Table 7.

The characteristics of mixed-methods research in mHealth-based diabetes management studies examined in this review (part 2).

Author, year	Legitimation methods described	Sources of qualitative data	Sources of quantitative data	Limitations described
Allen et al, 2009 [33]	Inside-outside legitimation	A 1-hour, structured, focus group interview (n=7) following the completion of the quantitative phase. Field notes were also taken on key discussion points and observations (eg, body language and group mood).	Descriptive measures of the sample (n=9). Wearable Continuous Glucose Monitoring System, activity monitor data, and activity counts reviewed for each participant.	Small sample size and lack of control group setting in quantitative phase were reported.
Baron et al, 2015 [34]	Inside-outside legitimation	Interviews, meetings, field notes, and communications between team members.	A 9-month randomized controlled trial (n=81) to assess intervention delivery and fidelity (patients and nurses).	A possible sample selection bias was indicated.
Baron et al, 2016 [35]	Inside-outside legitimation and conversion legitimation (quantizing the qualitative data)	Semistructured interviews (n=26) on perceived effects of mobile telehealth system on diabetes self-management.	A randomized controlled trial (n=81) with intervention and control groups was conducted. Self-report measures of self-efficacy, illness beliefs, and self-care were taken at baseline and 3- and 9-month points.	Sample size was indicated as insufficient to make generalizations.
Burner et al, 2013 [36]	Inside-outside legitimation	Two focus groups of 90-minute duration, one in English, one in Spanish (n=8), were conducted with a structured guide.	A 1-month bilingual diabetes SMS text messaging intervention (n=23). Quantitative data included demographic, clinical, and biometric data of patients, and measures of health behaviors, knowledge, and beliefs were taken.	Small sample size was indicated as a limitation to the generalizability of the results.
Carroll et al, 2007 [37]	Weakness minimization legitimation: large focus groups to support small-scale usability test	A series of focus groups (10; n=59) was conducted before testing a prototype cell phone with a glucose monitoring system.	A pilot usability test to evaluate satisfaction with the new system (n=10). A 15-item questionnaire is used.	Sample size and sample selection, intervention duration, and incentives to the participants were seen as barriers to generalizability of findings.
Franklin et al, 2008 [38]	Inside-outside legitimation and conversion legitimation	Content analysis of text messages and messaging patterns of a 12-month Sweet Talk intervention period.	A 12-month 3-armed randomized controlled trial of a text messaging support system, Sweet Talk (n=64), was conducted. Observational data on messaging patterns were triangulated with patient clinical and demographic data. Post hoc analyses combining qualitative data and demographic variables were made.	Small sample size was indicated as a limitation to generalizability of the results.
Froisland et al, 2012 [39]	Inside-outside legitimation	Semistructured in-depth interviews lasting between 45 and 90 minutes (n=12) were conducted at the end of the quantitative phase.	A pilot test of 2 mobile apps (n=12), after a 3-month trial.	Possible sampling bias, small sample size, and short intervention period were indicated.
Georgsson and Staggers, 2016 [40]	Inside-outside legitimation, conversion legitimation	Think aloud protocol and open-ended interviews (15-20 minutes) were conducted (n=20).	First, a brief demographic questionnaire, and, at the end of the intervention, a posttest questionnaire measuring the usability of an interactive SMSa- text messaging system for a randomly selected sample of patients with diabetes (n=10) were conducted.	Using a convenient sample frame and the novelty of the system to patients were indicated as a limitation to the generalizability of the findings.
Grindrod et al, 2014 [41]	Outside legitimation, sequential legitimation, sample integration legitimation	A 10-minute group discussion of what medication management meant before each usability evaluation and 30-minute focus group discussion after each session (n=35).	A 2-hour usability testing (n=35) of different mobile apps using a 10-item system usability scale and a visual analog scale was used.	Short intervention period was indicated as a limitation of the study.
Jones et al, 2015 [42]	Inside legitimation	Four focus groups consisting of 2-5 participants (n=11 in total) were conducted, maximum duration of 60 minutes. Individual interviews (n=15) ranged from 25-45 minutes.	A cross-sectional study (n=26) was conducted with eligible group of patients. The questionnaire included measures for personal and family health history and technology feasibility and acceptability.	The purposive sampling and small sample size were seen as barriers to the generalizability of the results.
Nundy et al, 2014 [43]	Inside-outside legitimation	Approximately 1-hour, semistructured, in-depth interviews (n=14) based on topic guides and open-ended questions after the intervention.	A longitudinal observational cohort study (n=74) was conducted and data were collected at baseline, 3 months (mid-intervention), and 6 months (end of intervention). Diabetes self-care, medication adherence, self-efficacy, health beliefs, and social support measures were used.	The limitations were described as the lack of control group measure and sole use of SMS text messaging intervention, which may create a causality problem. Sample size was small to make proper generalizations.
Osborn and Mulvaney, 2013 [44]	Inside-outside legitimation	Motivational interviewing, face-to-face interviews (n=20) before and after trial, at baseline, and after week 3.	Secondary research: previous descriptive data on target population obtained, and self-administered daily text messages and interactive voice response calls are collected for analysis (n=20).	Sampling size was indicated as small to generalize results.
Verwey et al, 2016 [45]	Inside and outside legitimation, conversion legitimation, sample integration	30-Minute semistructured telephone interviews with the nurses about the receipt of intervention and the evaluation forms regarding consultations were used.	A longitudinal 3-armed cluster randomized controlled trial in a total of 24 family practice locations; evaluation questionnaire after intervention with practice nurses (n=20) and patients (n=131; 71 with type 2 diabetes and 42 with chronic obstructive pulmonary disease).	A possible sample bias was indicated as a limitation of the study.
van der Weegen et al, 2014 [46]	Multiple legitimation: weakness minimization, conversion legitimation, inside-outside legitimation	Heuristic evaluation with 6 experts, thinking aloud procedure and video recordings of 5 patients at two different stages, a series of interviews with patients in the pilot test.	A usability test with 5 patients, a pilot test in real-life settings with 20 patients, and a poststudy system usability test were conducted.	The small sample size was indicated as a limitation to the generalizability of the findings.

^aSMS: short message service.