Mohan 2014.

Study characteristics
Methods	Study design: RCT, 2 arms Geographic location: Tennessee, USA Ethical approval: yes Recruitment setting: safety net clinic, Nashville Method of recruitment: research assistants screened patient charts and received referrals from clinic staff to identify patients with reported diabetes; patients were directly approached by research assistants in the clinic waiting room and other clinic areas. Length of follow‐up: 1 week after intervention Dropouts: 2 in the intervention group were lost to follow‐up, 1 in the control group were lost to follow‐up A priori calculation of effect size/power?: not reported
Participants	Description: Latinos with diabetes prescribed for at least 1 chronic medication Health topic Diabetes Inclusion criteria ≥ 18 years, diagnosis of diabetes recorded in the medical chart, prescribed for at least 1 chronic medication Exclusion criteria Unavailable list of their medications, corrected visual acuity > 20/50 using a Rosenbaum Pocket Screener, hearing deficit, dementia, psychosis, disorientation, belonging to a special human subjects population (e.g. pregnant or prisoner), being unable to communicate in English or Spanish, without a regular phone number Intervention group PictureRx illustrated medication list (103 randomised and 99 analysed) Control group Handwritten list of medications, but no illustrations (105 randomised and 101 analysed) Note: 4 participants were subsequently excluded from each arm for not meeting eligibility criteria. PROGRESS‐Plus Place of residence: urban, USA Race/ethnicity: Latinos Gender: Intervention: 61.6% female Control: 77.2% female Education (years), mean: 8; 29.0% had at least high school education Age (years), mean: 50 Health literacy (baseline) Assessment tool, range, score: Brief Health Literacy Screen (BHLS), validated in Englisch and Spanish, 3 to 15, higher score is better Intervention group, mean (SD): 10.5 (3.0) Control group, mean (SD): 10.4 (3.3) 59% had limited health literacy
Interventions	Intervention: PictureRx illustrated medication list Theoretical framework: not reported Description: the participant's prescribed medication regimen was entered into a secure website by a research assistant to prepare and print a colour PictureRx illustrated medication schedule. It showed the full medication regimen, dosing of medication and included a picture of each medication to show its purpose. Medication instructions were printed in plain language (English and Spanish). The research assistant explained the PictureRx to the participant and showed a 2‐minute video about it. Patients received a 1‐page sheet with tips on how to use the PictureRx. Intervention provider: research assistant Delivery method/mode: written information, face‐to‐face instruction, 2‐minute instruction video Language of delivery: language concordant (bilingual) Format: standard Setting/location: safety net clinic Consumer involvement: linguistically adapted through involvement of members from the community of interest Comparator Type: no health literacy intervention Description: usual care; the treating provider reviewed medication instructions with the patient and the patient received a handwritten list of medications in their preferred language, with instructions for use and the drug indications, but no illustrations.
Outcomes	Outcomes assessed in the study: medication understanding, medication adherence Outcomes considered in this review Health literacy Understand (medication understanding) Health behaviour (medication adherence) Methods of assessing outcomes Baseline questionnaire after enrolment in the study administered by research assistant, telephone administered follow‐up interview (also by research assistant) Medication understanding: Medication Understanding Questionnaire (MUQ), 0 to 100 (representing percentage correct), higher score is better Translation procedure: "MUQ was translated, checked for accuracy, and pilot‐tested among a small population of Spanish‐speaking patients." (Mohan 2014, p. e550) Reliability/validity: validation within study sample unclear Medication adherence: 8‐item sub‐scale of the Spanish translation of Adherence to Refills and Medications Scale (ARMS), self‐report measure that assesses patients' self‐reported adherence under various circumstances (sub‐scale is opposed to medication refills), 8 (most adherent) to 32 (least adherent), lower score is better Translation procedure: translated Spanish version Reliability/validity: validated Spanish version Language of assessment: Spanish Timing of outcome assessment: short‐term (at 1‐week follow‐up)
Health literacy	Definition: "(…) evidence suggests that health literacy – or the constellation of skills needed to effectively function in the health care environment – plays an important role." (Mohan 2012, p. 2) Timing of assessment: baseline Health literacy components addressed by the intervention Steps of information processing Understand Apply Health domain: health care
Notes	Trial ID: not reported Funding: funding was provided by Small Business Innovation Research award (no. R43 MD004048) (Riley/Boyington), from the HHS National Institute on Minority Health and Health Disparities (NIH) of the National Institutes of Health.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The randomization codes were prepared in advance using a computer random number generator, in permuted blocks of varying size, and sealed individually in opaque envelopes to maintain concealment of treatment allocation." Participants in the intervention arm were more likely to be male (38% vs 23%; P = 0.017) and more likely to be white (98% vs 92%; P = 0.05). However, the type of randomisation indicates that imbalances occurred by chance.
Allocation concealment (selection bias)	Low risk	Allocation was concealed, indicating a low risk of bias.
Blinding of participants and personnel (performance bias) All outcomes	High risk	"Research staff and patients were not blinded. Investigators and the biostatistician were blinded." Personnel and participants were not blinded to group allocation and medication adherence was measured subjectively.
Blinding of outcome assessment (detection bias) subjective outcome measures	High risk	"Research staff and patients were not blinded. Investigators and the biostatistician were blinded." Outcome assessors were not blinded and medication adherence was measured via self‐report, indicating a high risk of bias.
Blinding of outcome assessment (detection bias) objective outcome measures	Low risk	No blinding of participants and personnel but medication understanding was objectively measured and not subject to interpretation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	"208 patients were randomized, 105 to usual care and 103 to the intervention. Upon further assessment, 4 patients were subsequently excluded from each arm for not meeting eligibility criteria, leaving 101 patients in the usual care arm and 99 in the intervention arm. Of those 200 patients, 197 (98.5%) completed the follow‐up outcome assessment, including the medication understanding measure." "The primary analysis was an intention‐to‐treat comparison of medication understanding among patients randomized to receive the intervention versus patients randomized to usual care alone." Attrition rates are low and numbers and reasons for dropouts are reported in figure 2. An intention‐to‐treat‐analysis was performed. Therefore, the risk of attrition bias is low.
Selective reporting (reporting bias)	Low risk	Both outcomes reported in the methods section are reported in the results of the paper.