes mellitus after hematopoietic stem cell transplantation and effects of immunosuppressants on glucose metabolism.

RESULTS

Within 2 years after hematopoietic stem cell transplantation, up to 30% of patients may have diabetes. Although some of these cases resolve, the rates of diabetes and metabolic syndrome remain elevated in comparison with those in the nontransplant patient population during long-term follow-up. Traditional risk factors for diabetes as well as features related to the transplantation process, including immunosuppressive medications, are associated with posttransplant diabetes. Cardiovascular risk also appears to be increased in this population. Limited data are available on hypoglycemic agents for posttransplant diabetes; thus, treatment decisions must be based on safety, efficacy, and tolerability, with consideration of each patient's transplant-related medications and comorbidities.

CONCLUSION

Treatment of diabetes mellitus in patients who have undergone hematopoietic stem cell transplantation necessitates attention to the posttransplant medication regimen and clinical course. Although no guidelines specific to treatment of posttransplant diabetes in this patient population currently exist, treatment to goals similar to those for nontransplant patients with diabetes should be considered in an attempt to help reduce long-term morbidity and mortality.

Insulin resistance indexes in renal transplant recipients maintained on tacrolimus immunosuppression

BACKGROUND

Insulin resistance is common posttransplantation and contributes to both new onset diabetes after transplantation and the metabolic syndrome. Insulin resistance indexes have never been validated in transplant recipients on tacrolimus compared with cyclosporine, although it is more diabetogenic. We aimed to assess these indexes in renal transplant recipients on tacrolimus as primary immunosuppressant.

METHODS

Retrospective analysis of 76 frequently sampled, intravenous glucose tolerance tests (for insulin sensitivity) in 38 nondiabetic renal transplant recipients on tacrolimus-centered immunosuppression. Indexes tested were fasting glucose/insulin ratio, homeostasis model assessment (HOMA) index, 1/HOMA, log (HOMA), quantitative insulin sensitivity check index, and the McAuley's index. Indexes were also compared against waist/hip ratio and C-reactive protein (CRP). Multivariate linear regression analysis was performed to determine independent variables predictive for insulin resistance.

RESULTS

Insulin sensitivity successfully correlated with all indexes: fasting glucose/insulin ratio (r=0.246, P=0.033), HOMA index (r=-0.240, P=0.038), 1/HOMA (r=0.282, P=0.014), log (HOMA) (r=-0.316, P=0.006), quantitative insulin sensitivity check index (r=0.320, P=0.005), and McAuley's index (r=0.323, P=0.005). McAuley's index also correlated strongest with waist/hip ratio (r=-0.425, P<0.001). All indexes failed to correlate with CRP. Variables independently associated with insulin sensitivity were HbA1c (r=0.189, P=0.019), pulse pressure (r=0.146, P=0.021), and CRP (r=0.210, P=0.010).

CONCLUSIONS

Insulin resistance indexes are valid in transplant recipients taking tacrolimus, with McAuley's index the strongest surrogate.