RU2801174C1 - Method of predicting the risk of developing type 2 diabetes mellitus in obese and/or pre-diabetic individuals - Google Patents

Abstract

FIELD: medicine, endocrinology and therapy.

SUBSTANCE: invention can be used to predict the risk of developing type 2 diabetes mellitus (DM) within 3 years in patients with obesity and/or prediabetes. A clinical and anamnestic examination is carried out with clarification of sex, age, the presence of obesity in the mother and with the calculation of the ratio of waist circumference to hip circumference and a molecular genetic study, where, if the CT genotype or TT rs5219 polymorphism of the KCNJ11 gene is detected, the probability of developing type 2 diabetes is determined according to the formula . If the p value is equal to or more than 23.7%, a high risk of developing type 2 diabetes within 3 years is predicted. If the p value is below 23.7%, a low risk of developing the disease is predicted.

EFFECT: method improves the accuracy of predicting the risk of developing type 2 diabetes by conducting a clinical and anamnestic examination and a molecular genetic study of the rs5219 polymorphism of the KCNJ11 gene.

1 cl, 1 tbl, 2 ex

Description

The invention relates to medicine, in particular to endocrinology and therapy, and can be used to predict the risk of developing type 2 diabetes mellitus (DM) in people with obesity and/or early disorders of carbohydrate metabolism (impaired glucose tolerance or impaired fasting glycemia).

In recent years, clinical and molecular genetic predictors leading to a high risk of developing type 2 diabetes have been actively studied. Various prognostic models and risk scales (“riskometers”) of type 2 diabetes are widely used in clinical practice for the primary prevention of type 2 diabetes and early disorders of carbohydrate metabolism.

Because genetic risk remains constant throughout a person's life, it can be predicted at birth, before exposure to many environmental risk factors. Despite the good predictive power of traditional models based on already known clinical risk factors (e.g., age, sex, smoking, body mass index (BMI), type 2 diabetes, and history of arterial hypertension), additional improvement is being actively explored. predictive performance of such risk models by adding genetic information [Buijsse B, Simmons RK, Griffin SJ, Schulze MB. Risk assessment tools for identifying individuals at risk of developing type 2 diabetes. Epidemiol Rev. 2011;33(1):46-62]. In this regard, some studies, mostly foreign, show that the addition of new single nucleotide polymorphism (SNP) loci can potentially increase the predictive power of new models [Wray NR, Yang J, Hayes BJ, et al. Pitfalls of predicting complex traits from SNPs. Nat Rev Genet . 2013;14(7):507-515; Khera AV, Chaffin M, Wade KH, et al. Polygenic Prediction of Weight and Obesity Trajectories from Birth to Adulthood. cell . 2019;177(3):587-596.e9; Liu W, Zhuang Z, Wang W, et al. An Improved Genome-Wide Polygenic Score Model for Predicting the Risk of Type 2 Diabetes. Front Genet . 2021;12:632385]. However, the limitation of the use of these models is that they were mostly developed on the basis of material obtained from people of the Caucasoid race. Therefore, the predictive power of diabetes risk scores that have been developed for populations of different ethnic origins can vary significantly between populations, and it is worth adding to the predictive risk scales only those polymorphisms that have confirmed their association with the risk of developing type 2 DM in several studies on different populations.

A known method for predicting the risk of developing type 2 diabetes mellitus (Patent RU No. 2611900 C1, IPC A61B 5/00, G01N 33/48 - 03/01/2017, Bull. No. 7), which consists in determining clinical and anamnestic data: BMI, WC, the presence of AH, the presence of diabetes in close relatives; as well as laboratory data: TG, HDL cholesterol, readings of SBP and DBP, blood sugar levels. The results obtained are evaluated using a point scale. With a score of less than 8, a low risk of developing type 2 diabetes in the next 10 years is judged. If the total score is more than or equal to 8, a high degree of risk of developing type 2 diabetes is judged.

The disadvantages of this method are its complexity, since a package of special programs is required for processing the obtained data, as well as the fact that many informative indicators, including molecular genetic features, are not taken into account.

Previously, a method was proposed for predicting the risk of developing type 2 diabetes mellitus in hypertensive patients, characterized by DNA extraction and analysis of the polymorphic variant of the lymphotoxin α gene (+250G/A Ltα ) (Patent RU No. 2521202 C1, IPC G01N 33/68 - 06/27/2014, Bulletin No. 18). The presence of the +250G Ltα allele predicts an increased risk of developing diabetes mellitus against the background of hypertension, and carriers of the +250АА Ltα genotype have a low risk of developing type 2 diabetes in natives of the Central Chernozem region with hypertension.

However, the main disadvantage of this method is that it can only be applied to natives of the Central Chernozem region, since molecular genetic markers may differ depending on the structure of the population, and this method has not been tested on other populations; the method also does not include simple, readily available clinical characteristics of the patient.

A known method for predicting the development of type 2 diabetes mellitus in patients with metabolic syndrome, characterized in that the coefficient of metabolic dyslipidemia is calculated in the form of a ratio (TG+LDL-C)/HDL-C and an anthropometric coefficient in the form of a ratio of BMI/WC/OB (Patent RU No. 2264170 C2 , IPC A61B 10/02, A61B 10/00, G01N 33/50, G01N 33/92 - 11/20/2005, Bull. No. 32). When the value of the anthropometric coefficient is less than 37.9 kg/m ² and the coefficient of metabolic dyslipidemia is more than 9.2 c.u. predict the maximum risk of developing the disease.

The disadvantages of this method are its complexity, since it requires the determination of several laboratory parameters (TG, LDL cholesterol, HDL cholesterol), insufficient consideration of some informative prognostic indicators, including genetic ones, and the fact that the method can only be used in a group of people with metabolic syndrome.

The closest analogue of the claimed technical solution is a method for predicting the development of type 2 diabetes mellitus in persons living in Bashkortostan, including DNA isolation from peripheral venous blood lymphocytes, genotyping by polymerase chain reaction of DNA synthesis of polymorphisms rs2107538 of the CCL5 chemokine gene and the rs6749704 region of the CCL20 chemokine gene (Patent RU No. 2688208 C1, IPC G01N 33/48 - 05/21/2019, Bull. No. 15). Detection of the C/T or T/T genotypes of the rs2107538 polymorphic locus of the CCL5 gene or the C/C genotype of the rs6749704 polymorphic locus of the CCL20 gene predicts the risk of developing type 2 diabetes mellitus.

This patent is taken as a prototype.

The method has the following disadvantages: due to the fact that the pathogenesis of type 2 DM is largely based on the genes responsible for beta-cell dysfunction and genes associated with insulin resistance, it is most likely that the genes of the inflammatory system, which include the CCL20 gene, are involved in the development of type 2 diabetes to a lesser extent. The method also does not include simple, readily available clinical characteristics of the patient and has not been tested in other populations.

The objective of the claimed invention is to develop a method for predicting the risk of developing type 2 diabetes in people with obesity and / or prediabetes, which is highly informative, good sensitivity and specificity, and is also easy and fast to use in an outpatient clinic.

The technical result of the claimed invention is to improve the accuracy of predicting the risk of developing type 2 diabetes.

The technical result of the claimed invention is achieved by conducting a clinical and anamnestic examination (gender, age, obesity in the mother, calculation of the OT / OB ratio), the peculiarity lies in the fact that a molecular genetic study is carried out to analyze the polymorphism of the rs5219 gene of the KCNJ11 gene, after what data is entered into the formula:

, Where

p is the probability of developing type 2 diabetes within 3 years in %

Y = -18.31 + 0.07 × X1 - 1.16 × X2 + 0.75 × X3 + 12.2 × X4 + 2.09 × X5 + 1.77 × X6

X1 - patient's age in years;

X2 - gender of patients, coded as 0 - female, 1 - male;

X3 - obesity in the patient's mother, coded as 0 - no, 1 - presence;

X4 - OT / OB ratio;

X5 - KCNJ11 CT genotype, coded as 0 - no, 1 - yes;

X6 - KCNJ11 TT genotype, coded as 0 - no, 1 - yes,

with the obtained risk probability of 23.7% and above, patients are at high risk of developing the disease, below 23.7% - at low risk.

Implementation of the invention.

The method includes:

1) Identification of risk factors for the development of type 2 diabetes (gender, age, maternal obesity);

2) Measurement of anthropometric parameters (OT, OB);

3) Isolation of DNA from whole blood (or buccal epithelium) with subsequent analysis of the polymorphism of the rs5219 gene of the KCNJ11 gene by real-time polymerase chain reaction;

4) Selection of prognostic factors using univariate analysis.

5) Calculation of the probability of developing type 2 diabetes within 3 years according to the formula.

To develop this method, we conducted a study involving 112 overweight/obese patients who were assessed for the occurrence of type 2 diabetes during 3 years of follow-up. Analysis of potential predictors (anamnestic, anthropometric, laboratory) of transformation of overweight/obesity and/or prediabetes into type 2 DM showed that maternal obesity, WC, WC/height and WC/ ABOUT. Table 1 presents data characterizing the quality of diagnostic indicators, which are significant risk factors for the development of type 2 diabetes.

Table 1. Diagnostic indicators that determine an increased risk of developing type 2 diabetes Name of indicator Area under the curve, AUC odds ratio 95% confidence interval P Maternal obesity 0.56 1.66 1.01; 2.83 0.0510 FROM 0.55 1.92 1.11; 3.54 0.0249 FROM/OB 0.60 2.02 1.09; 4.10 0.0363 OT/height 0.57 1.87 1.10; 3.36 0.0259

According to the result of logistic regression (p = 0.003), carriage of the T allele KCNJ11 rs5219 is an independent risk factor for the development of type 2 DM, regardless of gender, age, WC, WC/OB ratio, and WC/height index and can be attributed to a marker of an increased risk of developing diabetes. type 2 diabetes in obese and/or pre-diabetic individuals.

Therefore, the presence of maternal obesity, WC/height, WC/OB ratios, the rs5219 polymorphism of the KCNJ11 gene, adjusted for sex and age, showed their association with the prognosis of the risk of developing type 2 DM and can be used as predictors in the development of prognostic models for the risk of transition to SD type 2.

The predictive value of the predictors was assessed using ROC analysis and calculation of the area under the ROC curve (AUC), as well as pseudo-R2 Nigelkerke. The maximum AUC value was found in the OT/OB parameter (AUC = 80.8). Therefore, this anthropometric indicator was added to the formula.

Patients undergo a clinical and anamnestic examination: factors for the development of type 2 diabetes (gender, age, maternal obesity) are clarified, as well as WC, OB are assessed, followed by the calculation of the OT/OB ratio. Then a molecular genetic study is carried out to analyze the polymorphism of the rs5219 gene of the KCNJ11 gene. DNA from previously isolated blood leukocytes was used by the sorbent method using the AmpliPrime DNA-sorb-B reagent kit (InterLabService, Russia). PCR was performed in real time on a CFX-96 amplifier (Bio-Rad Laboratories, USA) using commercial reagent kits (Testgen, Russia).

Further, all indicators are substituted into the formula:

, Where

p is the probability of developing type 2 diabetes within 3 years in %

Y = -18.31 + 0.07 × X ₁ - 1.16 × X ₂ + 0.75 × X ₃ + 12.2 × X ₄ + 2.09 × X ₅ + 1.77 × X ₆

X ₁ - patient's age in years;

X ₂ - gender of patients, coded as 0 - female, 1 - male;

X ₃ - obesity in the patient's mother, coded as 0 - no, 1 - presence;

X ₄ - ratio FROM / ABOUT;

X ₅ - KCNJ11 CT genotype, coded as 0 - no, 1 - yes;

X ₆ - KCNJ11 TT genotype, coded as 0 - no, 1 - yes.

With a predicted risk probability of 23.7% and above, patients are at high risk of developing the disease, below 23.7% - at low risk.

Clinical examples.

Example 1

Woman, 50 years old, Waist circumference = 95cm, Hip circumference = 105cm, Maternal obesity - no, KCNJ11 gene polymorphism - genotype CT.

Substituting the obtained data into the above formula (y=-18.31+0.07*50-1.16*0+0.75*0+12.2*0.905+2.09*1+1.77*0= -1.68), we find that the risk of developing type 2 diabetes over the next 3 years (p= =1/(1+EXP(-(-1.68))) *100%) will be 15.7%. This value does not exceed the threshold value of 23.7%, therefore, the patient is predicted to have a low risk of developing type 2 diabetes.

Recommendations:

1. Given the low risk of developing type 2 diabetes in a patient with obesity and / or prediabetes for 3 years, it is necessary to prescribe non-drug treatment, including active lifestyle changes (the decision on the need for drug treatment is made individually depending on the comorbid pathology).

2. Conduct a follow-up appointment to screen for carbohydrate metabolism disorders and consider drug treatment of obesity or intensification of previously prescribed therapy after 1 year.

Example 2

Woman, 60 years old, Waist circumference = 100cm, Hip circumference = 100cm, Maternal obesity - yes, KCNJ11 gene polymorphism - TT genotype.

Substituting the obtained data into the above formula

(y=-18.31+0.07*60-1.16*0+0.75*1+12.2*1+2.09*0+1.77*1=0.61) we get, that the risk of developing type 2 diabetes over the next 3 years (p==1/(1+EXP(-0.61)))*100%) will be 64.8%. This value exceeds the threshold value of 23.7%, therefore, the patient is predicted to have a high risk of developing type 2 diabetes.

Recommendations:

1. Given the high risk of developing type 2 diabetes in a patient with obesity and / or prediabetes for 3 years, the priority is to prescribe medication for obesity and / or early disorders of carbohydrate metabolism, subject to lifestyle changes.

2. Conduct a second appointment no later than 3-6 months later.

Thus, understanding the reasons for the high risk of developing type 2 diabetes in individuals with existing risk factors (for example, overweight, obesity, or prediabetes), as well as the identification of new molecular genetic markers among a particular ethnic group, may provide an opportunity to develop an optimal prognostic scale for the development risk. Type 2 diabetes and to establish the optimal frequency of dispensary observation of such patients.

The advantage of the proposed method is its speed, simplicity and reproducibility, as well as the availability of diagnostic equipment, since the analysis of the KCNJ11 gene polymorphism is offered in most commercial laboratories in the country. The results obtained will contribute to timely prediction and/or early detection of a high-risk group for developing type 2 diabetes, which will stop the progression of early disorders of carbohydrate metabolism, and help determine the tactics of managing patients with existing risk factors.

Claims (11)

A method for predicting the risk of developing type 2 diabetes mellitus (DM) for 3 years in patients with obesity and / or prediabetes, including a clinical and anamnestic examination specifying gender, age, obesity in the mother and calculating the ratio of waist circumference to hip circumference (RT /OB) and molecular genetic study, where, in case of detection of the CT or TT genotype of the rs5219 polymorphism of the KCNJ11 gene, in a patient with obesity and / or prediabetes, the probability of developing type 2 diabetes within 3 years is determined by the formula: , Where p is the probability of developing type 2 diabetes in%; Y = -18.31 + 0.07 × X1 – 1.16 × X2 + 0.75 × X3 + 12.2 × X4 + 2.09 × X5 + 1.77 × X6; X1 is the patient's age in years; X2 is the gender of the patient, coded as 0 is female, 1 is male; X3 - obesity in the patient's mother, coded as 0 - absence, 1 - presence; X4 – OT/OB ratio; X5, KCNJ11 CT genotype, coded as 0, no, 1, yes; X6 - KCNJ11 TT genotype, coded as 0 - no, 1 - yes, with a p value equal to or more than 23.7%, a high risk of developing type 2 diabetes is predicted for 3 years, with a p value below 23.7%, a low risk of developing the disease is predicted.