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Mobile health technologies have the potential to improve the reach and delivery of interventions for promoting long-term secondary prevention of coronary heart disease.
This study aims to determine the effectiveness of an SMS text messaging intervention (Text4HeartII) for improving adherence to medication and lifestyle changes over and above usual care in people with coronary heart disease at 24 and 52 weeks.
A two-arm, parallel, randomized controlled trial was conducted in New Zealand. Participants with a recent acute coronary syndrome were randomized to receive usual cardiac services alone (control, n=153) or a 24-week SMS text message program for supporting self-management plus usual cardiac services (n=153). The primary outcome was adherence to medication at 24 weeks, defined as a medication possession ratio of 80% or more for aspirin, statin, and antihypertensive therapy. Secondary outcomes included medication possession ratio at 52 weeks, self-reported medication adherence, adherence to healthy lifestyle behaviors, and health-related quality of life at 24 and 52 weeks.
Participants were predominantly male (113/306, 80.3%) and European New Zealanders (210/306, 68.6%), with a mean age of 61 years (SD 11 years). Groups were comparable at baseline. National hospitalization and pharmacy dispensing records
were available for all participants; 92% (282/306, 92.1%) of participants completed a 24-week questionnaire and 95.1% (291/306) of participants completed a 52-week questionnaire. Adherence with 3 medication classes were lower in the intervention group than in the control group (87/153, 56.8% vs 105/153, 68.6%, odds ratio 0.60, 95% CI 0.38-0.96;
Text4HeartII did not improve dispensed medication or adherence to a favorable lifestyle over and above usual care. This finding contrasts with previous studies and highlights that the benefits of text interventions may depend on the context in which they are used.
Australian New Zealand Clinical Trials Registry ACTRN12616000422426; http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=370398.
RR2-10.1186/s13063-018-2468-z
Coronary heart disease (CHD) is a leading cause of premature death and disability worldwide [
Despite its benefits, participation in CR has been shown to be inadequate in all countries in which it has been measured [
SMS text messaging is the most widely used mobile phone intervention [
To address these limitations, we conducted the Text4HeartII trial across 2 district health boards in Auckland, New Zealand. This trial extended our previous Text4Heart randomized controlled pilot trial (n=123) [
This study aimed to determine the effectiveness of the Text4HeartII self-management program for improving adherence to medication and lifestyle changes in addition to usual care in people with an acute coronary syndrome (ACS) at 24 and 52 weeks.
A two-arm, parallel RCT was conducted in 2 large metropolitan hospitals in Auckland, New Zealand between July 2016 and November 2019. The study was approved by the New Zealand Health and Disability Ethics Committee (15/NTA/205), and the protocol was registered and published before the conclusion of recruitment (Australian New Zealand Clinical Trials Registry, ID: ACTRN12616000422426. Registered, April 1, 2016). The trial was developed and reported in accordance with the CONSORT (Consolidated Standards of Reporting Trials) statement (
Eligible participants were adults with an ACS (including those who had undergone a percutaneous coronary revascularization procedure), clinically stable, able to read English, and able to provide informed consent. Participants were excluded if they had untreated ventricular tachycardia, severe heart failure, life-threatening coexisting disease with life expectancy of less than 1 year, and significant exercise limitations other than cardiovascular disease. Given the high level of mobile phone penetration (there were 6.5 million mobile connections in New Zealand in 2020; population 5.0 million people), mobile phone ownership was not considered in the eligibility criteria [
Research nurses recruited participants from 2 metropolitan hospitals in the Auckland region of New Zealand (Auckland City and North Shore Hospitals) before discharge from the hospital following an ACS or post discharge (within 6 weeks) via telephone. Potential participants were contacted in person to determine their interest in the study. Nurses undertook screening to determine their eligibility. Those who met the eligibility criteria were provided with a participant information sheet and consent form. For this trial, informed consent was obtained verbally or in person depending on when the participant agreed to participate. Interested participants contacted the research nurse to schedule a time for baseline assessments.
The trial was nested within the existing Australian and New Zealand Acute Coronary Syndrome-Quality Improvement (ANZACS-QI) program, which allowed routinely collected data to be accessed for baseline and follow-up assessments. ANZACS-QI [
A total sample of 330 participants (165 per group) was estimated to provide 80% power at the 5% level of significance (two-sided) to detect an absolute between-group difference of 15% in the proportions of participants adherent to medication at the end of the 24-week intervention (assuming a control rate of 30%). The conservative control rate was based on self-reported medication data from our original Text4Heart study and on previous New Zealand research [
Upon submission of baseline data, eligible participants were randomly allocated in a 1:1 ratio to the intervention or control groups using block randomization with variable block sizes of 2 or 4, stratified by hospital. The randomization sequence was generated by a biostatistician (YJ). Study investigators (but not participants) were blinded to the intervention allocation during the trial. Primary outcome data (prescribed medication) were obtained via the Ministry of Health National Data Linkage, thereby mitigating any bias associated with self-reported outcome assessments.
All participants received usual medical management and were offered center-based CR as per guidelines. CR offered at the participating hospital sites consisted of a 1-hour outpatient education program per week for 6 weeks at a hospital or community center covering a range of topics, such as cardiovascular risk factors, lifestyle changes, and psychosocial support. Patients were also encouraged to attend a 16-session supervised exercise program at the participating hospital or outpatient center. Participants could also participate in usual care CR from the point of discharge to 24 weeks after their cardiac event. In addition to usual care, the intervention group received a 24-week program of automated daily SMS text messages commencing within a week of the baseline assessment. All participants were telephoned at 24 and 52 weeks post randomization to obtain follow-up self-reported outcome data.
Text4HeartII comprised a personalized, automated program of self-management that was delivered via SMS text messages over 24 weeks (full details are provided in the study protocol) [
Participants received a minimum of 1 core heart message per day for 24 weeks, with an additional 35 messages sent over the first 12 weeks; all messages were sent from a centralized server. Messages were sent at times to suit the participants and were personalized with the participant’s name. Messages were predominantly unidirectional, but participants were able to text the research team to share their progress if they wanted (eg, goals achieved). Brief training was offered to all participants at enrollment on how to read a text message and how to delete or save messages. No changes were made to the intervention content or delivery during the study period. Examples of the SMS text messages are provided in
T4H: Know your numbers – when is the last time you’ve had your cholesterol or blood pressure checked? Ask next time you see your GP.
T4H: High cholesterol or high blood pressure is not good for your heart condition. Your medications will help improve these.
T4H: Think about your future health. How do you want to feel in 6 months? Try setting small goals with your GP or support person to reach that.
T4H: It can be scary to think about the chance of having another heart problem. Taking your pills and changing your lifestyle can lower the risk.
T4H: It’s important to take your medications regularly. To help remember make this part of your daily routine, such as after brushing your teeth.
T4H: Changing it up can improve your fitness. Do long slow walks, then head for some hills, then hit the track for speed. Start slow & build.
T4H: Sometimes, it is hard to exercise when it is raining, try an indoor activity or grab an umbrella and wrap up.
T4H: Be wary of low-fat food. Not all are good for you, some are still high in sugar. Read your food labels and compare using the 100g column.
T4H: To increase your servings of fruit & veg, add a can of tomatoes to your dish or pour frozen veggies into stews/soups/risottos.
T4H: Draw a habit map. When I smoke at work its because..., when I smoke at home its because..., think of the reasons, fix the causes!
T4H: Find yourself a quit buddy who you can call or txt if you get down. You can make each other feel better with encouragement & share tips.
T4H: If you feel discomfort after your heart event, such as feeling angry, sad or withdrawn, consider talking to a health professional.
T4H: If you feel stressed, close your eyes and imagine a scene where you feel calm. It might be a tropical beach, a forest, or a favorite spot.
All outcomes were assessed at 24 and 52 weeks post randomization. The primary outcome was patient adherence to prescribed medication at 24 weeks, defined as an MPR of 80% or more for 3 medication classes, namely, antiplatelet agent (aspirin), statin, and antihypertensive therapy (angiotensin-converting enzyme inhibitor [ACEI] or angiotensin receptor blocker [ARB] and/or a β-blocker), consistent with the guideline-recommended therapy [
The MPR for each class of medication (aspirin, statins, ACEI/ARB, and/or β-blockers) was also assessed at 52 weeks using the same approach as used at 24 weeks. Blood pressure, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol data were obtained from the ANZACS-QI registry; these were based on routinely collected data.
Self-reported outcomes were measured by a trained research assistant during a telephone call at 24 and 52 weeks. Self-reported medication adherence was assessed using the Morisky 8-item Medication Adherence Scale [
Smoking status was measured using 3 items from a validated smoking history questionnaire [
Physical activity level was assessed using items adapted from the New Zealand Health Survey to assess the daily time spent in light-, moderate-, and vigorous-intensity activities [
Alcohol consumption was measured using the alcohol use disorders identification test of alcohol consumption questions [
Fruit and vegetable intake were assessed by 2 New Zealand–specific questions used in the 2006/2007 New Zealand Health Survey (N=12,488, including adults with CHD) [
Participants received a score on a 4-point scale for each of the key risk factors, with 1 point each assigned for being a current nonsmoker, meeting physical activity guidelines to achieve some health benefits (≥150 min of MVPA per week), consuming 14 or fewer standard alcoholic drinks per week, and consuming at least five servings of fruits and vegetables per typical day. A total score of 3 or 4 was considered adherence to healthy behaviors. No changes were made to study the outcomes once the trial commenced.
Health-related quality of life was assessed using the European Quality of Life 5 dimensions [
During the 24-week follow-up telephone call, participants were asked to respond to specific questions about Text4HeartII. Questions were based on those used in the Text4Heart pilot trial and included their perceptions of the program, technical issues experienced, and whether they changed behaviors. Participants who responded that they had changed behaviors were asked to indicate which specific behaviors they had changed.
All participants were telephoned at 24 and 52 weeks by a trained researcher to determine whether the participants had experienced any serious adverse events during the course of the study. Serious adverse events were reported to a registered medical physician to determine whether they were associated with the study treatment and to determine the course of action (if needed).
Trial data collected from all eligible participants were linked to the national database using encrypted NHIs for the purpose of analysis. Treatment evaluations were performed according to the intention-to-treat principle. There were no missing data on the MPR (primary outcome), which were obtained via national data linkage. Continuous variables were summarized as mean and SD, and categorical variables were summarized as frequency and percentage. Logistic regression was conducted to evaluate the main treatment effects on medication adherence at 24 and 52 weeks, adjusting for hospital (stratification factor). Odds ratios (ORs) and associated 95% CI were reported at each visit. The same regression models were used for adherence to healthy behaviors at 24 and 52 weeks. The analysis of covariance regression model was used to evaluate the treatment effect on continuous secondary outcomes, adjusting for the baseline value and hospital. Model-adjusted mean differences were reported with 95% CI. Statistical analysis was performed using SAS version 9.4 (SAS Institute Inc.). All statistical tests were two-sided at a 5% significance level.
Participant flow.
The participants were predominantly male (113/306, 80.3%) and New Zealand European (210/306, 68.6%), with a mean age of 61 years (SD 11) years. The groups were comparable at baseline (
Baseline demographic, clinical, and behavioral data of all randomized participants (N=306).
Characteristic | Control (n=153) | Intervention (n=153) | ||||||
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Age (years), mean (SD) | 61 (11) | 61 (11) | |||||
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Male, n (%) | 113 (73.8) | 123 (80.4) | |||||
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New Zealand European | 102 (66.7) | 108 (70.6) | ||||
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Maori | 11 (7.2) | 12 (7.8) | ||||
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Pacific | 8 (5.2) | 5 (3.3) | ||||
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Asian | 13 (8.5) | 11 (7.2) | ||||
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Other | 19 (12.4) | 17 (11.1) | ||||
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Self-employed | 33 (21.6) | 29 (18.9) | ||||
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Full-time employment | 55 (35.9) | 60 (39.2) | ||||
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Part-time employment | 9 (5.9) | 5 (3.3) | ||||
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Retired | 46 (30.1) | 46 (30.1) | ||||
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Other (full-time homemaker, student, unemployed, or beneficiary) | 10 (6.5) | 13 (8.5) | ||||
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Married or living with partner | 124 (81) | 106 (69.3) | ||||
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Separated, divorced, or widowed | 24 (15.7) | 33 (21.6) | ||||
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Never married | 5 (3.3) | 14 (9.1) | ||||
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BMI (kg/m2) | 29.21 (5.6) | 29.74 (5.9) | |||||
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Total | 4.74 (1.2) | 5.07 (1.3) | ||||
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HDL-Ca | 1.19 (0.3) | 1.20 (0.5) | ||||
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LDL-Cb | 2.63 (1.1) | 2.99 (1.2) | ||||
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Systolic blood pressure (mm Hg) | 129 (16) | 129 (18) | |||||
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Diastolic blood pressure (mm Hg) | 74 (10) | 75 (13) | |||||
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Meeting MVPAc guidelines, n (%) | 70 (46) | 75 (49) | |||||
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Not smoking, n (%) | 140 (91) | 138 (90) | |||||
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Number of drinks ≤14 per week, n (%) | 132 (86) | 133 (87) | |||||
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Fruit and vegetables serves ≥5 week, n (%) | 84 (55) | 71 (46) | |||||
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HRQoLd—health state score, mean (SD) | 64 (22) | 62 (22) |
aHDL-C: high-density lipoprotein cholesterol.
bLDL-C: low-density lipoprotein cholesterol.
cMVPA: moderate-to-vigorous physical activity.
dHRQoL: health-related quality of life.
Adherence to the 3 medication classes (aspirin, statin, and any antihypertensive) in the intervention group was worse than that in the control group at 24 weeks (OR 0.60, 95% CI 0.38-0.96;
The effect of intervention on medication adherence at 24- and 52-week follow-up (full cohort).
Adherence to | 24 weeks (N=306) | 52 weeks (N=306) | |||||||
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Control (n=153), n (%) | Intervention (n=153), n (%) | Adjusted ORa (95% CI) | Control (n=153), n (%) | Intervention (n=153), n (%) | Adjusted OR (95% CI) | |||
All 3 drug classes (aspirin, statin, and any BPb-lowering drug): primary outcome | 105 (68.6) | 87 (56.8) | 0.60 (0.38-0.96) | .03 | 104 (67.9) | 83 (54.2) | 0.56 (0.35-0.89) | .01 | |
All 4 drug classes (aspirin, statin, β-blocker, and ACEIc/ARBd) | 71 (46.4) | 56 (36.6) | 0.67 (0.42-1.05) | .08 | 70 (45.7) | 56 (36.6) | 0.68 (0.43-1.08) | .11 | |
Statin | 131 (85.6) | 122 (79.7) | 0.66 (0.36-1.20) | .18 | 129 (84.3) | 119 (77.7) | 0.65 (0.36-1.16) | .15 | |
Aspirin | 124 (81.0) | 122 (79.7) | 0.92 (0.52-1.62) | .78 | 123 (80.3) | 119 (77.7) | 0.85 (0.49-1.49) | .58 | |
β-Blocker | 103 (67.3) | 100 (65.3) | 0.92 (0-1.48) | .73 | 102 (66.6) | 89 (58.1) | 0.69 (0.43-1.11) | .13 | |
ACEI/ARB | 119 (77.7) | 97 (63.4) | 0.49 (0.30-0.82) | .006 | 123 (80.3) | 97 (63.4) | 0.42 (0.25-0.71) | .001 | |
BP-lowering drugs (ACEI/ARB and/or β-blocker) | 137 (89.5) | 122 (79.7) | 0.46 (0.24-0.88) | .02 | 139 (90.8) | 113 (73.8) | 0.28 (0.15-0.55) | <.001 |
aOR: odds ratio; odds ratio compares the estimated odds between intervention and control groups.
bBP: blood pressure.
cACEI: angiotensin-converting enzyme inhibitor.
dARB: angiotensin II receptor blockers.
Similar results were found for medication adherence at 52 weeks (secondary outcome), with higher adherence to 3 medication classes in the control group than in the intervention group (OR 0.56, 95% CI 0.35-0.89;
The composite measure of adherence with lifestyle behaviors was similar for both the intervention and control groups at 24 weeks (OR 1.11, 95% CI 0.65-1.90;
The effect of intervention on adherence to lifestyle risk factors (secondary outcomes) at 24- and 52-week follow-up.
Adherence to | 24 weeks (n=282) | 52 weeks (n=291) | |||||||||||
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Control | Intervention | Adjusted ORa (95% CI) | Control | Intervention | Adjusted OR (95% CI) | |||||||
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Sample size, n | Participant, n (%) | Sample size, n | Participant, n (%) |
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Sample size, n | Participant, n (%) | Sample size, n | Participant, n (%) |
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Lifestyle behaviors (composite) | 141 | 94 (66.7) | 141 | 100 (70.9) | 1.11 (0.65-1.90) | .70 | 146 | 95 (65.1) | 145 | 96 (66.2) | 0.97 (0.58-1.62) | .90 | |
Physical activity guideline | 141 | 68 (48.3) | 140 | 79 (56.4) | 1.43 (0.87-2.35) | .16 | 146 | 80 (54.8) | 145 | 88 (60.7) | 1.25 (0.75-2.09) | .39 | |
Smoking cessation | 141 | 132 (93.6) | 141 | 138 (97.8) | 5.75 (1.08 -30.61) | .04 | 146 | 139 (95.2) | 145 | 139 (95.7) | 1.38 (0.39-4.88) | .62 | |
Low alcohol consumption | 140 | 132 (94.3) | 141 | 130 (92.2) | 0.68 (0.24-1.87) | .45 | 145 | 141 (97.2) | 145 | 136 (93.8) | 0.33 (0.09-1.28) | .11 | |
Fruit and vegetable guidelines | 141 | 67 (47.5) | 141 | 64 (45.4) | 1.01 (0.61-1.66) | .98 | 144 | 64 (44.4) | 145 | 54 (37.2) | 0.81 (0.49-1.33) | .40 |
aOR: odds ratio; odds ratio compares the estimated odds between intervention and control groups.
Participants’ responses on Text4HeartII (n=139).
Question | Sample size, n | Participants, n (%) | ||||||
“Did you have any technical problems with the program?” | 139 | 136 (97.8) | ||||||
“Would you recommend the program to other people who have had a heart event?” | 138 | 134 (97.1) | ||||||
“Did taking part in this program help you learn about heart condition?” | 138 | 86 (62.3) | ||||||
“Did taking part in this program help you in the recovery from your heart condition?” | 138 | 114 (82.6) | ||||||
“ |
138 | 78 (56.5) | ||||||
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“ |
78 |
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“I became physically active” |
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41 (52.5) | ||||
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“I ate more fruit and vegetables” |
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34 (43.6) | ||||
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“I ate less saturated fat” |
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21 (26.9) | ||||
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“I took my medication regularly” |
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19 (24.3) | ||||
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“I drank less alcohol” |
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10 (12.8) | ||||
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“I ate less salt” |
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10 (12.8) | ||||
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“I lowered my level of stress” |
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9 (11.5) | ||||
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“I lost weight” |
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7 (9.0) | ||||
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“I stopped smoking” |
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5 (6.4) | ||||
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“I ate more healthy fat” |
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4 (5.1) | ||||
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“I had regular GPa checks” |
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3 (3.8) | ||||
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“I watched less TVb” |
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0 (0) | ||||
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“I got more adequate sleep” |
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0 (0) |
aGP: general practitioner.
bTV: television.
The Text4HeartII trial extended our pilot trial to determine the effectiveness of an SMS text messaging–based intervention to improve adherence to medication and lifestyle behaviors at both 24 and 52 weeks. Overall, we found no evidence to support the effectiveness of the program on dispensed medication or on adherence to a composite measure of lifestyle change over and above usual care.
The strengths of this trial were the RCT design and the objective assessment of medication adherence. Our study addressed criticisms of previous SMS text messaging trials [
The lack of a positive effect on mediation adherence was surprising and contrary to previous research. A meta-analysis of 16 RCTs (N=2742) showed that SMS text messaging significantly improved medication adherence across a range of conditions (OR 2.11, 95% CI 1.52-2.93;
Our findings differ from previous SMS text messaging trials in people with cardiovascular disease. A recent review (Text2PreventCVD) involving 9 trials (N=3779) and individual participant data (5 trials; n=2612) meta-analysis of SMS text messaging interventions demonstrated positive effects across a host of risk factors (BMI, systolic blood pressure, and diastolic blood pressure) [
Given the existing body of evidence supporting SMS text messaging on medication adherence, it is clear that Text4HeartII did not have the desired effect on the population and setting in this trial. This may be attributed to personal factors associated with our cohort; randomized participants appeared to be more motivated to adhere than those in previous studies. The results showed that the difference between the control and intervention groups was relatively small and driven predominantly by MPR for antihypertensive medication. Despite similar days in hospital between groups at 24 weeks (approximately 1 day), adherence to all medication classes for both groups was higher than our proposed control rate (30%); approximately 41.5% (127/306) of the participants had an MPR >0.8. Our original control rate was based on previous research, which found that 59.3% (8028/13,520) of patients had an MPR >0.8 for statins only [
Surprisingly, the effects observed on lifestyle behaviors differed from those in our original pilot study [
Despite the lack of effect observed in our trial, SMS text messaging as an intervention has the potential to improve outcomes in people with CHD and other conditions. Findings from this study suggest that the context in which SMS text messaging interventions are delivered is important to consider and may have a significant impact on whether an intervention is effective or not. Future studies need to explore both individual- and organizational-level factors that may affect the adoption, implementation, and effectiveness of such interventions. For example, the RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance) framework [
There was no evidence to support the effectiveness of Text4HeartII on dispensed medication or adherence to a favorable lifestyle over and above usual care. In its current form, Text4HeartII cannot be used to augment existing services. The findings of this study are in contrast with those of previous studies and highlight the importance of evaluating interventions in the setting they are likely to be used before widespread adoption. Changes to the intervention program are warranted to justify its future implementation.
CONSORT (Consolidated Standards of Reporting Trials) statement checklist.
angiotensin-converting enzyme inhibitor
acute coronary syndrome
Australian and New Zealand Acute Coronary Syndrome-Quality Improvement
angiotensin receptor blocker
coronary heart disease
Consolidated Standards of Reporting Trials
cardiac rehabilitation
medication possession ratio
moderate-to-vigorous physical activity
National Health Index
odds ratio
randomized controlled trial
Reach, Effectiveness, Adoption, Implementation and Maintenance
The authors would like to thank all the participants involved in the Text4HeartII trial. The authors would also like to acknowledge the participating hospitals (Auckland, North Shore, and Waitakere) and the cardiac staff who assisted with recruitment and conduct of the trial. Finally, the authors wish to thank the Vascular Informatics Using Epidemiology and the Web and the ANZACS-QI teams for providing access to data for this study. The Text4HeartII trial was funded by the Health Research Council of New Zealand and the National Heart Foundation.
RM conceived the idea, procured funding, was responsible for the overall conduct of the trial, and drafted the manuscript. YJ performed data analyses. LD was involved in the original Text4Heart pilot trial on which this study was based. All investigators were involved in the conduct of the trial, contributed to the interpretation of the findings, and reviewed the manuscript.
None declared.