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Retinal clinical trials indicate that almost 50% of studies have non-compliance issues

Clinical research has indicated that almost half of trial studies have noncompliance issues, creating negative impact outcomes for research.  A recent study has shown that 54.4% of patients were compliant with completing all study visits while 45.6% of subjects were noncompliant.  Given that trials are a cornerstone to collect patient data in order to build new medical treatments, the loss of compliance eventually harms patients.  If patients leave before the end of a clinical trial there will be significant losses of time, effort and financial resources.  While there are many reasons why a clinical trial fails, several factors include faults in study design, the length of a trial, patients’ comorbidities, medication (and the number of medications), distance of travel and other reasons for loss-to-follow-up rates (LTFU).


The research analysis, published in the American Journal of Ophthalmology, 2019, showed that 390 patients in clinical trials had noncompliance issues due to worsening health, death, no longer wishing to participate in the study, adverse event (AE) occurrence, employment issues and transportation problems.  The research indicated that about half of the subjects enrolled in the ten (10) investigator-initiated trials had noncompliant issues while commercial trials have different rates. In ophthalmic studies collected, HAWK and HARRIER had mean completion rates of 89.5% and 93.4%, respectively, at the end of 1 year. Similarly, RISE and RIDE had mean completion rates of 83.3% and 84.6%, respectively, at the end of 2 years and, VISTA and VIVID had mean completion rates of 76.6% and 74.4%, respectively, at the end of 3 years. Across the studies, noncompliance has found that concomitant medications have a significant issue, for example, with >15 medications, there are a 2.16 times greater odds of a patient being noncompliant than with <8 concomitant medications. In addition, chronic conditions including diabetes, hypertension, and hyperlipidemia have been associated with nonadherence to medications in general.


Noncompliance in a trial also occurs when studies can be too long.  Study design is a well-recognized determinant of the outcomes of trials and this has been seen all types of trials.  The researchers have found that the length of study was one of the most influential factor in determining noncompliance.  Analysis showed that the odds of noncompliance in subjects enrolled in studies lasting 25-36 months were 5.12 times greater than the odds of noncompliance in subjects enrolled in studies lasting 1-12 months.  Commenting on their study, researchers stated that, “clinicians designing research studies may consider using these results to anticipate noncompliance based on the type of study and medical history of the subjects enrolled and consider adjusting enrollment numbers accordingly to prevent loss of statistical power”.  It is clear that these lessons may provide very valuable knowledge to design all future trials.