You have some studies about effectiveness of the nursing intervention
Young, J. M., Butow, P. N., Walsh, J., Durcinoska, I., Dobbins, T. A., Rodwell, L., & ... Solomon, M. J. (2013). Multicenter randomized trial of centralized nurse-led telephone-based care coordination to improve outcomes after surgical resection for colorectal cancer: the CONNECT intervention. Journal Of Clinical Oncology: Official Journal Of The American Society Of Clinical Oncology, 31(28), 3585-3591. doi:10.1200/JCO.2012.48.1036; Wheeler, E., & Waterhouse, J. (2006). Telephone interventions by nursing students: improving outcomes for heart failure patients in the community. Journal Of Community Health Nursing, 23(3), 137-146; Singh, K., & Warnock, C. (2013). Assessing the value of a nurse.led telephone advice and triage service. Cancer Nursing Practice, 12(4), 30-35... If you have access to EBSCO Database in Nursing field you'll find a lot of information! Hope it can help! Regards
I add the following reference regarding your question:
Thome M. & Alder B. (1999). A Telephone Intervention To Reduce Fatigue And Symptom Distress In Mothers With Difficult Infants In the Community. Journal of Advanced Nursing, 29(1), 128-137