Retention in care and virologic suppression are the key final steps of the HIV treatment cascade. Poor or intermittent retention has been associated with later initiation of antiretroviral therapy, virologic failure, and death. Regular HIV care has also been associated with a decrease in HIV transmission risk behavior. Despite the proven health and prevention benefits of consistent HIV care, only 40-50% of those infected with HIV in the United States are estimated to meet current retention in care standards and even fewer - only about 25% - are estimated to be virologically suppressed.

The Behavioral Model for Vulnerable Populations provides a useful framework for understanding broad areas that may impact adherence to care and treatment. Individual-level domains include vulnerable (e.g., depression, stigma), enabling (e.g., social support, positive affect), and need (e.g., co-morbidities) factors, and structural domains include, for example, features or the clinic and the provider-patient relationship.

Short message service (SMS) technology represents a new and exciting tool to help retain HIV-infected patients in care and treatment. SMS interventions have been deployed successfully in support of antiretroviral adherence and virologic suppression in sub-Saharan Africa, where two randomized trials have showed clear benefits. A pilot study conducted in our clinic suggests that use of SMS messages to promote adherence to care and treatment in the urban HIV-infected poor is both feasible and acceptable.

The investigators believe that combining SMS technology with content-specific messages designed to impact factors highlighted in the Behavioral Model for Vulnerable Populations can improve retention in care and virologic suppression for an urban public hospital population living with HIV, thus the investigators propose the following specific aims.

Specific Aim 1: Determine whether a behavioral theory-based SMS intervention improves virologic suppression [primary outcome] and retention in care [secondary outcome] for a vulnerable urban HIV-infected population through a randomized trial of this technology compared to SMS appointment reminders alone. Retention in care will also be analyzed as a mediator of virologic suppression. Exploratory outcomes include time to virologic suppression, sustained virologic suppression, emergency department utilization and antiretroviral adherence, as well as levels of depression, positive affect, social support and empowerment.

Specific Aim 2: Examine patient experiences with the SMS intervention, focusing specifically on: 1) satisfaction with this technology; 2) identifying barriers to and facilitators of patient use of this technology, and; 3) the preferred frequency and content of intervention messages.

Specific Aim 3: Conduct cost and cost-effectiveness analyses of the SMS intervention.

Inclusion Criteria:

• HIV-infected
• Age 18 or over
• English-speaking
• Able to give informed consent
• Have a cell phone and willing to send/receive up to 25 text messages/month
• Detectable viral load plus either 1) new to clinic (no more than 2 primary care visits) or 2) history of poor retention (one missed visit or lack of six-month visit constancy in the past year)

Exclusion Criteria:

• HIV-uninfected
• Under age 18
• Monolingual speaker of a language other than English
• Unable to give informed consent
• Undetectable viral load
• Perfect appointment adherence