Eligible studies needed to be randomised or quasi-experimental controlled trials of interventions for disease prevention or management conducted in any population that used text messaging as the primary mechanism for intervention delivery. Studies were required to assess change in health behaviour, health outcomes and/or clinical outcomes using pre-post tests. Feasibility and pilot studies were eligible. Studies that used communication technologies other than text messaging were included only if the other technologies were used in a supplementary way. Interventions mainly for appointment reminders were excluded, as were adherence studies unless they targeted an ongoing preventive health behaviour.
Five studies were concerned with disease prevention and seven dealt with disease management. Disease prevention included medication adherence, weight loss, physical activity and smoking cessation. All disease-management studies targeted diabetes except for one that focused on management of asthma. Studies were conducted worldwide; only one took place in a developing country. Studies were published between 2005 and June 2009. All studies except one targeted people with a specific condition. Age ranged from 15 years to 45 years. Four studies specifically targeted adolescents and young adults. Gender was almost equally distributed in most studies. Intervention length ranged from three months to 12 months.
Outcomes analysed included adherence to vitamin C, changes in waist circumference, dietary habits, changes in physical activity, smoking, glycaemic control and glucose levels. Some studies included intermediate follow-up. No studies had long-term follow-up that extended beyond completion of the trial. Frequency of text messaging ranged from once weekly to five times a day or more. A small number of studies allowed participants to dictate the frequency of messaging. All disease prevention studies used automated messaging and, despite this, provided tailored messages in all studies except one.
The authors did not state how many reviewers were involved in the selection of studies for the review.