international journal of medical informatics 79 ( 2 0 1 0 ) 65–70 journal homepage: www.intl.elsevierhealth.com/journals/ijmi The impact of short message service text messages sent as appointment reminders to patients’ cell phones at outpatient clinics in São Paulo, Brazil Thiago Martini da Costa a,* , Paulo Lísias Salomão b , Amilton Souza Martha b , Ivan Torres Pisa c , Daniel Sigulem c a Postgraduate Program in Health Informatics at Federal University of São Paulo (UNIFESP), Rua Botucatu 862, São Paulo 04038-032, SP, Brazil b Katu Company, São Paulo, São Paulo, SP, Brazil c Department of Health Informatics at UNIFESP, São Paulo, SP, Brazil article info Article history: Received 6 May 2009 Received in revised form 9 July 2009 Accepted 3 September 2009 Keywords: Nonattendance Cell phones Text messages SMS abstract Objective: Nonattendance for appointments remains a challenge to health care managers and providers. The objective of this article is to present the results of a study on the impact of appointment reminders sent as short message service text messages to patients’ cell phones on nonattendance rates at outpatient clinics in São Paulo, Brazil. Design: Data were collected on scheduled appointments in four medical clinics using Clinic Manager ® or Clinic Web ® systems that can send automated messages to patients. Data on appointment attendance were collected from these systems. Measurements: More than 29,000 appointments were scheduled between July 1, 2007, and May 31, 2008, and for 7890 of them a text message reminder was sent to the patient’s cell phone. The rates of nonattendance were compared between those who were sent and those who were not sent a text message as an appointment reminder. Results: The nonattendance reduction rates for appointments at the four outpatient clinics studied were 0.82% (p = .590), 3.55% (p = .009), 5.75% (p = .022), and 14.49% (p = <.001). Conclusion: The study results indicate that sending appointment reminders as text mes- sages to patients’ cell phones is an effective strategy to reduce nonattendance rates. When patients attend their appointments, the facility providing care and the patients receiving uninterrupted care benefit. © 2009 Elsevier Ireland Ltd. All rights reserved. 1. Introduction There have been many advances in health care. The development of new drugs, the introduction of new tech- niques and technologies for medical diagnosis, and more ∗ Corresponding author. Tel.: +55 11 632 4935. E-mail addresses: tmartinicosta@gmail.com (T.M. da Costa), paulosalomao@katusis.com.br (P.L. Salomão), amiltonmartha@katusis.com.br (A.S. Martha), ivan.pisa@unifesp.br (I.T. Pisa), sigulem@gmail.com (D. Sigulem). widespread promotion of preventive measures such as vac- cination are good examples of health care advances seen in recent decades. However, nonattendance for scheduled appointments remains a challenge to health care managers and providers because it can hamper patient treatment [1,2]. 1386-5056/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijmedinf.2009.09.001