MSRA MSRA Data Interpretation 2

Question 1

A study reports a relative risk reduction of 30% for a new drug compared to placebo. The control event rate is 6%. What is the absolute risk reduction?

Accepted Answer

1.8%

Answer

Absolute risk reduction = relative risk reduction × control event rate = 0.30 × 6% = 1.8%; the NNT would be 1/0.018 ≈ 56 patients.

Question 2

A new screening test has sensitivity 95% and specificity 80%. In a population with 5% disease prevalence, a patient tests positive. What is the approximate positive predictive value?

Accepted Answer

~20%

Answer

In low-prevalence populations, even a test with high sensitivity and specificity yields a low PPV (~20%) because false positives outnumber true positives.

Question 3

A randomised controlled trial reports a p-value of 0.03 and a 95% confidence interval for the mean difference of 0.5 to 4.5 mmHg. What can be concluded?

Accepted Answer

The result is statistically significant but clinical significance requires assessment of the effect size

Answer

A p-value <0.05 and CI not crossing zero indicate statistical significance, but whether a 0.5–4.5 mmHg difference is clinically meaningful requires separate evaluation.

Question 4

Urinalysis shows: protein 3+, blood 1+, and microscopy reveals red cell casts. Serum creatinine has doubled in 2 weeks. What does this suggest?

Accepted Answer

Nephritic syndrome with rapidly progressive glomerulonephritis

Answer

Red cell casts with haematuria, proteinuria, and rapidly rising creatinine is the hallmark of nephritic syndrome with rapidly progressive glomerulonephritis requiring urgent renal biopsy.

Question 5

A CXR shows bilateral hilar lymphadenopathy, diffuse interstitial shadowing, and no pleural effusion. ACE level is elevated. What is the most likely diagnosis?

Accepted Answer

Sarcoidosis

Answer

Bilateral hilar lymphadenopathy with interstitial infiltrates and elevated ACE is the classic radiological and biochemical pattern of pulmonary sarcoidosis.

MSRA Exam (Multi-Specialty Recruitment Assessment) Practice Test

MSRA Exam (Multi-Specialty Recruitment Assessment) Practice Test

MSRA MSRA Data Interpretation 2