A single SMS message per day can increase patient compliance, whether the aim is to help someone lose weight, stop smoking, or consistently take their medications, according to multiple studies. Mobile health is the new frontier for medical research and SMS is shows great promise for improving public health initiatives.
Over the last decade, the Center for Wireless and Population Health Systems (CWPHS), a research organization at the University of California, San Diego (UCSD), has studied how two-way text interactions can be used to promote health and prevent disease and disability. CWPHS has conducted 16 SMS studies. It has sent over 889,000 text messages to nearly 1,800 study participants, and received over 238,000 responses. Today, all SMS projects at CWPHS are built on Twilio—the standard for two-way notifications to and from study participants.



In 2007, CWPHS started testing the impact of using systems-level interventions that were purely SMS-based in its research. Initially, it relied on the carriers’ email gateways for two-way notifications. But that became difficult with the increased use of smartphones. It then turned to cellular modems, but those too had limitations for long-term use. The modems were unable to scale and often experienced hiccups that resulted in undelivered messages.
Twilio offered exactly what CWPHS needed: reliability, scale, and ease of use.
“We looked at other solutions, but Twilio is clearly superior to what others offer,” said Fredric Raab, senior systems engineer at the UCSD Center for Wireless and Population Health Systems. “Twilio is incredibly reliable and from a programming point of view, very easy to interface to.”
We looked at other solutions, but Twilio is clearly superior to what others offer. Twilio is incredibly reliable and from a programming point of view, very easy to interface to.
The CWPHS messaging engine enables highly personalized interactions with users in multiple languages, across all providers and devices. In less than 48 hours, CWPHS connected the Twilio API, providing the ability to send and receive messages.
Twilio is a one-stop shop for all two-way texting communication. CWPHS can build all SMS projects on the same core engine and customize the rules and messages displayed for each new application. It also can create a full decision tree on Twilio—based on how the patient responds, the built-in logic allows the system to reply with additional questions, make recommendations, and reach out to doctors, case managers, or in some cases, even escalate it to emergency personnel. All of this supports its goal to make the patients feel as if they are communicating with a live health coach, and not a robot.

A large number of SMS apps built on Twilio serve as medication reminders, such as iTAB for HIV+ patients. A text message is sent to ask a patient whether he took his medication, at which point the patient can respond with a single character: Y for “yes,” N for “no,” S for “snooze” (e.g. “remind me in an hour”). If the patient didn’t take his medication, the system is prompted to text “Why?” And if the medication runs out, for example, a message is automatically sent to the physician requesting a refill.
With Twilio, CWPHS also can quickly and cost effectively set up an SMS system for study participants anywhere in the world.
Additional behavioral and clinical text messaging applications that CWPHS built on Twilio include:
mDIET (mobile Dietary Intervention through Electronic Technology) aimed to promote short-term weight loss in overweight adults. The expert system initially had 3,000 message options with 1,500 rules to determine what messages to send at certain times of day based on individual preferences and how they responded to other messages. Today, it has grown to more than 15,000 messages and has been translated into Spanish.
PsyPhone was created to show patients with schizophrenia the relationship between taking medication and hearing voices. Daily text messages ask about mood and whether the patient has been bothered by voices, along with whether the patient has taken medication. Based on the two-way texts, daily non-compliance reports are emailed to case managers and weekly reports are emailed to the patient’s doctor.
MD2Me sends daily messages to children with diabetes, cystic fibrosis, or inflammatory bowel disease to help them and their families better manage the disease. If a child has certain symptoms, she can reply “help.” A decision tree then determines the severity of her symptoms, escalating the issue by texting a parent or on-call doctor. If there is a particularly long message, it is automatically sent to the case manager, who can reply via text directly through Twilio.
ConTxt sends several messages a day to encourage positive eating behaviors and physical activity for overweight adults.
Profast tests the theory that fasting for 12 hours after the evening meal increases the body’s metabolism, which leads to weight loss. Participants sent a message to Profast after their last meal or snack in the evening; the system then sent reminders in the morning for when the participant could eat, along with a text showing fast duration and success rate.
With Twilio, CWPHS has seen an increase in reliability, with increased messages deliverability compared to any other system it has used. It is also easy to use, which is a critical success measure for both internal operations and supporting increased compliance from patients.
At less than $0.05 per day per participant, Twilio has proven to be a very cost-effective solution. CWPHS can also spin up multiple phone lines, anywhere in the world, for a dollar a month. “Nobody else lets you do that,” said Raab.

Most telling of the success with Twilio is the impact on research funding. With proven methodology and technology that continue to deliver significant results, CWPHS can secure additional grants from funding Institutions such as the National Institutes of Health (NIH) to extend these successful SMS programs to new patient populations.