In an RCT of a new oral hypoglycaemic agent, 15% of patients assigned to the drug stopped taking it after two months, and some controls started metformin outside the protocol. To preserve the validity of the randomized comparison at final analysis, the investigators should analyse patients according to:

• A The treatment actually received throughout the trial
• B Their original random allocation ✓
• C Only those who completed the full follow-up
• D Their baseline HbA1c category

Explanation

Intention-to-treat analysis keeps every participant in the arm to which they were randomized regardless of adherence, preserving the prognostic balance that randomization created and reflecting real-world effectiveness. Analysing by treatment received or restricting to completers is a per-protocol approach that invites attrition bias and can exaggerate efficacy. Baseline stratification does not address non-adherence.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.