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The Prevention With Mediterranean Diet (PREDIMED) trial supported the effectiveness of a nutritional intervention conducted by a dietitian to prevent cardiovascular disease. However, the effect of a remote intervention to follow the Mediterranean diet has been less explored.
This study aims to assess the effectiveness of a remotely provided Mediterranean diet–based nutritional intervention in obtaining favorable dietary changes in the context of a secondary prevention trial of atrial fibrillation (AF).
The PREvention of recurrent arrhythmias with Mediterranean diet (PREDIMAR) study is a 2-year multicenter, randomized, controlled, single-blinded trial to assess the effect of the Mediterranean diet enriched with extra virgin olive oil (EVOO) on the prevention of atrial tachyarrhythmia recurrence after catheter ablation. Participants in sinus rhythm after ablation were randomly assigned to an intervention group (Mediterranean diet enriched with EVOO) or a control group (usual clinical care). The remote nutritional intervention included phone contacts (1 per 3 months) and web-based interventions with provision of dietary recommendations, and participants had access to a web page, a mobile app, and printed resources. The information is divided into 6 areas:
A total of 720 subjects were randomized (365 to the intervention group, 355 to the control group). Up to September 2020, 560 subjects completed the first year (560/574, retention rate 95.6%) and 304 completed the second year (304/322, retention rate 94.4%) of the intervention. After 24 months of follow-up, increased adherence to the Mediterranean diet was observed in both groups, but the improvement was significantly higher in the intervention group than in the control group (net between-group difference: 1.8 points in the MEDAS questionnaire (95% CI 1.4-2.2;
The remote nutritional intervention using a website and phone calls seems to be effective in increasing adherence to the Mediterranean diet pattern among AF patients treated with catheter ablation.
ClinicalTrials.gov NCT03053843; https://www.clinicaltrials.gov/ct2/show/NCT03053843
Atrial fibrillation (AF) is currently the most common cardiac arrhythmia. In 2010, AF affected more than 33.5 million persons worldwide (20.9 million men and 12.6 million women) [
The Mediterranean diet is considered an ideal nutritional model for cardiovascular health [
As far as we know, no previous study has assessed the effect of a Mediterranean diet intervention on preventing recurrences of AF after ablation. The PREvention of recurrent arrhythmias with Mediterranean diet (PREDIMAR) study is an ongoing secondary prevention trial aimed at assessing the effect of a Mediterranean diet enriched with EVOO [
The principal objective of this study is to assess the effect of a web-based and telephone intervention in obtaining favorable dietary changes in the context of a secondary prevention trial of AF. In addition, we provide a detailed description of the remote nutritional intervention conducted in the PREDIMAR trial.
The PREDIMAR study was a multicenter, randomized, controlled, single-blind trial. The study protocol has been described in detail elsewhere [
Between March 2017 and January 2020, 1422 patients were invited to participate in the study (
Flowchart of participant screening, recruitment, and randomization.
After catheter ablation for the treatment of AF, all participants who gave their informed consent, and who fulfilled the inclusion criteria were randomly assigned to the intervention (Mediterranean diet enriched with EVOO) or the control group (usual clinical care). The intervention period took 2 years (
The trial was registered at ClinicalTrials.gov NCT03053843. The Research Ethics Committees from each recruitment center approved the protocol. All participants provided written informed consent after they received the information sheet and additional verbal explanation of the study characteristics.
The aim of the nutritional intervention of the PREDIMAR study is to improve adherence to the Mediterranean diet. The Mediterranean diet is characterized by the exclusive use of EVOO for all culinary purposes and high consumption of vegetables, fruits, whole grains, legumes, and nuts; moderate consumption of fish; and very low consumption of red and processed meats, refined grains, sweet desserts, and whole-fat dairy products (only fermented dairy products, cheese and yogurt, are consumed in moderation) and ultraprocessed foods [
In the PREDIMAR study, we used a remote nutritional intervention rather than an in-person approach. This remote intervention was conducted by a team of registered dietitians by phone and on the internet, and participants had access to web-based information on a website, a mobile app, and printed material. The intervention was conducted by the same group of dietitians to all participants from the 4 centers. This characteristic allowed a highly homogeneous intervention according to the protocol of the study, but it also allowed for tailored nutrition education through personal interviews conducted by phone and web-based communication with the dietitians.
A multidisciplinary group of dietitians-nutritionists, epidemiologists, medical doctors, and chefs developed the content of the website for this study, and professional multimedia programmers produced it (Nubba Group).
Once a participant was randomized, they received an automated email with a username and password to access the PREDIMAR website. Participants in the control group had access to general information about AF only.
For participants in the intervention group, the content of the website was divided into 6 areas:
The information of the different areas of the web page was updated every week and was sequentially and automatically activated according to the number of weeks that each participant had been followed up in the study.
The first entry of the
The area
The
Finally, testimonials from volunteers of the PREDIMAR study were included in the
The intervention program also included an Android and iPhone app that allowed participants to access the web page content in an easier manner (
Data on the frequency of access to the website and the mobile app were provided by the same web page to the dietitians, and this information was used to determine the level of engagement of each participant and to orient the intervention of the dietitian during the phone call with each participant during the follow-up. In these phone calls, participants were informed about the tools available on the web page and encouraged to use it every week.
Biweekly automated email notification was sent, announcing the updated information of each area according to the number of weeks that each participant had been followed up in the study.
Participants in the intervention group also received printed material across the time of the study. Once participants were assigned to the intervention group, they received a book about the traditional Mediterranean diet [
Later in the first follow-up clinical visit (third month), participants in the intervention group received a binder with the first print module, which corresponds to the information of the first 8 weeks of the website. Subsequently, every 8 weeks, participants were sent 10 print modules with the information of the website.
A second book was provided to participants at the sixth month of the intervention [
Finally, in the 12th month clinical visit, a magnetic board was given to each volunteer of the intervention group. This board was a helpful tool to improve weekly eating plans.
The intervention began with a phone call from the dietitian once the patient had agreed to participate in the study and was randomly assigned to the intervention or control group. During this first phone call, the dietitian collected information about lifestyle, nutrition, and quality of life from all participants [
Every 3 months during the 2-year follow-up, participants in the intervention group were contacted by the dietitian by phone to complete the MEDAS questionnaire (
The aim of this tailored nutritional education was to increase the quality of the participants’ diet according to the traditional Mediterranean diet and to adapt these general recommendations to the personal food preferences and lifestyles of each participant. Thus, volunteers with excessive body weight, with diabetes, or with any other disease related to nutrition, received specific recommendations by the dietitian to avoid contradictory information from other care professionals because in some cases, the intake of some foods is limited.
On the basis of behavioral literature showing the importance of continued contact during intervention [
Each participant in the intervention group received 0.5 L of EVOO per week for free. The EVOO was provided at each clinical visit, and the aim was to encourage participants to consume at least four spoons of EVOO per day. As part of the Mediterranean diet intervention, participants were encouraged to use EVOO as the culinary fat in their homes.
Trained registered dietitians collected data on food habits during the phone calls at baseline and at years 1 and 2 of follow-up. Adherence to the traditional Mediterranean diet was appraised by a validated 14-item MEDAS questionnaire (
Information on the hydroxytyrosol content in foods was obtained from the Phenol-Explorer database. When an item of the FFQ included more than one food, we used a weighted average according to the typical relative frequency of consumption in the Spanish population [
At baseline, registered dietitians also collected information about sociodemographic characteristics (education level, civil status, and working status), smoking habit, and anthropometric measurements (self-reported weight and height). During this phone call, information about the physical activity was also collected with a physical activity questionnaire validated for the Spanish population [
In clinical visits, the cardiologists collected AF-related variables, complications related to catheter ablation, presence of concomitant chronic diseases, and changes in medication related to arrhythmia, among others. Electrocardiographic monitoring was performed at each visit [
For this study, we used the PREDIMAR database generated until September 2020, including 1- and 2-year follow-up data. Quantitative variables were expressed as means and SDs, whereas categorical variables were described as number and percentages (n [%]). The Student
Between March 2017 and January 2020, 720 patients started the intervention (
Baseline characteristics of the participants in the prevention of recurrent arrythmias with Mediterranean diet trial.
Characteristics | Intervention (n=365) | Control (n=355) | ||
Age, years, mean (SD) | 59.9 (10.5) | 59.6 (10.9) | .77 | |
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Men | 283 (77.5) | 266 (74.9) |
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Women | 82 (22.5) | 89 (25.1) |
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Persistent | 147 (40.3) | 142 (40.0) |
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Paroxysmal | 218 (59.7) | 213 (60.0) |
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BMI (kg/m2) | 27.8 (4.0) | 27.8 (4.3) | .92 | |
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Secondary or less | 198 (54.2) | 202 (56.9) |
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University | 167 (45.7) | 153 (43.1) |
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Single | 24 (6.6) | 27 (7.6) |
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Married | 278 (76.2) | 275 (77.5) |
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Others | 63 (17.3) | 53 (14.9) |
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Working | 199 (54.5) | 191 (53.8) |
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Retired | 139 (38.1) | 133 (37.5) |
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Others | 27 (7.4) | 31 (8.7) |
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Never | 139 (38.1) | 121 (34.1) |
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Former | 206 (56.4) | 208 (59.6) |
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Current | 20 (5.5) | 26 (7.3) |
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Physical activity (METb-hours/week) | 33.4 (20.7) | 34.1 (22.1) | .67 | |
MEDASc score (14 items) | 7.8 (2.0) | 7.2 (2.0) | <.001 | |
Energy intake (kcal/day) | 2396 (670) | 2527 (813) | .01 | |
Carbohydrate intake g/day) | 251.5 (5.2) | 275.7 (5.6) | .002 | |
Protein intake (g/day) | 94.3 (1.3) | 99.9 (1.4) | .002 | |
Fat intake (g/day) | 104.8 (1.5) | 107.6 (2.0) | .21 |
aAF: atrial fibrillation.
bMET: metabolic equivalent.
cMEDAS: Mediterranean Diet Adherence Screener.
After 12 and 24 months of follow-up, an increase in the adherence to the Mediterranean diet was observed in both groups (
Adherence to the Mediterranean diet among participants in the intervention group in each follow-up phone call.
As intended, the Mediterranean diet intervention group showed a significant improvement in the consumption of vegetables, fruits, whole grain cereals, pulses, nuts, white fish, fatty fish, white meat, and VOO compared with the control group at 1-year follow-up (
Baseline food groups consumption and changes by randomized treatment group at 12- and 24-month follow-up visits of participants in the prevention of recurrent arrythmias with Mediterranean diet trial.
Food groups | Group intervention | Between group differencea, mean (95% CI) | ||||||||
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Intervention, mean (95% CI) | Control, mean (95% CI) |
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Baseline | 217.3 (208.1 to 226.5) | 228.2 (217.3 to 239.1) | N/Ac | N/A | |||||
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1-year change | 65.2 (52.1 to 78.4) | 23.4 (9.8 to 37.0) | 41.9 (23.0 to 60.8) | <.001 | ||||
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2 years change | 33.1 (19.8 to 46.3) | 52.6 (36.7 to 68.6) | −19.5 (−40.3 to 1.2) | .06 | ||||
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Baseline | 313.7 (293.2 to 334.2) | 313.7 (291.6 to 335.9) | N/A | N/A | |||||
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1-year change | 151.2 (127.6 to 174.7) | 13.9 (−6.8 to 34.6) | 137.3 (105.9 to 168.7) | <.001 | ||||
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2 years change | 125.7 (99.8 to 151.7) | −9.5 (−40.3 to 21.3) | 135.2 (94.9 to 175.5) | <.001 | ||||
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Baseline | 122.8 (110.4 to 135.2) | 131.8 (119.8 to 143.9) | N/A | N/A | |||||
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1-year change | −56.5 (−67.8 to −45.2) | −20.4 (−32.0 to −8.8) | −36.1 (−52.3 to −19.9) | <.001 | ||||
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2 years change | −66.6 (−80.6 to −52.6) | −23.5 (−38.1 to −9.0) | −43.0 (−63.2 to −22.9) | <.001 | ||||
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Baseline | 40.3 (33.5 to 47.2) | 36.2 (29.3 to 43.1) | N/A | N/A | |||||
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1-year change | 10.1 (1.9 to 18.4) | −7.7 (−15.3 to 0.00) | 17.8 (6.5 to 29.1) | .002 | ||||
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2 years change | 7.1 (−1.1 to 15.3) | −13.2 (−22.8 to −3.7) | 20.3 (7.8 to 32.9) | .002 | ||||
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Baseline | 120.7 (112.9 to 128.4) | 131.5 (122.5 to 140.4) | N/A | N/A | |||||
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1-year change | 65.6 (53.9 to 77.4) | 14.0 (0.4 to 27.7) | 51.6 (33.6 to 69.7) | <.001 | ||||
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2 years change | 54.9 (44.6 to 65.1) | 2.0 (−12.3 to 16.2) | 52.9 (35.3 to 70.4) | <.001 | ||||
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Baseline | 133.9 (119.7 to 148.0) | 88.9 (78.7 to 99.1) | N/A | N/A | |||||
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1-year change | 66.5 (48.5 to 84.5) | 14.2 (−0.23 to 28.6) | 52.4 (29.3 to 75.4) | <.001 | ||||
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2 years change | 59.9 (40.1 to 79.7) | 12.9 (−2.7 to 28.6) | 47.0 (21.7 to 72.2) | <.001 | ||||
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Baseline | 292.4 (272.5 to 312.3) | 333.1 (309.4 to 356.9) | N/A | N/A | |||||
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1-year change | 9.1 (−11.3 to 29.5) | 18.2 (−7.7 to 44.0) | −9.1 (−42.0 to 23.8) | .59 | ||||
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2 years change | 15.7 (−7.6 to 39.1) | 46.3 (18.8 to 73.8) | −30.5 (−66.6 to 5.5) | .10 | ||||
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Baseline | 443.1 (415.5 to 470.7) | 483.4 (453.9 to 513.0) | N/A | N/A | |||||
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1-year change | 105.6 (74.1 to 137.1) | −1.3 (−32.9 to 30.3) | 106.9 (62.3 to 151.6) | <.001 | ||||
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2 years change | 84.9 (49.7 to 120.2) | −33.0 (−70.4 to 4.4) | 117.9 (66.5 to 169.3) | <.001 | ||||
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Baseline | 210.6 (195.4 to 225.9) | 222.0 (204.9 to 239.1) | N/A | N/A | |||||
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1-year change | 104.6 (79.6 to 129.6) | 19.1 (−1.1 to 39.3) | 85.5 (53.3 to 117.6) | <.001 | ||||
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2 years change | 70.0 (46.1 to 93.8) | 9.7 (−13.8 to 33.2) | 60.3 (26.8 to 93.7) | <.001 | ||||
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Baseline | 436.6 (414.5 to 458.7) | 392.3 (369.7 to 414.8) | N/A | N/A | |||||
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1-year change | 22.2 (−0.7 to 45.1) | −23.6 (−46.6 to −0.6) | 45.8 (13.3 to 78.3) | .006 | ||||
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2 years change | 29.4 (2.4 to 56.3) | −29.2 (−62.3 to 3.9) | 58.6 (15.9 to 101.2) | .007 | ||||
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Baseline | 580.6 (542.3 to 619.0) | 655.8 (618.1 to 693.5) | N/A | N/A | |||||
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1-year change | −136.4 (−174.3 to −98.6) | −21.4 (−63.5 to 20.8) | −115.1 (−171.8 to −58.4) | <.001 | ||||
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2 years change | −172.2 (−213.6 to −130.9) | −52.3 (−90.9 to −13.7) | −119.9 (−176.5 to −63.3) | <.001 | ||||
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Baseline | 29.3 (27.1 to 31.5) | 28.3 (26.3 to 30.3) | N/A | N/A | |||||
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1-year change | 0.4 (−1.5 to 2.4) | 2.2 (−0.3 to 4.8) | −1.8 (−5.0 to 1.4) | .27 | ||||
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2 years change | 0.7 (−1.5 to 2.8) | 3.9 (1.2 to 6.6) | −3.2 (−6.7 to 0.2) | .07 | ||||
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Baseline | 2.9 (2.0 to 3.8) | 4.0 (2.9 to 5.2) | N/A | N/A | |||||
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1-year change | −2.7 (−3.6 to −1.7) | −0.2 (−1.5 to 1.1) | −2.5 (−4.1 to −0.9) | .003 | ||||
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2 years change | −2.4 (−3.3 to −1.5) | 1.2 (−0.7 to 3.0) | −3.6 (−5.6 to −1.5) | .001 | ||||
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Baseline | 34.5 (32.8 to 36.2) | 30.5 (28.7 to 32.3) | N/A | N/A | |||||
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1-year change | 10.5 (8.5 to 12.4) | −2.2 (−4.4 to −0.0) | 12.7 (9.7 to 15.7) | <.001 | ||||
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2 years change | 8.8 (6.3 to 11.3) | −2.6 (−5.5 to 0.3) | 11.4 (7.6 to 15.3) | <.001 | ||||
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Baseline | 2.0 (1.5 to 2.4) | 3.0 (2.2 to 3.7) | N/A | N/A | |||||
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1-year change | −1.3 (−1.7 to −0.9) | −0.8 (−1.5 to −0.04) | −0.5 (−1.3 to 0.3) | .25 | ||||
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2 years change | −1.2 (−1.7 to −0.7) | −0.02 (−1.1 to 1.1) | −1.2 (−2.4 to 0.02) | .05 | ||||
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Baseline | 217.7 (188.7 to 246.6) | 392.9 (335.2 to 450.7) | N/A | N/A | |||||
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1-year change | −43.0 (−79.3 to −6.7) | 50.5 (−25.3 to 126.4) | −93.5 (−177.6 to −9.5) | .03 | ||||
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2 years change | −81.9 (−113.4 to −50.4) | 94.9 (17.9 to 171.9) | −176.8 (−260.0 to −93.6) | <.001 | ||||
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Baseline | 5.3 (4.3 to 6.2) | 4.4 (3.5 to 5.3) | N/A | N/A | |||||
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1-year change | 1.0 (0.1 to 1.9) | 0.5 (−0.2 to 1.3) | 0.5 (−0.7 to 1.7) | .42 | ||||
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2 years change | 1.1 (0.04 to 2.2) | 0.3 (−0.5 to 1.2) | 0.8 (−0.6 to 2.1) | .27 | ||||
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Baseline | 0.7 (0.2 to 1.1) | 0.4 (0.2 to 0.5) | N/A | N/A | |||||
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1-year change | 0.2 (−0.1 to 0.6) | 0.5 (0.1 to 0.9) | −0.2 (−0.7 to 0.2) | .33 | ||||
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2 years change | −0.01 (−0.6 to 0.5) | 0.4 (0.07 to 0.8) | −0.4 (−1.1 to 0.2) | .18 | ||||
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Baseline | 3.1 (2.5 to 3.8) | 2.7 (2.1 to 3.4) | N/A | N/A | |||||
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1-year change | −0.7 (−1.3 to −0.07) | 0.2 (−0.5 to 1.0) | −0.9 (−1.9 to 0.04) | .06 | ||||
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2 years change | −0.6 (−1.2 to −0.03) | 0.5 (−0.4 to 1.5) | −1.2 (−2.3 to −0.06) | .04 | ||||
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Baseline | 0.7 (0.4 to 1.0) | 0.5 (0.4 to 0.7) | N/A | N/A | |||||
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1-year change | −0.09 (−0.5 to 0.3) | 0.3 (0.02 to 0.6) | −0.4 (−0.9 to 0.09) | .11 | ||||
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2 years change | −0.2 (−0.6 to 0.05) | 0.4 (−0.09 to 0.8) | −0.6 (−1.2 to −0.07) | .03 |
aCalculated using mixed-effect models with center as random factor.
b
cN/A: not applicable.
At 2 years of intervention, between-group differences were sustained except for the consumption of vegetables, beer, and other alcoholic drinks (liquors and distilled beverages). There was a significant increase in the consumption of vegetables within the intervention group, although the difference in changes between the intervention groups was not statistically significant. The intervention group reduced the consumption of beer and other alcoholic drinks (liquors and distilled beverages) compared with the control group after 2 years of follow-up, but not during the first year of follow-up.
Consistent with changes in consumption of food groups associated with the Mediterranean diet, significant between-group differences were observed for increased intake of fat, MUFA, PUFA, omega-3, and fiber, for the intervention group versus the control group at 1 year of the intervention (
Baseline nutrient intake and changes by randomized treatment group at 12- and 24-month follow-up visits of participants in the prevention of recurrent arrythmias with Mediterranean diet trial.
Energy or nutrient | Group intervention | Between group differencea, mean (95% CI) | ||||||||
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Intervention, mean (95% CI) | Control, mean (95% CI) |
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Baseline | 2396 (2328 to 2465) | 2527 (2443 to 2612) | N/Ac | N/A | |||||
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1-year change | −9.1 (−85.9 to 47.7) | −61.6 (−154.8 to 31.7) | 42.5 (−71.2 to 157.2) | .47 | ||||
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2 years change | −1467 (−224 to -68.1) | −31.5 (−133.5 to 70.4) | −114.6 (−243.0 to 13.7) | .08 | ||||
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Baseline | 104.8 (101.8 to 107.8) | 107.6 (103.7 to 111.5) | N/A | N/A | |||||
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1-year change | 5.6 (2.2 to 9.1) | −1.6 (−6.0 to 2.7) | 7.3 (1.7 to 12.8) | .01 | ||||
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2 years change | 1.2 (−2.6 to 4.9) | 2.4 (−2.6 to 7.5) | −1.3 (−7.6 to 5.1) | .70 | ||||
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Baseline | 54.2 (52.6 to 55.9) | 54.6 (52.5 to 56.8) | N/A | N/A | |||||
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|||||
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1-year change | 5.7 (3.5 to 7.8) | −0.1 (−2.7 to 2.5) | 5.8 (2.5 to 9.1) | .001 | ||||
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|||||
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2 years change | 3.0 (0.7 to 5.4) | 2.3 (−0.8 to 5.4) | 0.7 (−3.2 to 4.6) | .72 | ||||
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Baseline | 18.7 (18.0 to 19.3) | 18.7 (17.9 to 19.5) | N/A | N/A | |||||
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|||||
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1-year change | 1.8 (0.9 to 2.7) | −0.4 (−1.3 to 0.6) | 2.2 (0.9 to 3.5) | .001 | ||||
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|||||
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2 years change | 1.0 (0.02 to 2.0) | −0.06 (−1.1 to 1.0) | 1.1 (−0.4 to 2.5) | .15 | ||||
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Baseline | 26.2 (25.3 to 27.2) | 27.8 (26.6 to 28.9) | N/A | N/A | |||||
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|||||
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1-year change | −1.7 (−2.5 to −0.8) | −0.6 (−1.7 to 0.5) | −1.1 (−2.5 to 0.3) | .14 | ||||
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|||||
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2 years change | −2.5 (−3.5 to −1.5) | 0.5 (−0.8 to 1.7) | −3.0 (−4.6 to −1.3) | <.001 | ||||
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Baseline | 0.8 (0.8 to 0.8) | 0.9 (0.8 to 0.9) | N/A | N/A | |||||
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|||||
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1-year change | 0.3 (0.2 to 0.4) | 0.05 (−0.01 to 0.1) | 0.3 (0.2 to 0.4) | <.001 | ||||
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|||||
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2 years change | 0.2 (0.1 to 0.3) | 0.01 (−0.05 to 0.08) | 0.2 (0.09 to 0.3) | <.001 | ||||
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||||||||||
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Baseline | 94.3 (91.8 to 96.8) | 99.9 (97.2 to 102.5) | N/A | N/A | |||||
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|||||
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1-year change | 2.0 (−0.4 to 4.4) | −1.1 (−3.9 to 1.8) | 3.1 (−0.6 to 6.8) | .10 | ||||
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|||||
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2 years change | −3.0 (−5.6 to −0.3) | -2.2 (−5.4 to 1.1) | −0.8 (−5.0 to 3.4) | .70 | ||||
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Baseline | 251.5 (241.4 to 261.6) | 275.7 (264.1 to 287.2) | N/A | N/A | |||||
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|||||
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1-year change | −20.2 (−29.9 to −10.5) | −13.7 (−26.6 to −0.7) | −6.6 (−22.7 to 9.6) | .43 | ||||
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|||||
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2 years change | −36.4 (−47.7 to −25.1) | −15.3 (−29.4 to −1.3) | −21.0 (−39.1 to −3.0) | .02 | ||||
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Baseline | 24.1 (23.2 to 25.0) | 25.1 (24.1 to 26.2) | N/A | N/A | |||||
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|||||
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1-year change | 6.1 (5.0 to 7.2) | 0.5 (−0.8 to 1.9) | 5.6 (3.8 to 7.3) | <.001 | ||||
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|||||
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2 years change | 4.1 (2.9 to 5.2) | −0.02 (−1.5 to 1.4) | 4.1 (2.2 to 6.0) | <.001 | ||||
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Baseline | 3390 (3267 to 3512) | 3523 (3398 to 3648) | N/A | N/A | |||||
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|||||
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1-year change | −558.4 (−684.3 to −432.6) | −268.9 (−403.9 to −133.9) | −289.5 (−474.1 to −105.0) | .002 | ||||
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|||||
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2 years change | −803.6 (-943.1 to −664.1) | −308.9 (−472.0 to −145.7) | −494.7 (−709.4 to −280.1) | <.001 |
aCalculated using mixed-effect models with center as random factor.
b
cN/A: not applicable.
dMUFA: monounsaturated fatty acid.
ePUFA: polyunsaturated fatty acid.
fSFA: saturated fatty acid.
Finally, regarding total hydroxytyrosol intake, no significant differences between groups at the 1- and 2-year follow-up visits were found. However, when we studied the intake of hydroxytyrosol derived from olive oil (one of the two main sources of this polyphenol in the diet), we observed that the intervention group increased the intake of hydroxytyrosol from olive oil after 1 and 2 years of follow-up, compared with the control group. Meanwhile, the intake of hydroxytyrosol derived from wine (the other main source of hydroxytyrosol of the diet) did not change at 1- and 2-year follow-up visits between groups.
First, this work describes in detail the nutritional intervention of the PREDIMAR trial, which is, to our knowledge, the first remote dietary intervention based on the Mediterranean diet specifically designed for patients with AF treated with catheter ablation. Second, our results demonstrate that a remote nutritional intervention is a useful tool kit to improve the quality of the diet according to the goals of the Mediterranean diet.
Although nutritional interventions are typically derived face to face, at present, remote nutritional interventions (web page, mobile phone app, email, text messaging, and phone calls) are becoming more frequent. This could be in part because of the increase in the use of the internet and other technological resources as well as the high economic costs of traditional interventions. As far as we know, our research is unique in that it is a remote nutritional intervention using different behavioral change strategies including a web page and mobile app, printed material, and personalized advice by phone call and email. Remotely, intervention permits overcoming the barriers of in-person interventions such as lack of staff and institutional resources to reach a large number of participants, and that the participants have to attend to the onsite meetings (group or individual meetings), which in turn require substantial organizational skills [
Participants’ baseline scores showed that they had a reasonably good Mediterranean-style food pattern, according to previous studies developed in the Mediterranean area with patients at risk or with any cardiovascular disease [
We observed a higher increase in the consumption of plant-based foods (fruits, vegetables, whole grain cereals, olive oil, pulses, and nuts) and fish in the intervention group than in the control group during the intervention period. Similar results were found in the PREDIMED study after 1 year of face-to-face intervention [
It is evident that the intervention group adopted healthier behaviors during the first year of follow-up. However, in general, dietary habits were sustained in the longer term, and even a high decrease in the intake of red and processed meat, refined cereals, and sweets was observed at 2 years of follow-up among participants of the intervention group. These findings are consistent with those reported in the literature [
In line with previous intervention studies, we found an increase of 1 serving per day of VOO (including extra virgin) and a reduction of refined olive oil in the intervention group compared with the control group [
There are several strengths and limitations of this study that should be considered when interpreting the results. First, these findings are based on preliminary analyses within the context of an ongoing randomized controlled trial, and it is unknown whether and how these results may be related to beneficial health outcomes. Second, the results of the nutritional intervention may not be applicable to the general population for 2 main reasons. On the one hand, the population of this study was patients with AF, and therefore they could be worried about their health. On the other hand, the free provision of EVOO, which could be a strength of our study, can also represent a barrier because of the high cost of this product. Third, although the clinical providers were blinded to the allocation group, the dietitians were not blinded. Fourth, we used a self-reported FFQ instead of objective instruments, such as biomarkers. Recall bias, social desirability bias, and other potential reporting biases may have affected the results. However, the FFQ has been previously validated and is suitable for repeatedly ranking people according to their food and nutrient intake [
We found that a multifaceted remote nutritional intervention seems to be effective in increasing the knowledge and skills of participants and improving their dietary intake in the direction of the Mediterranean diet pattern. Moreover, our study suggests that remote health promotion interventions could offer a cost-effective community approach to address the increasing health burden.
Clinical follow-up visits and intervention period.
English version of the 14-item Mediterranean adherence screener (MEDAS) questionnaire.
Screenshots of the prevention of recurrent arrythmias with Mediterranean diet (PREvención con DIeta Mediterránea de Arritmias Recurrentes) website.
Screenshots of the prevention of recurrent arrythmias with Mediterranean diet app.
Food frequency questionnaire.
Adherence to the Mediterranean diet at baseline, after 12- and 24-month follow-up visits according to intervention groups.
CONSORT-eHEALTH (V 1.6.1).
atrial fibrillation
extra virgin olive oil
food frequency questionnaire
Mediterranean diet adherence screener
monounsaturated fatty acids
prevention of recurrent arrythmias with Mediterranean diet (PREvención con DIeta Mediterránea de Arritmias Recurrentes)
prevention with Mediterranean diet (PREvención con DIeta MEDiterránea)
polyunsaturated fatty acids
saturated fatty acids
virgin olive oil
Design and concept: LG, MB, MM, JA, and MR. Drafting of the paper: LG and MR. Analysis and interpretation of the data: LG, VD, MM, and MR. Critical revision of the paper for important intellectual content: LG, VD, MB, JA, MM, MR. Collection and assembly of data: LG, VD, MB, PR, LT, JL, EC, AC, RR, JI, JA. Final approval of the paper: LG, VD, MB, PR, LT, JL, EC, AC, RR, JI, JA, MM, MR. This work was funded by the Spanish Government Official Agency for funding biomedical research—Instituto de Salud Carlos III (ISCIII), with competitive grants through the Fondo de Investigación Sanitaria y Fondo Europeo de Desarrollo Regional (PI17/00718, PI17/00748, PI17/01870), the Regional Government of Navarra (46/2016), and the Spanish Society of Cardiology (FEC/2016). Innoliva is providing the necessary amounts of EVOO, and the Basque Culinary Center has collaborated in the elaboration of videos for the nutritional intervention. The authors thank all the volunteers of the PREDIMAR study as well as the dietitians Estíbaliz Goñi and María José Cobo, the medical doctor Liz Ruiz, and the nurses and research coordinators from each recruitment center.
None declared.