Intervention With Vitamin D and Omega-3 Supplements and Incident Heart Failure
Phase: PHASE3
Conditions: Heart Failure
Sponsor: Brigham and Women's Hospital

 
 
 
 
 
 
Title: Intervention With Vitamin D and Omega-3 Supplements and Incident Heart Failure 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
NCT #: NCT02271230 
 
 
 
 
 
 
 
 
 
 
 
Date:  December 31, 2020 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Study Protocol and Statistical Analysis Plan 
 
1. Overview of parent VITAL  
VITAL is an ongoing and NIH-funded (R01 CA138962) randomized, double-blind, placebo-controlled trial using 
a 2x2 factorial design to test the effects of 2,000 IU/d of vitamin D and 1 g/d of EPA/DHA (EPA: DHA ratio of 
1.3:1) supplements in the primary prevention of cardiovascular disease and cancer among 25,871 men and 
women during 5 years of treatment and follow-up.  
 
Enrollment, eligibility, run-in, and randomization.  For enrollment into VITAL, 1.2 million ethnically and racially 
diverse people, including health professionals, AARP members, Essence subscribers, professionals, college-
educated individuals, and Black business professionals, were mailed a detailed description of VITAL’s 
objectives, an informed consent form, a brief questionnaire, and a self-addressed, pre-paid envelope for 
returning the forms. Eligibility criteria for VITAL included (1) age ≥50 (men) or ≥55 (women); (2) no history of 
cancer (except non-melanoma skin cancer), myocardial infarction, stroke, transient ischemic attack, angina 
pectoris, coronary artery bypass graft, or percutaneous coronary intervention; (3) no history of safety 
exclusions: kidney stones, renal failure or dialysis, hypercalcemia, hypo- or hyperparathyroidism, severe liver 
disease, sarcoidosis, active chronic tuberculosis, or Wegener’s granulomatosis; (4) no allergy to fish (for 
EPA+DHA); (5) no other serious illness that would preclude participation; (6) consumption of <800 IU vitamin D 
from all supplemental sources combined; (7) current intake of <1.2 g/d of calcium from all supplemental 
sources combined; (8) not taking fish oil supplements; and (9) ability to sign the informed consent form. Table 
1 shows baseline characteristics of VITAL participants. 
A run-in phase was designed to eliminate poor compliers prior to randomization to increase statistical power.  
Willing and eligible participants were mailed placebo for vitamin D and EPA/DHA to assess potential 
compliance and side effects.  After 3 months, a follow-up questionnaire was used to query about continued 
eligibility, willingness, compliance, and potential side effects. Non-responders were mailed 2nd and 3rd requests.   
 
For randomization into VITAL, participants are required to be: (i) compliant 
(taking two-thirds or more of the study pills during run-in); (ii) willing to 
continue; (iii) eligible based upon the above criteria; and (iv) willing to limit 
supplemental vitamin D intake and forego fish oil supplements. 
Randomization is being stratified by 5-year age groups, and in blocks of 8 
individuals, with 2 individuals in each of the 4 treatment combinations. Pilot 
mailings indicated that 40,000 individuals, including >10,000 minority 
participants, were willing and eligible for the run-in, of whom 65% (n = 
~26,000) 
were 
compliant 
and 
remained 
willing 
and 
eligible 
for 
randomization. 
 
Baseline questionnaire and food frequency questionnaire (FFQ): Each 
VITAL participant completed a comprehensive baseline questionnaire to 
collect information on demographics, medical history, medication use, 
vitamin D, fish oil, and other supplement use, lifestyle and clinical risk 
factors, and potential effect modifiers of vitamin D such as skin pigmentation 
and sunlight exposure. A self-administered FFQ was also mailed to 
participants during the run-in. The FFQ has been shown to be an efficient and valid instrument to assess 
individuals’ diet and to derive nutrients. To capture changes in dietary habits over time, a second FFQ will be 
administered to all VITAL participants at 24 months of follow up. Average dietary intake of vitamin D, EPA, and 
DHA and other important nutrients will be estimated from the FFQ for proposed analyses.  
Baseline and follow-up blood collection: Blood collection kits were sent to willing subjects during the run-
in period to collect fasting blood samples; subjects were asked to record the time of venipuncture and their last 
meal. Collected blood samples are being sent back to our laboratory in freezer packs within 24 hours of blood 
collection. Upon receipt, we process and aliquot these specimens into multiple vials that are then kept at -170º 
Celsius in liquid nitrogen. Blood samples are processed within hours of receipt to ensure that samples are 
frozen within 30-36 hours after venipuncture. In addition, a random sample of 2,000 individuals will have follow-
up blood drawn after 24 and 48 months of follow-up at the Boston Clinical and Translational Science Center 
Table 1. Baseline characteristics 
of VITAL cohort (n=25,874)  
Male  
50% 
Mean age (±SD) -Years 
67±7 
Mean BMI (±) - kg/m2 
29±6 
Non-Hispanic White  
71% 
African Americans 
20% 
Age ≥ 65  
63% 
≥High school graduate  
99% 
Exercise (MET/week) 
15 
Any alcohol use  
69% 
Aspirin use  
45% 
Income <$15,000 
6% 
Use of multivitamin 
44% 
Current smoker  
4% 
History of diabetes  
13% 
Prevalent hypertension  
53% 
Current statin use  
37% 

(CTSC) to assess compliance and changing trends in background fortification with vitamin D and marine 
omega-3 fatty acids, as well as to evaluate physiologic changes in selected biomarkers. To date, we have 
collected baseline blood collection 16,361 VITAL participants. 
 
Quality assurance and follow up. Quality assurance testing ensures that the intervention (vitamin D and 
EPA/DHA) contains the correct doses and is free of contaminants. At 6 months and at each anniversary date 
of randomization, each participant will receive a follow-up questionnaire and a re-supply of study treatments.  
Each annual follow-up questionnaire assesses compliance, use of non-trial vitamin D and fish oil, dietary intake 
of vitamin D and fish, information on interim medication use, physical activity, weight, comorbidity including HF, 
etc. Data on potential side effects are being collected and tracked by a Data and Safety Monitoring Board. 
Non-respondents receive multiple mailed requests, followed by a telephone call to collect data. For non-
respondents, vital status will be ascertained. To further test compliance, 250 VITAL subjects residing in New 
England will receive unannounced visits to draw bloods to measure plasma vitamin D and EPA/DHA.  
2. Follow-up and adjudication procedures for HF (requiring hospitalization) and recurrent HF 
hospitalizations.  
The main method of follow-up is mailed questionnaires and review of medical records to confirm study 
endpoints. Participants receive follow-up questionnaires at 6 months and 1 year after randomization and 
annually thereafter. A new supply of study pills is mailed with each annual questionnaire. The questionnaires 
ask about compliance with randomized treatments, use of non-study supplements of vitamin D and marine 
omega-3 fatty acids, development of major illnesses including HF, cancer and CVD, and potential side effects 
of the study agents. Non-responders receive two additional requests by mail and are then telephoned to collect 
study data. At a minimum, vital status is ascertained. 
 
Participants who report a HF diagnosis are asked to sign a medical release for relevant medical records. An 
Endpoints Committee of physicians blinded to treatment assignment ( including Drs. Djousse, Gaziano, and 
Albert) will review the records to confirm or disconfirm the diagnosis of HF. Deaths are confirmed by convincing 
evidence from available sources, including death certificates, hospital records, autopsy reports, and for deaths 
outside the hospital, observer accounts. For deaths reported by family members, the next-of-kin is asked to 
provide medical records and a copy of the death certificate. If the latter is not provided, a copy is obtained from 
the appropriate state vital records bureau. If records are not available (or if participants are lost to follow-up), 
we search the National Death Index Plus to obtain an International Classification of Disease-coded cause of 
death based on death-certificate information. 
 
We will use criteria outlined by the American College of Cardiology/American Heart Association Task 
Force on Clinical Data Standards to define HF. This definition requires ALL of the following four elements 
to be met: 
1. Patient’s admission to the hospital with a primary diagnosis of HF 
2. New or worsening symptoms due to HF on presentation including at least ONE of the following: 
dyspnea, worsening peripheral edema, decreased exercise tolerance, fatigue, and other symptoms 
of worsened end-organ perfusion or volume overload 
3. At least TWO physical signs (including rapid weight gain, pulmonary rales, increased jugular 
venous pressures and/or hepatojugular reflux, peripheral edema, increasing abdominal distension 
or ascites in the absence of primary liver disease, and S3 gallop) or ONE physical sign plus at 
least ONE laboratory criterion obtained within 24 hours of presentation (increased B-natriuretic 
peptide, radiologic evidence of pulmonary congestion, and non-invasive or invasive diagnostic 
evidence of elevated left- or right-sided ventricular filling pressure or low cardiac output) 
4. Patient receives initiation or intensification of HF treatment including at least ONE of the following 
[(i) significant augmentation in oral diuretic therapy, (ii) intravenous diuretic, inotrope, or vasodilator 
therapy, and (iii) mechanical or surgical intervention such as mechanical circulatory support or 
mechanical fluid removal]. 
The same definition will be used to adjudicate recurrent HF hospitalizations. Once pertinent information has 
been abstracted from the medical records using the data form, two physician adjudicators will review each 
chart independently, followed by a joint meeting of the entire HF Endpoint Committee to discuss cases where 
disagreement exists among the two reviewers. Here, we will adopt a simple majority vote. Each event will be 

evaluated for presence of HFpEF (EF≥ 50%) or HFrEF (EF<50%) based on ejection fraction (EF) obtained 
during the index hospitalization. Whenever possible, we will assign the etiology of HF (i.e., valvular, arrhythmia, 
coronary artery disease, etc).   
 
Linkage to the Centers for Medicare & Medicaid Services (CMS) 
To supplement the number of self-reported HF from follow-up questionnaires, we will also identify VITAL 
participants (mean age 67 y) with incident HF by linking our data with the CMS database. We will use HF 
diagnoses (ICD-9 codes 428) for such linkage. Costs associated with CMS linkage are covered by the parent 
VITAL trial. Each year, we will obtain Medicare Data Files through ResDAC, a CMS contractor for academic 
researchers.  Although CMS might be more likely to capture older subjects (65+ years), women, and white 
participants, we anticipate equal proportion of subjects randomized to either intervention or corresponding 
placebo given randomization and a large sample size. Hence, the difference between intervention and placebo 
should remain constant.  
 
3. Research Design and Methods 
Measurement of other important variables  
Information on demographics, anthropometrics, lifestyle factors, family history of coronary artery disease, and 
comorbidity will be obtained at baseline and during follow-up via study questionnaires.  
 
Data management and cleaning 
Our team has developed a sophisticated computer system to create and maintain data. A computing system 
tracks each participant’s stage and level of participation in VITAL by automatically generating letters, 
questionnaires, and phone call reminders. Questionnaires are being optically scanned using TELEform and 
Alchemy (Cardiff Software) programs, which have been successfully used for our other mail-based clinical 
trials (PHS, WHS). Out-of-range, internally inconsistent, and unclear data are reviewed and corrected as 
necessary. Unscannable forms and name or address changes are double entered into the system. All data 
undergo additional within-form and across-time checks to verify accuracy. The VITAL database will be 
maintained on a UNIX server that is backed up nightly, ensuring at least two current copies at all times.  
 
Data entry is performed using formatted screens with built-in error checking. Each follow-up questionnaire is 
entered by two different persons. The two generated files are compared using an interactive verification 
program that allows for immediate correction of any discrepancies. Before being added to the database, the 
data undergo further within-form and across-time verifications to assure completeness, accuracy, and 
participant identification number. Any errors in coding or keying are corrected promptly.  
 
Statistical analyses by specific Aim 
Primary Aim 1: Quantify the effects of vitamin D3 intervention vs. placebo on incidence rate of HF. 
Hypothesis: Intervention with vitamin D3 reduces the incidence rate of HF among VITAL participants. 
Study design: Randomized double-blind, placebo-controlled, 2x2 factorial trial of vitamin D3 and EPA/DHA. 
Study subjects: Participants included in the VITAL (n=25,871). 
Primary outcome: Incidence of HF hospitalization 
Statistical model: We will exclude any prevalent HF at baseline and use Cox proportional hazards model to 
estimate effects. Time-to-event will be calculated as the interval between time of randomization and the earliest 
of: 1) HF incidence, 2) death, or 3) end of the study. Analyses of treatment effects will be based on the intent-
to-treat principle. The first analysis will compare baseline characteristics by randomized treatment assignment 
to ensure that balance was achieved by the randomization. Characteristics to be examined include known risk 
factors for HF, such as age; gender; race/ethnicity; body mass index; smoking; alcohol use; physical activity; 
medical conditions such as hypertension, hyperlipidemia, diabetes, and family history of coronary disease; and 
baseline vitamin D and omega-3 fatty acid levels as assessed by FFQ. The large sample size, as well as 
successful balance of known potential confounders, will provide assurance that unmeasured or unknown 
potential confounders will also be equally distributed across randomized treatment groups 
 
In this 2x2 factorial design, the primary aim is to compare the main effects of intent-to-treat with vitamin D3 on 
incidence rate of HF. We will use the Cox proportional hazards model to allow for variable follow-up lengths 
and will estimate the hazard ratio for vitamin D3 intervention using indicators for treatment exposure, 
controlling for EPA/DHA intervention, age, and gender. Because the cohort will consist of older individuals, 

competing risks due to deaths from other causes will be considered. The primary analysis will estimate the 
cause-specific hazard and the hazard ratio comparing intervention groups for HF by censoring individuals with 
deaths due to competing causes. To estimate the cumulative incidence function, the subdistribution of HF will 
be plotted over time. The alternative Fine and Gray approach models the effect of treatment on the 
subdistribution hazard or directly on the cumulative incidence function. While we will consider this and compare 
its fit to the model-free cumulative incidence curves, the proportional hazards approach will be our primary 
analysis. Beyond the primary analyses, we will examine effect modification by EPA/DHA intervention, baseline 
risk factors, and time.  
 
Statistical power: We computed statistical power assuming a) 2x2 factorial trial of 25,871 subjects at risk; b) 
equal and independent treatment allocation; c) mean follow-up of 5 years with minimal loss to follow-up; d) 
incidence rate of 8.29 cases per 1,000 person-years (40% of the rate reported in the ARIC and CHS studies 
(21/1000 person-years) in order to account for healthy volunteer effect in VITAL) , and e) a non-compliance 
rate of 20%. We also used 30% [6.19 cases /1,000 person-years] of the rates seen in the ARIC and CHS to be 
more conservative. We used a log-rank analysis with a 2-tailed p-value of 0.05. We have 80% power to detect 
a 18% reduction in the incidence of HF (Table 2).  
 
 
 
 
 
 
 
Primary Aim 2:  Effects of EPA/DHA intervention vs. placebo on incidence rate of HF. 
Study design: Randomized, placebo-controlled, double-blind, 2x2 factorial trial of vitamin D and EPA/DHA. 
Hypothesis: Intervention with 1g/d of EPA/DHA supplements vs. placebo reduces the incidence rate of HF. 
Study subjects: A total of 25,871 VITAL participants. 
Statistical model: Cox proportional hazards model as detailed above for the primary aim. 
To determine whether treatment effects vary over time, we will use time-dependent Cox models to update 
covariates over time (i.e., dietary EPA/DHA and other nutrients, anthropometric, comorbidity, and lifestyle 
factors collected repeatedly during the trial).  
 
Statistical power: For primary analyses for EPA/DHA, we will have identical statistical power presented in 
Table 2 above.  
 
Secondary Aim: Effects of vitamin D3 and EPA/DHA on incidence rate of recurrent HF hospitalizations. 
Study design: Randomized, placebo-controlled, double-blind, 2x2 factorial trial of vitamin D3 and EPA/DHA. 
Hypothesis: Intervention with either vitamin D3 or EPA/DHA reduces the rate of recurrent HF hospitalization. 
Study subjects: All 25,871 VITAL participants. 
Statistical model: We will analyze recurrent HF hospitalizations using the Andersen-Gill model, which allows 
for varying numbers of events per person with different time between events. It can accommodate correlated 
observations within individuals by using robust covariance estimates. This method has been found to produce 
similar results to Poisson regression models allowing for over-dispersion. 
 
Statistical power: To estimate the statistical power for recurrent HF hospitalization, we assumed a Poisson 
distribution with over-dispersion, following Cook et al. Rates of recurrence were based on those seen in the 
Olmstead County data with 16.5% recurrent hospitalization rate (0.144 per person-year). We will have 80% 
power to detect 16% reduction in recurrent HF hospitalization (RR=0.84) if we assume an incidence rate of 
8.29/1000 person-years and 83% power to detect 19% reduction in recurrent HF hospitalization (RR=0.81) 
assuming a HF rate of 6.19/1000 person-years. We expect 280 recurrent HF hospitalizations with latter rate. 
  
 
Table 2. Statistical power (%) to detect vitamin D3 effect on HF incidence 
 
 
 
Observed RR* 
0.82 
0.81 
0.80 
0.79 
0.78 
0.77 
0.76 
0.75 
0.74 
0.73 
0.70 
True RR† 
0.78 
0.76 
0.75 
0.74 
0.73 
0.71 
0.70 
0.69 
0.68 
0.66 
0.63 
Power (rate 8.29/1000) 
80 
84 
87 
91 
93 
95 
96 
98 
98 
99 
>99 
Power (rate 6.19/1000) 
67 
72 
76 
81 
84 
87 
90 
92 
94 
96 
99 
*Observed RR=intent-to-treat relative risk with 80% compliance;     †True RR=Relative risk under perfect compliance