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Do we really need follow up studies of randomised clinical trials in RA?
In rheumatology we have been told for years that the results of randomised controlled trials may not be extrapolated to the long term, and that a gain in the beginning may not necessarily mean a gain in what we solemnly call the “final outcome”. In almost every review on disease modifying antirheumatic drugs (DMARDs) in rheumatoid arthritis (RA), long term efficacy and long term toxicity are always considered. The importance of long term data is repeatedly stated, without, however, explaining what information is really necessary. And regulatory authorities nowadays require long term studies before approving drugs which claim, for example, to preserve function.
Probably as a consequence of this, we are now facing an increasing number of published follow up reports of clinical trials—for example, references 1–6a.1–6a The conclusion is always that some drug is still as effective and as toxic as its comparator, x years after the start of the trial, or that drug A “maintains its efficacy or its superiority over drug B” over time.
REASONS TO PERFORM FOLLOW UP STUDIES OF CLINICAL TRIALS
A large number of arguments are mentioned by different authors to justify follow up studies. These arguments—more or less valid—include doubts about long term clinical efficacy, effects on radiological progression and function, long term toxicity, “drug survival time”, cost effectiveness, and quality of life. Intuitively, follow ups of randomised controlled trials (RCTs) enjoy a greater respect than observational studies, because patients were allocated to groups by chance, and most authors assume they can make an appropriate between-group comparison at the end.
The questions to be asked in this editorial are:
Does the methodology used in follow up studies of RCTs provide data which are valid?
Do these studies really increase our knowledge of particular drugs and their long …