Diabetes has become a global problem. Type 2 diabetes accounts for about 95% of all diabetic cases in the United States (
15). Oral antidiabetics usually can be initially used to reach the target blood glucose level in patients with type 2 diabetes. However, ultimately, due to the nature of a progressive disease, most patients need insulin therapy. Given the high metabolic benefits of insulin hormone, the early onset of insulin injection is proposed to maintain an ideal level of HbA1c (
16,
17). In this study, we found a compliance level of insulin treatment in 62% of patients who had not used insulin ever. However, physicians may tend to start insulin therapy earlier because of mistrust that patients observe oral medication and diabetes diet. Therefore, the high tendency of physicians toward insulin therapy and over-training of insulin injection to patients by experts may have led to an acceptable percentage of insulin therapy and bias. Nonetheless, 38% of patients with type 2 diabetes did not tend to be treated with insulin injections, which is much lower than in similar studies. In the survey by Azmiah et al. (
6) and Wong et al. (
7), 50.7% and 70.6% of patients did not tend to use insulin injections, respectively. Polonsky indicated that the level of insulin therapy resistance was 28.2% (
3). No statistically significant difference was seen between the patients’ attitudes, age, sex, monthly income, life model (living alone or with family), and duration of type 2 DM. In our study, there was no significant difference between gender and willingness to insulin therapy, whereas Nam et al. (
18) showed that women and religious minorities had more psychological barriers to insulin treatment. Another study stated that women tend to have less insulin therapy due to the fear of needle injection so they have more negative attitudes than men (
19). In our research, even though about 62% of patients who did not accept insulin therapy had a low education level (illiterate or below a high school diploma), no significant difference was found between the education level and insulin therapy acceptance. In a survey by Wong et al. (
7), patients with higher education had 55% less resistance to insulin therapy. Besides, a statistically significant difference was observed between patients’ attitudes at different levels of education. In the current investigation, the highest percentage of agreement (100%) in the insulin compliance group was related to statement “Insulin injection prevents complications of diabetes (micro and macrovascular)” whereas most of the patients (68.4%) in the noncompliance group agreed with “Insulin injection helps improve my diabetes”. This high percentage of agreement in the noncompliance group indicated they had a good perception of the insulin effect on hyperglycemia control. In Polonsky study (
10), among the positive attitude items, the most important belief was about statements :insulin therapy improves blood glucose control” (86% agreement), “it reduces complications of illness” (77% agreement), and “it improves the quality of life” (61% agreement).
There are many reasons for resistance to insulin therapy in the literature such as the fear of injection, fear of hypoglycemia and obesity, the difficulty of insulin injection management, etc. Besides, patients with diabetes may think that insulin therapy means the worsening of their conditions and a failure to manage their illness (
3). In a study of 1,267 patients with type 2 diabetes, the most important cause of negative attitude toward insulin therapy was the belief in the wrong method of injection by the patient (
20). The improvement of insulin injection needles (insulin pens) has led to less pain and discomfort in patients. However, many patients still refuse insulin therapy due to poor awareness and lack of proper injection training (
21).
Hypoglycemia is one of the main causes of the fear of insulin injection in diabetic patients, which accounted for a high percentage of agreement (89.5%) in the noncompliance group in the current survey. Hypoglycemia after insulin injection is a medical emergency and research has shown that patients with the fear of hypoglycemia have a lower quality of life. Most of the patients in the rejecting group believed that the hypoglycemia attack is embarrassing in the workplace. Some patients did not accept insulin injections to avoid disturbing their family and friends (
17). Although in this survey, the mean monthly family income was higher in the insulin compliance group than in the noncompliance group, there was no significant difference between the two groups (P = 0.5). The reason for this can be an appropriate health insurance coverage for all types of insulin among patients in Iran. However, due to the 30% out-of-pocket payment imposed on patients, insulin compliance was more in the higher income group.
There were some limitations to this investigation. The limited number of patients decreased the power of the study. Besides, most patients belonged to the lower socioeconomic level, as the study setting was a public hospital in the South of Tehran. Therefore, performing studies with a larger sample size and various socioeconomic levels are proposed.