after institutional review board approval , we identified the study cohort by systematic chart review . absence of diabetes before transplantation was documented in the form submitted to united network for organ sharing , with the information obtained from documentation provided by a medical care provider before transplant . additionally , all patients had a fasting plasma glucose < 126 mg / dl and hba1c < 6.5% at pretransplant testing . we used steroid - based maintenance immunosuppression before june 2003 , and afterward we used rapid steroid withdrawal maintenance immunosuppression except in patients who required prednisone for nontransplant indications or who were at high risk of rejection for immunologic reasons ( positive cross - match ) ; thus , the cohort included patients prescribed or not prescribed maintenance prednisone . induction therapy with rabbit antithymocyte immunoglobulin or basiliximab was used in rapid steroid withdrawal patients and some patients who were continued on maintenance steroids . all patients received a 5-day tapering course of glucocorticoids ( methylprednisolone intravenously 500 mg on day 1 , 250 mg on day 2 , 125 mg on day 3 , oral prednisone 60 mg on day 4 , and 30 mg on day 5 , then discontinued if in the rapid steroid withdrawal group ) . patients requiring ongoing steroid therapy received the same initial 5-day corticosteroid treatment with tapering of prednisone over 812 weeks to maintenance with 5 mg prednisone daily . tacrolimus was initiated when serum creatinine dropped > 30% ; the day of tacrolimus initiation was variable for each patient . mycophenolate mofetil and tacrolimus were the maintenance immunosuppressants for all patients who did not require ongoing steroid therapy . nodat was diagnosed if a patient had hba1c 6.5% , fasting venous plasma glucose 126 mg / dl , or was receiving diet or medical therapy for diabetes between 1 month and 1 year posttransplant . 6.5% has recently been adopted as a new diagnostic criterion for diabetes ( 7 ) , and we used these composite diagnostic criteria previously ( 6 ) . the time period for development of nodat ( 1 month to 1 year posttransplant ) was chosen because patients are clinically stable and on stable doses of immunosuppression by 4 weeks posttransplant , and this period excludes patients who developed transient hyperglycemia in the immediate posttransplant period as a result of stress of surgery and/or high - dose corticosteroid therapy . additionally , the highest incidence of nodat occurs within the 1st year posttransplant ( 3,4 ) . in addition to demographic , anthropometric , and pretransplant laboratory assessments , we ascertained pretransplant if corticosteroids would be used posttransplant for nontransplant indications or as maintenance immunosuppression . logistic regression was used to determine the risk of nodat associated with pretransplant patient characteristics . we first constructed univariate models to determine the association of individual pretransplant variables with development of nodat . variables significant at p < 0.10 in univariate models were then included in multivariate analyses . we conducted two multivariate analyses : 1 ) a standard model , in which continuous variables and discrete variables were included without categorization ; and 2 ) a dichotomized model , where variables were assigned binary values , using clinically relevant cut points . three models of the pretransplant risk score were then created from the multivariate logistic regression models : 1 ) a standard model , in which both continuous and discrete variables were included and weighted according to the -coefficients in the multivariate logistic model ; 2 ) a dichotomous model , in which continuous variables were dichotomized based on clinically relevant cut points ( values below and above the cut point were assigned a value of 0 and 1 , respectively ) and were weighted according to the -coefficients in the multivariate logistic model ; and 3 ) a summary score calculated as the sum of the points accrued by each individual using the dichotomized measures from the dichotomous model . receiver operating curves ( rocs ) were created for each of the three models to compare the accuracy of each in predicting nodat . statistical analyses were conducted with stata statistical software , version 10.0 ( statacorp , college station , tx ) or sas version 9.2 . we conducted a retrospective cohort study of all adult , nondiabetic patients undergoing a first kidney transplant at the mayo clinic arizona between june 1999 and january 2008 . after institutional review board approval , we identified the study cohort by systematic chart review . absence of diabetes before transplantation was documented in the form submitted to united network for organ sharing , with the information obtained from documentation provided by a medical care provider before transplant . additionally , all patients had a fasting plasma glucose < 126 mg / dl and hba1c < 6.5% at pretransplant testing . we used steroid - based maintenance immunosuppression before june 2003 , and afterward we used rapid steroid withdrawal maintenance immunosuppression except in patients who required prednisone for nontransplant indications or who were at high risk of rejection for immunologic reasons ( positive cross - match ) ; thus , the cohort included patients prescribed or not prescribed maintenance prednisone . induction therapy with rabbit antithymocyte immunoglobulin or basiliximab was used in rapid steroid withdrawal patients and some patients who were continued on maintenance steroids . all patients received a 5-day tapering course of glucocorticoids ( methylprednisolone intravenously 500 mg on day 1 , 250 mg on day 2 , 125 mg on day 3 , oral prednisone 60 mg on day 4 , and 30 mg on day 5 , then discontinued if in the rapid steroid withdrawal group ) . patients requiring ongoing steroid therapy received the same initial 5-day corticosteroid treatment with tapering of prednisone over 812 weeks to maintenance with 5 mg prednisone daily . tacrolimus was initiated when serum creatinine dropped > 30% ; the day of tacrolimus initiation was variable for each patient . mycophenolate mofetil and tacrolimus were the maintenance immunosuppressants for all patients who did not require ongoing steroid therapy . nodat was diagnosed if a patient had hba1c 6.5% , fasting venous plasma glucose 126 mg / dl , or was receiving diet or medical therapy for diabetes between 1 month and 1 year posttransplant . 6.5% has recently been adopted as a new diagnostic criterion for diabetes ( 7 ) , and we used these composite diagnostic criteria previously ( 6 ) . the time period for development of nodat ( 1 month to 1 year posttransplant ) was chosen because patients are clinically stable and on stable doses of immunosuppression by 4 weeks posttransplant , and this period excludes patients who developed transient hyperglycemia in the immediate posttransplant period as a result of stress of surgery and/or high - dose corticosteroid therapy . additionally , the highest incidence of nodat occurs within the 1st year posttransplant ( 3,4 ) . in addition to demographic , anthropometric , and pretransplant laboratory assessments , we ascertained pretransplant if corticosteroids would be used posttransplant for nontransplant indications or as maintenance immunosuppression . logistic regression was used to determine the risk of nodat associated with pretransplant patient characteristics . we first constructed univariate models to determine the association of individual pretransplant variables with development of nodat . variables significant at p < 0.10 in univariate models were then included in multivariate analyses . we conducted two multivariate analyses : 1 ) a standard model , in which continuous variables and discrete variables were included without categorization ; and 2 ) a dichotomized model , where variables were assigned binary values , using clinically relevant cut points . three models of the pretransplant risk score were then created from the multivariate logistic regression models : 1 ) a standard model , in which both continuous and discrete variables were included and weighted according to the -coefficients in the multivariate logistic model ; 2 ) a dichotomous model , in which continuous variables were dichotomized based on clinically relevant cut points ( values below and above the cut point were assigned a value of 0 and 1 , respectively ) and were weighted according to the -coefficients in the multivariate logistic model ; and 3 ) a summary score calculated as the sum of the points accrued by each individual using the dichotomized measures from the dichotomous model . receiver operating curves ( rocs ) were created for each of the three models to compare the accuracy of each in predicting nodat . statistical analyses were conducted with stata statistical software , version 10.0 ( statacorp , college station , tx ) or sas version 9.2 . patient characteristics and their associations with nodat are described in tables 1 and 2 , respectively . maintenance immunosuppression was predominantly tacrolimus and mycophenolate mofetil : 93 and 86% were prescribed tacrolimus at 4 and 12 months posttransplant , respectively . clinical characteristics of the study participants association of variables and development of nodat in univariate logistic regression analysis of 316 patients in whom all variables were measured , seven pretransplant risk factors  older age , higher pretransplant fasting glucose , triglycerides and bmi , family history of t2 dm , use of gout medicines , and use of corticosteroids posttransplant ( ascertained pretransplant)were associated with higher risk of nodat ( p < 0.10 ) . risk factors with p  0.10 were not included : minority race , dialysis modality pretransplant , donor type , duration of dialysis , uric acid , and hepatitis c seropositivity . pretransplant age , fasting glucose , fasting triglycerides , and use of corticosteroids posttransplant were associated with increased risk of nodat in multivariate analyses in both the standard model and in the dichotomized model ( table 3 ) . logistic regression models : association of continuous variables and dichotomized variables to development of nodat * table values are odds ratio ( 95% ci ) , p value for the given variable . the risk calculators created from the multivariate analyses were as follows : probability of nodat = 1/ 1 + e(fn[x ] ) where f[x ] = 9.6288 + 0.02397  age ( years ) at transplant + 0.5624 ( if family history of t2 dm ) + 0.7624 ( if steroid maintenance ) + 0.03021  pretransplant fasting glucose ( mg / dl ) + 0.0259  pretransplant bmi ( kg / m ) + 0.4467  log2 pretransplant triglyceride ( mg / dl ) + 0.7481 ( if gout medicine used pretransplant ) . probability of nodat = 1/ 1 + e(fn[x ] ) where f[x ] = 2.4684 + 0.5396 ( if transplant age 50 years ) + 0.4914 ( if family history of t2 dm ) + 0.7410 ( if steroid maintenance ) + 0.7285 ( if pretransplant fasting glucose 100 mg / dl ) + 0.3693 ( if pretransplant bmi 30 kg / m ) + 0.8440 ( if pretransplant triglyceride 200 mg / dl ) + 0.7917 ( if gout medicine used pretransplant ) . one point was assigned to each of the following : age above 50 years , family history of t2 dm , pretransplant assignment to corticosteroid maintenance protocol , pretransplant fasting glucose 100 mg / dl , pretransplant bmi 30 kg / m , pretransplant triglycerides 200 mg / dl , and use of gout medicine areas under the roc for predicting nodat were 0.72 , 0.71 , and 0.70 for the three models , respectively , and not significantly different from each other ( fig . the summary scores were also grouped as low ( 0 or 1 ) , intermediate ( 2 or 3 ) , or a high - risk group ( 4 , 5 , or 6 ) ; prediction of nodat by group is shown in fig . probability of nodat = 1/ 1 + e(fn[x ] ) where f[x ] = 9.6288 + 0.02397  age ( years ) at transplant + 0.5624 ( if family history of t2 dm ) + 0.7624 ( if steroid maintenance ) + 0.03021  pretransplant fasting glucose ( mg / dl ) + 0.0259  pretransplant bmi ( kg / m ) + 0.4467  log2 pretransplant triglyceride ( mg / dl ) + 0.7481 ( if gout medicine used pretransplant ) . probability of nodat = 1/ 1 + e(fn[x ] ) where f[x ] = 2.4684 + 0.5396 ( if transplant age 50 years ) + 0.4914 ( if family history of t2 dm ) + 0.7410 ( if steroid maintenance ) + 0.7285 ( if pretransplant fasting glucose 100 mg / dl ) + 0.3693 ( if pretransplant bmi 30 kg / m ) + 0.8440 ( if pretransplant triglyceride 200 mg / dl ) + 0.7917 ( if gout medicine used pretransplant ) . one point was assigned to each of the following : age above 50 years , family history of t2 dm , pretransplant assignment to corticosteroid maintenance protocol , pretransplant fasting glucose 100 mg / dl , pretransplant bmi 30 kg / m , pretransplant triglycerides 200 mg / dl , and use of gout medicine . areas under the roc for predicting nodat were 0.72 , 0.71 , and 0.70 for the three models , respectively , and not significantly different from each other ( fig . the summary scores were also grouped as low ( 0 or 1 ) , intermediate ( 2 or 3 ) , or a high - risk group ( 4 , 5 , or 6 ) ; prediction of nodat by group is shown in fig . a simple risk score using the sum of seven dichotomized pretransplant risk factors is as good at predicting nodat as a standard multivariate model using continuous variables in this sample from one institution . a score of 07 , calculated from pretransplant age , family history of t2 dm , bmi , fasting glucose and triglycerides , use of gout medicine , and predicted use of corticosteroids posttransplant ( nontransplant indications or immunologic indications ) predicted incidence of nodat at 1 year posttransplant . the risk of nodat ranged from 7% , for a score of 0 , to 56% , for a score of 4 . a simple summary score is valuable because it demonstrates the additive nature of the individual variables and integrates the impact of single baseline variables on development of nodat . we constructed three logistic regression models for predicting nodat , ranging from a model that used continuous variables as such to a simple score that adds the number of variables having values above a cut point . we included a dichotomous model as an intermediate , in which each variable was dichotomized but weighted according to its importance rather than weighted equally as in the summary score . we anticipated that the continuous model would provide the best predictive power and the summary score the least . although this was the case , surprisingly there were no important or statistically significant differences in the predictive abilities of the three models , as judged by areas under the roc ( fig . the simplest model can be used at the bedside for rapid evaluation without extensive computation . before applying this to other populations or settings , serum uric acid and gout have been identified as risk factors for t2 dm but have not been reported as risk factors for nodat . interestingly , serum uric acid itself did not predict nodat , but gout medication did . most patients with end - stage renal disease undergoing dialysis have elevated serum uric acid levels because of renal failure and inadequate clearance by dialysis , but do not develop gout . rather , other factors predict gout in patients with end - stage renal disease , including african american ethnicity , older age , bmi , female sex , hypertension , and alcohol use ( 8) . in end - stage renal disease patients undergoing dialysis therapy , gout is a risk factor for mortality ( 8) but has not been reported as an independent risk factor for diabetes . alternatively , the medicines for gout may themselves be diabetogenic , but we are unaware of evidence for this . this question should be pursued in studies that are large enough to include users of different types of gout medicines . these risk scores were developed primarily for future application in clinical trials to evaluate measures to prevent nodat . like many other risk calculators , these were created for a specific population of patients scheduled to undergo kidney transplantation and may not apply to general patient populations . however , the risk scores may eventually prove to be clinically useful in patients similar to those in our cohort . of the pretransplant risk factors for nodat that emerged from this study , only bmi , fasting glucose , and triglycerides are amenable to modification . treatment for gout , although a significant risk factor , is more likely a marker of genetic and metabolic abnormalities , some of which may be modifiable by dietary and other measures . use of corticosteroid therapy posttransplant may or may not be modifiable , depending on its indications . whether lifestyle modification or medicines will reduce the risk for nodat remains an important question . the diabetes prevention program and other clinical trials showed that t2 dm could be delayed or prevented ( 913 ) . because nodat has a significant impact on graft survival , patient survival , and cost , prevention of nodat may be very valuable . if prevention of nodat in patients at risk is possible , the simple risk score could be used to identify those pretransplant patients at the greatest need of intervention . the question of which patients should be enrolled in such clinical trials or given interventions , however , depends on more than their estimated risk . although our simple risk score separated those with low risk ( 12% developed nodat ) from those at high risk ( 56% developed nodat ) , the majority of the cases ( 50 of 85 ) occurred in those at intermediate risk ( fig . if safe , effective , and affordable interventions were available , consideration should be given to providing them to all transplant patients . on the other hand , if the only effective interventions had serious side effects or other costs , they might be appropriate only for those at higher risk first , we used a composite definition of nodat ( fasting venous glucose 126 mg / dl , hba1c 6.5% , or drug therapy for diabetes ) rather than the american diabetes association diagnostic criteria . although our criteria have been used previously ( 6 ) , our definition differed from the 2010 american diabetes association criteria ( 7 ) by not using an oral glucose tolerance test . however , hba1c 6.5% has recently been suggested as the sole diagnostic criterion for diabetes ( 14 ) . had we used an oral glucose tolerance test , it is likely that some of our patients would have been excluded for having pretransplant diabetes and some additional ones would have been diagnosed with nodat . second , because precise time to event was not available , we used logistic regression rather than time - to - event analysis to develop our risk score . this was appropriate because of the short time period to event ( within 1 year ) and no loss to follow - up before 1 year posttransplant . finally , this study was performed in a single center with a cohort of 318 patients . kidney transplantation is widely acknowledged to be the best therapy for end - stage renal disease , but its advantages are severely undermined by nodat . nodat diminishes patient and allograft survival and quality of life and increases the cost of care . the use of a simple summary risk score can identify patients at highest risk of nodat so that interventions may begin . the pretransplant risk factors for future nodat overlap with those for t2 dm in general , thus emphasizing the need for future clinical intervention studies similar to the diabetes prevention program to decrease nodat .