Effectiveness of a line application-based support program on insulin adherence and glycemic control in patients with uncontrolled type 2 diabetes: A quasi-experimental study

Abstract

Objective

To assess the effectiveness of a LINE-based insulin injection support program on knowledge, insulin adherence, and capillary blood glucose levels in patients with uncontrolled type 2 diabetes.

Methods

A quasi-experimental, two-group pretest–posttest study was conducted with 60 patients from a diabetes clinic in a tertiary hospital in southern Thailand, recruited via simple random sampling. The control (n = 30) and the experimental (n = 30) groups were analyzed using descriptive statistics, Chi-square, Fisher's exact, paired t-tests, and independent t-tests.

Results

The study found that, after the intervention, the experimental group demonstrated significant improvements in knowledge (M = 4.90, SD = 1.47) and insulin adherence behaviors (M = 17.53, SD = 1.70) compared to both their baseline and the control group (p < 0.05). In contrast, no significant difference in blood glucose levels was observed between the groups (t = −0.41, p > 0.05). Baseline scores for knowledge, insulin adherence, and blood glucose levels did not differ significantly between the groups (p > 0.05).

Conclusion

A LINE-based insulin injection support program effectively improves knowledge and insulin adherence in patients with type 2 diabetes. Nurses can use this program to provide education and monitor adherence, promoting sustained behavioral improvements.

Introduction

Diabetes mellitus is classified as a noncommunicable chronic disease that affects approximately 537 million adults worldwide. According to the International Diabetes Federation, the number of people living with diabetes is projected to reach 643 million by 2030. ¹ In Thailand, data from the health and medical information system of the Ministry of Public Health reported that, by 2024, over 3.5 million Thai people were diagnosed with diabetes mellitus. Among them, more than 2.4 million individuals, approximately 67%, had uncontrolled diabetes mellitus. ² Furthermore, the Public Health Statistics 2022 revealed that diabetes was responsible for 16,856 deaths in 2020, with a mortality rate of 25.9 per 100,000 people. ³

Appropriate control of blood glucose in patients with diabetes can prevent macrovascular and microvascular complications resulting from vascular degeneration. ⁴ Effective diabetes management encompasses three key aspects: dietary management, physical activity, and especially medication adherence. Medication adherence directly influences treatment outcomes and reduces complications, making it a primary determinant of treatment success. ⁵ Additionally, the inability to control blood glucose levels with oral medications may lead physicians to consider combining treatments with insulin injections.

Originally, insulin injections were administered using syringes, which presented several limitations for patients or caregivers at home. Challenges associated with syringe insulin injections include the complexity of preparing insulin for injection, inaccuracies in dosing, and the high-frequency scale on syringes, which poses barriers for visually impaired patients. ⁶ To address these limitations, insulin pens were developed, offering several advantages, such as accurate and precise insulin dosing, particularly for low-dose administration, and reduced pain during injections. ⁷

However, insulin pens may be complicated for some patients. ⁸ Studies by Bari et al. ⁹ identified inappropriate insulin administration practices, such as incorrect injection sites, failure to hold the needle beneath the skin for 10 s, excessive injection force, improper lifted skinfold techniques, and injected into areas of subcutaneous lipohypertrophy. Health personnel must provide guidance on the correct and appropriate use of insulin injections when patients are discharged from the hospital. However, clinical settings often face time limitations and workload constraints. ¹⁰ Although patients receive insulin injection training during the initial stages of insulin use, they do not undergo continuous monitoring of their injection practices afterward. Consequently, inappropriate insulin injection techniques remain prevalent, resulting in suboptimal glycemic control and common skin-related complications, such as subcutaneous lipohypertrophy. ¹¹

Nowadays, digital health technologies are widely used by healthcare personnel to promote patient care. These technologies facilitate continuous health monitoring, empower patients to self-advocate, and provide essential health-related information. ¹² Among various communication methods, the LINE application stands out as a popular mobile messaging app across all age groups. LINE allows users to send messages, photos, videos, stickers, and make real-time video calls, seamlessly connecting individuals while enabling self-expression in ways they may not have thought possible. ¹³ Although insulin injection support applications for diabetic patients often include features such as blood sugar graph displays and diabetes-related knowledge, they lack reminders for insulin injections and continuous reinforcement to empower patients in maintaining appropriate behaviors. Studies by Kim et al. ¹⁴ and Sayin et al. ¹⁵ have shown that insulin injection support programs commonly incorporate interventions such as health education handouts, videos, reinforcement via text or audio messages, video-based injection training, and medication reminders. Providing knowledge and reinforcement has been shown to promote behavioral change in patients. However, previous research has largely relied on direct follow-ups through nurse-led telephone interventions to encourage consistent insulin injection adherence.

The researchers developed a penfill insulin injection support program for patients with type 2 diabetes, utilizing the LINE application on smartphones and based on the Information, Motivation, and Behavioral Skills (IMB) Model by Fisher and Fisher. ¹⁶ The IMB Model, which promotes health behaviors through three core components, was integral to the program design. The information component included a knowledge repository on self-care for type 2 diabetes and demonstrations of proper penfill insulin injection techniques. The motivation component focused on enhancing personal and social motivation, addressing patients’ perceptions and attitudes toward appropriate insulin injection practices, and providing reminders via the LINE application, supportive stickers, and group online meetings to discuss concerns and reflect on behaviors. The behavioral skills component emphasized developing patients’ abilities to apply the learned behaviors through accurate information, motivation, and practical demonstrations of insulin injection techniques. This comprehensive approach aimed to empower patients to improve their adherence and achieve better glycemic control.

Methods

Study design

A quasi-experimental study with a two-group pretest–posttest design was conducted over a four-week intervention period, implemented between April and July 2024.

Study sampling

The sample consisted of patients with uncontrolled type 2 diabetes mellitus receiving ongoing care at a diabetic clinic in a tertiary hospital in the lower southern region of Thailand. Participants were selected purposively based on the following inclusion criteria: (I) individuals aged 18 years or older, male or female; (II) diagnosed with type 2 diabetes mellitus and continuously treated with penfill insulin injections for at least one year, with uncontrolled blood glucose levels (HbA1C > 7%) at the most recent follow-up; (III) self-administration of penfill insulin injections for at least six consecutive months, with at least one inappropriate insulin injection behavior out of the following five skills: preparing the insulin injection device, attaching a pen needle, assessing readiness for insulin injection, setting the insulin dose, or administering the insulin injection; (IV) ownership of a smartphone and ability to use the LINE application with internet access; (V) ability to communicate, read, and write in Thai; and (VI) voluntary agreement to participate in a four-week trial period. Exclusion criteria included: (I) patients with severe conditions such as severe hypoglycemia or hyperglycemic crises requiring hospitalization, and (II) those unable to complete all stages of the experiment.

The sample size for this study was determined using G*Power analysis software version 3.1.9.7. The effect size was based on a previous study that applied the IMB Model to medication adherence in people with diabetes at Photharam Hospital, Ratchaburi Province. ¹⁰ At a significance level (α) of 0.05 and a power of 0.80, the calculated effect size was 1.17, indicating a large effect. However, due to differences in study settings, the researchers adjusted the effect size to 0.80. The sample size was then calculated using Polit and Beck's power table, ¹⁷ resulting in a required sample size of 50 participants. To account for an anticipated dropout rate of 20%, ¹⁸ the final sample size was set at 60 participants, with 30 in each group.

Sample selection and group allocation

Sample Selection: Based on an initial survey, it was found that the diabetes clinic operates on official working days from Tuesday to Friday, excluding public holidays. Therefore, the researcher employed a simple random sampling technique to select 4 out of the 5 operating days for data collection by drawing lots. The first two randomly selected days were designated as the experimental group, and the remaining two days were assigned as the control group. As a result, Tuesday and Wednesday were allocated to the experimental group, while Thursday and Friday were assigned to the control group. To control for confounding variables and enhance comparability between groups, matched-pair sampling was applied based on the following characteristics: (1) gender, (2) age, (3) type of insulin injection, (4) type of oral hypoglycemic agents, (5) body mass index (BMI), and (6) A1C laboratory results. Matching was conducted until 30 pairs were formed. If any participants could not be matched according to these criteria, new participants were randomly selected to complete the pairing.

Instruments

The research instruments comprised three parts. All instruments used in this study were employed with formal permission from the respective copyright holders, as described below:

1. Screening Instrument: The Mini-Cog test was used to detect cognitive impairment in older adults, specifically for patients aged 60 years and older. A score of less than 3 indicates cognitive impairment. ¹⁹

2. Instruments for Data Collection

   The instruments used for data collection in this study included:

   • 2.1. General Information Questionnaire: This questionnaire collected demographic and clinical data, including sex, age, educational level, comorbidities, time since diagnosis of type 2 diabetes mellitus, duration of insulin pen use, types of insulin, daily insulin injection frequency, type of oral diabetes medications, BMI, and hemoglobin A1C levels.
   • 2.2. Penfill Insulin Injection Knowledge Questionnaire: This questionnaire was adapted by the researcher from a previous study developed by Jittsue et al. ²⁰ It comprised seven items scored on a scale of 0 to 1. A score of 1 was assigned for a “yes” response, while “no” or “don’t know” responses were scored as 0. Total scores ranged from 0 to 7, with knowledge levels categorized as follows: Good (4.67–7.00), Moderate (2.34–4.66), and Poor (<2.33).
   • 2.3. Observational Checklist on Penfill Insulin Injection Behaviors: This checklist, also adapted from Jittsue et al., ²⁰ assessed patients’ insulin injection behaviors. It consisted of 20 items evaluating key aspects such as preparing the insulin injection device, attaching a pen needle, assessing readiness for injection, setting the insulin dose, and insulin injection technique. Each item was scored 1 for correct performance and 0 for incorrect or uncertain performance. Total scores ranged from 0 to 20, with behavior levels categorized as follows: good (13.35–20.00), moderate (6.68–13.34), and poor (<6.67).

The content validity index (CVI) of the instruments was evaluated by five experts: one internist specializing in diabetes and endocrinology, two nursing instructors specializing in diabetes care, one registered diabetes nurse, and one professor of pharmacology. The CVI values for the instruments were 0.86 and 1.0, respectively. Inter-rater reliability was assessed using the intraclass correlation coefficient, yielding values of 0.96 and 0.96, respectively.

• 2.4. Blood Glucose Measurement: The ACCU-CHEK INSTANT blood glucose meter was used to measure fasting blood glucose levels. Samples were collected via finger-prick after the patient had fasted for at least 8 h.

• 3. Instruments for experimental intervention

The instruments used for the experimental intervention included:

• 3.1 Instructional Plan for Penfill Insulin Injection: The instructional plan for penfill insulin injection was developed with a CVI of 1.0.

• 3.2 Insulin Injection Support Program via LINE Application: The insulin injection support program was developed by the researcher based on the IMB Model, achieving a CVI of 1.0. The program comprises five main components available as a “rich menu” within the LINE application: personal health information, insulin injection reminders, penfill insulin injection demonstration videos, a type 2 diabetes knowledge bank, and appointment scheduling. Details of these components are as follows:

  • 3.2.1 Type 2 Diabetes Knowledge Bank: This feature presents educational content via video media developed by the Diabetes Association of Thailand. Topics include diet, exercise, and insulin injection therapy.
  • 3.2.2 Penfill Insulin Injection Demonstration Videos: Demonstration videos for two commonly used insulin pen models (Novopen4 and Mypen2) are included to guide patients in proper insulin injection techniques.
  • 3.2.3 Personal Health Information: This section displays patients’ personal details, including weight, height, BMI, glycemic assessments (HbA1C, FBS, DTX), and blood pressure. A line graph visually tracks trends in health data over time.
  • 3.2.4 Insulin Injection Reminders: This feature provides reminders for insulin injection times based on the specific insulin type prescribed to the patient. Notifications are sent through messages, prompting the user to confirm whether the injection has been administered.
  • 3.2.5 Appointment Scheduling: This feature facilitates the scheduling of follow-up appointments related to the insulin injection support program during the research phase, as well as regular appointments at the Diabetes Clinic. A calendar displays the scheduled dates and times for the patient's reference.

Data collection procedure

We confirm that written informed consent was obtained from all participants prior to the initiation of the study. All participants were provided with detailed information regarding the purpose, procedures, potential risks, and benefits of the study, and they voluntarily agreed to participate by signing a written consent form.

Control group

The control group received standard nursing care, which consisted of routine follow-up appointments, health education, insulin injection demonstration based on the instructional plan, and individual counseling provided by diabetes clinic nurses.

The intervention included two main activities:

Week 1 (Baseline): Data collection included questionnaires, an observational checklist, and a finger-prick blood test conducted by a research assistant. Participants received health education and a demonstration of insulin administration based on the instructional plan.

Week 4 (Postintervention): A follow-up session was conducted to provide feedback on insulin injection behaviors and reinforce techniques. Postintervention data were collected by a research assistant using questionnaires, an observational checklist, and a second finger-prick blood test.

Experimental group

The experimental group also received standard nursing care identical to that provided to the control group. This included routine follow-up appointments, health education, insulin injection demonstration based on the instructional plan, and individual counseling conducted by diabetes clinic nurses. The intervention consisted of four key activities over four weeks:

Week 1: Baseline data collection was conducted by a research assistant, including questionnaires, an observational checklist, and a finger-prick blood test. Participants received health education, a demonstration of insulin administration based on the instructional plan integrated into the intervention procedure to ensure that participants developed the necessary knowledge and skills for insulin self-administration, and instructions on using the LINE-based support program.

Week 2: Group meetings via LINE (3–5 participants per group) focused on video-based lessons about the importance of insulin and dispelling misconceptions. Participants received motivation and guidance to maintain appropriate behaviors.

Week 3: Group meetings via LINE continued with lessons on insulin storage, glucose testing, and dose adjustment. Discussions addressed barriers and reinforced positive behaviors.

Week 4: Final meeting at the diabetes clinic for postintervention data collection (questionnaires, checklist, and a second blood test) by a research assistant. The session concluded with a summary of activities, feedback, and encouragement for behavior maintenance.

However, during the outcome measurement phase for both the control and experimental groups, no blinding technique was applied to the evaluators assessing the participants. The insulin dose was kept constant, with no adjustments made throughout the study period.

Data analysis

The data were analyzed using SPSS software, with the level of significance set at 0.05. Descriptive statistics were used to analyze participants’ demographic characteristics and dependent variables. Fisher's exact test and Chi-square were applied to compare categorical variables between the experimental and control groups. Paired t-tests and independent t-tests were used to compare mean scores of knowledge, insulin penfill adherence behaviors, and blood glucose levels within and between groups, respectively. The Shapiro–Wilk test was conducted to assess the normal distribution of data prior to analysis.

Results

The participants were divided into an experimental group and a control group, each with 30 participants. Experimental group: most participants were female (53.3%), aged 37–73 years (M = 54.90, SD = 10.03), with 30% holding a bachelor's degree. Hypertension was the most common comorbidity (50%). Time since diabetes diagnosis ranged from 2 to 35 years (M = 14.97, SD = 9.43), and the duration of insulin pen therapy averaged 9.77 years (SD = 6.97). Most were treated with premixed insulin (73.3%) and Metformin (80%). Mean BMI was 28.38 kg/m² (SD = 5.06). Control group: most participants were female (53.3%), aged 35–74 years (M = 58.23, SD = 9.46), with 50% having primary education. Hypertension was also the most common comorbidity (50%). Time since diabetes diagnosis ranged from 2 to 35 years (M = 19.00, SD = 9.50), and the duration of insulin pen therapy averaged 12.37 years (SD = 7.99). Most were treated with premixed insulin (73.3%) and Metformin (80%). Mean BMI was 27.11 kg/m² (SD = 5.59) (see Table 1).

Table 1.

Comparison of number and percentage of personal information of type 2 diabetic patients using insulin pens in the experimental and the control groups.

	Control group (n = 30)		Experimental group (n = 30)
Demographic data	Number	%	Number	%	p value
Gender					1.000a
Male	14	46.70	14	46.70
Female	16	53.30	16	53.30
Age (years)	M = 58.23	SD = 9.46	M = 54.90	SD = 10.03	0.191c
	Max = 74, Min = 35		Max = 73, Min = 37
Education level					0.132b
Primary school	15	50.00	7	23.30
Secondary education	8	26.70	8	26.70
Associate's degree	3	10.00	4	13.30
Bachelor's degree	4	13.30	9	30.00
Postgraduate degree	0	0.00	2	6.70
Comorbidities
None	8	26.67	6	20.00	0.760a
Hypertension	15	50.00	15	50.00	1.000a
Dyslipidemia	11	36.70	12	40.00	1.000a
Chronic kidney disease	2	6.67	4	13.33	0.671b
Heart disease	4	13.33	2	6.67	0.671b
Cerebrovascular disease	1	3.33	1	3.33	1.000b
Other diseases	4	13.33	6	20.00	0.729a
Duration of diabetes (years)	M = 19.00 Max = 35	SD = 9.50 Min = 2	M = 14.97 Max = 35	SD = 9.43 Min = 2	0.104c
Duration of insulin pen therapy (years)	M = 12.37 Max = 30	SD = 7.99 Min = 1	M = 9.77 Max = 25	SD = 6.97 Min = 1	0.184c
Type of insulin
Rapid-acting insulin	3	10.00	3	10.00	1.000b
Intermediate acting insulin	5	16.67	5	16.67	1.000a
Long-acting insulin	3	10.00	3	10.00	1.000b
Premixed insulin	22	73.33	22	73.33	1.000a
Oral hypoglycemic agents
None	8	26.67	8	26.67	1.000a
Metformin	24	80.00	24	80.00	1.000a
Other	5	16.67	5	16.67	1.000a
BMI (kg/m2)	M = 27.11	SD = 5.59	M = 28.38	SD = 5.06	0.360c
	Max = 37.46, Min = 17.80		Max = 36.98, Min = 20.20

^aChi-Square Test.

^bFisher's Exact Test.

^cIndependent t-test.

The experimental group demonstrated a significant improvement in mean knowledge scores on insulin pen usage after participating in the LINE-based insulin injection support program (M = 4.90, SD = 1.47) compared to preintervention (M = 3.53, SD = 1.52; t = −6.29, p < 0.001), as shown in Table 2. Preintervention, knowledge scores were comparable between the experimental group (M = 3.53, SD = 1.52) and the control group (M = 3.40, SD = 1.54), with no significant difference (t = −0.34, p > 0.05). Postintervention, the experimental group's knowledge score (M = 4.90, SD = 1.47) was significantly higher than the control group's score (M = 3.73, SD = 1.13; t = −3.45, p < 0.001), highlighting the program's effectiveness in enhancing knowledge (see Table 2).

Table 2.

Comparison of the mean knowledge scores regarding penfill insulin injection in type 2 diabetes patients within groups and between groups, between the control group and the experimental group (N = 60).

Penfill insulin injection knowledge	Control group (n = 30)			Experimental group (n = 30)			p valuea
	Mean	SD	Level	Mean	SD	Level
Before	3.40	1.54	Moderate	3.53	1.52	Moderate	0.366
After	3.73	1.13	Moderate	4.90	1.47	Good	<0.001
p valueb	.092			<0.001

p < 0.05.

^aIndependent t-test (one tailed).

^bPaired t-test (one tailed).

The experimental group showed a significant improvement in the mean behavior score for insulin pen usage after participating in the LINE-based insulin injection support program (M = 17.53, SD = 1.70) compared to preintervention (M = 14.37, SD = 2.33; t = −8.19, p < 0.001), as shown in Table 3. Preintervention behavior scores were similar between the experimental group (M = 14.37, SD = 2.33) and the standard care group (M = 14.77, SD = 1.48), with no significant difference (t = 0.80, p > 0.05). Postintervention, the experimental group's behavior score (M = 17.53, SD = 1.70) was significantly higher than that of the standard care group (M = 14.97, SD = 1.33; t = −6.53, p < 0.001), demonstrating the program's effectiveness (see Table 3).

Table 3.

Comparison of the mean behavior scores regarding insulin penfill adherence in type 2 diabetes patients within groups and between groups, between the control group and the experimental group (N = 60).

Insulin penfill adherence behaviors	Control group (n = 30)			Experimental group (n = 30)			p valuea
	Mean	SD	Level	Mean	SD	Level
Before	14.77	1.48	Good	14.37	2.33	Good	0.215
After	14.97	1.33	Good	17.53	1.70	Good	<0.001
p valueb	0.132			<0.001

p < 0.05.

^aIndependent t-test (one tailed).

^bPaired t-test (one tailed).

The results indicated no significant change in the mean blood glucose level of the experimental group after participating in the LINE-based insulin injection support program (M = 164.47, SD = 40.58) compared to preintervention (M = 165.43, SD = 36.68; t = 0.22, p > 0.05), as shown in Table 4. Preintervention blood glucose levels were comparable between the experimental group (M = 165.43, SD = 36.68) and the standard care group (M = 163.37, SD = 33.54), with no significant difference (t = −0.23, p > 0.05). Similarly, postintervention blood glucose levels did not differ significantly between the experimental group (M = 164.47, SD = 40.58) and the standard care group (M = 160.17, SD = 41.45; t = −0.41, p > 0.05), as shown in Table 4.

Table 4.

Comparison of the mean blood glucose levels in type 2 diabetes patients within groups and between groups, between the control group and the experimental group (N = 60).

Capillary blood glucose	Control group (n = 30)		Experimental group (n = 30)		p valuea
	Mean	SD	Mean	SD
Before	163.37	33.54	165.43	36.68	0.411
After	160.17	41.45	164.47	40.58	0.343
p valueb	.556		.587

p < 0.05.

^aIndependent t-test (one tailed).

^bPaired t-test (one tailed).

Discussion

The findings revealed that the experimental group demonstrated significantly higher mean scores in knowledge and insulin penfill adherence behaviors after the intervention compared to the control group receiving standard care. However, there was no statistically significant difference in blood glucose levels between the two groups postintervention (t = −0.41, p > 0.05). The insulin injection support program via the LINE application, based on the IMB Model, included key components: providing information on type 2 diabetes and insulin pen use, reinforcing personal and social motivation, and practicing insulin injection skills. This highlights the program's effectiveness in improving knowledge and adherence behaviors. At baseline, the experimental group had moderate knowledge levels, with the lowest scores in three areas: insulin injection sites, proper use of pen needles, and insulin storage. This aligns with Alhazmi et al.'s study, ²¹ which found that 54.7% of patients stored used insulin pens improperly in a refrigerator door, and only 37.5% stored them correctly in the refrigerator. During the four-week intervention, participants received diabetes and insulin injection education through “Insu Sugar,” a LINE official account with a rich menu, including a type 2 diabetes knowledge bank. Patients were evaluated on lesson participation using pre- and post-tests. Despite improvements, the average participant age (54.90–58.23 years) might have influenced memory retention due to physiological aging processes. ²² The LINE application proved advantageous for delivering knowledge, offering visually engaging, easy-to-understand content accessible at any time, while promoting better learning outcomes.

At baseline, the mean behavior score was good, but the lowest scores were in wiping vial stoppers with alcohol, assessing insulin readiness, and holding the needle for 10 s. During the four-week intervention, patients improved their penfill insulin injection skills through LINE-based resources, including a knowledge bank, demonstration videos, group meetings, and reminders. Despite over 10 years of insulin pen use by most participants, inappropriate behaviors persisted, highlighting the value of structured education and motivation via the program. In addition, there was no significant difference in mean blood glucose levels between the control and intervention groups after the intervention. This study measured blood glucose using finger-prick tests after fasting for at least 8 h. However, the four-week intervention period was relatively short to observe significant changes in glycemic control. Capillary blood glucose measurements provide limited insights into trends, whereas HbA1C is a more robust clinical indicator, reflecting blood glucose control over a three-month period. ²³ Additionally, other confounding factors such as dietary control, physical activity levels, psychological stress, and sleep patterns, all of which are known to influence glycemic outcomes, may not have been adequately controlled.

The findings align with a randomized controlled trial by Kim et al., ¹⁴ which implemented an IMB model-based smartphone application for diabetes self-management in patients with type 2 diabetes. That study showed significant improvements in diabetes self-management knowledge and behaviors in the intervention group compared to the control group (p < 0.05). Similarly, Sayin et al. ¹⁵ reported that model-based telephone counseling grounded in the IMB model significantly enhanced self-management behaviors after three months of follow-up. The results of this study provide evidence that the insulin injection support program significantly improved knowledge and penfill insulin injection adherence behaviors. However, no improvement in blood glucose control was observed in the experimental group. This outcome may have been influenced not only by the intervention itself but also by confounding factors during the intervention phase that could not be controlled statistically. In addition to quantitative improvements, informal feedback from participants during LINE-based group discussions and follow-ups revealed increased confidence and motivation in insulin self-administration. Several participants expressed that the reminders and educational content helped them feel more engaged in their diabetes care. Although not formally measured, these qualitative impacts support the potential value of the intervention in enhancing patient empowerment.

Limitations and future work

This study has several limitations that should be acknowledged. First, the lack of a blinding technique may have introduced bias, as research assistants were aware of participants’ group assignments. Additionally, while HbA1C was used as an inclusion criterion, retrospective test results were sometimes relied upon, with a maximum gap of six months, potentially affecting the accuracy of baseline data. The short intervention period also limited the ability to observe long-term changes in blood glucose control. Future studies should consider using HbA1C as a primary metric for monitoring glycemic control, as it provides a more comprehensive assessment over time. Moreover, adopting a blinding technique in comparative studies could minimize participant and researcher bias, ensuring more reliable outcomes. Addressing these limitations could strengthen the validity and applicability of future research findings.

Conclusion

This study demonstrated that the LINE-based insulin injection support program effectively improved knowledge and insulin adherence behaviors in patients with type 2 diabetes mellitus. However, no significant difference in blood glucose levels was observed between the control and intervention groups. Despite this, the program plays a vital role in monitoring and reinforcing insulin adherence behaviors, supporting patients in consistently maintaining appropriate practices.