Number needed to treat/harm US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Number needed to treat/harm. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Number needed to treat/harm US Medical PG Question 1: A research team develops a new monoclonal antibody checkpoint inhibitor for advanced melanoma that has shown promise in animal studies as well as high efficacy and low toxicity in early phase human clinical trials. The research team would now like to compare this drug to existing standard of care immunotherapy for advanced melanoma. The research team decides to conduct a non-randomized study where the novel drug will be offered to patients who are deemed to be at risk for toxicity with the current standard of care immunotherapy, while patients without such risk factors will receive the standard treatment. Which of the following best describes the level of evidence that this study can offer?
- A. Level 1
- B. Level 3 (Correct Answer)
- C. Level 5
- D. Level 4
- E. Level 2
Number needed to treat/harm Explanation: ***Level 3***
- A **non-randomized controlled trial** like the one described, where patient assignment to treatment groups is based on specific characteristics (risk of toxicity), falls into Level 3 evidence.
- This level typically includes **non-randomized controlled trials** and **well-designed cohort studies** with comparison groups, which are prone to selection bias and confounding.
- The study compares two treatments but lacks randomization, making it Level 3 evidence.
*Level 1*
- Level 1 evidence is the **highest level of evidence**, derived from **systematic reviews and meta-analyses** of multiple well-designed randomized controlled trials or large, high-quality randomized controlled trials.
- The described study is explicitly stated as non-randomized, ruling out Level 1.
*Level 2*
- Level 2 evidence involves at least one **well-designed randomized controlled trial** (RCT) or **systematic reviews** of randomized trials.
- The current study is *non-randomized*, which means it cannot be classified as Level 2 evidence, as randomization is a key criterion for this level.
*Level 4*
- Level 4 evidence includes **case series**, **case-control studies**, and **poorly designed cohort or case-control studies**.
- While the study is non-randomized, it is a controlled comparative trial rather than a case series or retrospective case-control study, placing it at Level 3.
*Level 5*
- Level 5 evidence is the **lowest level of evidence**, typically consisting of **expert opinion** without explicit critical appraisal, or based on physiology, bench research, or animal studies.
- While the drug was initially tested in animal studies, the current human comparative study offers a higher level of evidence than expert opinion or preclinical data.
Number needed to treat/harm US Medical PG Question 2: A 33-year-old man is brought by ambulance to the emergency room after being a passenger in a motor vehicle accident. An empty bottle of whiskey was found in his front seat, and the patient admits to having been drinking all night. He has multiple lacerations and bruising on his face and scalp and a supportive cervical collar is placed. He is endorsing a significant headache and starts vomiting in the emergency room. His vitals, however, are stable, and he is transported to the CT scanner. While there, he states that he does not want to have a CT scan and asks to be released. What is the most appropriate course of action?
- A. Have the patient fill the appropriate forms and discharge against medical advice
- B. Explain to him that he is intoxicated and cannot make health care decisions, continue as planned (Correct Answer)
- C. Release the patient as requested
- D. Agree to not do the CT scan
- E. Call security
Number needed to treat/harm Explanation: ***Explain to him that he is intoxicated and cannot make health care decisions, continue as planned***
- The patient's **intoxication** (empty whiskey bottle, admitted drinking all night) and **head injury symptoms** (headache, vomiting after MVA) suggest he lacks the capacity to make informed medical decisions.
- When a patient lacks capacity, the medical team has an ethical and legal obligation to act in their **best interest**, which includes performing necessary diagnostic tests like a CT scan to rule out serious intracranial injuries.
*Have the patient fill the appropriate forms and discharge against medical advice*
- Discharging a patient against medical advice requires they have the **full capacity** to understand the risks and benefits of their decision, which is compromised by intoxication and head trauma.
- Doing so without ensuring capacity places the patient at significant risk and could have **legal implications** for the healthcare provider and institution.
*Release the patient as requested*
- Releasing an intoxicated patient with a potential **head injury** into the community is medically negligent and highly dangerous given the risk of worsening neurological status.
- Such an action disregards the principle of **beneficence** and the duty to prevent harm, especially when capacity is in question.
*Agree to not do the CT scan*
- Refusing a necessary diagnostic test like a **CT scan** for a patient with head trauma and altered mental status (due to intoxication) can lead to missed diagnoses of life-threatening conditions like intracranial hemorrhage.
- This decision would allow the patient to leave without proper assessment, potentially jeopardizing their life and violating the standard of care to **stabilize** and **diagnose**.
*Call security*
- While security might be needed if the patient becomes disruptive or aggressive, simply calling security without attempting to explain the situation or assess capacity doesn't address the primary medical and ethical dilemma.
- The immediate priority is to ensure the patient's well-being and assess their cognitive ability to make choices, with security being a secondary measure for **safety** if necessary.
Number needed to treat/harm US Medical PG Question 3: A 58-year-old man presents to the clinic concerned about his health after his elder brother recently became bed-bound due to a brain condition. He has also brought a head CT scan of his brother to reference, as shown in the picture. The patient has type 2 diabetes mellitus, hypertension, osteoarthritis, and hypercholesterolemia. His medication list includes aspirin, diclofenac sodium, metformin, and ramipril. He leads a sedentary lifestyle and smokes one pack of cigarettes daily. He also drinks 4–5 cups of red wine every weekend. His BMI is 33.2 kg/m2. His blood pressure is 164/96 mm Hg, the heart rate is 84/min, and the respiratory rate is 16/min. Which of the following interventions will be most beneficial for reducing the risk of developing the disease that his brother has?
- A. Statin therapy
- B. Quit smoking
- C. Stop aspirin
- D. Blood sugar control
- E. Blood pressure control (Correct Answer)
Number needed to treat/harm Explanation: ***Blood pressure control***
- The brother's CT scan shows features of **white matter hyperintensities (WMH)**, indicative of **cerebral small vessel disease**, a significant risk factor for **neurodegenerative conditions** and dementia, which can cause a patient to become bedridden.
- **Hypertension** is the most potent and modifiable risk factor for the development and progression of WMH and other forms of cerebral small vessel disease; therefore, strict **blood pressure control** is the most beneficial intervention.
*Statin therapy*
- Statins are crucial for managing **hypercholesterolemia** and reducing the risk of **atherosclerotic cardiovascular disease** and stroke.
- While beneficial for overall vascular health, **dyslipidemia** is less strongly associated with WMH and cerebral small vessel disease than hypertension.
*Quit smoking*
- **Smoking** is a significant risk factor for **stroke**, **atherosclerosis**, and several neurodegenerative disorders.
- While important for overall health, **smoking cessation** has a less direct and immediate impact on the progression of existent WMH compared to **blood pressure control**.
*Stop aspirin*
- **Aspirin** is used for **primary or secondary prevention** of cardiovascular events due to its **antiplatelet effects**.
- There is no indication that stopping aspirin would benefit in preventing further cerebral small vessel disease; rather, it could increase the risk of other vascular events in this patient with multiple risk factors.
*Blood sugar control*
- **Type 2 diabetes mellitus** is a known risk factor for **vascular dementia** and can contribute to small vessel disease.
- While important for long-term health, the impact of **blood sugar control** on WMH progression is less substantial compared to **blood pressure control**.
Number needed to treat/harm US Medical PG Question 4: A 62-year-old man comes to the physician in May for a routine health maintenance examination. He feels well. He underwent a right inguinal hernia repair 6 months ago. He has hypertension and type 2 diabetes mellitus. There is no family history of serious illness. Current medications include metformin, sitagliptin, enalapril, and metoprolol. He received the zoster vaccine 1 year ago. He received the PPSV23 vaccine 4 years ago. His last colonoscopy was 7 years ago and was normal. He smoked a pack of cigarettes a day for 20 years but quit 17 years ago. He drinks two to three alcoholic beverages on weekends. He is allergic to amoxicillin. He is scheduled to visit Australia and New Zealand in 2 weeks to celebrate his 25th wedding anniversary. He appears healthy. Vital signs are within normal limits. An S4 is heard at the apex. The remainder of the examination shows no abnormalities. Which of the following is the most appropriate recommendation at this time?
- A. Colonoscopy
- B. Influenza vaccine (Correct Answer)
- C. Pneumococcal conjugate vaccine 13
- D. Cardiac stress test
- E. Abdominal ultrasound
Number needed to treat/harm Explanation: ***Influenza vaccine***
- Current guidelines recommend annual **influenza vaccination** for all adults, particularly those over 60 years old and those with chronic medical conditions like diabetes and hypertension.
- **Critical timing consideration**: The patient is traveling to Australia and New Zealand (Southern Hemisphere) in 2 weeks, where it will be **winter season** (May-September) with peak influenza activity.
- He is a **high-risk patient** (age >60, diabetes, hypertension, cardiovascular disease) who should receive influenza vaccine before travel to areas experiencing influenza season.
- This is the **most appropriate and time-sensitive recommendation** at this visit.
*Colonoscopy*
- The patient had a normal colonoscopy 7 years ago; current guidelines suggest a repeat colonoscopy every **10 years** for average-risk individuals.
- There are no new symptoms, family history, or risk factors that would necessitate an earlier repeat colonoscopy at this time.
*Pneumococcal conjugate vaccine 13*
- The patient received **PPSV23** four years ago at approximately age 58.
- Per **current CDC guidelines (2019+)**, PCV13 is **no longer routinely recommended** for immunocompetent adults ≥65 years old.
- PPSV23 alone is now the standard recommendation for adults ≥65, which this patient has already received.
- PCV13 may be considered through **shared decision-making** in specific circumstances, but is not a routine or urgent recommendation.
*Cardiac stress test*
- Although the patient has risk factors for cardiovascular disease (hypertension, diabetes, former smoker) and an **S4 heart sound** (indicating **left ventricular hypertrophy**), he is asymptomatic.
- Routine **screening stress tests** are not recommended for asymptomatic individuals without signs of active cardiac ischemia.
*Abdominal ultrasound*
- There are **no symptoms** or specific indications (e.g., abdominal aortic aneurysm screening criteria not met - would need age 65-75 with smoking history).
- The patient is 62 years old and quit smoking 17 years ago, so AAA screening criteria are not yet met.
- Routine screening abdominal ultrasounds are not indicated.
Number needed to treat/harm US Medical PG Question 5: A research team is studying the effects of a novel drug that was discovered to treat type 2 diabetes. In order to learn more about its effects, they follow patients who are currently taking the drug and determine whether there are adverse effects that exceed anticipated levels and may therefore be drug-related. They discover that the drug causes an excess of sudden cardiac death in 19 patients with renal failure out of 2 million total patients that are followed. Based on these results, an additional warning about this serious adverse effect is added to the investigator brochure for the drug. Which of the following clinical phase studies does this study most likely describe?
- A. Phase IV (Correct Answer)
- B. Phase II
- C. Phase V
- D. Phase III
- E. Phase I
Number needed to treat/harm Explanation: ***Phase IV***
- This study occurs **after a drug has been approved and marketed**, focusing on post-marketing surveillance for long-term safety, effectiveness, and real-world side effects in a large and diverse patient population.
- The discovery of a rare but serious adverse effect (sudden cardiac death) in a large patient population (2 million) after the drug is already in use is characteristic of a **Phase IV clinical trial**.
*Phase II*
- Phase II trials involve a **larger group of patients (hundreds)** and focus on evaluating the drug's effectiveness and further assessing safety in patients with the target condition.
- This phase is typically conducted **before widespread marketing** and would not involve 2 million patients.
*Phase V*
- There is **no widely recognized "Phase V"** in standard clinical trial terminology (Phases I-IV focus on drug development and post-marketing surveillance).
- This term is sometimes used informally to refer to **health economics and outcomes research** or implementation studies, which are not described in the scenario.
*Phase III*
- Phase III trials are large-scale studies involving **thousands of patients** to confirm effectiveness, monitor side effects, compare the drug to standard treatments, and collect information for safe use.
- While large, these trials are conducted **before regulatory approval** and marketing, and would not typically follow 2 million patients already taking the drug in the real world.
*Phase I*
- Phase I trials are the **first stage of human testing**, involving a small group of healthy volunteers (20-100) to assess safety, dosage, and pharmacokinetics.
- The primary goal is to determine if the drug is safe enough for further testing, not to identify rare adverse events in a large patient population.
More Number needed to treat/harm US Medical PG questions available in the OnCourse app. Practice MCQs, flashcards, and get detailed explanations.
