Pilot implementation of short message service for randomisation in a multisite pragmatic factorial clinical trial in Kenya

Abstract

Background
The traditional use of sealed envelopes for randomisation is susceptible to manipulation and the risk of damage to envelopes during shipping and storage. Additionally, the filling and sealing of envelopes are tedious, time-consuming, and error-prone. Other randomisation alternatives such as web-based methods are preferred. However, they are expensive and unsuitable in settings with poor internet infrastructure. Mobile phone-based randomisation using short message service (SMS) potentially offers a low-cost and reliable alternative.

Methods
We developed an SMS-based method for random allocation of treatments. Plain text messaging or an Android app was used to formulate text messages using a fixed syntax consisting of the participant’s unique identifier, trial site, stratum, and the trial name as input parameters. The system verified the input parameters and obtained an allocation from the database before returning a response to the sender. The text response contained the details of the treatment allocation. This was a Study Within A Trial (SWAT) conducted in two sites of a multi-site 3 × 2 factorial clinical trial in Kenya involving two interventions with up to nine possible allocations. SMS randomisation feasibility was assessed by comparing treatment allocations against the master randomisation list for each processed SMS, measuring SMS latency (in seconds), and gathering user feedback via a post-implementation survey.

Results
A total of 218 participants were randomised between the 7th of February 2022 and the 11th of April 2022, out of which 179 were randomised to only one arm while 39 were randomised to both treatment arms. Allocation accuracy was 100%. Median latency was 22 s with the fastest message processed in 10 s and the slowest (non-network delayed) message processed in 2129 s. Four users completed a post-implementation survey.

Conclusions
The pilot study demonstrated that SMS randomisation is easy, user-friendly, fast, accurate, and a feasible alternative randomisation technique.

Full text

Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
https://doi.org/10.1186/s40814-025-01610-y
METHODOLOGY Open Access
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Pilot and Feasibility Studies
Pilot implementation ofshortmessage
service forrandomisation inamultisite
pragmatic factorial clinical trial inKenya
Mercy Chepkirui1,2,3* , Dennis Kimego1, Charles Nzioki4, Elizabeth Jowi5, Charles Opondo6,7 and
Ambrose Agweyu1,8
Abstract
Background The traditional use of sealed envelopes for randomisation is susceptible to manipulation and the risk
of damage to envelopes during shipping and storage. Additionally, the filling and sealing of envelopes are tedious,
time-consuming, and error-prone. Other randomisation alternatives such as web-based methods are preferred. How-
ever, they are expensive and unsuitable in settings with poor internet infrastructure. Mobile phone-based randomisa-
tion using short message service (SMS) potentially offers a low-cost and reliable alternative.
Methods We developed an SMS-based method for random allocation of treatments. Plain text messaging
or an Android app was used to formulate text messages using a fixed syntax consisting of the participant’s unique
identifier, trial site, stratum, and the trial name as input parameters. The system verified the input parameters
and obtained an allocation from the database before returning a response to the sender. The text response contained
the details of the treatment allocation. This was a Study Within A Trial (SWAT) conducted in two sites of a multi-site
3 × 2 factorial clinical trial in Kenya involving two interventions with up to nine possible allocations. SMS randomi-
sation feasibility was assessed by comparing treatment allocations against the master randomisation list for each
processed SMS, measuring SMS latency (in seconds), and gathering user feedback via a post-implementation survey.
Results A total of 218 participants were randomised between the 7th of February 2022 and the 11th of April 2022,
out of which 179 were randomised to only one arm while 39 were randomised to both treatment arms. Allocation
accuracy was 100%. Median latency was 22 s with the fastest message processed in 10 s and the slowest (non-net-
work delayed) message processed in 2129 s. Four users completed a post-implementation survey.
Conclusions The pilot study demonstrated that SMS randomisation is easy, user-friendly, fast, accurate, and a feasible
alternative randomisation technique.
Keywords SWAT , Mobile SMS randomisation, Envelope concealment, Envelope randomisation, Randomised
controlled trials, Digital randomisation, Plain text messaging, Clinical trials, Allocation concealment
*Correspondence:
Mercy Chepkirui
Mercy.Chepkirui@lstmed.ac.uk
Full list of author information is available at the end of the article
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Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
Background
Randomisation of participants in clinical trials has
become the standard method of experimental control
aimed at reducing selection bias and eliminating con-
founding from known and unknown factors [1]. e pro-
cess of randomisation generally involves two steps: (i)
generating an unpredictable sequence of random assign-
ments and (ii) implementing the sequence in a way that
conceals the treatment assigned to potential study par-
ticipants until eligibility is determined [2, 3]. Failure to
achieve proper randomisation and allocation conceal-
ment may result in biased estimates of treatment effects
and potential loss of integrity of trial results [4].
Traditionally the use of sequentially numbered,
opaque, sealed envelopes has been regarded as an accept-
able method for concealing allocation of interventions in
trials. However, this method is now falling out of favour
due to its vulnerability to manipulation [5]. Further-
more, sealed envelopes are susceptible to damage during
shipping and storage. e process of filling and sealing
envelopes is also a time-consuming manual process that
is prone to human error, particularly in large complex
studies.
In response to the limitations associated with sealed
envelopes and recognising inadequate methodological
approaches in controlled trials, there is a growing inclina-
tion towards the adoption of centrally administered web-
based or telephone-based randomisation in large studies.
However, implementing these methods is challenging in
settings with inadequate communication infrastructure
[6] and unreliable internet connectivity.
An alternative approach to randomisation, which is low
in cost, auditable, and particularly suited for low- and
middle-income countries where access to mobile phone
technology has rapidly expanded [7, 8], involves the use
of mobile phone-based short messaging service (SMS).
SMS is a method of communication that transmits text
messages up to 160 characters in length, among mobile
devices or from a computer to a mobile device. Kenya is
reported to have 98% mobile penetration amongst adults
[9].
Bulk messaging enables the synchronous delivery of
SMS text messages to a vast number of recipients mini-
mizing delays and overlapping requests. In clinical trials,
text messaging has proven effective in reducing missed
appointments [10] and has served as a cost-effective
intervention for managing patients with chronic illnesses
[11–14].
We developed an SMS-based method for the random
allocation of treatments and subsequently undertook
a pilot study comparing an SMS-based randomisation
platform versus the conventional approach using sealed
opaque envelopes. e study was conducted in parallel
with a 3 × 2 factorial pragmatic randomised controlled
trial of alternative treatments for severe pneumonia
among children aged 2–59months [15].
Our aims were to evaluate the feasibility and accu-
racy of randomisation using text messaging by estimat-
ing the response time of SMS delivery for randomisation
requests, assessing the user experience for envelope ran-
domisation and SMS randomisation approaches, cor-
rect treatment allocation, and determining allocation
sequence concordance for envelope randomisation and
SMS randomisation.
Methods
We conducted a prospective two-arm pilot study nested
within an actively recruiting randomised controlled trial.
is study was conducted in two phases. e develop-
ment phase (phase 1) involved the design specification of
the SMS platform, and initial testing in web-based, text
messaging, and Android applications. e implemen-
tation phase (phase 2) involved the deployment of the
application at two public hospitals in Kenya: Machakos
Level 5 and Mama Lucy Kibaki Hospitals selected pur-
posively from a pool of 12 clinical trial sites due to their
high participant recruitment rates. A consecutive sam-
pling method was employed at each site to recruit 200
participants.
Phase 1: Development phase
We designed and developed a three-tier SMS-based ran-
domisation system consisting of data, application, and
presentation interfaces (Fig.1). e requirements of the
application were derived from standard operating pro-
cedures for randomisation in the larger clinical trial.
erefore, the logic was structured to accommodate a
multi-step factorial randomisation design involving two
interventions with up to nine possible allocations (Fig.2).
Each message consisted of a predefined ordered syntax
comprising the participant’s unique identifier, trial site,
stratum, and trial name. Detailed descriptions of the syn-
tax, message scenarios, and expected responses are pro-
vided in Tables1 and 2.
e application tier verified the input parameters
received from the mobile network operator through SMS
or hypertext transfer protocol via a Representational
State Transfer Application Programming Interface (REST
API), obtaining an allocation from the data tier stored on
a local database. It then returned a response to the sender
through an SMS. e text response contained details of
the treatment allocation, participant identifier, and iden-
tity of the study staff undertaking randomisation. e
system was designed to identify duplicate randomisation
attempts using unique patient identifiers (IPNO).
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Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
e randomisation application logged all the SMS
processed (Table 3). ese included invalid text mes-
sages, duplicated attempts to randomise, non-authorised
requests from users not registered, and successfully pro-
cessed valid randomisation requests. Valid randomisa-
tion and allocations were logged and captured in the
Fig. 1 SMS platform design framework. The data tier stored all the system data, the business logic tier processed all the system transactions,
and the presentation tier was the point of interaction between the user and the system
Fig. 2 Factorial allocation of treatments. Three antibiotic treatment arms (crystalline penicillin and gentamicin, ceftriaxone, and intravenous (IV)
amoxicillin-clavulanic acid) and two supportive care treatment arms (Nasogastric feeds and IV fluids)
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Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
Table 1 SMS formulation syntax of a randomisation request
a The unique patient identier primarily assigned to a patient at the public hospital
Type of message Input parameter formats Example text
A request to randomise a participant in each stratum
at a trial site in a multisite clinical trial Randomise [IPNO] to [study name] [sitename] [stratum name] {Randomise
RL567 to
SEARCH MKSRT
supportive}
RL567 – IPNOa
SEARCH –
Study name
MKSRT – Site
name
Supportive –
stratum
A request to randomise a participant in each site (not
stratified) in a multisite clinical trial Randomise [IPNO] to [Study name] [sitename] {Randomise
KL789 to
SEARCH MMLY}
KL789 – IPNO
SEARCH –
study name
MMLY – site
name
Table 2 Various SMS formulation request scenarios and their respective expected responses
Event scenario Expected response
Non-registered user The number [phone number] does not belong to an active user who is authorised to randomise
study participants at [site name]. Contact [ administrator contact] for more details
Exhausted allocation list Random allocations to the [study name] study is no longer available. Please contact the study co-
ordination centre [Phone number]
Invalid message format Incorrect message format; use: randomise [IPNO] to [studyID] [siteID] or: randomise [IPNO]
to [studyID] [siteID] [phoneNO] without the straight brackets. You may also add your phone number
at the end of the message if using an authorised phone that does not belong to you
An attempt to randomise a participant twice The participant with the [IPNO] is already allocated [allocation] by [username] at [timestamp]
An attempt to deactivate non-existing user Deactivation failed; there is no record with the phone number [phone number] in the list of users
Successful user deactivation The user with the phone number [phone number], is now an inactive user
Successful user registration [Username] phone number [phone number], has been added to the list of users authorised to ran-
domise participants to the [study name] study at the [site name] site
Delete user The phone number [phone number], has been removed from the list of users
An attempt to add user twice [username], phone number [phone number], already exists in the list of users
Successful randomisation Participant [IPNO] has been randomised to [allocation] in the [study name] study. The unique number
for the participant is [participant randomisation ID]. Randomised by [trial staff name] on [timestamp]
Table 3 SMS request categories
No Category Denition
1 Duplicate attempts An SMS request that attempted to randomise a participant who had already been allocated a treatment in any
arm
2 Exhausted sequence An attempt to randomise when an allocation sequence had been exhausted or fully utilised
3 Invalid non-authorised request A non-authorised user attempted to randomise a participant by sending a non-structured SMS
4 Non-authorised valid request A non-authorised user attempted to randomise a participant by sending a correctly structured SMS
5 Valid successful randomisation A randomisation attempt that was processed and a treatment allocation was sent out as a response to the user
6 Unregistered user A user who had not been registered attempts to randomise a participant
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Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
administrative dashboard for review during trial moni-
toring. is log captured allocations for the two clinical
trial arms—antibiotic care and supportive care. Antibi-
otic treatment allocation was the first step of randomisa-
tion consisting of three antibiotic regimens: crystalline
penicillin and gentamicin, ceftriaxone, and intravenous
(IV) amoxicillin-clavulanic acid. A supportive care arm
was allocated as the second randomisation step consist-
ing of two treatments: Nasogastric (NG) feeds and IV flu-
ids (Fig.2).
e administrative dashboard was a central hub for
monitoring all transactions and randomisation logs. It
stored the randomisation sequence, which was uploaded,
during the set up allowed administrators to supervise
trial randomisation, manage users, and track recruit-
ment across different sites and strata. A feature phone
and a mobile application served as randomisation access
points.
e mobile application was developed in Java for
Android, and the web-based platform was developed
using the hypertext preprocessor scripting language
Laravel framework. e platform is integrated with an
SMS Application Programming Interface (API) from a
local premium rate service provider (PRSP). One local
mobile network operator was chosen for piloting due to
cost-related estimations. e source code for the SMS
dashboard and the mobile application of this project is
archived on GitHub [16, 17]. e web-based administra-
tive dashboard is locally hosted on the KEMRI-Wellcome
Trust servers following data management procedures
outlined in the study protocol. At the time of develop-
ment of this manuscript, the mobile application had not
yet been published on the Google Play Store.
Phase 2: Pilot SMS randomisation
Four clinical trial clinicians carried out the SMS ran-
domisation pilot, with two clinicians stationed at each
trial site. All users underwent training on how to use the
SMS randomisation prior to piloting. e SMS platform
was implemented in two modes: through text messaging
on feature phones and smartphones using an Android
mobile application. SMS randomisation was conducted
alongside the traditional method of using envelopes.
Each clinician was provided with a tablet computer with
a subscriber identity module card registered to the study.
e custom Android application was installed on each of
the tablets with each clinician having a separate account
with a designated role to randomise participants. All sys-
tem users were pre-registered in the database.
A study clinician would first screen patients for eligi-
bility and then proceed to randomise them using sealed
envelopes (the primary method) and finally repeat the
process using text messaging. Randomisation requests
were submitted in structured text format, either manually
typed in the phone’s default text messaging application
or formulated automatically by the Android application.
Texts from the Android app included a phone number at
the end while manually typed texts did not. From a design
standpoint, we would not expect substantial latency vari-
ations between the plain text and mobile app requests.
Both requests were processed by the same API algorithm.
e sole difference was in the user interface for initiating
the request: one involved a mobile application, while the
other used plain text sent to a specific number code.
Randomisation marked the final step in recruitment
before treatment was allocated to a participant. Treat-
ment allocation and administration were based on the
envelope concealment method. Patient care was always
the priority, ensuring that the study procedures did not
delay or interfere with treatment. ere was no direct
risk to participants from the procedures of this study. If
technical issues arose, the clinicians were able to call the
user support team at the KEMRI-Wellcome Trust Pro-
gramme for help. Additionally, weekly review meetings
were held to assess progress and address any emerging
challenges.
A post-implementation survey was used to evaluate
user feedback. We built a user feedback questionnaire
into the mobile application, which only became active
after the pilot implementation was completed. Each user
of the randomisation module completed the question-
naire. e survey explored challenges associated with
envelope-based randomization, user preferences for ran-
domization methods (plain text vs. mobile app), under-
standing of text randomization processes, obstacles
encountered during text randomization, time spent on
the process, preferred method (plain text or mobile app),
and suggestions for improving the text randomization
experience.
e study covered the cost of the premium SMS sub-
scription package, ensuring that users did not incur any
additional charges.
Feasibility outcomes
e following parameters were used to measure
feasibility:
– Latency: Average response time (in seconds) for SMS
delivery following each randomisation request.
– Allocation accuracy: Concordance between treat-
ment allocation sequence and the expected randomi-
sation list.
– User feedback: Subjective experience from users
comparing envelope and SMS randomisation
approaches.
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Sample size justication
Pilot studies are not powered like definitive trials [18,
19]. Our sample size was guided by feasibility assessment
needs, rather than a formal power calculation for efficacy
[18, 20]. e initial target sample size for this pilot study
was 200 participants; however, 218 participants were ulti-
mately randomised using the SMS approach. Recruiting
beyond the original target allowed us to gather a richer
dataset for assessing feasibility outcomes, particularly the
latency of the SMS system under varying traffic loads and
across the 3 × 2 factorial design allocation possibilities.
is approach aligns with recommendations to maximise
information gained from pilot studies, even if the sample
size exceeds initial targets [18].
Data analysis
e SMS platform logged data for each SMS request
made, capturing both the initiation time of the request
and the time a response was delivered to the user. is
enabled us to calculate a turnaround time, or SMS
latency, in seconds for each processed message. We then
analysed the data by computing the medians with inter-
quartile ranges (IQRs) for turnaround time in seconds.
To better describe the range of SMS requests made, we
grouped all requests into six distinct categories with
each SMS assigned to a group (Table3). We only com-
puted the SMS latency for valid randomisation requests
(group 5 in Table3). A valid request was defined by the
correct structured syntax with all the input parameters
required for randomisation. We calculated the percent-
age of requests with valid syntax that were successfully
processed and resulted in an allocation treatment being
delivered to the user, along with the corresponding bino-
mial exact confidence interval (CI).
To determine the validity of an (In-Patient Number)
(IPNO), we extracted all IPNOs in each SMS request and
compared them against the IPNOs in the clinical trial
database. We evaluated the accuracy of treatment alloca-
tions by comparing SMS request response for treatment
allocation with the master randomisation list for each
processed message. Survey responses from all the users
were reviewed and summarised.
Results
In the testing and pilot phases of the study, we logged a total
of 580 SMSs, which we categorised as shown in Table4. We
noted various types of SMS requests. For 151 (26%) that fell
under the invalid non-authorised request category, mes-
sages consisted of syntax completely unrelated to randomi-
sation, often missing the keyword randomise. e system
reported 22 (4%) requests attempting to randomise par-
ticipants who were already allocated treatments. One SMS
reported under the exhausted sequence category was a test
case scenario where the allocation sequence was no longer
available for randomisation. Two unregistered users made
attempts to randomise participants, while 402 (69.3%; 95%
CI 65.4 to 73.0%) requests had valid syntaxes that were pro-
cessed, and an allocation treatment was delivered to the
user as a response.
e SMS latency for the valid successful randomisation
processed requests is as shown in Table 5. e median
latency was 22s, with the fastest processed SMS taking just
10s (IQR 29.75s). We observed one delayed response, which
was eventually delivered 35min later. It stands out as an
outlier as the majority of the SMSs were processed in under
100s.
Between February 2022 and May 2022, 218 participants
were successfully randomised in the two participating clini-
cal trial sites using the SMS approach. One hundred sev-
enty-nine participants (82.1%) were randomised to receive
an antibiotic treatment alone, while 39 participants (17.9%)
were randomised to an antibiotic and a supportive care
treatment.
Allocation accuracy was 100% when compared to the
allocation sequence. Four clinicians completed a post-pilot
survey. From the responses, it took a clinician less than 2
min to compose a randomisation text. Two exclusively
used the mobile app for randomisation, while two utilised
both feature phones and the app. Generally, the clinicians
reported that they found SMS randomisation easy to grasp
and use. However, opinions on preference were split; two
clinicians favoured envelopes, while two preferred text
messaging. e Android application was notably preferred
over manual texting for composing the randomisation
texts. A recurring challenge was forgetfulness in using text
randomisation.
Discussion
Our research provides unique insights as, to the best
of our knowledge, it is the first study investigating a
Mobile SMS randomisation approach in a low-income
Table 4 Total SMSes processed during the testing and piloting
phases of the study
Text request category Count Percentage (%)
Duplicate attempts 22 4
Exhausted sequence 1 0.2
Invalid non-authorised request 151 26
Non-authorised valid request 2 0.3
Valid successful randomisation 402 69
Unregistered user 2 0.3
Total 580 100
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Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
setting within a complex randomised controlled clini-
cal trial. Envelope randomisation, a manual and tradi-
tional method, is reliant on the integrity of filling, sealing,
transporting, and storage of envelopes, highlighting the
need for digital alternatives such as SMS. In our pilot
study, we found SMS randomisation to be user-friendly,
efficient, fast, and accurate. It also addressed significant
challenges associated with envelope randomisation, such
as the time-consuming process of preparing envelopes
and uncertainties related to envelopes being unsealed or
damaged. Additionally, it eliminates the needs for paper,
printing, and shipping.
Given the high mobile penetration and widespread
use of SMS messaging [21] with the low cost of SMS
at $0.0078 per unit, the potential of SMS randomisa-
tion is evident. SMS processing through a local network
recorded a turnaround time of 22 s. is highlights the
approach’s practical potential in pragmatic trials, ensur-
ing that there are no delays in service delivery within a
busy public routine care hospital setting during SMS ran-
domisation. e introduction of the mobile application
that automated SMS formulation made randomisation
more efficient, and no internet connectivity was needed.
Despite the predominance of feature phones in the Ken-
yan Market [22], our solution demonstrates versatility,
proving that mobile applications and feature phones can
be seamlessly integrated and used interchangeably for
SMS randomisation. is ensures broad accessibility and
efficiency across different device types.
Digital randomisation techniques
As randomisation is a key determinant of the effective-
ness of a clinical trial, trialists need to embrace improved
and innovative methodologies that include the use of
technology where applicable. Trialists are increasingly
exploring digital options for conducting randomised con-
trolled trials to mitigate challenges affecting recruitment
in clinical trials [23–25]. Digitization stands out in ensur-
ing correct and accurate treatment allocation. is not
only helps in maintaining the integrity of the clinical trial
but also plays a crucial role in minimizing and scrutiniz-
ing potential biases in trial outcomes, thereby enhanc-
ing the credibility of the results. Clinical trial monitoring
becomes more efficient as trial progress can be readily
traced in real-time through a randomisation dashboard
integrated into the trial data collection process. is fea-
ture is particularly beneficial for adaptive clinical trial
designs, where the ability to make data-driven decisions
in real time is paramount [26].
e use of a numeric short code, which can be unin-
tentionally used by unauthorised mobile subscribers, led
to a significant increase in invalid, unauthorised requests,
particularly for plain-text randomisation. Unlike mobile
app randomisation, which is restricted to registered users
and pre-validates SMS values before processing, plain-
text messaging lacks this safeguard, making it a less reli-
able option. Successful use of plain-text messaging relies
heavily on user diligence and adequate training, whereas
the mobile app provides a guided experience that mini-
mises errors. Additionally, messages sent to a number
code cannot be strictly controlled, increasing the risk of
accidental use by unauthorised individuals.
Clinical trials inlow-resource settings
Mobile-based randomisation can solve a number of
clinical trial challenges inherent in low-resource set-
tings such as financial constraints, operational barri-
ers such as remote locations of study sites, and limited
human capital [27]. Setting up clinical trials with com-
plex designs can be prohibitively expensive in such set-
tings [28]. is calls for effective methods of conducting
trials that deliver credible results while minimizing cost.
Our approach, developed using open-source tools, serves
as a testament to the feasibility of digitizing clinical trial
methods in low-resource settings. Representing margin-
alised populations in health research and innovation is
crucial for addressing the significant disease burden in
low-income countries in a fair and equitable manner [27,
29–31]. ere is an urgent need for investment in solu-
tions that will increase the number of clinical trials con-
ducted in low-income countries [32]. As our approach
only targets two components of clinical trials—ran-
domisation and trial monitoring—additional research is
required to pilot other low-cost tools that could improve
the quality of clinical trials in similar contexts.
Limitations andrecommendations
We acknowledge various limitations to our study. e
pilot was done in a restricted context with a limited num-
ber of users and trial sites. Users were clinicians already
Table 5 SMS latency IQR table for valid successful randomisation requests
Latency range Total
SMSes Min 1st Qu Median Mean 3rd Qu Max
Less than 100 s 393 (98%) 10.00 16.00 21.00 31.65 44.00 96.00
All 402 10.00 16.00 22.00 46.05 45.75 2129.00
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Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
involved in the larger randomised controlled trial, which
could have influenced their feedback and experience.
ere may be a learning curve or initial hesitations for
naïve. Clinicians admitting to often forgetting to send the
text request after opening the envelope also highlights
a behavioural aspect that could be addressed in future
implementations to ensure consistent use of the system.
e application logic was informed by a simple randomi-
sation technique and tested in an urban setting in Kenya
setting with local SMS service providers.
is paper does not extend the discussion to imple-
mentation in other countries or in rural Kenya where
network connectivity may be unstable. Nonetheless, our
findings are promising and recommend conducting pilots
in various settings, clinical trial designs, and geographical
locations.
Treatment allocation accuracy depended on the system
design. However, because the pilot study aimed to estimate
expected latency rather than meeting a pre-defined latency
target, no specific feasibility criteria were defined a priori.
Future iterations of the SMS-based system in stud-
ies to assess acceptability, adaptability, integration, and
practicality at scale applying theories of implementation
science could introduce enhancements that optimise reli-
ability and guarantee integrity.
Training recommendations
The success of SMS randomisation heavily relies on training. The train-
ing should equip participants with the necessary skills to effectively use
the system for randomisation and trial monitoring. The training should
cover the following key areas:
• SMS structure: Participants should learn how to construct an SMS
request according to the project’s specific format
• Mobile application usage: Training should focus on navigating
the mobile application and its features
• Randomisation monitor dashboard: Participants should be trained
on how to use the dashboard to monitor the randomisation process
To ensure a smooth learning experience, all apps are designed
with user-friendly interfaces. This will enable new users to quickly
and easily navigate the system
Additional considerations for dissemination purposes:
• Tailored training: The training should be tailored to the specific
needs and technical proficiency of the target audience
• Hands-on training: Practical, hands-on exercises should be incorpo-
rated to reinforce learning
• Training materials: Comprehensive training materials, such as manu-
als, guides, and presentations, should be developed and distributed
• Post-training support: Ongoing support, such as help desks
or online forums, should be provided to address questions and trouble-
shoot issues
By following these guidelines, the training can effectively disseminate
knowledge and skills to the target audience, ensuring the successful
implementation of the SMS randomisation process
Conclusions
e promising results from our pilot indicate that there
is potential for wider implementation in large-scale clini-
cal trials. e observed improvements in efficiency, high
accuracy, and user acceptance point to the viability of
SMS randomisation in clinical research in both low- and
high-resource settings. We used open-source tools for
the development and testing of the SMS platform, ensur-
ing accessibility for further development and improve-
ments. ese lessons from this trial serve as a reference
point for future low-cost technology-driven innovations
to expand the reach and quality of clinical trials globally.
Abbreviations
SMS Short message service
API Application Programming Interface
REST API Representational State Transfer Application Programming Interface
IPNO Inpatient Admission Number
ID Identifier
PHP Hypertext preprocessor scripting language
IV Intravenous
NG Nasogastric
HTTP Hypertext transfer protocol
PRSP Premium rate service provider
IQRs Interquartile ranges
SIM Subscriber identity module
SWAT Study Within A Trial
SQL Structured query language
MySQL My—Structured Query Language (open-source relational data-
base management system)
Acknowledgements
This project would not have been possible without the kind of support and
help from many individuals. We would like to extend our sincere gratitude to
the following: SEARCH Clinical Trial Management Group, Mama Lucy Kibaki
Hospital and Machakos Level 5 Hospital study clinicians, paediatric team, data
clerks, study participants and their caregivers, and the KEMRI – Wellcome Trust
Operations Department.
Authors’ contributions
CO conceived the project, and MC and DK developed the SMS platform. AA
and CO supervised the development of the application. The first draft of the
manuscript was prepared by MC and further developed by AA and CO. CN
and EJ provided clinical trial site supervision. All authors critically reviewed the
paper before submission.
Funding
This project is funded through the MRC/NIHR Trials Methodology Research
Partnership (MR/S014357/1) and a DFID/MRC/NIHR/Wellcome Trust Joint
Global Health Trials Award (MR/R006083/1). This UK-funded award is part of
the EDCTP2 programme supported by the European Union. Funders had no
role in the study design, implementation, analysis, interpretation, or decision
to publish.
Data availability
The data utilised in this work was generated from the SMS randomisation
system. Further access to the data and additional system design materials can
be sought through a request to KEMRI Wellcome Trust Research Programme’s
Data Governance Committee through email: dgc@kemri-wellcome.org.
Declarations
Ethics approval and consent to participate
The Kenya Medical Research Institute (KEMRI) Scientific and Ethics Review Unit
approved the collection of the deidentified data analysed in this study. The study
clinicians consented to participate in the SMS randomisation pilot and to use
their names and email addresses for SMS notification and verification purposes.
Consent for publication
None applicable.
Competing interests
The authors declare that they have no competing interests.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.

Page 9 of 9
Chepkiruietal. Pilot and Feasibility Studies (2025) 11:29
Author details
1 Epidemiology and Demography Department, KEMRI-Wellcome Trust
Research Programme, Nairobi, Kenya. 2 Malaria Branch, KEMRI – Centre
for Global Health Research, Kisumu, Kenya. 3 Clinical Sciences Department, Liv-
erpool School of Tropical Medicine, Liverpool, UK. 4 Department of Paediatrics,
Machakos Level 5 County Referral Hospital, Machakos, Kenya. 5 Department
of Paediatrics, Mama Lucy Kibaki Hospital, Nairobi, Kenya. 6 National Perinatal
Epidemiology Unit, University of Oxford, Oxford, UK. 7 Department of Medi-
cal Statistics, London School of Hygiene and Tropical Medicine, London, UK.
8 Department of Infectious Disease Epidemiology, London School of Hygiene
and Tropical Medicine, London, UK.
Received: 26 February 2024 Accepted: 27 February 2025
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