Objective: Growth hormone deficiency (GHD) is one of the most important endocrine and treatable causes of short stature. Insulin-like growth factor 1 (IGF-1) concentration is not recommended to establish the diagnosis of GHD. The aim of our study was to analyze the relevance of IGF-1 concentration as a screening test for the diagnosis of GHD. Materials and Methods: We retrospectively studied patients who were evaluated for short stature at the Endocrinology Department of King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia from January 2015 to December 2018. For IGF-1, laboratory reference ranges were based on age and sex. For all eligible patients, IGF-1 concentration was determined and an ITT was performed. Patients with a peak GH of ≤ 5.0 ng/ml were considered to be GHD and patients with a peak GH of ≥ 5.1 ng/ml were considered non-GHD (nGHD). Results: We retrospectively included 47 patients for analysis. Mean age was 14.7 ± 1.7 years. There were 38 males (80.9%) and 9 females (19.1%) and mean IGF-1 concentration was 146.4 ± 69.4 ng/dl. Results from the ITT indicated that 27 (57.4%) had GHD. Age was not significantly different between GHD and non-GHD (14.7 ± 1.8 vs. 14.8 ± 1.6 years, P = 0.9). There were non-significantly more males than females in GHD patients (59% vs. 50%, P = 0.7). Mean IGF-1 concentration was not significantly different (146.9 ± 70.4 ng/dl vs. 145.7 ± 69.8 ng/dl, P = 0.9). IGF-1 concentration below the reference ranges for age and gender was non-significantly higher in patients with GHD compared to non-GHD (53.8% vs. 46.2%, P = 0.8). The mean peak for GH concentration was significantly lower in patients with GHD (2.2 ± 1.3 ng/ml vs. 9.9 ± 5.6 ng/ml, P < 0.0001).  Peak GH concentration was not significantly correlated with IGF-1 concentration (r = 0.213, P = 0.2). We plotted a ROC curve of IGF-1 concentration according to the diagnosis of GHD as established using ITT. The AUC was 49%. An IGF-1 threshold of 154 ng/dl was selected to emphasize sensitivity rather than specificity. With a threshold of 154 ng/dl, sensitivity was 52% (95% confidence interval (95% CI); 32%, 71%), specificity was 40% (95% CI; 19%, 64%) and the negative predictive value for the diagnosis of GHD was 38% (95% CI; 24%, 54%). With a threshold of 105 ng/dl, the sensitivity was 41% and the specificity was 70%. A threshold of 74 ng/dl, gave a positive predictive value of 60% but a negative predictive value of 43%. 7 of the patients with IGF-1 concentration above the threshold of 154 ng/dl (N = 20) were normal and 13 had GH deficiency. These 13 GHD patients had IGF-1 concentration that differs significantly from those of their GH-sufficient counterparts (105 ± 35 vs. 222 ± 49 ng/dl, P < 0.0001). If IGF-1 was used as a screening test (with a concentration threshold of 154 ng/dl) and ITT as a confirmatory test, 20 (43%) out of 47 ITT would not have been performed, leading to the misdiagnosis of 13 GH-deficient adults. Thus, in our study population, such a procedure would misdiagnose 13 out of 27 GHD patients (48%) and yield a sensitivity of 52%. Conclusion: Many reports have already reported that IGF-1 concentration is lower in patients with GHD than in the general population, our study demonstrated the poor negative predictive value of IGF-1 concentration for the diagnosis of GHD, making it the need of the use of the “gold standard” method ITT. This observation remains to be validated by population-based studies.

Background: Type 2 diabetes mellitus (T2DM) has been a medical and social problem worldwide. For nutritional therapy, Low Carbohydrate Diet (LCD) and Calorie restriction (CR) have discussed for long, where authors continued clinical research. Subjects and Methods: Subjects were 68 patients with T2DM with 62.1 years on average. Methods included i) standard CR was provided a day with 1400 kcal and 60% of carbohydrate, ii) measurement of daily profile of blood glucose, iii) insulinogenic index (IGI) (0-30 mins) exam for breakfast including 70g of carbohydrate, iv) calculation of IGI by delta and Area Under the Curves(AUC). Results: Basal data revealed that HbA1c 7.9%, fasting glucose 163 mg/dL, average glucose in a day 210 mg/dL, M value 117 in the median. Increment of glucose/IRI was 48.0 mg/dL/8.6 μU/mL, respectively. Delta or AUC ratio of IGI was 0.14[0.08-0.26] and 3.3[2.5-5.2], respectively. There were significant correlations between M value and Delta or AUC ratio, with a higher coefficient in the latter. Discussion and Conclusion: IGI study in Meal Tolerance Test (MTT) would be useful for pancreas function evaluation. AUC ratio method has superiority than Delta ratio with higher correlation coefficient. Current results could be the fundamental data for the related range of research, and further development will be expected.