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Effects of a mobile phone short message service on antiretroviral treatment adherence in Kenya (WelTel Kenya1): a randomized trial
Global Health Sciences Literature Digest
Published February 14, 2011
Journal Article

Lester RT, Ritvo P, Mills EJ, et al. Effects of a mobile phone short message service on antiretroviral treatment adherence in Kenya (WelTel Kenya1): a randomized trial. Lancet. 2010;376:1838-1845.

In Context

Adherence to antiretroviral therapy (ART) is central to achieving and maintaining optimal viral load suppression, reducing the development of drug resistance, improving health outcomes, reducing and HIV transmission.(1, 2, 3) Limited infrastructure in developing countries remains a barrier to controlling the HIV epidemic. The widespread and increased use of mobile phones in resource-constrained areas may offer a method to increase communication between health care providers and patients.


To assess the effect of mobile phone communication between health-care workers and patients initiating ART on improved adherence to antiretroviral therapy and viral load suppression.


Three clinics in Kenya: one serving an impoverished community in Nairobi, a second serving a higher income community in Kenya, and a clinic serving the rural population. Patients aged 18 years and above initiating ART at one of the study sites and with access to a mobile phone daily or almost daily and communicate using short message service (SMS).


Participants were randomized using simple randomization based on a computer generated program, and were distributed to the three study sites with group assignments in a concealed envelop. Subjects were then randomly assigned to the intervention or usual care. ART was provided at no cost and using national guidelines. Patients routinely received one or two counseling sessions prior to beginning treatment.

Participants assigned to the intervention received training on use of phones and SMS and informed that SMS was not to replace routine adherence counseling, care, or emergency services. Each Monday morning the site nurse or clinical officer sent an SMS to the intervention group participants inquiring on their status and to remind them about the availability of phone-based support. Participants were instructed to respond to the SMS within 48 hours and to indicate if they were doing well or if they had a problem. Participants who reported a problem or who did not respond to the SMS within two days were called by the clinician. All communication between the health workers and participants was recorded in a study log.

Subjects were followed-up at six and 12 months. Adherence was measured by asking participants if how many pills they missed in the previous 30 days. Adherence was defined as having reported taking more than 95% of their pills. Viral suppression was defined as HIV-RNA under 400 copies/mL at the 12 month visit.

Randomization, laboratory assays, and analyses were done by investigators blinded to group assignment, but the study design prohibited blinding by study participants and clinic staff. Analysis was done using an intention-to-treat approach. The number needed to treat (NNT) was calculated.


A total of 581 participants were enrolled between May 2007 and October 2008. Consecutive enrollment was done at two sites and alternate patients were enrolled at one clinic. There were 39 patients excluded because they lacked consistent access to a phone and four declined. Two hundred seventy-three participants were assigned to the SMS group. Seven participants in the SMS group and three in the control group withdrew.

Characteristics of participants in the intervention and control arms were similar, including greater than 60% females. Self-reported adherence and viral suppression were more frequent in the SMS group. Of the 278 participants in the SMS group, 168 (62%) of the SMS group reported adherence >95% compared to 132 of the 265 (50%) in the control group (RR 0.81, 95% CI 0.69-0.94). A total of 57% of the SMS participants achieved viral suppression compared to 48% in the control group (RR0.85, 95% CI 0.72-0.99). After adjustment in the intention to treat analysis, viral load suppression was improved in the SMS group (OR 0.71, 95% CI 0.50-1.01). The NNT to achieve viral suppression was 11 (95% CI 5.8-227.3). Analysis restricted to completed cases only found that adherence did not differ between groups but viral suppression was higher in the SMS group.


SMS reminders and communication between clinicians and patients improved adherence and viral suppression.

Study Quality

This study met the criteria for a high quality randomized controlled trial; randomization was true, group assignment concealed, assessors blinded when feasible, loss to follow-up was accounted for and relatively small, and the analysis was done using the intention to treat approach.

Programmatic Implications

This study demonstrates the effectiveness of SMS as a method to improve adherence and viral suppression. Use of mobile devices is part of the UNAIDS and WHO strategic plans(4, 5) and this study provides evidence for the efficacy of mobile phones as a method to improve health outcomes. Developing methods to implement this strategy appears warranted.


  1. Remien RH, Berkman A, Myer L, Bastos FI, Kagee A, El-Sadr WM. Integrating HIV care and HIV prevention: legal, policy and programmatic recommendations. AIDS 2008; 22 (suppl 2): S57-65.
  2. Cohen MS, Hellmann N, Levy JA, DeCock K, Lange J. The spread, treatment, and prevention of HIV-1: evolution of a global pandemic. J Clin Invest 2008; 118: 1244-54.
  3. Wood E, Hogg RS, Yip B, Harrigan PR, O'Shaughnessy MV, Montaner JS. Effect of medication adherence on survival of HIV-infected adults who start highly active antiretroviral therapy when the CD4+ cell count is 0.200 to 0.350 x 10(9) cells/L. Ann Intern Med 2003; 139: 810-16.
  4. Vitoria M, Granich R, Gilks CF, et al. The global fight against HIV/AIDS, tuberculosis, and malaria: current status and future perspectives. Am J Clin Pathol 2009; 131: 844-48.
  5. UNAIDS. Telecom: tools connecting the world and communicating about HIV. 2009 Oct 5.