Intervention
TG
In the mHealth group, the patients utilized a researcher-made mobile-based app on the Android platform. This app is being registered under the Di Care trademark in the Intellectual Property Center of the Islamic Republic of Iran, whose main language was Persian. Before designing the app, patients’ needs and other similar applications and studies were investigated and checked by the researchers, and the final version was published after a long-term revision, which was held by the researchers and application developers. In the first training session, the Di Care app was installed on the patients’ smartphones in the mHealth group and its correct operation was ensured. For example, a reminder was set for one of the patient’s medications. To confirm the correct operation of the software, ​one of the researchers, with a master’s degree in nursing and two years of experience in the HD center, met the patients in the group trained with the app weekly and answered their possible questions.The Di Care app consisted of different features. Its educational materials were prepared in three-minute videos on seven topics for the patients. In these videos, some images, texts, and audios were used simultaneously (Fig. 
Different parts of Di Care app. In the face-to-face training group, the educational materials prepared for the Di Care app were taught to the patients in person by the same researcher who evaluated the correct functioning of the software. The patients were thus consulted about the timing of the training during HD. The training was completed in 12 sessions (for four weeks and three sessions per week) and lasted for at least 10 min. The training sequence was the same as that provided by the app. At the end of each training session, the patients could also raise their questions about the issues related to the topics taught. In addition, at the end of each session per week, the educational materials taught in the previous week were delivered in writing to the patients.​Twelve weeks after the onset of the intervention program (viz. eight weeks after the last training session), the mean IDWG in the patients was measured and recorded in the three training sessions of the twelfth week, the blood samples were taken to measure the serum K, P, TC, TG, AL, and FER levels, and sent to the hospital laboratory, where the study was being performed. The criteria for dietary and fluid intake non-adherence were as following: the IDWG of more than 5.7% of dry weight, the serum K level of more than 6 mmol/l, P of more than 7.5 mg/dl, TC of more than 200 mg/dl, TG of more than 150 mg/dl, AL less than 3.5 g/dl, and FER less than 30 and more than 300 µg/l [
The study process