Weekly text messages improve HIV drug adherence in Kenya

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Weekly text message (SMS) reminders increased the proportion of patients who achieved 90% adherence to antiretrovirals by 13-16% over one year in a randomised trial in rural Kenya, Cristian Pop-Eleches and colleagues report in the advance online edition of AIDS.

Weekly reminders also reduced the frequency of treatment interruptions, strongly linked to treatment failure and the development of drug resistance. Second-line therapy in resource-poor settings is often unavailable and when it is the cost can be as much as 17 times greater than first-line, note the authors. So prevention of adherence-related treatment failure is critical.  

While antiretroviral therapy continues to reduce death and disease in people living with HIV, incomplete treatment adherence is a major factor of treatment failure, drug resistance, HIV disease progression and death.



The result of a statistical test which tells us whether the results of a study are likely to be due to chance and would not be confirmed if the study was repeated. All p-values are between 0 and 1; the most reliable studies have p-values very close to 0. A p-value of 0.001 means that there is a 1 in 1000 probability that the results are due to chance and do not reflect a real difference. A p-value of 0.05 means there is a 1 in 20 probability that the results are due to chance. When a p-value is 0.05 or below, the result is considered to be ‘statistically significant’. Confidence intervals give similar information to p-values but are easier to interpret. 

control group

A group of participants in a trial who receive standard treatment, or no treatment at all, rather than the experimental treatment which is being tested. Also known as a control arm.

treatment failure

Inability of a medical therapy to achieve the desired results. 

drug resistance

A drug-resistant HIV strain is one which is less susceptible to the effects of one or more anti-HIV drugs because of an accumulation of HIV mutations in its genotype. Resistance can be the result of a poor adherence to treatment or of transmission of an already resistant virus.

disease progression

The worsening of a disease.

In resource-poor settings evidence suggests adherence is as good, if not better than in resource-rich settings. However, some studies have found adherence declines over time. Reasons include: increasingly larger numbers of people are on ART in rural areas where access to continued care and support is severely limited because of a lack of financial, human and transportation resources.

Mobile phone messaging has been proposed as one way to support adherence and minimise loss to follow-up among people with HIV taking antiretroviral therapy.

The study released this week is the second randomised trial conducted in Africa to show that text message adherence alerts improve some aspect of adherence. A study also conducted in Kenya reported significantly better adherence and viral suppression in those who received weekly reminders.

The authors looked at the efficacy of text message reminders on adherence to ART among patients attending the Chulaimbo Rural Health Center (CRHC) in Nyanza Province, Kenya. CRHC, a government-run health facility, hosts an HIV clinic run by the Academic Model Providing Access to Healthcare (AMPATH) since 2005. 45% of the study participant households reported having a cell phone and 97% lived within an area of cell phone network coverage.

Beginning in June 2007 431 patients, eighteen years of age and older, who had started ART within the previous three months were enrolled and randomly assigned to a control group or one of the four intervention groups. Participants received SMS reminders in one of three languages (English, Dholuo and Kiswahili). Messages were of either short (“This is your reminder”) or long (“This is your reminder. Be strong and courageous, we care about you”) text and sent on a daily or weekly basis. Adherence was measured using the medication event monitoring system (MEMS). All participants received mobile phones to use as they wished. All participants received assistance to charge their phones and phone credit was added on a regular basis.

Overall adherence in the control group after 48 weeks was 75.8%, declining over time. 60% of the control group achieved 90% adherence within the first two weeks which declined to 46% in weeks 37-48. The authors note that 90% of the control group had at least one treatment interruption that lasted more than two days. This increased over time from 40% in weeks 1-12 to 58% in weeks 37-48 (P=0.001).

The number of participants with 90% adherence in the two groups receiving weekly reminders (short and long texts) was significantly higher than in the control group (53% compared to 40%, P=0.03). In the group receiving daily reminders attainment of 90% adherence did not differ much from the control group (41% compared to 40%, P=0.92).

In addition those receiving weekly reminders were also much less likely to have treatment interruptions for longer than 48 hours during the 48 week follow-up time (81% compared to 90%, P=0.03).

However the authors note that adding words of encouragement was no more effective than a short reminder or no reminder. They suggest that future cell phone interventions look at how message content and form affect behaviour. Shared mobile phone use and the real possibility of changing numbers also need to be considered.

Further study is needed to understand why weekly reminders were more effective in improving adherence than daily reminders, the authors note. They add that sending the reminder was not linked to the time when the MEMS bottle was opened. Technology is now available to link the two.

Limitations include the fact that no distinction could be made between improved dose-taking behaviour and improved use of the electronic medication monitor. Viral load measures were not taken so differences in adherence were not linked to viral suppression.

The authors conclude that “these results suggest that SMS reminders may be an important tool to achieve optimal treatment response in resource-limited settings.”


Pop-Eleches, C et al. Mobile phone technologies improve adherence to antiretroviral treatment in a resource-limited setting: a randomized controlled trial of text message reminders. Advance on line edition AIDS, 2011 doi:10.1097/QAD.0b013e32834380c1 (free abstract available here).