Dietary adherence and the associated factors among Indonesian patients with type 2 diabetes: what should we be concerned about?^†

Diabetes mellitus is one of the main causes of death in the world. The International Diabetes Federation (IDF) reported that, every 8 s, 1 person dies due to diabetes.¹ The prevalence of diabetes is currently 425 million cases worldwide and it is predicted to steadily increase every year. The type 2 diabetes mellitus (T2DM) is more frequent among all types of diabetes, accounting for about 90% of diabetes cases.^1,2 Indonesia was ranked sixth among the countries with the highest numbers of diabetes cases, with 10.3 million diabetic patients reported in 2017.¹ Data from the national survey in Indonesia indicated that Yogyakarta is 1 of top 3 areas with the highest prevalence of diabetes.³

All people living with diabetes need to do diabetes management to improve their quality of life and reduce the risk of complications.^4,5 The Indonesian Endocrinology Association (known as Perkeni) recommends that there are 4 pillars in the management of diabetes: regular education, medical nutritional therapy, physical activity, and pharmacological therapy.⁶ To get effective management outcomes, patients with T2DM should maintain an ideal body weight and modify their daily activities into the healthy lifestyle and behaviors.^7–9

As the main recommendation, dietary management is one of the keys in diabetes management. Typically, the registered dieticians or professional nutritionists provide the medical nutritional therapy.¹⁰ The principle of diet management for diabetes is consumption of the balanced foods according to the daily-required calorie and nutrient intake per each individual to gain metabolic control.⁹ People living with diabetes should be aware about the importance of regular eating schedule, ideal types of food, and total caloric needs.⁶

Adherence to diet is problematic and often becomes challenging for diabetic patients. Some patients with diabetes are reported to suffer due to lacking specific knowledge about recommended daily intake.⁹ Previous studies investigated various dietary adherence issues among diabetic patients. The results indicated that almost one-half of the patients with diabetes had a low dietary adherence.¹¹ The lack of adherence following dietary recommendations is caused by difficulty in managing the daily portions of food, barriers in picking recommended foods, and limited social and economic support. Therefore, it is crucial to consider that the dietary adherence among people living with diabetes is a complex issue and requires particular attentiveness. This study aimed to identify the level of dietary adherence and determine which particular foods are challenging for people living with diabetes in Indonesia, as well as the associated factors.

The respondents mostly had an age of above 55 years, and this finding was in accordance with the results of the Indonesian national survey, in which the prevalence of diabetes is highest at the age of 55-64 years.³ This is because after the age of 30 years, the aging process causes various deteriorating changes in the human body, both biologically and physiologically. These result in a decreasing of a person’s body functions, including in the use of insulin. In addition, at the age of 40-65 years, the incidence of insulin resistance increases and stimulates the diabetes symptoms.²² The respondents were predominantly female diabetic patients, and this phenomenon can be attributed to the high increase of the lipid levels and fats in the body reserves in women.²³

The majority of respondents in this study were married and unemployed. This finding was in accordance with the results of the national database for the population living in Yogyakarta.^18,24 Previous research also identified that most diabetic patients were married and not working.^23,25,26 The changes after marriage, i.e., psychological and hormonal changes, energy balance, and eating patterns, potentially affect the fat distribution in the body and the health condition.²⁵ The advanced age of diabetic patients also affects their activities and productivity, which results in a situation wherein most diabetic patients are not actively working.²³

As much as one-half of the participants were living with diabetes in conjunction with one or more comorbidities, among which hypertension was the most common comorbidity. A previous study in Yogyakarta also showed a similar trend.²³ Insulin resistance can increase vascular resistance and blood vessel contractility in conjunction with increased norepinephrine and angiotensin II. The renin-angiotensin aldosterone system influences the systemic vascular resistance that affects high blood pressure.²⁷

The average random blood sugar level obtained was 187.8 mg/dL, showing that glycemic control was in the moderate level among the respondents.²¹ From all respondents, there were 60% whose blood sugar levels were below 200 mg/dL, which indicated a controlled blood sugar level, and 31.8% had random blood glucose of more than 200 mg/dL. The moderate glycemic control may relate with the implementation of comprehensive education programs for diabetes in primary health care (known as Prolanis). The Prolanis activities include medical consultation, home visits, regular monitoring, dietary advice, peer support, and education.²⁸ A previous study showed that there was a significant association between the compliance in terms of joining Prolanis and the stability of the blood glucose level.²⁶

The results of the dietary adherence scores indicated that less than half of the respondents had relatively close to minimum score (29.7 + 8.85). Previous research in Canada showed the mean score of dietary adherence was 32.7, whereas it was 31.5 in India.^25,29 Other studies in Jordan found that about 50% of the respondents did not comply with dietary recommendations even though they had received guidance from nutritionists.³⁰ The reasons were the lack of information about a healthy diet, frequent eating of foods outside the home, and financial constraints. Some diabetic patients may know how to do dietary management, but many may have limited proper information about consuming a healthy diet or face some barriers in adherence. Most diabetic patients may face a difficulty related to the daily caloric needs and healthy diet choices in their dietary practice. In addition, taking a meal in restaurants or cafés as a common habit may contribute to non-adherence to diet. For some people, consuming a healthy diet means they should allocate more money, which becomes a financial barrier. Overall, the changing of their behaviors could be challenging for diabetic patients.³¹

Based on our data, we identified that the patients with diabetes showed a high score of adherence on fruits and vegetables, limited high-sugar diets, and limited high-fat diets. A previous study indicated that high consumption of fruits and vegetables among the Indonesian population was common in the elderly people.³² According to our data, most of the diabetic patients comprised in the present study as respondents are elderly (aged more than or equal to 60 years). Accordingly, the consumption of fruits and vegetables for this age population indicated higher adherence. Du et al.³³ reported that consumption of fresh fruits was related to reduction in the risk of death and macrovascular complications. People living with diabetes generally adhere to limited high-sugar and high-fat foods because they received diabetes education on dietary recommendations for diabetes.^21,28 This practice was known to be associated with preventing the diabetes-related cardiovascular complications.^21,34,35 This finding was in accordance with the national data, in which there was a decrease of high-sugar consumption in several previous years.³⁶ On the other hand, the consumption of high-fat diets is related to high-caloric diets,³⁷ and the extra calories become potentially trapped in adipose tissues as the body fats. Among people with obesity, there is an increase of fatty substances in the body, such as non-esterified fatty acid (NEFA), glycerol, and cytokines, while some of these are related to insulin resistance.³⁸

Besides the identification of the foods with high scores of adherence, there were several foods in which the diabetic patients had a low score of adherence. These foods included low-sugar carbohydrates, high- fiber diets, fish and other diets with omega-3, and olive or organic oils. The low score of adherence on low-sugar foods was due to the lack of dietary information related to those foods, psychological stressors, and limited food products with low-sugar or low caloric foods.³⁹ High-fiber foods such as oats, whole-grain bread, and cereals are not actually common dishes for our population. Furthermore, the prices of those foods are mostly too expensive for some people. This was one of the main reasons why the results showed lower scores.⁴⁰ Consumption of fish and high omega-3 foods such as salmon, sardines, tuna, mackerel, oysters, caviars, chia seeds, and walnuts also indicated lower scores of dietary adherence.¹² It reflects one of the core dietary problems for the Indonesian population, which involves the low consumption in this group of foods. The adherence in the organic or olive oils showed as the lowest score among other recommended foods for diabetes. Olive and virgin coconut oils (VCO) have positive effects on people living with diabetes. They do not settle in the blood circulation and directly convert as energy. In addition, the VCO facilitates blood sugar control through insulin stimulation and secretion.⁴¹ The corn oils also have a similar effect as the VCO in reducing the blood sugar level.⁴²

People living with diabetes who did not have complications showed a higher score of dietary adherence. A survey conducted by the Diabetes and Nutrition Study Group of the Spanish Diabetes Association (GSDA) for 6.5 years showed that individuals with diabetes who complied with the dietary recommendation could reduce their risk of complications 3.4–8.2 times in comparison with those of the non-adherent patients.⁴³ A previous research also identified that a significant correlation was identified between adherence to diabetes management, including the dietary adherence, and the incidence of complications.⁴⁴ People living with diabetes who adhere to diabetes management potentially have a good diabetes control and this results in lower risk of complications.

Patients living with diabetes for more than 10 years indicated a higher score of dietary adherence than those living with the same for less than 10 years. These results exhibited a similarity with another finding on medication adherence among patients with diabetes.²⁸ It was related to their understanding and living the experience of diabetes. People living with diabetes for a longer period tend to have more information and education regarding their diseases. This resulted in better management and control of diabetes.⁴⁵

We identified that our samples were limited due to the prior criteria we set regarding our research. These results are applicable for diabetes patients joining the Prolanis program. In fact, the characteristics of our participants are parallel with the characteristics of patients constituted in the diabetes national survey,³ and thus it is still relevant to Indonesian diabetes patients. Although this limitation may affect the external validity of this research, the findings are practicable for diabetes patients in Indonesia. Future research with higher numbers of Prolanis diabetes patients is recommended. Another limitation is related to the food lists in the questionnaire. We used the PDQA tool to identify the adherence of dietary habit and it worked for the foodbased groups only (i.e., low-sugar carbs, high-fat diets, etc.). We were not in a position to assess any detailed lists of food items consumed by the diabetes patients. Therefore, in the next research, we suggest to combine the PDAQ and open-ended questions for participants related to food lists. Thus, researchers could elaborate and analyze the findings, thereby arriving at suggestions for the local-based and culturally sensitive diet for this population.

This study identified that the level of dietary adherence among patients with diabetes was still low. Although some foods were recognized as having high adherence to the dietary recommendation for patients with diabetes, there were several foods in relation to which patients reported non-compliance. Those foods included low-sugar products, high-fiber diets, fish and foods-containing high omega-3, and olive/organic oils for frying. Accordingly, nurses and other health care providers employed in a primary health care setting should be concerned about these 4 food groups during diabetes education and counseling. Moreover, patients should receive information related to the healthy foods and alternative products in terms of these 4 food groups. They need to be encouraged to consume these specific types of foods in their daily dietary practice. In addition, this study showed that people living with diabetes for more than 10 years and no other comorbidity indicated a significantly higher dietary adherence. The public health workers should thus make more efforts to promote a healthy diet among people living with diabetes, particularly those patients who have had diabetes for less than 10 years and in conjunction with other comorbidities.