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McCallum et a I. BMC Public Health 2014, 14:622 

Public Health 


Mobile phones support adherence and retention 
of indigenous participants in a randomised 
controlled trial: strategies and lessons learnt 

Gabrielle B McCallum 1 " Lesley A Versteegh 1 , Peter S Morris 1,2 , Clare C Mckay 1 , Nerida J Jacobsen 3 , Andrew V White 3 , 
Heather A D'Antoine 1 and Anne B Chang 1 ' 4 


Background: Ensuring adherence to treatment and retention is important in clinical trials, particularly in remote 
areas and minority groups. We describe a novel approach to improve adherence, retention and clinical review rates 
of Indigenous children. 

Methods: This descriptive study was nested within a placebo-controlled, randomised trial (RCO on weekly azithromycin 
(or placebo) for 3-weeks. Indigenous children aged <24-months hospitalised with acute bronchiolitis were recruited from 
two tertiary hospitals in northern Australia (Darwin and Townsville). Using mobile phones embedded within a 
culturally-sensitive approach and framework, we report our strategies used and results obtained. Our main outcome 
measure was rates of adherence to medications, retention in the RCT and self-presentation (with child) to clinic for a 
clinical review on day-21. 

Results: Of 301 eligible children, 76 (21%) families declined participation and 39 (13%) did not have access to a mobile 
phone. 186 Indigenous children were randomised and received dose one under supervision in hospital. Subsequently, 
182 (99%) children received dose two (day-7), 169 (93%) dose three (day-14) and 180 (97%) attended their clinical 
review (day-21). A median of 2 calls (IQR 1-3) were needed to verify adherence. Importantly, over 97% of children 
remained in the RCT until their clinical endpoint at day-21. 

Conclusions: In our setting, the use of mobile phones within an Indigenous-appropriate framework has been an 
effective strategy to support a clinical trial involving Australian Indigenous children in urban and remote Australia. 
Further research is required to explore other applications of this approach, including the impact on clinical outcomes. 

Trial registration: ACTRN 126080001 50347 (RCT component). 

Keywords: Mobile phones, SMS, Adherence, Randomised controlled trial, ALRTI, Bronchiolitis, Indigenous 


In the Northern Territory (NT), Indigenous children 
have high hospitalisation rates of bronchiolitis (352 per 
1000) and more severe disease. Most children admitted 
are retrieved from remote communities [1,2], Hospitalised 
episodes of lower respiratory infections are associated with 
later development of chronic lung disease [3,4]. In an 
attempt to improve clinical outcomes, we conducted a 
double blind randomised controlled trial (RCT) (using 

* Correspondence: 

1 CZhi Id Health Division, Menzies School of Health Research, Charles Darwin 

University, Darwin, Northern Territory, Australia 

Full list of author information is available at the end of the article 

(3 BioMed Central 

azithromycin) [5] within an evidence-based framework 
for assessing and prioritising health interventions. RCTs 
are accepted as the highest level of evidence available. 
However, the lack of appropriate RCTs may contribute 
to poor participation, attrition and treatment inequalities 
in minority groups [6]. While some progress has been 
made in reducing health disparities, there is a continued 
need for intervention studies, both prevention and treat- 
ment trials, that focus on minority population(s) [7]. 

There are several possible methods that can be used 
to increase the adherence and reduce attrition (increase 
retention) in RCTs. One such method is the use of mobile 
phones as a means of communication. Mobile phones 

© 2014 McCallum et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative 
Commons Attribution License (http://creativecommons.Org/licenses/by/2.0), which permits unrestricted use, distribution, and 
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain 
Dedication waiver (http://creativecommons.Org/publicdomain/zero/1.0/) applies to the data made available in this article, 
unless otherwise stated. 

McCallum et a I. BMC Public Health 2014, 14:622 

Page 2 of 7 

offer the advantage of real time communication, do not 
require high skills to function, are easily accessible, 
affordable and not restricted to computer or land line 
access [8]. The number of published research using the 
short message service (SMS) component of mobile phones 
to evaluate a range of health conditions has increased. 
However, the conditions studied have commonly focused 
on adult disease surveillance and chronic diseases [9-12]. 
Data on SMS outcomes in paediatric conditions; [13] i.e. 
acute illnesses, Indigenous populations or remote areas 
are limited. 

In this study, we report on a novel approach to 
improve adherence, retention and clinical follow-up 
post-hospitalisation in 186 Australian Indigenous children 
participating in a RCT. 


Study design 

This study is embedded within a double-blinded, placebo- 
controlled, RCT conducted at the Royal Darwin Hospital 
and The Townsville Hospital between June 2010 and 
September 2013. We briefly describe the RCT below as 
the protocol has been published [5]. The RCT examines 
the question: amongst children hospitalised with acute 
bronchiolitis, does azithromycin (compared to placebo) 
given once/week for three doses improve clinical out- 
comes?' For this study, we describe the cohort of children 
enrolled in this RCT, strategies used and results obtained in 
ensuring adherence, retention and presentation to the clinic 
for follow-up. The trial was approved by each institutions 
Human Research Ethics Committee and was registered 
with the Australian and New Zealand Clinical Trials Regis- 
ter: Clinical trials number: ACTRN12608000150347. 

Study population 

Children were eligible if they were Indigenous, aged <24 
months, admitted to hospital with a clinical diagnosis 
of acute bronchiolitis, recruited within 24 hours of ad- 
mission. There was also a requirement for the parent to 
have a mobile phone. 

Recruitment and retention approach 

Research nurses visited the paediatric wards twice daily to 
screen recently admitted children. Only parents whose 
child met eligibility criteria were approached. A summary 
of our frame work is presented in Table 1. Often parents 
had come to hospital in the early hours of the morning, 
were sleep deprived and had not retained information 
hospital staff provided. Therefore, research nurses always 
provided additional education on bronchiolitis using a 
pictorial-based flipchart ( 
Time was spent with parents discussing the treatment and 
management of bronchiolitis and what to expect post 

discharge, regardless of the decision to be involved in 
the RCT. This appeared to enhance relationships and 
trust. Only when parents understood what bronchiolitis 
was, did research nurses proceed with discussion about 
the RCT. A pictorial consent flipchart was used in 
conjunction with a plain language information booklet 
(endorsed by the Menzies Child Health Indigenous 
Reference Group), to assist in the consent process. The 
time from screening to enrolment was recorded. 

Once written informed consent was obtained from the 
parent or guardian, children were randomised to receive 
either azithromycin or placebo. The first dose was directly 
supervised in hospital; the remaining two doses were 
supervised by research nurses (urban-based children) 
or given at home by parents (remote-based children) 
(between days 5-9 and 10-12). The endpoint was a 
clinical review on day-21 (between days 20-30) by research 
nurses (urban-based children) or at the local health clinic 
(remote-based children) to determine presence of persistent 
respiratory symptoms and signs. Remoteness was defined 
as more than 100 km from a tertiary hospital. 

Standardised assessment forms were used to collect 
clinical information from each child. Prior to discharge, 
parents were shown how to constitute the medication 
and were given the remaining medications in a sealed 
plastic bag which included syringes, 10 ml sterile water 
vials and a fridge magnet (with reminders when each 
medication and the clinical review was due). 

We advised parents that we would ring or SMS when 
children were due to receive the medications and attend 
the clinic for their clinical review (remote-based children) 
or visit at home (urban-based children). For remote-based 
children, a phone call was also made to the local health 
clinic explaining the child's involvement in the RCT and 
follow up required as part of routine clinical care post 
hospitalisation. A template was faxed to the health clinic 
and faxed back after the clinical review was completed. 
The number of contacts and reasons why contact could 
not be made were recorded (if applicable). A $20 mobile 
recharge voucher was sent via SMS after the third dose 
(but before clinical review) to thank parents for their 

Other strategies used 

A number of strategies were implemented to help main- 
tain contact with parents throughout the RCT. Firstly, 
research nurses called parents mobile phones prior to 
discharge. This ensured the number was transcribed 
correctly and started mobile phone contact while still 
meeting in person. Secondly, we obtained an additional 
mobile number for occasions when we were unable to 
contact the parent. Thirdly, we identified that parents 
would rarely answer phone calls from a blocked (un- 
known) number. Research nurses therefore called from 

McCallum et a I. BMC Public Health 2014, 14:622 

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Table 1 Framework used in our study 

Pre study discussion • Indigenous Reference Group (IRG) (consultation and endorsement of study) 

• Data Safety Monitoring Board (DSMB) (endorsement of study plan) 
On the ground • Clinical Nurses with broad experience working in 

• Indigenous health 
Research team • Paediatrics 

• Clinical research 

• Remote health settings 
Project specific • Briefings to IRG on study progress. 

• DSMB updates on recruitment and retention. 

• Providing education on bronchiolitis to parents using pictorial flipchart. 

• Research nurses spending time discussing child's treatment and management in hospital and home. 

• Consent process: using a pictorial flipchart in conjunction with a plain language information booklet. 

• Education on how to prepare, when to give medication and attend health clinic for 21 day review. 

• Education to nursing staff on paediatric wards to improve awareness and understanding of bronchiolitis. 
Mobile phone specific • Calling parent in hospital (number transcribed correctly and enabled two way communication). 

• Obtaining additional number (if able). 

• Calling parent from personal/study mobiles. 

• Providing parents with option of calling from free 1800 number. 

their personal mobiles (or a study mobile). Parents also 
had the option to call research nurses on the free 1800 
number if they had any questions or concerns. However, 
we did not receive any call on this number. Parents pre- 
ferred to call the personal mobiles of the research nurses. 

Statistical analysis 

Data were entered on an Access database and analysed 
using Stata version 12 (Stata corp College Station, Texas, 
USA). Data are presented as numbers and percentages, 
median and interquartile range (IQR 25-75% and or 
range). We describe feedback from parents and staff 
experiences in text. 



Of 301 eligible children, 76 (21%) families declined par- 
ticipation and 39 (13%) did not have access to a mobile 
phone. A total of 186 children were enrolled; 161 in 
Darwin and 25 in Townsville. The median time taken to 
enrol participants was 30 minutes (range 20 minutes - 
5 hours). The median age was 5.4 months (IQR 3-9); 
111 (60%) boys, and 75 (40%) girls. Four children were 
withdrawn from receiving further medications (n = 3 
for dose 2 and n = 4 for dose 3) by the paediatric team 
at site hospitals due to other medical reasons. The 
remaining children were followed up until they reached 
their endpoint (day-21 clinical review). More than two 
thirds of the children 144 (70%) lived in remote Indi- 
genous communities. Of the Darwin-based cohort, 139 
(85%) children were from remote-based communities. 

In contrast, only 5 (20%) children enrolled in Townsville 
were remote-based. Figure 1 illustrates approximate loca- 
tions of all communities and distances from site hospitals. 

Medication and clinical review 

All children 186 (100%) received the first dose of medi- 
cation in hospital. A small number of children received 
dose-2 (n = 17 (8%)) and dose-3 (n = 3 (1%)) in hospital. 
For the remainder, research nurses made contact with 
parents on their mobiles when medication(s) and the 
clinic review were due. The adherence, retention and 
follow-up rate for the entire cohort was very high. Over- 
all, 182 (99%) children received dose two (day-7), 169 
(93%) received dose three (day-14) and 180 (97%) children 
attended their day-21 clinical review. Table 2 summarises 
the number of medication doses received, clinic reviews 
attended, missed and the median number of phone calls 
required to contact the carer. 

For dose-2, 62% of parents were able to be contacted 
on the first attempt; this reduced to 39% by dose-3 and 
18% for the clinical review (Figure 2). However, only a 
small number of calls were needed to verify when medi- 
cation^) and the clinical review were completed (median 
2 calls (IQR 1-3)). Reasons for calls not being taken were 
most frequently due to (i) mobile phones being turned off; 
(ii) mobile phones not charged; or (iii) parents not answer- 
ing a call from a blocked (private) number. 


In our setting, it appears that mobile phones, combined 
with a culturally sensitive approach, were a simple and 

McCallum et a I. BMC Public Health 2014, 14:622 

Page 4 of 7 

# Recruiting hospitals • Communities where children came from 

Figure 1 Map of communities. NB: Some communities appear to be located in the ocean, however are Islands north of the mainland. 

effective tool to facilitate adherence in a clinical trial 
To our knowledge, this is the first RCT involving Indigen- 
ous children that has used mobile phones to support 
adherence to research protocols. The success of our 
strategies is documented by a 97% retention rate, the 
highest we have ever achieved in a setting that involved 
children in the community. 

The use of mobile phones in studies is not new. Previous 
research has shown mobile phones can have important 
benefits for clinic attendance, adherence to medications 
and treatment plans [14-17]. However we found only 3 
studies involving children and none were relevant to 
Indigenous Australians or in acute illnesses [13,18,19] 
Two of the 3 studies related to immunisations, [13,18] 
and the third was on reminders for appointments before 
and after cataract surgery in a large Chinese city hospital 
[19]. Two studies reported an improvement in the 
intervention group, compared to controls 43% vs. 39.9% 

[18] and 91% vs. 62% respectively [19]. The third study 
reported similar adherence in both groups using an 
intention to treat analysis 66% vs. 68% [13]. In contrast 
to the above studies, our study is not a RCT on mobile 
phones but a unique report on how we achieved an 
exceptional high retention and follow-up rate in a study 
setting where adherence to medications and follow-up 
has been reported to be generally difficult. While we 
were unable to observe adherence with doses 2 and 3 
for remote-based children (we were reliant on parents 
providing this information), the day-21 follow-up rate 
of >97% at the local health clinic provides evidence of 
the success of our approach. 

Including minorities in RCTs is important in addressing 
health gaps [20]. Adherence has been reported to be 
particularly challenging in those who are socially disad- 
vantaged communities [7]. Improving adherence and 
reducing attrition is important in all clinical trials. 

Table 2 Medication doses and clinic review by site 

Trial procedures 





Number contacts 



Number contacts 

(n = 161) 

N (%) 

median (range)# 

(n = 25) 

N (%) 

median (range) 

Dose 1 

161 (100%) 

0 (0%) 


25 (100%) 

0 (0%) 


Dose 2* 

157 (98%) 

4 (2%) 

1 (1-12) 

25 (100%) 

0 (0%) 


Dose 3* 

147 (91%) 

14 (9%) 

2 (1-13) 

22 (88%) 

3 (12%) 


Clinical review 

156 (97%) 

5 (3%) 


24 (96%) 

1 (4%) 


*3 children withdrawn from dose 2, 4 children withdrawn from dose 3 by the medical team. 
#Combination of phone calls/SMS. 

McCallum et a I. BMC Public Health 2014, 14:622 

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Dose 2 

Dose 3 


6 7 8 9 10 11 12 13 14 15 16 17 

Number of contacts 

Graphs by Visit 

Figure 2 Number of contacts medication dose and clinical follow up. 

Strategies to reduce attrition have the potential to increase 
power and generalisability of results [21]. Our study has 
also shown that adherence to medications in the commu- 
nity setting is feasible, thus the opportunity for community 
based clinical care and follow-up can be highly successful. 
In addition to our mobile phone strategies, appropriate 
measures include: (i) building relationships and trust with 
parents; (ii) using culturally appropriate educational mater- 
ial; and (iii) personal contact with parents. It may also be 
important that all research staff were paediatric-trained 
with experience in working with Indigenous parents and 

Our mobile phone strategy not only included obtaining 
multiple phone numbers but also calling from a mobile 
that displayed a number that could be identified by the 
parent. Over the past 14 years, network coverage in 
remote Australia has substantially improved. A study in 
the NT reported that mobile phones have become an 
essential part of relaying information to family members 
who were travelling or away from home [22]. 

Our strategies and findings have to be interpreted in 
the context of our target population and study settings. 
We recruited only children whose parents had a mobile 
phone as geographical remoteness limited our options to 
ascertain adherence. Although we did not expect the 
high number of mobile phone ownership, we found that 
only a small number of parents (13%) did not have access 
to a mobile phone at time of recruitment. It was not 
feasible for us to request community health clinics to 
supervise medication dosing as most of the children 

come from remote clinics with very high workloads. 
The clinical review was attended by health clinic staff 
as part of best practice guidelines for routine clinical 
care post hospitalisation for a respiratory infection in 
Australia and many affluent countries. 

Families received a $20 mobile recharge voucher after 
the final medication dose, to thank them for their par- 
ticipation. While we provided this incentive, we do not 
feel this was fundamental to the adherence and retention 
of participants in our trial. Importantly, the incentive 
was provided before the day-21 clinical review, where 
the presentation rate was 97%. Previously, incentives in 
clinical trials have only reported small improvements in 
participant retention between 2-13% [21,23]. One RCT 
involved SMS reminders and provided a $20 gift card at 
time of enrolment [24]. The RCT [24] described that gift 
cards were not important to 22% of participants, some- 
what important in 50%, and very important to 28% with 
regard to their participation in the RCT [13]. 

We speculate that building relationships and trust 
were fundamental to our high success of adherence and 
retention in this trial. In general, parents expressed how 
they felt supported in hospital and at home, knowing 
that our staff were there to talk to if they had queries or 
concerns about their child. In our setting, displacement 
to a major teaching hospital from a remote community 
can be distressing for Indigenous people. The approach 
used by our research nurses helped alleviate parents 
anxiety by providing support and understanding of 
bronchiolitis and thus we feel fundamental to them 

McCallum et a I. BMC Public Health 2014, 14:622 

Page 6 of 7 

continuing in the trial until the child's endpoint This 
was part of our culture-appropriate framework (Table 1). 
Our framework is supported by a similar strategies used to 
enhance participation of Maori people in a cardiovascular- 
based RCT in New Zealand. The NZ study outlined the 
importance of involving experienced Maori researchers at 
each time point of the trial, employing experienced Maori 
researchers, who used culturally specific processes for 
participation and retention of Maori participants and 
ongoing contact with Maori researchers and participants 
[24]. Such frameworks are important and highlight the 
effectiveness of strategies that are culturally appropriate, 
thus improving the participation and retention rates in 
minority populations. 

Within our framework, we implemented multiple strat- 
egies to support adherence and retention of participants. 
It is difficult to ascertain the relative contribution to these 
strategies. This study was embedded within an RCT, thus 
is complex with the respect to the possible interaction 
between both a treatment intervention (azithromycin 
or placebo) and enhancing support (implementing cultural 
framework). Future treatment trials should account for 
these factors. One of our study's limitations includes the 
lack of in-depth qualitative data to explore this issue. Also, 
our intervention period is relatively short (3 weeks). 
Whether or not these strategies will also be successful in 
longer term interventions remains unknown. Although 
the data presented are not high-level evidence (i.e. not a 
RCT), we have shown that the use of strategies employed 
here has led to an exceptionally high adherence and reten- 
tion rate. This may have implications for clinical service 
in remote Indigenous settings and may improve health 
outcomes. It should be further studied as provision of 
high quality clinical service and ensuring adherence is a 
challenge in many settings, particularly in remote Indi- 
genous settings. 


Our data have provided important and novel data that the 
use of mobile phones, in conjunction with a culturally 
sensitive approach, is an effective strategy to support clin- 
ical trial protocols in Indigenous children living in urban 
and remote Australia. There is an opportunity to use these 
strategies to support health service delivery in remote 
communities that may improve adherence to medications 
and clinic attendance. Further research is required to ex- 
plore the feasibility in these setting for health outcomes, 
cost effectiveness and long term sustainability using our 
described framework. 


ACTRN: Australian New Zealand Clinical Trials Registry; IQR: Interquartile 
range; NT: Northern territory; RCT: Randomised controlled trial; SMS: Short 
message service. 

Competing interests 

The authors declare that they have no financial competing interests. 
Authors' contributions 

GBM set up and coordinated the study, recruited participants, performed 
the data analysis and drafted the manuscript. LAV, CCM, NJ, AVW recruited 
participants and edited the manuscript. ABC, PSM conceptualised the study, 
interpreted the data and edited the manuscript. HD provided cultural integrity 
support. All authors contributed to the study design and critically reviewed the 
manuscript and approved the final version. 


We are grateful to all the children and families who participated in this 
study, and to the members of the Indigenous Reference Group for their 
advice ( 
committees/lndigenous_Reference_Group/). We thank the medical and 
nursing staff for their support and helping identify children for the study and 
members of the DSMB (Dr Kerry Ann O'Grady, Dr William Frishman, Professor 
Alan Isles, A/Prof Alan Ruben, Ms Linda Ward). We also thank the remote 
health clinics for their support. This study was funded by NHMRC (grant 
number 605809, on-going) and supported by a NHMRC Centre for Research 
Excellence in Lung Health of Aboriginal and Torres Strait Islander Children 
(grant number 1040830). GBM is supported by a NHMRC scholarship (grant 
1055262); AC is funded by a NHMRC practitioner fellowship (grant 545216). 

Author details 

1 CZhi Id Health Division, Menzies School of Health Research, Charles Darwin 
University, Darwin, Northern Territory, Australia, department of Paediatrics, 
Royal Darwin Hospital, Darwin, Northern Territory, Australia, department of 
Paediatrics, The Townsville Hospital, Townsville, Queensland, Australia. 
Queensland Children's Respiratory Centre, Queensland Children's Medical 
Research Institute, Royal Children's Hospital, Brisbane, Queensland, Australia. 

Received: 2 October 2013 Accepted: 12 June 2014 
Published: 18 June 2014 


1. O'Grady KA, Lee KJ, Carlin JB, Torzillo PJ, Chang AB, Mulholland EK, Lambert SB, 
Andrews RM: Increased risk of hospitalization for acute lower respiratory 
tract infection among Australian indigenous infants 5-23 months of age 
following pneumococcal vaccination: a cohort study. Clin Infect Dis 2010, 

2. Bailey EJ, Maclennan C, Morris PS, Kruske SG, Brown N, Chang AB: Risks of 
severity and readmission of indigenous and non-indigenous children 
hospitalised for bronchiolitis. J Paediatr Child Health 2009, 45:593-597. 

3. Galobardes B, McCarron P, Jeffreys M, Vey-Smith G: Medical history of 
respiratory disease in early life relates to morbidity and mortality in 
adulthood. Thorax 2008, 63:423-429. 

4. Tennant PW, Gibson GJ, Pearce MS: Lifecourse predictors of adult 
respiratory function: results from the Newcastle Thousand Families 
Study. Thorax 2008, 63(9):823-830. 

5. Chang AB, Grimwood K, White AV, Maclennan C, Sloots TP, Sive A, 
McCallum GB, Mackay IM, Morris PS: Randomized placebo-controlled trial 
on azithromycin to reduce the morbidity of bronchiolitis in Indigenous 
Australian infants: rationale and protocol. Trials 2011, 12:94. 

6. Burlew K, Larios S, Suarez-Morales L, Holmes B, Venner K, Chavez R: Increasing 
ethnic minority participation in substance abuse clinical trials: lessons 
Learned in the National Institute on Drug Abuse's Clinical Trials Network. 
Cultur Divers Ethnic Minor Psychol 201 1 , 1 7(4):345-356. 

7. Yancey AK, Ortega AN, Kumanyika SK: Effective recruitment and retention 
of minority research participants. Annu Rev Public Health 2006, 27:1-28. 

8. Kaplan WA: Can the ubiquitous power of mobile phones be used to 
improve health outcomes in developing countries? Global Health 2006, 2:9. 

9. Fiordelli M, Diviani N, Schulz PJ: Mapping mHealth research: a decade of 
evolution. J Med Internet Res 2013, 15(5):e95. 

10. Institute E: Barriers and Gaps Affecting Mhealth in Low and Middle Income 
Countries: A Policy White Paper. Washington, D.C: mHealth Alliance; 2010. 

11. Car J, Gurol-Urganci I, de Jongh T, Vodopivec-Jamsek V, Atun R: Mobile 
phone messaging reminders for attendance at healthcare appointments. 
Cochrane Database Syst Rev 201 2, 7:CD007458. 

McCallum et a I. BMC Public Health 2014, 14:622 

Page 7 of 7 

12. Free C, Phillips G, Galli L, Watson L, Felix L, Edwards P, Patel V, Haines A: The 
effectiveness of mobile-health technology-based health behaviour 
change or disease management interventions for health care consumers: 
a systematic review. PLoS medicine 2013, 1 0(1 ):e1 001 362. 

1 3. Ahlers-Schmidt CR, Chesser AK, Nguyen T, Brannon J, Hart TA, Williams KS, 
Wittier RR: Feasibility of a randomized controlled trial to evaluate Text 
Reminders for Immunization Compliance in Kids (Tricks). Vaccine 2012, 

14. Fjeldsoe BS, Marshall AL, Miller YD: Behavior change interventions 
delivered by mobile telephone short-message service. Am J Prev Med 
2009, 36(2):165-173. 

15. Krishna S, Boren SA, Balas EA: Healthcare via cell phones: a systematic 
review, telemedicine journal and e-health. Telemed J E Health 2009, 

16. Wei J, Hollin I, Kachnowski S: A review of the use of mobile phone text 
messaging in clinical and healthy behaviour interventions. J Telemed 
Telecare 2011, 17(1):41-48. 

17. Gold J, Lim MS, Hellard ME, Hocking JS, Keogh L: What's in a message? 
Delivering sexual health promotion to young people in Australia via text 
messaging. BMC Public Health 2010, 10:792. 

18. Stockwell MS, Kharbanda EO, Martinez RA, Vargas CY, Vawdrey DK, Camargo 
S: Effect of a text messaging intervention on influenza vaccination in an 
urban, low-income pediatric and adolescent population: a randomized 
controlled trial. JAMA 2012, 307(1 6):1 702-1 708. 

19. Lin H, Chen W, Luo L, Congdon N, Zhang X, Zhong X, Liu Z, Chen W, Wu C, 
Zheng D, Deng D, Ye S, Lin Z, Zou X, Liu Y: Effectiveness of a short 
message reminder in increasing compliance with pediatric cataract 
treatment: a randomized trial. Ophthalmology 2012, 1 19(12):2463-2470. 

20. Glover MJV, Thomas DP, Brown N, Walker N, Chang AB, Bullen C, Segan C: 
Increasing Indigenous participation in tobacco control randomized 
controlled trials. Global Health Promotion 2013, in press. 

21. Daniels LA, Wilson JL, Mallan KM, Mihrshahi S, Perry R, Nicholson JM, 
Magarey A: Recruiting and engaging new mothers in nutrition research 
studies: lessons from the Australian NOURISH randomised controlled 
trial. Int J Behav Nutr Phys Act 201 2, 9:1 29. 

22. Taylor A: Information communication technologies and new indigenous 
mobilities? Insights from remote Northern Territory Communities. J Rural 
Community Dev 2012, 7(1):59. 

23. Booker CL, Harding S, Benzeval M: A systematic review of the effect of 
retention methods in population-based cohort studies. BMC Public Health 
2011, 11:249. 

24. Gulsvik A, Refvem OK: A scoring system on respiratory symptoms. 

Eur Respir J 1 988, 1 :428-432. 

doi:1 0.1 186/1471-2458-14-622 

Cite this article as: McCallum et a I.: Mobile phones support adherence 
and retention of indigenous participants in a randomised controlled 
trial: strategies and lessons learnt. BMC Public Health 2014 14:622. 

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