Potential bias in ophthalmic pharmaceutical clinical trials

Sociodemographic disparities in ophthalmological clinical trials

Introduction

In ophthalmology, clinical trials (CTs) guide the treatment of diseases such as diabetic retinopathy, myopia, age-related macular degeneration, glaucoma and keratoconus with distinct presentations, pathological characteristics and responses to treatment in minority populations.

Reporting gender and race and ethnicity in healthcare studies is currently recommended by National Institutes of Health (NIH) and Food and Drug Administration (FDA) guidelines to ensure representativeness and generalisability; however, CT results that include this information have been limited in the past 30 years.

The objective of this review is to analyse the sociodemographic disparities in ophthalmological phases III and IV CT based on publicly available data.

Methods

This study included phases III and IV complete ophthalmological CT available from clinicaltrials.org, and describes the country distribution, race and ethnicity description and gender, and funding characteristics.

Results

After a screening process, we included 654 CTs, with findings that corroborate the previous CT reviews’ findings that most ophthalmological participants are white and from high-income countries. A description of race and ethnicity is reported in 37.1% of studies but less frequently included within the most studied ophthalmological specialty area (cornea, retina, glaucoma and cataracts). The incidence of race and ethnicity reporting has improved during the past 7 years.

Discussion

Although NIH and FDA promote guidelines to improve generalisability in healthcare studies, the inclusion of race and ethnicity in publications and diverse participants in ophthalmological CT is still limited. Actions from the research community and related stakeholders are necessary to increase representativeness and guarantee generalisability in ophthalmological research results to optimise care and reduce related healthcare disparities.

Does Ophthalmology Need Philosophy?

Although ophthalmology has made significant progress and awareness about eye care and the accessibility of health technology has increased, there are still aspects that might be improved. One of the ways to achieve improvement is philosophical investigation of some reasoning and behavior styles in ophthalmology. Philosophy means love of wisdom, and the philosophical approach can contribute to increasing the wisdom of ophthalmologists. Logical fallacies currently affecting the decisions of ophthalmologists can be reduced. "ontology" can contribute to a better understanding of "the nature of reality". A detailed inquiry about the basic concepts concerning ophthalmology may support better reasoning styles. Reflecting on epistemological questions such as "What is true knowledge?", justifying information, and having a skeptical attitude may help to make decisions with more accurate information. The philosophy of science is concerned with the detailed investigation, questioning, and understanding of ophthalmologists' scientific activities and may form the missing link between ophthalmology and philosophy. Moreover, the claim that philosophy's contribution to science is of no interest to scientists warrants consideration. The philosophers of science Karl Popper and Thomas Kuhn have made significant contributions to the perception of science that are still valid today. Karl Popper proposed that a demarcation between science and pseudo-science might be made through the concept of "falsification". According to this concept, a statement is scientific if it can be tested and falsified using valid methods. Thomas Kuhn stated that major scientific changes (i.e., revolutions) occur through paradigm shifts. Although the areas of moral philosophy/ethics/bioethics have generated useful ideas and practices for the improvement of the art of medicine, bioethics in particular deserves to be questioned philosophically by physicians living in real life. Ophthalmologists can develop more beneficial and realistic ophthalmology education, research, diagnosis, treatment, and rehabilitation practices by utilizing the basic methods of philosophy.

Characteristics of Ophthalmology Trials Registered in ClinicalTrials.gov, 2007-2018

PURPOSE

To perform a comprehensive analysis of characteristics of ophthalmology trials registered in ClinicalTrials.gov.

DESIGN

Cross-sectional study.

METHODS

All 4,203 ophthalmologic clinical trials registered on ClinicalTrials.gov between October 1, 2007, and April 30, 2018, were identified by using medical subject headings (MeSH). Disease condition terms were verified by manual review. Trial characteristics were assessed through frequency calculations. Hazard ratios and 95% confidence intervals were determined for characteristics associated with early discontinuation.

RESULTS

The majority of trials were multiarmed (73.6%), single-site (69.4%), randomized (64.8%), and had <100 enrollees (66.3%). A total of 33% used a data-monitoring committee (DMC), and 50.6% incorporated blinding. Other groups (51.6%) were funded by industry, whereas 2.6% were funded by the US National Institutes of Health (NIH). NIH trials were significantly more likely to address oncologic (NIH = 15.5%, Other = 3%, Industry = 1.5%; P < 0.001) or pediatric disease (NIH = 20.9%, Other = 5.9%, Industry = 1.4%; P < 0.001). Industry-sponsored trials (69.6% of phase 3 trials) were significantly more likely to be randomized (Industry = 68.7%, NIH = 58.9%, Other = 60.8%; P < 0.001) and blinded (Industry = 57.2%, NIH = 42.7%, Other = 43.5%; P < 0.001). A total of 359 trials (8.5%) were discontinued early, and 530 trials (12.6%) had unknown status. Trials were less likely to be discontinued if funded by sources other than industry (hazard ratio [HR], 0.72; 95% confidence interval [CI], 0.55-0.95; P = 0.021) and/or had a DMC (HR, 0.71; 95% CI, 0.55-0.92; P = 0.010).

CONCLUSIONS

Ophthalmology trials in the past decade reveal heterogeneity across study funding sources. NIH trials were more likely to support historically underfunded subspecialties, whereas Industry trials were more likely to face early discontinuation. These trends emphasize the importance of carefully monitored and methodologically sound trials with deliberate funding allocation.

Noncompliance in Prospective Retina Clinical Trials: Analysis of Factors Predicting Loss to Follow-up

PURPOSE

Noncompliance during prospective studies can bias results and limit conclusions. The current study retrospectively investigated the relationship between study subject characteristics and rates of noncompliance in interventional trials involving common causes of blindness.

DESIGN

Retrospective analysis of 10 randomized clinical trials.

METHODS

Subjects were enrolled in investigator-initiated trials studying proliferative diabetic retinopathy, neovascular age-related macular degeneration, diabetic macular edema, and retinal venous occlusive disease. Records were reviewed for hypothesized risk factors of noncompliance and rates of noncompliance, which were defined as at least 1 missed visit or exiting the study early. Demographic information, systemic medical history, and ocular medical history, including visual acuity and central retinal thicknesses, were examined retrospectively using Student t test, Pearson χ² test, and logistic regression.

RESULTS

Of 390 subjects included, 212 (54.4%) were compliant with all scheduled study visits and 178 (45.6%) met criteria for noncompliance, with 53 (13.6%) subjects exiting early. Regression models identified 17 variables that were significant in determining subject noncompliance. Among those, distance, comorbidities, diabetic status, concomitant medications, previous clinic visits, length of study, disease under study, and severe adverse events were highly significant risk factors of noncompliance.

CONCLUSION

The current research identified a substantial proportion of subjects who met the criteria for noncompliance within the trials analyzed. The factors identified in the current work are consistent with published clinical observations and the results of previous clinical trials. These results highlight the importance of considering study design and medical history when designing prospective clinical trials in an attempt to minimize data loss.

Effect of funding source on reporting bias in studies of intravitreal anti-vascular endothelial growth factor therapy for retinal vein occlusion

PURPOSE

To examine the relationship between industry funding and outcome reporting bias in high-quality studies investigating the use of intravitreal anti-vascular endothelial growth factor (VEGF) agents for patients with macular oedema secondary to branch or central retinal vein occlusion (RVO).

METHODS

This systematic review in PubMed and Ovid MEDLINE examined all randomized clinical trials and meta-analyses published in journals with impact factor of ≥2 that investigated effectiveness of intravitreal anti-VEGF therapy in patients with RVO. The main outcome measure was correspondence between statistical outcome and abstract conclusion wording.

RESULTS

Forty-five studies met inclusion criteria; 38 (84%) showed correspondence between outcome and abstract conclusion without difference between industry-funded and nonindustry-funded publications (p = 0.39) or between publications in journals with impact factor ≥3 versus <3 (p = 0.96).

CONCLUSION

In high-quality studies of intravitreal anti-VEGF therapy for RVO, neither industry funding nor journal impact factor affected the rate of outcome reporting bias.