We previously conducted a systematic review and meta-analysis examining the effects of smartphone application-based interventions on blood pressure (BP). Building on that work, here we present a secondary analysis which explored the effects of these interventions on cardiometabolic risk factors. We searched MEDLINE, the Cochrane Library, and Ichushi for randomized controlled trials and observational studies comparing smartphone application-based interventions with usual care excluding digital technologies. Random-effects models were used to estimate pooled mean changes and 95% confidence intervals (CIs). A total of 76 studies involving 46459 participants were included. At 6-month follow-up, smartphone application-based interventions were significantly associated with reductions in fasting plasma glucose (-5.65 mg/dL, 95% CI: -10.12 to -1.19), body mass index (-0.58 kg/m, 95% CI: -0.80 to -0.36), waist circumference (-3.37 cm, 95% CI: -4.81 to -1.93), body weight (-1.60 kg, 95% CI: -2.30 to -0.90), low-density lipoprotein (LDL) cholesterol (-7.63 mg/dL, 95% CI: -11.64 to -3.62), total cholesterol (-9.01 mg/dL, 95% CI: -15.80 to -2.22), and triglycerides (-4.69 mg/dL, 95% CI: -8.69 to -0.70). These effects gradually declined by 12 months. BMI reduction showed a significant interaction with follow-up duration (p for interaction = 0.045). No significant differences in office BP reduction were observed across baseline BP levels. Notably, LDL cholesterol reduction was greater among East Asians than non-East Asians (p for interaction = 0.040). These findings highlight the potential of smartphone application-based interventions to improve cardiometabolic health and support self-management in adults.