Membership of the Royal College of Physicians (MRCP UK) Acute Medicine, Clinical Pharmacology and Professional Practice Flashcards

24 sample cards from the Acute Medicine, Clinical Pharmacology and Professional Practice deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. Differentiate cohort, case-control, and cross-sectional study designs.

   Cohort: prospective, follows exposed vs unexposed for outcomes; gives incidence and relative risk; good for rare exposures. Case-control: retrospective, compares cases vs controls for past exposure; gives odds ratio; good for rare diseases. Cross-sectional: snapshot at one time; gives prevalence.

2. Define sensitivity and specificity.

   Sensitivity $= \dfrac{TP}{TP + FN}$ = proportion of true positives correctly identified (rules OUT disease when negative — SnNout). Specificity $= \dfrac{TN}{TN + FP}$ = proportion of true negatives correctly identified (rules IN disease when positive — SpPin).

3. Define positive and negative predictive value and how prevalence affects them.

   PPV $= \dfrac{TP}{TP + FP}$ = probability disease is present given a positive test. NPV $= \dfrac{TN}{TN + FN}$ = probability disease is absent given a negative test. Both depend on prevalence: PPV rises and NPV falls as prevalence increases.

4. What are likelihood ratios and what values are clinically useful?

   $LR^{+} = \dfrac{\text{sensitivity}}{1 - \text{specificity}}$, $LR^{-} = \dfrac{1 - \text{sensitivity}}{\text{specificity}}$. $LR^{+} > 10$ or $LR^{-} < 0.1$ strongly changes probability; LRs are prevalence-independent and used with pre-test odds to get post-test odds.

5. Define relative risk (RR) and odds ratio (OR).

   $RR = \dfrac{\text{risk in exposed}}{\text{risk in unexposed}}$ (used in cohort/RCT). $OR = \dfrac{\text{odds in exposed}}{\text{odds in unexposed}}$ (used in case-control). OR approximates RR when the outcome is rare.

6. How are absolute risk reduction (ARR) and number needed to treat (NNT) calculated?

   $ARR = \text{CER} - \text{EER}$ (control vs experimental event rates). $NNT = \dfrac{1}{ARR}$, rounded up. NNT = number of patients treated to prevent one additional adverse outcome; lower NNT = more effective.

7. What is relative risk reduction (RRR) and why can it mislead?

   $RRR = \dfrac{\text{ARR}}{\text{CER}} = 1 - RR$. It can exaggerate benefit because it ignores baseline risk — a large RRR may correspond to a tiny absolute benefit (high NNT) when baseline risk is low.

8. What does a p-value and a 95% confidence interval tell you?

   P-value: probability of observing the result (or more extreme) if the null hypothesis were true; <$0.05$ conventionally 'significant.' 95% CI: range within which the true value lies with 95% confidence; if it crosses the null (1 for ratios, 0 for differences), the result is non-significant.

9. What is the difference between a Type I and Type II statistical error?

   Type I error ($\alpha$): false positive — rejecting a true null hypothesis (detecting an effect that isn't there). Type II error ($\beta$): false negative — failing to reject a false null hypothesis (missing a real effect). Power $= 1 - \beta$.

10. What is statistical power and what determines it?

    Power $= 1 - \beta$ = probability of detecting an effect when one truly exists (conventionally $\geq 80\%$). Increased by larger sample size, larger effect size, lower variance, and a higher (less strict) $\alpha$.

11. What is intention-to-treat (ITT) analysis and why is it preferred?

    ITT analyses participants in the groups to which they were randomised, regardless of compliance, crossover, or dropout. It preserves randomisation, avoids attrition bias, and reflects real-world effectiveness; per-protocol analysis can overestimate efficacy.

12. What is a forest plot in a meta-analysis and what does $I^{2}$ represent?

    A forest plot displays individual study effect sizes with confidence intervals and a pooled (diamond) estimate. $I^{2}$ quantifies heterogeneity (proportion of variation due to between-study differences rather than chance): >$50\%$ suggests substantial heterogeneity.

13. What is publication bias and how is it detected in a systematic review?

    Publication bias occurs when studies with positive/significant results are more likely to be published, skewing pooled estimates. Detected by funnel plot asymmetry (or Egger's test); asymmetry suggests missing small negative studies.

14. What are the components of critically appraising a paper (validity, results, applicability)?

    Validity: was the design appropriate, randomisation/blinding adequate, follow-up complete, groups comparable? Results: what is the effect size and precision (CI)? Applicability: are patients similar to mine, do benefits outweigh harms/costs, is it feasible? Tools: CASP checklists.

15. What is the difference between intention-to-treat and the levels of blinding in an RCT?

    Single-blind: participant unaware of allocation. Double-blind: participant and investigator/assessor unaware. Triple-blind: also the data analysts. Blinding reduces performance and detection bias; allocation concealment (separate concept) prevents selection bias at randomisation.

16. State Wilson and Jungner's key principles for a screening programme.

    The condition should be an important health problem with a recognisable latent stage and understood natural history; there should be an acceptable, sensitive/specific test; an effective accepted treatment; agreed policy on whom to treat; and the cost should be economically balanced. Screening should be a continuing process.

17. What is lead-time bias in screening?

    Lead-time bias is the apparent increase in survival time that results merely from earlier diagnosis through screening, without the natural course or time of death being altered — survival appears longer because the clock starts earlier.

18. What is length-time bias in screening?

    Length-time bias is the overrepresentation of slow-growing, less aggressive disease in screen-detected cases (because indolent disease has a longer detectable preclinical phase), making screening appear to improve outcomes more than it truly does.

19. Distinguish selection bias, recall bias, and confounding.

    Selection bias: systematic differences in who is included/retained. Recall bias: differential accuracy of recalled exposure (common in case-control). Confounding: a third variable associated with both exposure and outcome distorting the association (e.g. smoking confounding alcohol-cancer link).

20. How can confounding be addressed in study design and analysis?

    Design: randomisation, restriction, matching. Analysis: stratification, multivariable regression, standardisation, and propensity scoring. Randomisation is most powerful as it balances both known and unknown confounders.

21. What are the grades of pressure ulcers (EPUAP/NPUAP categories)?

    Grade 1: non-blanchable erythema, intact skin. Grade 2: partial-thickness loss (blister/abrasion, into dermis). Grade 3: full-thickness loss into subcutaneous fat. Grade 4: full-thickness loss exposing muscle/bone/tendon. Plus unstageable and deep tissue injury.

22. What are the main types of urinary incontinence and their mechanisms?

    Stress (leak on raised intra-abdominal pressure, sphincter weakness), Urge (overactive detrusor), Mixed (both), Overflow (chronic retention/obstruction), and Functional (cognitive/mobility barrier). Management is guided by type after assessment.

23. What tool assesses pressure ulcer risk and what are key prevention measures?

    The Waterlow score (or Braden scale) assesses risk. Prevention: regular repositioning (e.g. every 2 hours), pressure-redistributing mattresses/cushions, skin inspection, optimising nutrition and hydration, and keeping skin dry.

24. What is a multifactorial falls assessment and which interventions reduce falls?

    Assess gait/balance, vision, cognition, postural BP, medications, footwear, continence, environmental hazards, and bone health. Interventions: strength/balance exercise, medication review (reduce sedatives/antihypertensives), vision correction, home hazard modification, and vitamin D where deficient.

What this deck covers

Acute Medicine, Clinical Pharmacology and Professional Practice flashcards FAQ