Mobile phones have revolutionalized our lives. Short message service (SMS), an integral part of the mobile phone system, has several attractions. SMS is cheap, user-friendly; messages can be stored, retrieved and answered at user's convenience; and transmission is as quick or almost as quick as any phone call. SMS is particularly popular with the young [1
]. There is now a SMS culture, and even an emerging SMS language, the essence of which is basically "simple and short" as only up to 160 characters of text can be sent per transmission. It has been reported in a Malaysian daily (Star newspaper dated 12 May 2009 by columnist Abhinav Sharma) that young people, aged 16-24 years, send out anywhere between 40-60 text messages a day, and just about over 10 calls a day from their mobile phones. The mobile phone is considered an essential personal item by many young people, and is carried on the person almost any time of the day, at least during the waking hours. When asked how hard it would be to give up a specific technology, respondents are now more likely to say the cell phone would be the most difficult to do without, followed by the internet, TV, and landline telephone [1
]. As a corollary, SMS via mobile phone has become a powerful and inexpensive tool in getting in touch with people. Because of their high rate of ownership and frequent use, mobile phones show great promise as a communication tool in every arena of modern living including health care.
Review of the medical literature found many and varied uses of SMS in the health care context. In preventive medicine
, sending text message reminders on travel vaccine series completion was found to be an effective intervention measure, as compliance greatly improved with second and third doses of Hepatitis vaccines in the travel vaccine series [2
]. Similar immunization reminders to parents of adolescent children were well accepted. Parents in general felt that they would act on these text messages to improve on-time vaccination for their adolescent children [3
]. Both these papers detailed sending SMS reminders. The recipients were only required to retrieve and read the SMS on their mobile phone.
In promoting healthy behaviours
: A randomized controlled trial found text messaging an effective method in improving adherence to sunscreen application [4
]. The trial subjects were sent text messages but were not required to respond. In another randomized controlled trial, using SMS was effective in promoting weight loss over 4 months among a group of overweight and obese adults [5
]. Besides receiving text messages, these subjects were required to report their weight once a week by SMS.
In disease monitoring and self management
: text-messaging support system "Sweet Talk" enhanced self-efficacy, facilitated uptake of intensive insulin therapy and improved glycaemic control in paediatric patients with Type 1 diabetes mellitus [6
]. Similarly in patients with asthma, a Danish study found SMS collection of asthma diary data feasible, and SMS was successfully used as a tool for supporting self-management of asthma [7
]. Both these studies involved SMS interaction between study subjects and the researchers.
In health behavior intervention
, e.g. smoking cessation: text messaging based smoking cessation programme (i.e. regular personalized text messages providing smoking cessation advice, support and distraction) about doubled the quit smoking rates in 6 weeks among young adults in New Zealand [8
]. Likewise, a web and text messaging smoking cessation programme targeting college smokers found quit smoking rates comparable to most minimal contact or self-help smoking cessation interventions. Participants rated it high on acceptability, satisfaction and subjective ratings of success [9
]. Both these studies also involved text message interaction between study subjects and the researchers: including sending SOS text message that indicated craving for cigarette, and need for urgent support.
There is growing interest in the possibilities of using SMS in medical research
. In primary care research, the response rate of patients aged 16-24 years on their satisfaction with consultation was not significantly lower in the group using text messaging (n = 193, response rate 80.2%) compared to the group using card response method (n = 209, response rate 85.6%) [10
A randomized controlled trial comparing SMS, paper and online diaries in collecting weekly sexual behavior found SMS to be convenient and timely, though online data collection was preferable and more likely to be complete. SMS was also considered more private than paper diary collection. Besides, SMS was more convenient as diaries can be completed and sent from anywhere and at any time [11
Using text messaging to contact difficult to reach participants in "Safe Point" study, JE Maher et al reported that study participants found text messaging less of a time commitment and more private when others are present. Participants also felt less personal receiving text messages [12
The aim of this study is to evaluate the effectiveness of mobile phone short message service (SMS) in collecting weekly symptom scores of trial subjects in a double blind, randomized controlled trial assessing the efficacy and safety of a probiotic in the management of Irritable Bowel Syndrome (IBS). Previous SMS studies did not look at ways to ease the burden of repeated submission of SMS responses in longitudinal research. In this study, the process of submitting weekly symptom report was simplified using number codes to facilitate response (Table last column) [Additional file 1
]. A complete response with all 8 items answered contained 33 numbers and punctuation marks in total [Additional file 1
]. It was hypothesized that easing the burden of recording and submitting the weekly symptom report would improve response rate.
Efficacy parameters assessed by weekly diary
Subjects and methods
This is a cross sectional study conducted during a double blind randomized controlled trial comparing a probiotic with placebo in the management of Asian subjects with Irritable Bowel Syndrome (IBS). Ethics approval for the study was obtained from the Institutional Review Board (Reference number 135/2007, dated 11 April 2007). Subjects were identified to have IBS according to Rome III criteria in a previous university wide survey [13
]. They were all undergraduate students in a private medical university. Those who had accepted the invitation to participate in this study and given informed consent were randomized into two groups: one group receiving the trial probiotic for eight weeks, and the other group receiving placebo. Both investigators and subjects were blinded to the treatment. A 2 week-run-in observation period preceded the 8-week-treatment period. Subjects were required to record baseline and weekly response to 8-item-questionnaires on the satisfactory relief of IBS symptoms, bowel function, ease of passage, and symptom score including abdominal pain, bloating, flatulence and urgency (table ) through the entire 8 weeks. Subjects were also required to fill in a hard copy of the 34-item-IBS-QOL at the beginning, and at the end of the study [15
]. The study consisted of 3 face-to-face visits, spaced at 4 weeks apart: second visit at 28 ± 2 days, and third visit at 56 ± 2 days. During these visits, weight, pulse and blood pressure were checked. In the second and third visits, information on any adverse drug reaction was also recorded.
The aim of this present study was to assess the response rate of weekly symptom reports via Short Message System (SMS). At the start of the study, trial subjects were given the option to communicate their weekly symptom scores either by text messaging via mobile phones, or by email. All of them chose the text messaging option. Baseline symptom scores were collected via SMS at the beginning of the study on a Monday. For subsequent 8 weeks on every Monday, trial subjects were instructed to submit symptom scores using SMS to the research assistant without prompting. The weekly symptom report using 8-item-questionnaires (table ) was printed on the front and back of a thick pocket-sized card and given to individual trial subjects as a reminder to the different responses in each questionnaire. There were three to seven possible answers per item which the subjects could select from, based on their symptoms in response to trial medication. These answers were converted into simple number codes (table last column) [Additional file 1
]. The name and mobile number of the research assistant were printed at the bottom of the pocket sized card. When the research assistant did not receive the weekly response by Monday of the following week, a SMS reminder was sent on a daily basis for 3 consecutive days or till the arrival of the response, whichever being earlier. When the trial subjects failed to send in their weekly symptom report after 3 SMS reminders, they were reminded through phone calls. Subjects who were not contactable by phone were tracked down and met face to face. This was possible as this study was conducted in a single centre i.e. a private medical university with 2 campuses 70 km apart.
SMS reminders were also sent to trial subjects 2-3 days before the second and third face-to-face visits, at the end of 4 and 8 weeks respectively. At the third visit, the trial subjects completed the second set of paper based 34-item-IBS-QOL questionnaires.
Confidentiality was maintained as subjects were identified only by their respective mobile number, and the symptom data were communicated using number codes. Only the researcher, and the three research assistants had access to the identity of the trial subjects, as well as the symptom reports and other data submitted by them. Data analysis and reporting were anonymised.