In the "WelTel Kenya1" study, three clinics recruited 538 patients with the human immunodeficiency virus (HIV).
They either received the weekly SMS message on their mobile phone in addition to a standard course of antiretroviral drugs or were given standard care alone.
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The text recipients typically received the discreet message "Mambo?", which is Kiswahili for "How are you?" They were instructed to reply "Sawa" ("fine") or "Shida" ("problem") within 48 hours.
Those who said they had a problem or who failed to respond to the prompt within two days were then called by a nurse to find out what was wrong.
In the SMS group, the number of patients who achieved 100-percent adherence to their drug regimen was 12 percent higher than in the non-text group.
In addition, the numbers who were able to achieve suppression of HIV to below detectable levels in their blood -- a key benchmark of success -- was nine percent higher in the SMS group than in the standard-care group.
The technique was also cost-effective because it needed no additional equipment and little human intervention.
Each SMS cost only around five US cents, and the nurses who made the calls were able to send off the messages in computerised batches, rather than individually.
Only 3.3 percent of the prompts required a follow-up. As a result, one nurse could potentially manage 1,000 patients by SMS, and expect to make a follow-up call to only 33 patients per week.
On cost grounds, the SMS system could be a sure-fire winner compared to personal visits by a nurse, the researchers say. It could be less expensive just measured on travel costs alone.
The approach could well work in other cash-strapped countries which are fighting to get HIV patients adhere to antiretrovirals, but are also seeing an explosion in the use of mobile phones, the study suggests.
AIDS drugs often carry unpleasant or toxic side effects and -- in the absence of a cure -- have to be followed for the rest of one's life.
The study, led by Richard Lester of the British Columbia Centre for Disease Control in Vancouver, western Canada, is published online by The Lancet.
