Background Many app-based interventions targeting women with breast cancer have been developed and tested for effectiveness. However, information regarding the evaluation of the usage of these interventions is scarce. A better understanding of usage data is important to determine how women use apps and how these interventions affect health outcomes. Objective This study aimed to examine the usage duration and login frequency of an app-based intervention, the Breast Cancer e-Support (BCS) program, and to investigate the association between usage data and participants’ demographic and medical characteristics. Methods This study is a secondary data analysis of a randomized controlled trial assessing the effectiveness of the BCS program. The BCS program contains four modules: Learning Forum, Discussion Forum, Ask-the-Expert Forum, and Your Story Forum. A total of 57 women in the intervention group accessed the BCS program during their 12-week chemotherapy. The app’s background system tracked the usage duration and login frequency for each forum and the entire BCS program. Results The total usage duration per participant ranged from 0 to 9371 minutes, and the login frequency per participant ranged from 0 to 774 times. The Discussion Forum and the Learning Forum were the most frequently used modules. The general linear model showed that age, education, family monthly income, and employment were associated with BCS usage duration and/or login frequency. Age (F1,45=10.09, P=.003, B=115.34, 95% CI 42.22-188.47) and education level (F1,45=7.22, P=.01, B=1949.63, 95% CI 487.76-3411.50) were positively associated with the usage duration of the entire BCS program. Family monthly income was positively associated with the usage duration of the Learning Forum (F1,45=11.85, P=.001, B=1488.55, 95% CI 617.58-2359.51) and the login frequency of the entire BCS program (F1,45=4.47, P=.04, B=113.68, 95% CI 5.33-222.03). Employment was negatively associated with the usage duration of the Ask-the-expert Forum (F1,45=4.50, P=.04, B=–971.87, 95% CI –1894.66 to –49.07) and the Your Story Forum (F1,45=5.36, P=.03, B=–640.71, 95% CI –1198.30 to –83.11) and positively associated with the login frequency of the entire BCS program (F1,45=10.86, P=.002, B=192.88, 95% CI 75.01-310.74). No statistical differences were found between BCS usage data and cancer stage, BMI, comorbidity, types of surgery, or cycles of chemotherapy. Conclusions Overall, this study found considerable variability in the usage of app-based interventions. When health care professionals incorporate app-based interventions into their routine care for women with breast cancer, the learning and discussion functions of apps should be strengthened to promote engagement. Additionally, characteristics of women with breast cancer, such as age, level of education, income, and employment status, should be taken in consideration to develop tailored apps that address their particular needs and therefore improve their engagement with the app. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12616000639426; http://www.ANZCTR.org.au/ACTRN12616000639426.aspx

BACKGROUND Women with breast cancer receiving chemotherapy in China face challenges in accessing sufficient and continuous cancer care. Mobile applications (apps) can be a promising tool for delivering support to these women when and where needed. Many app-based interventions have been developed and tested for effectiveness. A better understanding of usage data is important to explain how women use apps and how these interventions affect women’s health outcomes. However, information regarding the evaluation of the usage of these app-based interventions is inadequate. OBJECTIVE This study aimed to examine the usage duration and login frequency of an app-based intervention, the Breast Cancer e-Support (BCS) program, and to identify the association between usage data and participants’ demographic and medical characteristics. METHODS This secondary data analysis focused on a randomized controlled trial assessing the effectiveness of the BCS program. The program contains four modules: Learning Forum, Discussion Forum, Ask-the-Expert Forum, and Your Story Forum. Women in the intervention group accessed the BCS program during their 12-week chemotherapy. The app’s background system tracked the usage duration and login frequency for each forum and the entire BCS program. RESULTS Usage statistics were collected for 12 weeks from 57 women with breast cancer (mean age: 46.2 years). The total usage duration per participant ranged from 0 to 9,371 min, and the login frequency per participant ranged from 0 to 774 times for the 12-week period. The Discussion Forum and Learning Forum were the two highly used modules. The Kruskal–Wallis test showed that education and family income were associated with the usage of the BCS program. Education was positively correlated with usage duration for the 12-week BCS program (χ2 = 15.99, P = .01), Discussion Forum (χ2 = 12.25, P = .02), Ask-the-Expert Forum (χ2 = 10.70, P = .03), and Your Story Forum (χ2 = 9.94, P = .04). Education was also positively correlated with login frequency for Learning Forum (χ2 = 9.71, P = .046), Discussion Forum (χ2 = 12.66, P = .01), and Ask-the-Expert Forum (χ2 = 11.70, P = .02). Family income was positively correlated with usage duration. Family income was also associated with usage duration for the BCS program (χ2 = 8.09, P = .04) and Your Story Forum (χ2 = 14.75, P = .01). No statistical difference was found between usage of the BCS program and age, BMI, cancer stage, employment, comorbidity, or type of surgery. CONCLUSIONS Overall, this study illustrated the individualized and diverse usage of app-based programs. The learning and discussion functions of the app need to be strengthened to promote participants’ engagement. The insights gained from this study could provide recommendations for further advances in the design of app-based programs. In developing tailored app-based programs that will engage women with diverse needs, the needs of women with different levels of education and income should be explored. CLINICALTRIAL ACTRN: ACTRN12616000639426, Registered May 17, 2016. http://www.ANZCTR.org.au/ACTRN12616000639426.aspx.