Impact of Weight Change on Glycemic Control and Metabolic Parameters in T2D: A Retrospective US Study Based on Real-World Data

INTRODUCTION

Weight loss has been identified as a key strategy for improving glycemic and metabolic outcomes in people with type 2 diabetes (T2D). However, the long-term, real-world impact of weight loss on these outcomes remains unclear. This study aimed to investigate (1) the association between weight loss and glycemic control, (2) association between weight loss and metabolic parameters, and (3) predictors of weight loss and how weight change trajectory varies based on index body mass index (BMI).

METHODS

A retrospective, longitudinal cohort study using the linked IQVIA Ambulatory electronic medical records and PharMetrics® Plus databases was performed from January 1, 2010 through December 31, 2019 in adults with T2D. Participants were categorized into 1-year and 5-year follow-up cohorts based on their observed weight change over time. Longitudinal values for vital signs and laboratory parameters, including BMI, weight, glycated hemoglobin (HbA1c), and metabolic parameters (liver enzymes and cholesterol), were reported at index date and every 6 months post index date. Multivariable logistic regression analysis was used to evaluate the factors associated with weight loss.

RESULTS

Of 1,493,964 people evaluated, 1,061,354 (71%) and 308,320 (20.6%) were classified into the 1-year and 5-year follow-up cohorts. Average HbA1c reductions of 1.2% and 0.5% were observed among people who lost ≥ 15% of index weight in the 1-year and 5-year follow-up cohorts, respectively. Higher weight loss percentages were associated with numerically greater improvements in metabolic parameters. The presence of bariatric surgery and higher index BMIs were identified as the strongest predictors of ≥ 15% and ≥ 10% weight loss in both follow-up cohorts.

CONCLUSION

Results from this study suggest that modest and sustained weight loss can lead to clinically meaningful improvements in glycemic and metabolic parameters among people with T2D. These findings highlight the importance of weight management in managing T2D and preventing its associated complications.

Examining the evidence for weight management in individuals with type 2 diabetes

The obesity epidemic has been linked to the worsening diabetes epidemic. Despite this, weight reduction for individuals with obesity is seen as a secondary, or even tertiary, consideration in the treatment of type 2 diabetes (T2D). The aim of this review is to examine the benefits of weight management in individuals with T2D. A literature review of current available published data on the benefits of weight reduction in individuals with T2D was conducted. In individuals with T2D who have obesity or overweight, modest and sustained weight reduction results in improvement in glycaemic control and decreased utilization of glucose-lowering medication. A total body weight loss of 5% or higher reduces HbA1c levels and contributes to mitigating risk factors of cardiovascular disease, such as hyperlipidaemia and hypertension, as well as other disease-related complications of obesity. Progressive improvements in glycaemic control and cardiometabolic risk factors can occur when the total body weight loss increases to 10% or more. In the approach to treating patients with T2D and obesity, prioritizing weight management and the use of therapeutics that offer glycaemic control as well as the additional weight loss should be emphasized given their potential to attenuate the progression and severity of T2D.

HbA1c Reduction in Dulaglutide-Treated Patients Irrespective of Duration of Diabetes, Microvascular Disease, and BMI: A Post Hoc Analysis From the REWIND Trial

OBJECTIVE

To evaluate participant characteristics and long-term changes in glycated hemoglobin (HbA1c) levels in patients treated with dulaglutide 1.5 mg in a post hoc analysis of the Researching cardiovascular Events with a Weekly INcretin in Diabetes (REWIND) trial.

RESEARCH DESIGN AND METHODS

Change from baseline in HbA1c was assessed during and up to 72 months of treatment before and after adjustment for duration of diabetes, prior microvascular disease (nephropathy or retinopathy), and BMI. Slope analyses were used to assess the change in HbA1c during 0-12 months and 12-72 months of therapy.

RESULTS

HbA1c was significantly reduced in patients treated with dulaglutide compared with placebo during 72 months of treatment (least-squares mean difference = -0.61%, P < 0.001), regardless of diabetes duration, prior microvascular disease, and BMI (all interaction P > 0.07). Significant reductions were apparent at all time points and were independent of these baseline characteristics. Slope analyses revealed that the dulaglutide group experienced a higher rate of HbA1c reduction compared with the placebo group from 0 to 12 months before and after adjustment. The dulaglutide group also experienced a higher rate of HbA1c increase from 12 to 72 months compared with the placebo group that became nonsignificant after adjustment for diabetes duration, prior microvascular disease, and BMI combined. Despite the greater rate of HbA1c increase in the dulaglutide group during this period, mean HbA1c values remained below baseline in the dulaglutide group and below mean HbA1c values in the placebo group.

CONCLUSIONS

Dulaglutide 1.5-mg treatment was statistically associated with a long-lasting decrease in HbA1c over 72 months, irrespective of baseline duration of diabetes, microvascular disease, and BMI.

A model-based simulation of glycaemic control and body weight when switching from semaglutide to 3.0- and 4.5-mg doses of once-weekly dulaglutide

AIM

To evaluate HbA1c and body weight changes when semaglutide 0.5- or 1.0-mg once-weekly (QW) is switched to dulaglutide 3.0- or 4.5-mg QW via exposure-response modelling.

METHODS

HbA1c and body weight time-course models were developed and validated with data from the SUSTAIN 1 to 10 trials for semaglutide and the AWARD-11 trial for dulaglutide. Simulations were conducted for HbA1c and body weight over 52 weeks. In the initial 26 weeks, semaglutide was initiated at 0.25-mg and titrated to 0.5- or 1.0-mg QW via 4-weekly stepwise titration, followed by 26 weeks of dulaglutide initiated at 0.75- or 1.5-mg QW and escalated to 3.0- or 4.5-mg QW via 4-weekly stepwise titration.

RESULTS

At 26 weeks, model-predicted mean changes from baseline in HbA1c and weight for semaglutide 0.5 mg were up to -1.55% and -3.44 kg, respectively. After switching to dulaglutide 3.0 mg, further reductions were 0.19% and 1.40 kg, respectively, at 52 weeks. Predicted mean HbA1c and weight changes for semaglutide 1.0 mg at 26 weeks were -1.84% and -4.96 kg, respectively; after switching to dulaglutide 4.5 mg, HbA1c was maintained with additional weight reduction of up to 0.57 kg at 52 weeks. Glycaemic control was preserved when switching from semaglutide 1.0 mg to dulaglutide 3.0 mg.

CONCLUSION

Switching from semaglutide 0.5 mg to dulaglutide 3.0 or 4.5 mg with dose escalation potentially yields additional HbA1c and weight reductions; switching from semaglutide 1.0 mg to dulaglutide 4.5 mg may enhance weight loss.

Effect of dulaglutide 3.0 and 4.5 mg on weight in patients with type 2 diabetes: Exploratory analyses of AWARD-11

AIM

To evaluate the impact of dulaglutide 3.0 and 4.5 mg versus 1.5 mg on body weight in patients with type 2 diabetes (T2D) based on exploratory analyses of the AWARD-11 trial.

MATERIALS AND METHODS

Patients were randomized to once-weekly dulaglutide 1.5 (n = 612), 3.0 (n = 616) or 4.5 mg (n = 614) for 52 weeks. The primary objective was superiority of dulaglutide 3.0 and/or 4.5 mg over 1.5 mg in HbA1c reduction at 36 weeks. Secondary and exploratory assessments included weight reduction in the overall trial population and baseline body mass index (BMI) and HbA1c subgroups.

RESULTS

At baseline, patients had a mean age of 57.1 years, HbA1c 8.6% (70 mmol/mol), weight 95.7 kg and BMI 34.2 kg/m² . At 36 weeks, dulaglutide 3.0 and 4.5 mg were superior to 1.5 mg for weight change from baseline (1.5 mg, -3.1 kg; 3.0 mg, -4.0 kg [P = .001]; 4.5 mg, -4.7 kg [P < .001]). Higher dulaglutide doses were associated with numerically greater weight reduction compared with 1.5 mg in each baseline BMI and HbA1c subgroup. Absolute weight reduction increased with increasing BMI category, but percentage weight loss was similar between subgroups. Weight reductions with dulaglutide were greater in patients with lower versus higher baseline HbA1c.

CONCLUSIONS

In patients with T2D, inadequately controlled by metformin, incremental weight loss was observed with dulaglutide 1.5, 3.0 and 4.5 mg doses regardless of baseline BMI or HbA1c. Although absolute weight loss was numerically greater in patients with higher baseline BMI, percentage of weight loss was similar between BMI subgroups.

Dulaglutide Shows Sustained Reduction in Glycosylated Hemoglobin Values: 2-Year US Real-world Study Results

PURPOSE

Due to the chronic and progressive nature of type 2 diabetes mellitus (T2DM), it is important to understand the long-term outcomes associated with antihyperglycemic medications. There are currently few long-term studies evaluating the real-world effectiveness of dulaglutide, a glucagon-like peptide-1 receptor agonist. The primary objective of this retrospective observational study was to evaluate glycemic control over a 24-month follow-up period among dulaglutide initiators with continuous treatment. The study used US claims data from the HealthCore Integrated Research Database between May 2014 and May 2019.

METHODS

Patients were included if they were ≥18 years old with T2DM and had ≥1 pharmacy claim for dulaglutide during the index period between November 2014 and May 2017 (with index date = set as the earliest dulaglutide fill during index period), continuous enrollment in the 6 months' preindex and 24 months' postindex, ≥1 claim for dulaglutide or ≥60 days' supply in every quarter during the 24-month follow-up period, and ≥1 glycosylated hemoglobin (HbA_1c) result at both baseline and 24 months.

FINDINGS

At baseline, 872 patients (47.5% female) had a mean (SD) age of 54.5 (8.2) years and an HbA_1c value of 8.68% (1.8%) (71.36 [19.7] mmol/mol). More than two thirds were being treated for dyslipidemia, hypertension, or cardiovascular disease. A significant HbA_1c reduction was observed from baseline to 24 months (-1.3% [-14.2 mmol/mol]; P < 0.0001) for dulaglutide initiators with continuous treatment. A significant reduction in HbA_1c level was also observed for all prespecified subgroups (age, index dulaglutide dose [0.75 mg or 1.5 mg], insulin use, sodium-glucose co-transporter 2 inhibitor use, and dipeptidyl peptidase-4 inhibitor use; all, P < 0.0001). Forty-three percent of patients achieved an HbA_1c value < 7% (53 mmol/mol), and 73% achieved an HbA_1c value < 8% (64 mmol/mol) at 24 months. Most (520 [59.6%]) patients were initiated on dulaglutide 0.75 mg. Of these patients, 70% increased to dulaglutide 1.5 mg during follow-up. The mean time to first dose change was 242 (196) days for 0.75 mg-1.5 mg and 225 (160) days for 1.5 mg-0.75 mg. Antihyperglycemic medication use preindex/postindex included: insulin, 28%/35%; dipeptidyl peptidase-4 inhibitors, 37%/20%; and sodium-glucose co-transporter 2 inhibitors, 29%/44%.

IMPLICATIONS

In this real-world study among dulaglutide initiators with continuous treatment, a clinically significant reduction in HbA_1c value was seen at the 3-month assessment and persisted for up to 24 months. These data support the use of dulaglutide as an effective long-term treatment for T2DM in clinical practice.

Real-world effectiveness, adherence and persistence among patients with type 2 diabetes mellitus initiating dulaglutide treatment

OBJECTIVES

To assess glycemic effectiveness, adherence and persistence within 6 months of treatment initiation with dulaglutide, a once weekly GLP-1 receptor agonist, in a US real-world setting.

METHODS

This retrospective claims analysis included adults (≥18 years) with T2DM from the HealthCore Integrated Research Database, who had HbA1c laboratory results around initiation and within 6 months after initiation. Glycemic control was assessed by change in HbA1c from pre-initiation to post-initiation. Patients were considered adherent if their proportion of days covered (PDC) was ≥0.80; persistence was measured as days of continuous therapy from initiation to 6 months after initiation with no gaps >45 days between fills.

RESULTS

Of the 308 analyzed patients, the majority (n = 188; 61%) were adherent to dulaglutide (mean PDC 0.76; SD 0.26), with 115 patients (37%) discontinuing treatment. Mean persistence was 152 days/5 months. Mean HbA1c decreased from 8.49% (SD 1.70, median 8.20%) at baseline to 7.59% (SD 1.51, median 7.30%) at follow-up, corresponding to a mean HbA1c change of -0.90% (95% confidence interval [CI] -1.08 to -0.73; p < .01; median -0.70%). Patients who were adherent to or persistent with dulaglutide experienced larger reductions (-1.14% and -1.12% respectively), as did those without prior GLP-1 RA use (-1.03%). The proportion of patients with HbA1c <7% increased from 18% to 40%.

CONCLUSIONS

Dulaglutide was associated with a significant decrease in HbA1c levels 6 months after treatment initiation. Patients who adhered to or persisted with dulaglutide therapy, or were naïve to GLP-1 RA use, experienced greater decreases in HbA1c levels.

Impact of Out-of-Pocket Pharmacy Costs on Branded Medication Adherence Among Patients with Type 2 Diabetes

BACKGROUND

Medication adherence is pivotal for the successful treatment of diabetes. However, medication adherence remains a major concern, as nonadherence is associated with poor health outcomes. Studies have indicated that increasing patients' share of medication costs significantly reduces adherence. Little is known about a potential out-of-pocket (OOP) cost threshold where substantial reduction in adherence may occur.

OBJECTIVE

To examine the impact of diabetes OOP pharmacy costs on antihyperglycemic medication adherence and identify the potential threshold at which significant reduction in adherence may occur among patients with type 2 diabetes mellitus (T2DM).

METHODS

This was an observational, retrospective cohort study using longitudinal U.S. pharmacy and medical claims data from the IMS Health Medical Claims (Dx) database. Patients with T2DM who initiated therapy with a branded antihyperglycemic medication during the index period (January 1, 2011, to December 31, 2011) and had 3 years of follow-up data were included. The primary outcome was adherence to antihyperglycemic medications, measured as the number of days covered. Propensity scores were calculated using baseline sociodemographic and clinical characteristics to control for potential confounding factors. Four strata were created based on mean propensity scores. Across each stratum, patients were assigned to 5 diabetes OOP pharmacy (including generics) cost levels: $0-$10, $11-$40, $41-$50, $51-$75, and > $75. Multivariate regression models were used to estimate association of diabetes OOP pharmacy costs and adherence for each stratum. Sensitivity analyses were conducted to assess the impact of total OOP pharmacy costs and index drug category OOP costs on adherence.

RESULTS

A total of 15,416 patients were assessed. Across each stratum in the diabetes OOP pharmacy cost analysis group, mean patient age ranged from 52.3 to 56.1 years, mean number of antihyperglycemic medication classes ranged from 1.5 to 3.2, and mean household income ranged from $60,763 to $79,373. Most patients used a commercial plan (55%-85%). The propensity-stratified multivariate regression model revealed an overall negative relationship between diabetes OOP pharmacy costs and adherence across several OOP cost levels. Diabetes OOP pharmacy cost level $51-$75 appeared as the threshold at which adherence reduced significantly (77-78 fewer days of coverage over 3 years of follow-up; P < 0.05) when compared with the lowest OOP costs ($0-$10) across all strata. Adherence reduced further (99-145 fewer days of coverage; P < 0.0001) for the higher diabetes OOP pharmacy cost levels (> $75) when compared with the lowest OOP cost levels. Sensitivity analyses with total OOP pharmacy costs and index drug category OOP costs revealed negative association with adherence across all strata.

CONCLUSIONS

Diabetes OOP pharmacy cost was negatively associated with patient adherence, and a potential OOP cost threshold ($51-$75) was identified at which adherence reduced significantly. The study findings may be beneficial in informing the design of health care plans to achieve optimal adherence and improve disease management in patients with T2DM.

DISCLOSURES

This study was funded by Eli Lilly and Company. Eli Lilly and Company was involved in the study design; collection, analysis, and interpretation of data; preparation of the manuscript; and decision to submit for publication. Fu is an employee of Eli Lilly and Company. Taylor and Kwan are employees of Lilly USA. Fu and Kwan hold stock or stock options in Eli Lilly and Company. Bibeau was an employee of Eli Lilly and Company at the time of this study and initial submission of this manuscript. Bibeau is currently employed by Janssen Scientific Affairs. The abstract for this study was presented at the AMCP Managed Care & Specialty Pharmacy Annual Meeting 2016; April 19-22, 2016; San Francisco, California. Bibeau and Fu contributed to the study design and collected the data. All authors contributed equally to data interpretation and manuscript preparation and revision.

Glucagon-like peptide-1 receptor agonists compared with basal insulins for the treatment of type 2 diabetes mellitus: a systematic review and meta-analysis

AIMS

Since 2005, several glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have been approved to treat people with type 2 diabetes. These agents are considered for use at the same point in the treatment paradigm as basal insulins. A comprehensive comparison of these drug classes, therefore, can help inform treatment decisions. This systematic review and meta-analysis assessed the clinical efficacy and safety of GLP-1 RAs compared with basal insulins.

MATERIALS AND METHODS

MEDLINE, EMBASE, CENTRAL and PubMed databases were searched. Randomized clinical trials (RCTs) of ≥16 weeks' duration comparing GLP-1 RAs vs basal insulins in adults with type 2 diabetes inadequately controlled with oral antihyperglycemic drugs were included. Data on the change from baseline to 26 weeks (±10 weeks) of treatment in hemoglobin A1c (HbA1c) and weight, as well as the proportion of patients experiencing hypoglycaemia, were extracted. Fixed-effect pairwise meta-analyses were conducted where data were available from ≥2 studies.

RESULTS

Fifteen RCTs were identified and 11 were meta-analysed. The once-weekly GLP-1 RAs, exenatide long acting release (LAR) and dulaglutide, led to greater, statistically significant mean HbA1c reductions vs basal insulins (exenatide: -0.31% [95% confidence interval -0.42, -0.19], dulaglutide: -0.39% [-0.49, -0.29]) whilst once-daily liraglutide and twice-daily exenatide did not (liraglutide: 0.06% [-0.06, 0.18], exenatide: 0.01% [-0.11, 0.13]). Mean weight reduction was seen with all GLP-1 RAs while mean weight gain was seen with basal insulins. Interpretation of the analysis of hypoglycaemia was limited by inconsistent definitions and reporting. Because of the limited number of available studies sensitivity analyses to explore heterogeneity could not be conducted.

CONCLUSIONS

Although weight reduction is seen with all GLP-1 RA's, only the once-weekly agents, exenatide LAR and dulaglutide, demonstrate significant HbA1c reductions when compared to basal insulins.

Relationship between weight change and glycaemic control in patients with type 2 diabetes receiving once-weekly dulaglutide treatment

AIM

To assess the relationship between weight change and glycated haemoglobin (HbA1c) change in dulaglutide-treated patients by analysing data from six head-to-head phase III AWARD clinical trials.

METHODS

At 26 weeks, the relationship between weight and HbA1c was analysed in each trial rather than by pooling data because of differences in design and background therapy. The effect of baseline characteristics was also evaluated with regard to weight and HbA1c response.

RESULTS

Across the studies, 87-97% and 83-95% of patients treated with dulaglutide 1.5 and 0.75 mg, respectively, had reductions in HbA1c levels, while 57-88% and 43-84% of patients treated with dulaglutide 1.5 and 0.75 mg, respectively, experienced weight loss. The majority (55-83%) of patients receiving dulaglutide 1.5 mg experienced weight loss and HbA1c reductions, while 41-79% of patients in the dulaglutide 0.75 mg arm lost weight and had reductions in HbA1c level. A weak and inconsistent correlation was observed between the changes in weight and HbA1c (range from -0.223 to 0.267) in patients treated with dulaglutide. The baseline characteristics of gender, age, duration of diabetes, HbA1c, body weight and BMI were not related to different combinations of weight and HbA1c responses.

CONCLUSIONS

Dulaglutide is an effective treatment option across the type 2 diabetes treatment spectrum. Dulaglutide showed dose-dependent effects on both weight loss and HbA1c reduction. These effects had a weak correlation and appeared to be independent.

Baseline factors associated with glycemic control and weight loss when exenatide twice daily is added to optimized insulin glargine in patients with type 2 diabetes

OBJECTIVE

To determine variables associated with glycemic and body weight responses when adding exenatide to basal insulin-treated type 2 diabetes.

RESEARCH DESIGN AND METHODS

Exploratory subgroup analyses based on baseline A1C, disease duration, and BMI of a 30-week study comparing exenatide twice daily to placebo, added to optimized insulin glargine (intent-to-treat analysis: 137 exenatide; 122 placebo).

RESULTS

Exenatide participants had greater A1C reductions compared with optimized insulin glargine alone, irrespective of baseline A1C (P < 0.001). Exenatide participants with longer diabetes duration and those with lower BMI had greater A1C reductions (P < 0.01). Exenatide participants lost more weight, regardless of baseline A1C or BMI (P < 0.05). Exenatide participants with longer diabetes duration lost the most weight (P < 0.001).

CONCLUSIONS

Exenatide added to optimized basal insulin was associated with improved glycemic control and weight loss, irrespective of baseline A1C, diabetes duration, and BMI. Changes were evident in modestly obese patients and in those with longer diabetes duration.

Use of twice-daily exenatide in Basal insulin-treated patients with type 2 diabetes: a randomized, controlled trial

BACKGROUND

Insulin replacement in diabetes often requires prandial intervention to reach hemoglobin A₁(c) (HbA₁(c)) targets.

OBJECTIVE

To test whether twice-daily exenatide injections reduce HbA₁(c) levels more than placebo in people receiving insulin glargine.

DESIGN

Parallel, randomized, placebo-controlled trial, blocked and stratified by HbA₁(c) level at site, performed from October 2008 to January 2010. Participants, investigators, and personnel conducting the study were masked to treatment assignments. (ClinicalTrials.gov registration number: NCT00765817)

SETTING

59 centers in 5 countries.

PATIENTS

Adults with type 2 diabetes and an HbA₁(c) level of 7.1% to 10.5% who were receiving insulin glargine alone or in combination with metformin or pioglitazone (or both agents).

INTERVENTION

Assignment by a centralized, computer-generated, random-sequence interactive voice-response system to exenatide, 10 µg twice daily, or placebo for 30 weeks.

MEASUREMENTS

The primary outcome was change in HbA₁(c) level. Secondary outcomes included the percentage of participants with HbA₁(c) values of 7.0% or less and 6.5% or less, 7-point self-monitored glucose profiles, body weight, waist circumference, insulin dose, hypoglycemia, and adverse events.

RESULTS

112 of 138 exenatide recipients and 101 of 123 placebo recipients completed the study. The HbA₁(c) level decreased by 1.74% with exenatide and 1.04% with placebo (between-group difference, -0.69% [95% CI, -0.93% to -0.46%]; P < 0.001). Weight decreased by 1.8 kg with exenatide and increased by 1.0 kg with placebo (between-group difference, -2.7 kg [CI, -3.7 to -1.7]). Average increases in insulin dosage with exenatide and placebo were 13 U/d and 20 U/d. The estimated rate of minor hypoglycemia was similar between groups. Thirteen exenatide recipients and 1 placebo recipient discontinued the study because of adverse events (P < 0.010); rates of nausea (41% vs. 8%), diarrhea (18% vs. 8%), vomiting (18% vs. 4%), headache (14% vs. 4%), and constipation (10% vs. 2%) were higher with exenatide than with placebo.

LIMITATIONS

The study was of short duration. There were slight imbalances between groups at baseline in terms of sex, use of concomitant glucose-lowering medications, and HbA₁(c) levels, and more exenatide recipients than placebo recipients withdrew because of adverse events.

CONCLUSION

Adding twice-daily exenatide injections improved glycemic control without increased hypoglycemia or weight gain in participants with uncontrolled type 2 diabetes who were receiving insulin glargine treatment. Adverse events of exenatide included nausea, diarrhea, vomiting, headache, and constipation.

PRIMARY FUNDING SOURCE

Alliance of Eli Lilly and Company and Amylin Pharmaceuticals.

IGF-I measurements in the diagnosis of adult growth hormone deficiency

Although serum insulin-like growth factor I (IGF-I) concentrations have utility as a screening test for growth hormone (GH) deficiency in children and young adults, they are less accurate for screening in adults over 40 years of age. There are two main limitations in the clinical use of IGF-I levels as a marker of GH secretion. First, IGF-I synthesis is not only regulated by GH but also by nutrient supply and by other hormones; second, low IGF-I levels in the presence of normal or increased GH secretion may reflect a peripheral resistance to GH action. Although serum IGF-I cannot be used as a stand-alone test for the diagnosis of adult GH deficiency, very low IGF-I levels in the context of documented hypothalamic or pituitary disease may be helpful in identifying patients with a high probability of GH deficiency. In the presence of two or more additional pituitary hormone deficiencies, an IGF-I level <84 microg/l (assayed by Esoterix Endocrinology, Inc. Calabasas Hills, CA, USA) indicates a 99% probability of GH deficiency. As this cut-off value has not been validated for other IGF-I assays, an IGF-I standard deviation score (SDS) of <-3 may be considered in adults over age 28; an even lower IGF-I SDS is needed for diagnosis in younger adults. In clinical practice, other causes of low serum IGF-I such as malnutrition, diabetes, hypothyroidism, liver disease, etc., should be excluded before applying these diagnostic criteria.