This study enrolled 73 elderly patients with type 2 diabetes who met the inclusion criteria in the Affiliated Hospital of Jiangnan University from December 2017 to November 2018. All patients were randomized 2:3 into Group C (n = 28) and Group E (n = 45). Anthropometric and biochemical measurements were taken at 0, 2, and 4 months. A total of 67 patients (Group C=24/Group E=43) eventually completed the intensive phase intervention and 45 patients (Group C=19/Group E=26) completed the maintenance phase intervention. There were no statistically significant differences in age, sex, or medication regimen among the groups during the intensive and maintenance phases (Table 1).
Effects of a dietary care model to reduce carbohydrate absorption during an intensive intervention on glucose and lipid metabolism in elderly T2DM patients
HbA1c is considered the gold standard for assessing long-term glycemic control in diabetic patients (14). The results of the within-group comparison showed that although there was no significant difference in HbA1c between Group E and Group C after dietary intervention for 2 months, there was a tendency to form a contrast. Group E showed a significant decrease in HbA1c after 2 months of dietary intervention compared to 0 months. However, it is worth noting that there was also a slight decrease in HbA1c in Group C, which may be related to our routine healthy diet education for patients in Group C, and patient compliance improved in the initial stage. The oral glucose tolerance test (OGTT) is a glucose load test used to understand islet cell function and the body's ability to regulate blood glucose. The results showed that FBG, 0.5-hPBG, 1-hPBG, 2-hPBG, and 3-hPBG decreased significantly compared with baseline after 2 months of dietary intervention. HOMA-IR is a measure used to evaluate an individual's level of insulin resistance, and the HOMA-IR index will gradually increase as the level of insulin resistance increases. The results showed no significant difference in HOMA-IR changes in Group E and Group C after 2 months of intervention. The area under the glucose curve in the OGTT showed a significant decreasing trend in Group E after 2 months, and it was different from Group C at 2 months .
CHOL is an essential raw material for synthesizing adrenocorticotropic hormone, sex hormones, bile acids, vitamin D, and other physiologically active substances. It is also the main component of the cell membrane, and its serum concentration can be used as an indicator of lipid metabolism. The results showed no significant trend in CHOL after two months of the intervention diet. TG, a fatty substance in the blood, is mainly obtained from the diet and is lower in Group E than Group C at 2 months. HDL particles are small, can freely enter and exit the arterial wall, take up low-density lipoprotein, cholesterol, triglycerides, and other harmful substances immersed in the intimal layer of the vascular wall, and transport them to the liver for decomposition and excretion (15). The results showed that HDL levels showed a significant decreasing trend in Group C and an increasing trend in Group E at 2 months. LDL is a lipoprotein particle that carries cholesterol into peripheral tissue cells and can be oxidized to oxidized LDL. When LDL, significantly oxidatively modified LDL (OX-LDL), is in excess, the cholesterol it carries accumulates on the arterial wall and quickly causes arteriosclerosis (16). The results showed that LDL levels increased in Group C and decreased significantly in Group E at 2 months. However, it is worth noting that due to the double-blind nature, we found a significant difference between the C and E groups at 0 months. HDL levels were significantly higher in Group C than in Group E, but LDL levels were significantly lower than in Group E. This difference may be related to the small sample size. With the intervention's progress, the difference between the two groups gradually narrowed at 2 months, and Group E developed better results, indirectly demonstrating that physical-based dietary intervention can regulate HDL and LDL in diabetic patients (Table 1).
Effects of a dietary care model to reduce carbohydrate absorption during maintenance on glucose and lipid metabolism in elderly T2DM patients
We performed statistical analysis again for the patients who participated in the study (4 months). It was found that even if the frequency of follow-up was reduced at a later stage, the overall results showed that HbA1c was significantly lower in Group E than in Group C after 4 months of dietary intervention. HbA1c also decreased significantly from baseline in Group E. OGTT results showed that blood glucose levels were significantly lower in Group E than Group C after 4 months of dietary care. Comparison of the results within groups indicated a significant decreasing trend in 0.5-hPBG, 1-hPBG, 2-hPBG, and 3-hPBG compared with baseline, except for FBG, which was not significantly different from baseline. It is worth noting that FBG, 0.5-hPBG, and 2-hPBG in Group C showed an increasing trend after 4 months, which may be related to our randomized double-blind, patients in the general nursing intervention group subjectively perceived the effectiveness of this model as poor. Patients are no longer willing to strictly control their diet and are associated with reduced cooperation and compliance in subsequent phases. The HOMA-IR results showed no significant change in HOMA-IR from baseline in Group E after 4 months of intervention. Still, because of the increase in Group C, a difference was formed between the two groups at 4 months. The reason for elevated HOMA-IR in Group C we used above. The area under the glucose curve in the OGTT showed a significant decreasing trend after 4 months in Group E, and it was different from Group C at 4 months (Table 2).
Analysis of lipid metabolism results showed no differences in CHOL or TG between the E and C groups at 4 months. HDL showed an upward trend in Group E and a downward trend in Group C at 4 months of intervention. LDL decreased in Group E but increased in Group C at 4 months of intervention. However, there were differences in HDL and LDL results between the C and E groups at baseline, with higher HDL levels and lower LDL levels in Group C than in Group E. With the progress of the intervention, there was a changeover phenomenon between the two groups at 4 months. Group E developed better results, indirectly demonstrating that physical-based dietary intervention can regulate HDL and LDL in diabetic patients (Table 2).
In the intensive intervention phase, we conducted dietary health education for the patients once a day according to their actual conditions without much influence on diet structure. Some patients will experience increased satiety and reduced carbohydrate intake later. It is necessary to assess the average carbohydrate intake of patients dynamically and timely adjust the dosage of WCBE promptly. At the end of the intensive intervention phase, 24 subjects in Group C (males 8 and females 16) and 43 subjects in Group E (males 25 and females 18) completed the second biochemical examination. 10.5% of patients in Group C were weaned from the experiment, compared with only 4% of patients in Group E (Table 1) . We then randomly selected 19 Group C participants (males 6 and females 13) and 26 Group E participants (males 13 and females 13) to continue the final phase of the intervention. To investigate the applicability and autonomy of patients to this dietary pattern, in the second stage, we reduced the frequency of follow-up and followed patients once a week. 13.7% of patients in Group C were taken off from the experiment, compared with only 7% of patients in Group E (Table 2) .
Patients in Group C dropped out of the investigation because of prolonged diabetic diet control, resulting in a sense of burnout. The patient's autonomy became less controlled, and his diet was not following the diabetic dietary requirements. And the patient subjectively did not want to continue the experiment. We did not interfere excessively with the structure of the diet of the patients in Group E. The patients in Group E did not want to continue the experiment because of the production of bloating.
In summary, patients in Group C had worse compliance and higher dropout rates than those in Group E due to continuous dietary control. Long-term dietary management is not easy for elderly diabetic patients.