Effects of Nature Image Exposure on Pain, Fear of Blood Glucose Testing and Fear of Self-injection in Patients With Type 2 Diabetes: A Randomized Controlled Trial

Study design This was a randomized controlled trial with blinded participants and blinded statistical analysis.

Setting and time The study was conducted between November 2023 and November 2024 in the Endocrinology Service Dicle University. The service consists of 8 rooms and 22 beds and is staffed by 5 faculty members, 4 residents, 1 diabetes education nurse, 9 clinical nurses, and 2 podologists. The diabetes education nurse provides individual education to all newly admitted patients with diabetes. This education includes insulin injection technique and rotation, insulin storage conditions, self-monitoring and follow-up, medical nutrition therapy, and exercise management. Education is also provided to patients' relatives.

Population and sample The study population consisted of 64 patients with type 2 diabetes who were followed in the Endocrinology Service of ---University -- between November 2023 and November 2024 and met the inclusion criteria. Inclusion criteria were: having been diagnosed with diabetes for at least one year, current use of insulin, ability to understand and speak Turkish, no prior exposure to nature image exposure interventions, performing insulin injections at least twice daily, and conducting blood glucose monitoring at least twice daily. Exclusion criteria included having a psychiatric diagnosis, refusal to participate, vertigo, visual or hearing impairment, and cognitive disability. Based on these criteria, eligible participants were identified, and a total of 64 patients were included in the study.

Sample size and power analysis Sample size estimation was performed a priori using G*Power version 3.1 [21] based on the fear of self-injection scale scores reported in the study by Aktura and Sarıtaş. [22] Assuming a large effect size (Cohen's d = 0.80), a statistical power of 80%, and a significance level of 5% (α = 0.05), the minimum required sample size was calculated as 42 participants, with at least 21 participants in each group. To compensate for potential participant loss and to increase the statistical robustness of the study, the sample size was expanded, and 32 participants were included in each group.

Blinding This was a randomized controlled trial in which participants were blinded to group allocation, and statistical analyses were performed by an independent statistician who was blinded to group assignments. However, outcome assessment and data collection were performed by the researcher, who was aware of group allocation; therefore, outcome assessors were not blinded.