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<h2 class="hd hd-2 unit-title">Section Introduction</h2>
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<h3>Introduction</h3>
<p>Before embarking on an investigation to provide data that may be used to inform the clinical question, it is important to formulate the research problem properly and transform it into a research query. The process of developing a research question involves defining several components of the study, which include:</p>
<ul>
<li>Study sample (For whom is this research question relevant?)</li>
<li>Exposure (The drug, maneuver, event or characteristic we are investigating)</li>
<li>Outcome of interest (What are we measuring as an outcome variable?)</li>
</ul>
<p>With these components in mind, the researcher must decide which study design is best or most feasible for answering the research question.</p>
<p>In this section, we will explore how researchers might work through converting a clinical question into a research question using the scenario of indwelling <span style="color: #313131;">arterial catheters (IAC) use during mechanical ventilation (MV).</span></p>
<p>Reference</p>
<p>1. MIT Critical Data - Secondary Analysis of Electronic Health Records. Chapter 9: Formulating the research question - Anuj Mehta, Brian Malley and Allan Walkey</p>
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<p></p>
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<h3>Learning Objectives</h3>
<ul style="text-rendering: optimizelegibility; border: 0px; outline: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 1.4em; font-family: 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif; vertical-align: baseline; color: #313131;">
<li style="text-rendering: optimizelegibility; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding: 0px; border: 0px; outline: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; font-stretch: inherit; font-size: inherit; line-height: 1.4em; font-family: inherit; vertical-align: baseline;">Understand how to turn a clinical question into a research question</li>
<li style="text-rendering: optimizelegibility; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding: 0px; border: 0px; outline: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; font-stretch: inherit; font-size: inherit; line-height: 1.4em; font-family: inherit; vertical-align: baseline;">Principles of choosing a sample</li>
<li style="text-rendering: optimizelegibility; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding: 0px; border: 0px; outline: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; font-stretch: inherit; font-size: inherit; line-height: 1.4em; font-family: inherit; vertical-align: baseline;">Approaches and potential pitfalls</li>
<li style="text-rendering: optimizelegibility; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding: 0px; border: 0px; outline: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; font-stretch: inherit; font-size: inherit; line-height: 1.4em; font-family: inherit; vertical-align: baseline;">Principles of defining the exposure of interest</li>
<li style="text-rendering: optimizelegibility; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding: 0px; border: 0px; outline: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; font-stretch: inherit; font-size: inherit; line-height: 1.4em; font-family: inherit; vertical-align: baseline;">Principles of defining the outcomes</li>
<li style="text-rendering: optimizelegibility; margin-top: 0px; margin-right: 0px; margin-left: 0px; padding: 0px; border: 0px; outline: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; font-stretch: inherit; font-size: inherit; line-height: 1.4em; font-family: inherit; vertical-align: baseline;">Selecting an appropriate study design</li>
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<h3>Credits</h3>
<p>Grigorij Schleifer, MD and Shrey Lakhotia.</p>
<p>Videos<span style="color: #313131; font-family: 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif;"> in this unit are presented by Allan J. Walkey, MD, MSc. The last video is presented by Omar Badawi </span><span style="color: #313131; font-family: 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif;">PharmD, MPH, FCCM</span><span style="color: #313131; font-family: 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 1em;">.</span></p>
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<h2 class="hd hd-2 unit-title">FINER Mnemonic</h2>
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<p>The <strong>FINER</strong> mnemonic is a framework used for formulating research questions and should help to define a research problem.</p>
<p>Every research question should be:</p>
<ul>
<li><strong>F</strong>easible</li>
<li><strong>I</strong>nteresting</li>
<li><strong>N</strong>ovel</li>
<li><strong>E</strong>thical</li>
<li><strong>R</strong>elevant </li>
</ul>
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<h3 class="hd hd-2">FINER</h3>
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<h2 class="hd hd-2 unit-title">The Clinical Scenario: Impact of Indwelling Arterial Catheters</h2>
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<p>In this chapter, we will explore how researchers might work through converting a clinical question into a research question using the clinical scenario of indwelling arterial catheters (IAC) use during mechanical ventilation (MV). </p>
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<h2 class="hd hd-2 unit-title">PICO Framework</h2>
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<h3>PICO Framework</h3>
<p>A useful mnemonic to help remember all of the components of a research query is the PICO framework:</p>
<ul>
<li><strong>P</strong>: The population of subjects defined by the researcher (<strong>P</strong>atients/study sample)</li>
<li><strong>I</strong>: The drug, event or characteristic that we are basing our alternative hypothesis on (<strong>I</strong>ntervention/exposure)</li>
<li><strong>C</strong>: The “unexposed” or control group needed to assess the effectiveness of healthcare interventions (<strong>C</strong>ontrol)</li>
<li><strong>O</strong>: The predefined outcome of interest (<strong>O</strong>utcome)</li>
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<h3 class="hd hd-2">PICO framework</h3>
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<h2 class="hd hd-2 unit-title">Patients (cohort/sample)</h2>
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<h3>Patients</h3>
<p>In the case of IAC (indwelling arterial catheters) use, one might imagine many potential study samples of interest: for example, one might include all ICU patients, all patients receiving mechanical ventilation, all patients receiving intravenous medications that strongly affect blood pressure, adults or children only, etc.</p>
<p>The choice of study sample will affect both the internal and the external validity (generalizability) of the study. A study focusing only on a pediatric population may not apply to the adult population. Similarly, a study focused on patients receiving mechanical ventilation may not be applicable to non-ventilated patients. Furthermore, a study including patients with different reasons for using an IAC, with different outcomes related to the reason for IAC use, may lack internal validity due to bias called ‘confounding’. Confounding is a type of study bias in which an exposure variable is associated with both the exposure and the outcome.</p>
<p>Imagine a scenario where the benefits of IACs are studied on all patients receiving mechanical ventilation. Some patients receive ventilation for asthma (which is a less severe condition), while others receive it for sepsis (which is a more severe condition). Septic patients are also more likely to be given an IAC than asthma patients. In such a study, researchers may conclude that IACs are associated with higher mortality only because IACs were used in sicker patients with a higher risk of dying. The variable “diagnosis” is therefore a confounding factor, associated with both the exposure (decision to insert an IAC) and the outcome (death).</p>
<p>Careful sample selection is necessary, but there is often a compromise between preserving internal validity (by choosing a homogeneous group) and generalizability (choosing a study population similar to the treated population).</p>
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<p>The <strong>exposure</strong> in our research question appears to be fairly clear: placement of an IAC. However, careful attention should be paid as to how each exposure or variable of interest is defined. Misclassifying exposures may bias results. How should IAC be measured? For example, investigators may use methods ranging from direct review of the medical chart to the use of administrative claims data (i.e. ICD-codes) to identify IAC use. Each method of ascertaining the exposure of interest may have pros (improved accuracy of medical chart review) and cons (many person-hours to perform manual chart review)</p>
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<h2 class="hd hd-2 unit-title">Control Group</h2>
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<p dir="ltr" style="line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt; text-align: justify;">Equally important to defining the group of patients who received or experienced an exposure is to define the “unexposed” or control group. In the case of the IAC study, the control group is fairly straightforward: patients receiving mechanical ventilation (MV) who did not have an IAC placed. However, there are important nuances when defining control groups. In our study example, an alternate control group could be all ICU patients who did not receive an IAC. However, the inclusion of patients not receiving MV results in a control group with lower severity of illness and expected mortality than patients receiving MV, which would bias in favor of not using IACs.</p>
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<p dir="ltr" style="line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt; text-align: justify;">A carefully defined control group is needed to properly interpret any conclusions drawn from the research process. Defining an appropriate control group is as important as defining the exposure.</p>
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<h2 class="hd hd-2 unit-title">Outcome</h2>
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<p>The investigator needs to determine the outcome of interest. Several different types of outcomes can be considered. </p>
<p><strong>Intermediate or mechanistic</strong> (Informs etiological pathways, but may not immediately impact patients)</p>
<ul>
<li>Number of arterial blood draws</li>
<li>Ventilator setting changes</li>
<li>Vasoactive medication change</li>
</ul>
<p><strong>Patient-centered </strong>(Informs outcomes important to patients, but may lack mechanistic insights)</p>
<ul>
<li>Comfort scales</li>
<li>Quality of life indices</li>
<li>Mortality (e.g. 28-day or 90-day mortality)</li>
<li>Adverse event rates</li>
</ul>
<p><strong>Healthcare-system centered</strong> (e.g. resource utilization, or costs)</p>
<ul>
<li>Hospitalization costs</li>
<li>Added clinician workload</li>
</ul>
<p>In our example of IAC use, several outcomes could be considered including intermediate outcomes (e.g. the number of arterial blood draws, ventilator setting changes, or vasoactive medication changes), patient-centered outcomes (e.g. 28-day or 90-day mortality, adverse event rates), or healthcare utilization (e.g. hospitalization costs, added clinician workload). More than one outcome should be chosen, but you should keep in mind a primary outcome.</p>
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<h2 class="hd hd-2 unit-title">A Research Question: An Example</h2>
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<h3>Example research question</h3>
<p>Our research query can be formulated as follows:</p>
<p>Among mechanically ventilated adult ICU patients who are not receiving vasoactive medications (i.e., the <strong>study sample</strong>), is placement of an IAC after initiation of MV (as compared with not receiving an IAC) (i.e. the <strong>exposure</strong> and <strong>control</strong> patients) associated with improved 28-day mortality rates (primary <strong>outcome</strong>, patient-centered) and the number of blood gas measurements per day (supporting secondary outcome, intermediate/mechanistic)?</p>
<p></p>
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<h2 class="hd hd-2 unit-title">Study Design</h2>
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<h3>Study Design</h3>
<p>Once the research question has been defined, the next step is to choose the optimal study design given the question and resources available. Broadly, the study design can be classified into Randomized Controlled Trials (RCTs) and observational studies. RCTs exhibit a stronger experimental design, that more easily establishes causality, but they have several practical limitations which will be discussed in this section. </p>
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<h2 class="hd hd-2 unit-title">Observational Studies</h2>
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<h3>Major types of observational research and their purpose</h3>
<ul>
<li><strong>Epidemiological: </strong>Define incidence, prevalence, and risk factors for disease</li>
<li><strong>Predictive modeling:</strong> Predict future outcomes</li>
<li><strong>Comparative effectiveness:</strong> Identify intervention associated with superior outcomes</li>
<li><strong>Pharmacovigilance:</strong> Detect rare adverse events occurring in the long-term</li>
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<h3>Problems with observational studies</h3>
<p>Observational studies may be more prone to bias (problems with internal validity) than RCTs due to difficulty obtaining the counterfactual control group whereas RCTs create two alternate ‘universes’ of patients that will be similar except with regard to the exposure of interest.</p>
<ol>
<li>Bias</li>
<ul>
<li>Selection Bias: This occurs during the process of selecting exposed and unexposed participants. Example: Survival bias.</li>
<li>Information Bias: Due to mismeasurement or misclassification of certain variables.</li>
<li>Confounding bias: This occurs when a third variable is correlated with both the exposure and outcome.</li>
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<li>Missing data</li>
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<h2 class="hd hd-2 unit-title">Randomised Controlled Trials (RCTs)</h2>
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<h3>Randomized controlled trials (RCTs)</h3>
<p>RCTs are the gold standard for establishing causal inference under ideal conditions, because they allow for the unobserved confounding to be controlled for through randomization. This means it is relatively simple to establish causality through the use of an RCT. However, they are not always practical, cost-effective, ethical or even possible for some types of questions. </p>
<p>For our question: “Among mechanically ventilated ICU patients not receiving vasoactive medications (study sample) is use of an IAC after initiation of MV (exposure) associated with improved 28-day mortality (outcome)?”, an RCT would be expensive and could be unethical if we suspected that the treatment and control arms were not in equipoise - i.e. that we did not know which arm offered superior treatment.</p>
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<h3>Problems in RCTs</h3>
<ul>
<li>Logistically complex</li>
<li>Risk of harm to participants - if one treatment is less effective than the other, then patients that are assigned to the arm may be harmed</li>
<li>Ethical concerns - some questions involve too much danger to participants, or potential participants may be unable to give full consent, so the study cannot be run</li>
<li>Expensive and may take a long time</li>
<li>Often have a homogeneous population due to stringent inclusion criteria</li>
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<h2 class="hd hd-2 unit-title">Data Sources</h2>
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<h3>Data sources</h3>
<p>A critical part of the research process is deciding what types of data are needed to answer the research question. Administrative/claims data, secondary use of clinical trial data, prospective epidemiological studies, and electronic health record (EHR) systems (both from individual institutions and those pooled from multiple institutions) are several sources from which databases can be built:</p>
<ul>
<li>Administrative/claims data: tend to provide very large sample sizes but lack granular patient-level data like vital signs, laboratory and microbiology data, timing data or pharmacology data.</li>
<li>Secondary use of clinical trial data and large epidemiologic studies: these types of databases often have detailed, granular information but researchers are often bound by the scope of data collection from the original research study which limits the questions that may be posed.</li>
<li>Electronic health record (EHR) systems: contain data from a variety of sources such as patient monitors, laboratory systems, and pharmacy systems which can then be translated into de-identified databases for research purposes that contain detailed patient demographics, billing and procedure information, timing data, hospital outcomes data, as well as patient-level granular data and provider notes which can be searched for using natural language processing tools.</li>
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<h2 class="hd hd-2 unit-title">Conclusion</h2>
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<h3>Conclusion</h3>
<p>Fewer than 10 % of clinical decisions are supported by high level evidence. Clinical questions arise approximately in every other patient and provide a large cache of research questions. When formulating a research question, investigators must carefully select the appropriate sample of subjects, exposure variable, outcome variable, and confounding variables. Once the research question is clear, study design becomes the next pivotal step. While RCTs are the gold standard for establishing causal inference under ideal conditions, they are not always practical, cost-effective, ethical or even possible for some types of questions. Observational research presents an alternative to performing RCTs, but is often limited in causal inference by unmeasured confounding.</p>
<p>Our clinical scenario gave rise to the question of whether IACs improved the outcomes of patients receiving MV. This translated into the research question:</p>
<p><em>“Among mechanically ventilated ICU patients not receiving vasoactive medications (study sample) is use of an IAC after initiation of MV (exposure) associated with improved 28-day mortality (outcome)?”</em></p>
<p>While an RCT could answer this question, it would be logistically complex, costly, and difficult. Using comparative effectiveness techniques, one can pose the question using a granular retrospective database comparing patients who received an IAC to measurably similar patients who did not have an IAC placed.</p>
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<h3>Key take aways</h3>
<ul>
<li>Most research questions arise from clinical scenarios in which the proper course of treatment is unclear or unknown.</li>
<li>Defining a research question requires careful consideration of the optimal study sample, exposure, and outcome in order to answer a clinical question of interest.</li>
<li>While observational research studies can overcome many of the limitations of randomized controlled trials, careful consideration of study design and database selection is needed to address bias and confounding.</li>
</ul>
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Question 1: PICO
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Question 2: Cohort and causality
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<legend id="dcdc8b87da9c4e89b9e64488a284ea9b_2_1-legend" class="response-fieldset-legend field-group-hd">You want to understand if a new cancer drug Yutuximab, is good at treating stage IV lung cancer in adults, what is an appropriate control group for your retrospective study?</legend>
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<input type="radio" name="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1" id="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_0" class="field-input input-radio" value="choice_0"/><label id="dcdc8b87da9c4e89b9e64488a284ea9b_2_1-choice_0-label" for="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_0" class="response-label field-label label-inline" aria-describedby="status_dcdc8b87da9c4e89b9e64488a284ea9b_2_1"> All hospital patients
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<input type="radio" name="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1" id="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_1" class="field-input input-radio" value="choice_1"/><label id="dcdc8b87da9c4e89b9e64488a284ea9b_2_1-choice_1-label" for="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_1" class="response-label field-label label-inline" aria-describedby="status_dcdc8b87da9c4e89b9e64488a284ea9b_2_1"> All adult hospital patients
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<input type="radio" name="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1" id="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_2" class="field-input input-radio" value="choice_2"/><label id="dcdc8b87da9c4e89b9e64488a284ea9b_2_1-choice_2-label" for="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_2" class="response-label field-label label-inline" aria-describedby="status_dcdc8b87da9c4e89b9e64488a284ea9b_2_1"> All adult patients with lung cancer
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<input type="radio" name="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1" id="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_3" class="field-input input-radio" value="choice_3"/><label id="dcdc8b87da9c4e89b9e64488a284ea9b_2_1-choice_3-label" for="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_3" class="response-label field-label label-inline" aria-describedby="status_dcdc8b87da9c4e89b9e64488a284ea9b_2_1"> All adult patients who have stage IV lung cancer
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<input type="radio" name="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1" id="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_4" class="field-input input-radio" value="choice_4"/><label id="dcdc8b87da9c4e89b9e64488a284ea9b_2_1-choice_4-label" for="input_dcdc8b87da9c4e89b9e64488a284ea9b_2_1_choice_4" class="response-label field-label label-inline" aria-describedby="status_dcdc8b87da9c4e89b9e64488a284ea9b_2_1"> All adult patients who die of stage IV lung cancer
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Question 3: Bias
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Question 4: RCTs
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<div class="wrapper-problem-response" tabindex="-1" aria-label="Question 1" role="group"><div class="choicegroup capa_inputtype" id="inputtype_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1">
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<legend id="2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1-legend" class="response-fieldset-legend field-group-hd">What are drawbacks to randomised controlled trials? (tick all that apply)</legend>
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<input type="checkbox" name="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1[]" id="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_0" class="field-input input-checkbox" value="choice_0"/><label id="2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1-choice_0-label" for="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_0" class="response-label field-label label-inline" aria-describedby="status_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1"> Logistically complex
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<input type="checkbox" name="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1[]" id="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_1" class="field-input input-checkbox" value="choice_1"/><label id="2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1-choice_1-label" for="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_1" class="response-label field-label label-inline" aria-describedby="status_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1"> Difficult to establish causality
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<input type="checkbox" name="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1[]" id="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_2" class="field-input input-checkbox" value="choice_2"/><label id="2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1-choice_2-label" for="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_2" class="response-label field-label label-inline" aria-describedby="status_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1"> Ethical concerns
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<input type="checkbox" name="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1[]" id="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_3" class="field-input input-checkbox" value="choice_3"/><label id="2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1-choice_3-label" for="input_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1_choice_3" class="response-label field-label label-inline" aria-describedby="status_2e436dbec2ea4479aa1b89c8ffc9fb8d_2_1"> Expensive and may take a long time
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