Nut602 Research Methods Fall 2024 PDF

NUT602: Research Methods in Fall Nutrition and Food Science 2024 Inclusion/Exclusion Criteria  A Study to Assess Prevalence of 2 Malnutrition in Patients with COPD Inclusion and exclusion criteria for a cross-sectional multicenter study of...

NUT602: Research Methods in Fall Nutrition and Food Science 2024 Inclusion/Exclusion Criteria  A Study to Assess Prevalence of 2 Malnutrition in Patients with COPD Inclusion and exclusion criteria for a cross-sectional multicenter study of patients with COPD Inclusion vs. Exclusion Criteria 3 ▪ Typical inclusion criteria include demographic, clinical, and geographic characteristics ▪ Exclusion criteria: features of the potential study participants who meet the inclusion criteria but present with additional characteristics that could interfere with the success of the study or increase their risk for an unfavorable outcome ▪ Common exclusion criteria include characteristics of eligible individuals that make them highly likely to be lost to follow-up, miss scheduled appointments to collect data, provide inaccurate data, have comorbidities that could bias the results of the study, or increase their risk for adverse events  4 Inclusion/Exclusion Criteria Reasons to consider Internal vs. Factors to consider participant external validity selection  Participants selection 5 Basic Questions How do you decide how How do you decide generalizable the which participants to participant sample study? should be? How do you How do you ensure that appropriately match you are studying who participant you want to study? characteristics to the outcomes of interest?  6 The Clinical Research Continuum Phase 1 Phase 2 Phase 3 Phase 4 Safety Efficacy Effectiveness Post-marketing Dose-ranging Highly controlled Less control Real-life Healthy Selected Less selected Community Very Small Small Big On-going  Why do we think about 7 participant selection? ▪ Clarifies the research question ▪ Helps clarify study design ▪ Characteristics of the study participants determines the ability to generalize the findings of the study ▪ Impacts feasibility ▪ Impacts outcomes ▪ The decisions made regarding the study population will markedly influence the causal inferences Study participants & generalizability 8 Internal vs. external validity ➔ a delicate balance External Validity Internal Validity Maximize Generalizability Maximize Control Across participants History effects Across situations Bias of all sorts Across time and place Experimenter effects Measurement effects Internal vs. external validity 9  Feasibility 10 Access to research participants with the desired demographic and clinical characteristics Likelihood of participation Adherence to protocol and treatment once enrolled Ethical questions: randomization to placebo, adverse event rates, participant burden, vulnerable participants, representativeness Timing of intervention (acute post-event, pre-event, etc.)  Impact on outcomes 11 ▪ Event outcome ➔ morbidity and mortality ▪ Surrogate/biomarkers outcomes ➔ cholesterol levels, cognitive score ▪ Patient-specific outcomes ➔ pain/symptoms, quality of life, self-rated health ▪ Composite outcomes  How does selection of participants 12 influence outcomes? Are the targeted outcomes feasible to measure, given A study measuring hard CV events (e.g., MI in 50- year-old healthy women with moderate BP participant characteristics elevation) could not be powered adequately (e.g., stage of disease)? Can outcomes change within the parameters of the trial, Planning to measure change in cognition over the course of a 3-month trial would not show given participant differences over time characteristics? Are participants able to Asking 5 year-old children to report what they eat in describe dietary intake? school may yield unreliable data  Factors to consider in participant 13 characteristics Entry Criteria Target of the intervention (e.g., individual, caregiver, community, etc.) Inclusionary Exclusionary Access Recruitment and retention Adherence No group or individual subject should be excluded without a scientifically sound reason or a requirement of the regulations to do so Entry Criteria: Main purpose 14 Inclusionary Exclusionary Criteria Criteria Targeting participants likely to be relevant to Safety your outcomes Balancing between- Control/confounding participant variance Reported (CONSORT) Feasibility  When should entry criteria 15 determined? ▪ EARLY! Before the first participant is recruited, before the IRB approves the protocol, before anyone sees and funds the study ▪ Determining these factors well before recruitment minimizes bias ▪ Be specific! ▪ Never change the entry criteria  16 Patient selection- Context Personal Experiences (consent) “To different degrees, all causal relationships are context-dependent, so the generalization of experimental Social Culture effects is always at issue” Environment (Shadish et al., 2002) Context is important!  17 Patient selection - Access ▪ Access to participants should be considered early in the planning phases ▪ Often requires building an interdisciplinary team ▪ May require multiple sites ▪ Generally should not include own patients or practice  Recruitment and Retention 18 Critical for success of a trial – and most challenging part of many RCTs Respondent burden Assessments Intensity, duration, and complexity of treatment Health of participant Logistics – transportation, etc. Inclusionary and representativeness  Improving recruitment 19 Use a layered approach Use community-based and social marketing strategies Targeted distribution of mailings Presentations at health fairs and community settings Referrals Set goals that are manageable at both ends of the study and monitor carefully Run-in period for acceptability Employ strategies for ensuring participants are representative  Improving retention 20 Manage (minimize) participant burden Employ shortest possible time period and least complex study requirements Optimize visits – convenient hours, efficient, culturally competent staff, provide attention Reduce barriers (parking, childcare, gas costs) Incentives Appointment reminders Schedule at the BEGINNING of follow-up window  Adherence 21 Measure it Diaries Pill count Blood tests Accelerometers/pedometers Pictorial food logs Microchip in paper diary… Optimize it (except in some types of studies) Motivational Interviewing – to decrease ambivalence, increase retention Orientation – provide information, outline expectations, answer questions, develop partnership, transparency Maintain contact back-ups Maintain contact with phone calls, birthday cards, newsletters, retention events Consider selecting participants based on some run-in data to determine potential adherence Let’s Practice 22 Let’s Practice 23 Let’s Practice 24 phase 2= efficacy  25 Let’s Practice Let’s Practice 26 Let’s Practice 27 Let’s Practice 28 29 30 Food-based clinical trials 31  Food-based clinical trials 32 Food-based clinical trials 33 Food-based clinical trials 34 Common Errors 35 ▪ Using the same variable to define both inclusion and exclusion criteria ▪ For example, in a study including only men, listing being a female as an exclusion criterion ▪ Selecting variables as inclusion criteria that are not related to answering the research question ▪ Not describing key variables in the inclusion criteria that are needed to make a statement about the external validity of the study results Let’s Practice: Strict Inclusion Criteria 36 Effects of a high-protein diet on weight loss and metabolic parameters in individuals with type 2 diabetes Inclusion criteria: diagnosed with Type 2 diabetes for at least 5 years, BMI 30-35 kg/m², aged 40-60 years old, and not be on insulin therapy Impact of omega-3 fatty acid supplementation on cognitive decline in elderly with mild cognitive impairment Inclusion criteria: have a clinical diagnosis of MCI, 65-75 years old, have no history of CVD, and not taking any other dietary supplements. Let’s Practice: Loose Inclusion Criteria 37 Dietary patterns and risk of cardiovascular disease across diverse populations Inclusion criteria: Participants aged 18-80, with or without a history of cardiovascular disease, from various ethnic backgrounds, and with varying dietary habits Effects of a plant-based diet on weight loss in the general population Inclusion criteria: Any adult willing to follow a plant-based diet for 12 weeks, regardless of their baseline diet, health status, or age Per Protocol vs. Intention To Treat 38 Take-home message 39