BackgroundNumerous factors are likely to result in poor treatment adherence, which is one of the important factors contributing to increased complications and the low efficacy of hemodialysis (HD), particularly inadequate knowledge of patients. This study aimed to compare the effects of a mobile health (mHealth) app (the Di Care app) use and face-to-face training on the clinical and laboratory parameters of dietary and fluid intake adherence in patients undergoing HD.MethodsThis single-blinded, two-stage/two-group randomized clinical trial was fulfilled in 2021-22 in Iran. Seventy HD patients were recruited, using the convenience sampling method, and were then randomized into two groups: mHealth (n = 35) and face-to-face training (n = 35). ​ The patients in both groups received the same educational materials via the Di Care app and face-to-face training for one month. Before and 12 weeks after the intervention, the mean interdialytic weight gain (IDWG), potassium (K), phosphorus (P), total cholesterol (TC), triglyceride (TG), albumin (AL), and ferritin (FER) levels were measured and compared. The data were analyzed using the SPSS via descriptive statistics (mean, SD, frequency, and percentage) and analytical tests (independent-samplest-test, paired-samplest-test, Wilcoxon signed-rank test, Mann-Whitney U test, Chi-square test, and Fisher’s exact test).Results​Prior to the intervention, the mean IDWG and the K, P, TC, TG, AL, and FER levels, were not significantly different in both groups (p> 0.05). The mean IDWG (p< 0.0001), and the K (p= 0.001), P (p= 0.003), TC/TG (p< 0.0001), and FER (p= 0.038) levels in the HD patients in the mHealth group decreased. ​As well, the mean IDWG (p< 0.0001), and the K (p< 0.0001) and AL (p< 0.0001) levels showed a descending trend in the face-to-face group. The fall in the mean IDWG (p= 0.001) and the TG level (p= 0.034) in the patients in the mHealth group was significantly greater than that in the face-to-face group.ConclusionsThe Di Care app use and the face-to-face training could improve dietary and fluid intake adherence in patients. However, mHealth could have more effect on the laboratory parameters than face-to-face training, largely reducing the IDWG.Trial registrationThis study was registered in the Iranian Registry of Clinical Trials (No. ID IRCT20171216037895N5).