The use of regular text messaging over one year to collect primary outcome data in a randomised controlled trial

Ogollah, Reuben; Lewis, Martyn; Konstantinou, Kika; Lawton, Sarah; Garner, Jamie; Foster, Nadine E.

Abstract

Background
Frequent data collection is desirable in randomised controlled trials (RCTs) where time-to-event is the primary outcome, in order to accurately capture the event of interest with reduced risk of recall bias. However, an inevitable problem with repeated data collection is missing data caused by participants’ loss to follow-up prior to the occurrence of the event or the end of the planned follow-up period. This undermines the Intent-To-Treat (ITT) principle, leads to reduced power, and possible bias. Analytical strategies for drawing inferences from incomplete data, including the non-informative censoring for
time-to-event data, rely on untestable assumptions about the missingness mechanism. Therefore, it is key to minimise the chance of dropouts at the design stage. Postal or electronically-sent questionnaires are not ideal for collecting frequent follow-up data as they often yield poor response rates even after reminder mailings. Short message service (SMS) using mobile telephones might offer a new way to enhance real-time outcome data collection. We describe the use of SMS to obtain weekly data on recovery of sciatica patients in the SCOPiC trial, describe the response patterns in the short and longer term and consider the implications for data analysis.

Method
We used data from 314 participants randomised to date (target recruitment of 470) to a trial that is testing the clinical and cost-effectiveness of stratified care versus usual care for patients with sciatica in primary care (SCOPiC Trial; HTA 12/201/09) in order to evaluate weekly response rates to SMS. The primary outcome measure is patient-reported time to resolution of sciatica symptoms (defined as completely recovered/much better) measured on a six-point global perceived change scale, collected using regular SMS (with the alternative of brief phone calls for those where text messaging is not possible or missed) for the first 16 weeks for all participants, and thereafter monthly up to month 12, or until stable resolution of symptoms (defined as two consecutive SMS responses of patient-reported resolution).

Results
In total, 90% (n = 283) of participants opted for SMS follow-up and 10% (n = 31) for phone calls. There have been 4,299 valid responses via SMS out of the expected 4,787 (90% response rate), compared to 74% (417/567) telephone call responses. The median (IQR) weekly response rate over the first 16 weeks was 93% (90%, 95%) and 75% (71%, 77%) for texts and calls, respectively. There was no evidence of decrease in weekly response rate over time (i.e. pattern of missingness was intermittent). The median response rate for months 5 to 12 was 70% (62%, 80%) for SMS and 67% (63%, 82%) for telephone calls. 190/283(67%) and 3/31(10%) participants completed 100% of the expected texts and calls, respectively. 243/283 (86%) and 20/31 (65%) participants completed 80% texts and telephone calls, respectively.

Conclusion
Collecting frequent follow-up outcome data with SMS is feasible in an RCT and provides high response to both short and longer term follow-up. This could be an additional and/or alternative strategy to collecting data in large pragmatic trials, and is particularly useful for collecting regular primary outcome data, which is key to time-toevent and pragmatic ITT-evaluation.

Citation

Ogollah, R., Lewis, M., Konstantinou, K., Lawton, S., Garner, J., & Foster, N. E. (2017, May). The use of regular text messaging over one year to collect primary outcome data in a randomised controlled trial. Poster presented at 4th International Clinical Trials Methodology Conference (ICTMC) and the 38th Annual Meeting of the Society for Clinical Trials, Liverpool, UK

• Presentation Conference Type: Poster
• Conference Name: 4th International Clinical Trials Methodology Conference (ICTMC) and the 38th Annual Meeting of the Society for Clinical Trials
• Conference Location: Liverpool, UK
• Start Date: May 7, 2017
• End Date: May 10, 2017
• Deposit Date: Jun 28, 2023
• Publisher URL: https://trialsjournal.biomedcentral.com/articles/10.1186/s13063-017-1902-y