Mediterranean diet app intervention for atrial fibrillation patients

PRIMARY OUTCOME

feasibility (retention rate) and inflammatory biomarkers

EXPECTED OUTCOMES

1. **Retention Rate:** ≥85% (51/60) of randomized participants complete the Week 24 assessment in both arms, with the intervention arm showing non-inferiority (expected 87-90% retention) 2. **hs-CRP Reduction:** Mean reduction of 1.8 ± 1.2 mg/L in the intervention group vs 0.4 ± 1.1 mg/L in the control group at Week 16 (between-group difference: -1.4 mg/L, 95% CI: -2.0 to -0.8 mg/L), p < 0.001 3. **Mediterranean Diet Adherence:** Mean increase of 4.2 ± 1.8 points on MEDAS-14 in intervention group vs 1.1 ± 1.4 points in control group at Week 16 (effect size d = 1.9) 4. **IL-6 Reduction:** Mean reduction of 2.3 ± 1.5 pg/mL in intervention vs 0.6 ± 1.2 pg/mL in control at Week 16 (p < 0.01) 5. **Omega-3 Index:** Mean increase from 6.2% to 8.1% (±1.0%) in intervention group vs no change (6.1% to 6.3% ± 0.9%) in control group at Week 16 (p < 0.001) 6. **AF Symptom Burden:** Mean improvement of 8.2 ± 5.4 points on AFEQT in intervention vs 2.9 ± 4.1 points in control at Week 16 (effect size d = 1.1) 7. **App Engagement:** Median of 85% (IQR: 72-94%) of prescribed meal logging entries completed by intervention participants over the 16-week intervention period ---

SUCCESS CRITERIA

- **Retention ≥85%:** At least 51 of 60 randomized participants complete the Week 24 primary assessment; Chi-square test p-value > 0.05 for between-group comparison demonstrating non-inferiority - **hs-CRP effect size ≥0.5:** Between-group standardized mean difference (Cohen's d) in hs-CRP change from baseline to Week 16 ≥ 0.5, with two-sided p-value < 0.05 - **Mediterranean Diet adherence increase ≥3 points:** Intervention group MEDAS-14 score increases by ≥3 points from baseline at Week 16; independent samples t-test p < 0.001 - **At least 70% app engagement:** ≥70% of daily meal logging entries completed by ≥80% of intervention participants; repeated measures ANOVA p < 0.001 for time × group interaction - **No safety signals:** Serious adverse events (SAEs) related to study procedures occur in <5% of participants; no statistically significant difference in SAE rates between arms (Fisher's exact test, p > 0.05) - **IL-6 reduction ≥1.5 pg/mL:** Intervention group demonstrates mean IL-6 reduction ≥1.5 pg/mL from baseline to Week 16 with between-group comparison p-value < 0.05 - **Quality of life improvement:** SF-36 physical component score increases by ≥3 points in intervention vs control, p < 0.05, with effect size ≥ 0.3 --- ### SAFETY MONITORING - Adverse event collection at every study contact - Data safety monitoring board (DSMB) reviewing unblinded data at 50% enrollment (N=30) - Pre-specified stopping rules: >10% SAEs related to study intervention ### ETHICS - IRB approval obtained prior to enrollment - All participants sign written informed consent - Trial registered prior to first enrollment

PROTOCOL

**Study Title:** Mobile Health Mediterranean Diet Intervention for Atrial Fibrillation Patients: A Randomized Controlled Feasibility Trial **Protocol Version:** 1.0 **Study Registration:** ClinicalTrials.gov (pending) **Funding Source:** Institutional Research Grant --- ### STUDY OVERVIEW **Design:** Two-arm parallel-group randomized controlled trial (RCT) **Population:** Adults with paroxysmal or persistent atrial fibrillation (AF) **Sample Size:** 60 participants (30 per arm) **Duration:** 24 weeks (6 months) **Setting:** Single-center, outpatient --- ### PHASE STRUCTURE #### Phase 1: Screening & Baseline (Week -2 to 0) - **Screening Visit (Visit 1):** Informed consent, eligibility confirmation, medical history, physical exam, 12-lead ECG, blood draw for baseline inflammatory biomarkers - **Baseline Assessment (Visit 2, Week 0):** Dietary assessment (Mediterranean Diet Score questionnaire), quality of life (SF-36, AF-specific symptom burden), physical activity monitoring (accelerometer), blood draw (fasting), anthropometrics - **Randomization:** Block randomization (block size 4), stratified by AF type (paroxysmal vs persistent) #### Phase 2: Run-in & App Training (Week 0 to Week 2) - **Group A (Intervention):** Install MedDiet-AF app; 60-minute individualized training session on app usage, Mediterranean diet principles, portion estimation; receive digital food diary setup - **Group B (Control):** Receive standard written dietary guidelines (ADA brochure); 15-minute nurse education session on general heart-healthy eating - **Dietary Compliance Assessment:** 3-day food diaries collected at Week 1 (phone follow-up) #### Phase 3: Active Intervention (Week 2 to Week 16) - **Intervention Group (MedDiet-AF App):** - Daily app check-ins: photo-based meal logging (breakfast, lunch, dinner + 2 snacks) - Automated feedback: personalized Mediterranean diet score (0-100 scale) updated daily - Weekly push notifications: educational content on Mediterranean diet components (olive oil, fish, nuts, vegetables) - Bi-weekly dietitian coaching calls (15-20 min each) - App incorporates: Oleic acid tracking, Omega-3 index estimation, polyphenol intake proxy - **Control Group (Standard Care):** - Monthly newsletter on general heart-healthy eating (no personalized feedback) - No dietary coaching calls - Quarterly check-in call to maintain engagement #### Phase 4: Mid-point Assessment (Week 8) - **Visit 3 (Week 8):** Blood draw (inflammatory biomarkers), 3-day food diary review, app engagement metrics (intervention only), adverse events, medication review, SF-36 questionnaire, AF symptom burden score #### Phase 5: End-of-Intervention Assessment (Week 16) - **Visit 4 (Week 16):** Blood draw (fasting, 8-12 hour overnight fast), anthropometrics, 3-day food diary, Mediterranean Diet Score questionnaire, SF-36, AF-specific symptom burden, physical activity accelerometer 7-day wear, medication review, adverse events, app satisfaction survey (intervention) #### Phase 6: Follow-up (Week 16 to Week 24) - **No active intervention** — participants maintain usual diet - **Visit 5 (Week 24):** Final blood draw, anthropometrics, dietary assessment, quality of life questionnaires, AF symptom burden, healthcare utilization recall, safety assessment --- ### METHODS #### Inclusion Criteria - Age 40-80 years - Documented paroxysmal or persistent AF (confirmed by ECG, Holter, or implantable device) - Stable anticoagulation for ≥4 weeks - Smartphone ownership with data plan - Able to read/understand English - Medically stable (CHF class I-II, no unstable angina, no recent MI within 3 months) #### Exclusion Criteria - Severe renal impairment (eGFR <30 mL/min/1.73m²) - Active liver disease - Omega-3 supplementation >2g/day - Current participation in another dietary intervention trial - Life expectancy <12 months - Cognitive impairment precluding app use - Prior Mediterranean diet adherence score ≥8/14 on MEDAS questionnaire #### Intervention: MedDiet-AF App - **Platform:** iOS and Android native application - **Developer:** Academic research team with validated Mediterranean diet scoring algorithm - **Key Features:** - Photo-based meal logging with automatic food identification - Mediterranean Diet Adherence Score (MDAS) algorithm using Mediterranean Diet Screener (MEDAS-14) items - Personalized daily/weekly MDAS feedback - Integration with Apple HealthKit/Google Fit for physical activity - Push notification schedule: 3 reminders/week for meal logging #### Control Intervention - Standard care with written materials only (American Heart Association Dietary Guidelines pamphlet) - No personalized feedback or coaching #### Biomarker Collection - **Blood collection:** 10 mL venous blood in EDTA tubes, placed on ice, centrifuged within 30 min at 2000×g for 15 min at 4°C - **Storage:** Plasma aliquoted into cryovials, stored at -80°C until analysis - **Batch analysis:** All samples analyzed in duplicate in a single batch at study completion, blinded to group assignment #### Inflammatory Biomarkers (ELISA) - **High-sensitivity C-reactive protein (hs-CRP):** R&D Systems Human CRP ELISA Kit (Cat# DCRP00), sensitivity 0.022 mg/L - **Interleukin-6 (IL-6):** R&D Systems Human IL-6 Quantikine ELISA Kit (Cat# D6050), sensitivity 0.039 pg/mL - **Tumor necrosis factor-alpha (TNF-α):** R&D Systems Human TNF-α Quantikine ELISA Kit (Cat# DTA00D), sensitivity 0.5 pg/mL - **Interleukin-1β (IL-1β):** R&D Systems Human IL-1β ELISA Kit (Cat# DLB50), sensitivity 0.125 pg/mL - **Soluble intercellular adhesion molecule-1 (sICAM-1):** R&D Systems Human sICAM-1 ELISA Kit (Cat# DCD540), sensitivity 0.096 ng/mL #### Dietary Assessment - **Mediterranean Diet Adherence Screener (MEDAS-14):** Validated 14-item questionnaire administered at baseline, Week 8, Week 16, Week 24 - **3-day food diaries:** 2 weekdays + 1 weekend day, analyzed using Nutrition Data System for Research (NDSR) software - **Plasma fatty acid profile:** Gas chromatography-flame ionization detection (GC-FID) for Omega-3 Index (脂肪酸甲基酯分析) #### AF Symptom Assessment - **AF Symptom Burden Questionnaire:** Heart Rhythm Society AF symptom classification (Class I-IV) - **AF生活质量问卷 (AFEQT):** Atrial Fibrillation Effect on QualiTy of Life questionnaire - **Symptom diary:** Daily symptom check-in via app (intervention) or paper diary (control) #### Quality of Life - **SF-36v2 Health Survey:** Standardized QoL instrument - **Physical Activity:** ActiGraph GT9X accelerometer, 7-day wear, wear time validation ≥4 days with ≥10 hours/day --- ### STUDY TIMELINE | Phase | Timepoint | Key Activities | |-------|-----------|----------------| | 1 | Week -2 to 0 | Screening, consent, baseline blood draw, randomization | | 2 | Week 0 to 2 | App training (intervention) or education (control), run-in | | 3 | Week 2 to 16 | Active intervention period | | 4 | Week 8 | Mid-point assessment, blood draw, interim analysis | | 5 | Week 16 | End-of-intervention assessment | | 6 | Week 24 | Final follow-up assessment | --- ### STATISTICAL ANALYSIS PLAN **Primary Outcome:** Retention rate (proportion of randomized participants completing Week 24 assessment) - Non-inferiority margin: 15% (intervention vs control retention ≥85% of control) **Secondary Outcomes:** - Change in hs-CRP from baseline to Week 16 - Change in Mediterranean Diet Score (MEDAS-14) from baseline to Week 16 - Change in AF symptom burden from baseline to Week 16 **Sample Size Justification:** - N=60 provides 80% power to detect a 20% difference in retention rate (85% vs 65%), assuming α=0.05 (one-sided) - For inflammatory biomarkers: N=30 per group provides 80% power to detect d=0.74 effect size (medium) in change from baseline, assuming α=0.05 **Analytical Approach:** - Intention-to-treat (ITT) analysis for all primary and secondary outcomes - Mixed-effects linear models for repeated measures - Multiple imputation for missing data under missing-at-random assumption - Bonferroni correction for multiple inflammatory biomarker comparisons ---

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