Bias and Loss to Follow-Up in Cardiovascular Randomized Trials: A Systematic Review

Factors Associated With Loss to Follow-Up in Surgical Trials: A Systematic Review and Meta-Analysis

INTRODUCTION

Loss to follow-up (LTFU) distorts results of randomized controlled trials (RCTs). Understanding trial characteristics that contribute to LTFU may enable investigators to anticipate the extent of LTFU and plan retention strategies. The objective of this systematic review and meta-analysis was to investigate the extent of LTFU in surgical RCTs and evaluate associations between trial characteristics and LTFU.

METHODS

MEDLINE, Embase, and PubMed Central were searched for surgical RCTs published between January 2002 and December 2021 in the 30 highest impact factor surgical journals. Two-hundred eligible RCTs were randomly selected. The pooled LTFU rate was estimated using random intercept Poisson regression. Associations between trial characteristics and LTFU were assessed using metaregression.

RESULTS

The 200 RCTs included 37,914 participants and 1307 LTFU events. The pooled LTFU rate was 3.10 participants per 100 patient-years (95% confidence interval [CI] 1.85-5.17). Trial characteristics associated with reduced LTFU were standard-of-care outcome assessments (rate ratio [RR] 0.17; 95% CI 0.06-0.48), surgery for transplantation (RR 0.08; 95% CI 0.01-0.43), and surgery for cancer (RR 0.10; 95% CI 0.02-0.53). Increased LTFU was associated with patient-reported outcomes (RR 14.21; 95% CI 4.82-41.91) and follow-up duration ≥ three months (odds ratio 10.09; 95% CI 4.79-21.28).

CONCLUSIONS

LTFU in surgical RCTs is uncommon. Participants may be at increased risk of LTFU in trials with outcomes assessed beyond the standard of care, surgical indications other than cancer or transplant, patient-reported outcomes, and longer follow-up. Investigators should consider the impact of design on LTFU and plan retention strategies accordingly.

The use of routinely collected healthcare records for outcome assessment in clinical trials: a UK perspective

The use of routinely collected electronic healthcare records (EHR) for outcome assessment in clinical trials has been described as a 'disruptive' new technique more than a decade ago. Despite this potential, significant methodological issues and regulatory barriers have hampered the progress in this area. This article discusses the key considerations that trialists should take into account when incorporating EHR into their trials. These include considerations of the clinical relevance of the outcome, data timeliness and quality, ethical and regulatory issues, and some practical considerations for clinical trials units. In addition, this article describes the benefits of using EHR which include cost, reduced trial burden for participants and staff, follow up efficiencies, and improved health economic evaluation procedures. We also describe the major regulatory and start up costs of using EHR in clinical trials. This article focuses on the UK specific EHR landscape in clinical trials and would help researchers and trials units considering the use of this method of outcome data collection in their next trial. If the issues described are mitigated, this method will be a formidable tool for conducting pragmatic clinical trials.

Loss to Follow-up in Head and Neck Cancer: A Systematic Review of Randomized Controlled Trials

OBJECTIVE

To evaluate the reporting and rates of loss to follow-up (LTFU) in head and neck cancer (HNC) randomized controlled trials based in the United States.

DATA SOURCES

Pubmed/MEDLINE, Cochrane, Scopus databases.

REVIEW METHODS

A systematic review of titles in Pubmed/MEDLINE, Scopus, and Cochrane Library was performed. Inclusion criteria were US-based randomized controlled trials focused on the diagnosis, treatment, or prevention of HNC. Retrospective analyses and pilot studies were excluded. The mean age, patients randomized, publication details, trial sites, funding, and LTFU data were recorded. Reporting of participants through each stage of the trial was documented. Binary logistic regression was performed to evaluate associations between study characteristics and reporting LTFU.

RESULTS

A total of 3255 titles were reviewed. Of these, 128 studies met the inclusion criteria for analysis. A total of 22,016 patients were randomized. The mean age of participants was 58.6 years. Overall, 35 studies (27.3%) reported LTFU, and the mean LTFU rate was 4.37%. With the exception of 2 statistical outliers, study characteristics including publication year, number of trial sites, journal discipline, funding source, and intervention type did not predict the odds of reporting LTFU. Compared to 95% of trials reporting participants at eligibility and 100% reporting randomization, only 47% and 57% reported on withdrawal and details of the analysis, respectively.

CONCLUSION

The majority of clinical trials in HNC in the United States do not report LTFU, which inhibits the evaluation of attrition bias that may impact the interpretation of significant findings. Standardized reporting is needed to evaluate the generalizability of trial results to clinical practice.

Clinical Trial Technologies for Improving Equity and Inclusion in Cardiovascular Clinical Research

Approximately one-third of clinical trials fail to meet their recruitment goals, which can cause costly delays to sponsors and compromise the scientific integrity and generalizability of a trial. Inadequate recruitment and retention of patient groups who have the disease under investigation may produce insufficient medical knowledge about the therapeutic effects of drugs or products for the population at large. It is essential to address these issues to ensure that certain groups are not unduly subjected to disproportionate risks or denied the benefits of research. This commentary will present opportunities for clinical trialists to use emerging technologies and decentralized approaches to improve clinical trial recruitment, mitigate disparities, and improve individual and population-level outcomes within cardiovascular medicine.

Changes Over a Decade in Patient-Reported Outcome Measures and Minimal Clinically Important Difference Reporting in Total Joint Arthroplasty

Background

When used appropriately, the minimal clinically important difference (MCID) provides a powerful tool for identifying meaningful improvements brought about by a given treatment, offering more clinically relevant information than frequentist statistical analysis. However, recent studies have shown inconsistent derivation methods and use of MCIDs. The goal of this study was to report the rate of patient-reported outcome measures (PROMs) and MCIDs use in the literature and assess how this rate has changed over time.

Methods

All articles published in 2010 and 2020 reporting on total hip arthroplasty or total knee arthroplasty in The Journal of Clinical Orthopaedics and Related Research, The Journal of Bone and Joint Surgery, and The Journal of Arthroplasty were reviewed. In each reviewed article, every reported PROM and, if present, its corresponding MCID was recorded. These data were used to calculate the rate of reporting of each PROM and MCID.

Results

While the total number of articles on total hip arthroplasty and total knee arthroplasty reporting PROMs increased over time, the proportion of articles reporting PROMs decreased from 49.8% (131/263) in 2010 to 35.5% (194/546) in 2020 (P = .011). Of these articles that report PROMs, the proportion of articles reporting any MCID increased from 2.3% (3/131) in 2010 to 16.5% (32/194) in 2020 (P = .002).

Conclusions

The rate of reporting of MCIDs among articles relating to total hip arthroplasty and total knee arthroplasty that report PROMs has increased significantly between 2010 and 2020 but remains low. Continued emphasis on appropriate inclusion and value of MCIDs when PROMS are reported in clinical outcomes studies is needed.

Cardiovascular Safety and Superiority of Anti-Obesity Medications

Over the past few decades, several anti-obesity medications have demonstrated an association with adverse cardiovascular outcomes, leading to their market withdrawal. This has caused researchers to investigate the cardiovascular safety of such medications in cardiovascular outcome trials. However, the data from these trials are limited, and their outcomes are not promising. Therefore, the aim of this review is to provide an overview of the current and past Food and Drug Administration-approved medications for weight loss, including novel diabetes medications (glucagon-like peptide 1 receptor agonists and sodium-glucose co-transporter-2 inhibitors) and non-diabetes medications, and to highlight the current designs of cardiovascular outcome trials and their importance in the evaluation of the overall safety concerns associated with these anti-obesity medications. The limitations of the trials and opportunities for improvement were also evaluated. Finally, we also briefly describe cardiovascular safety and risks in this review.

Bias and Loss to Follow-Up in Cardiovascular Randomized Trials: A Systematic Review

Background Loss to follow-up (LTFU) is common in randomized controlled trials. However, its potential impact on primary outcomes from cardiovascular randomized controlled trials is not known. Methods and Results We conducted a prospective systematic review (PROSPERO: CRD42019121959) for randomized controlled trials published in 8 leading journals over 5 years from January 2014 to December 2018. Extent, reporting, and handling of LTFU data were recorded, and the proportion of a trial's primary outcome results that lose statistical significance was calculated after making plausible assumptions for the intervention and control arms. These assumptions could drive differential treatment effects between the groups considering relative event incidence between LTFU participants and those included in the primary outcome. We identified 117 randomized controlled trials of which 91 (78%) trials reported LTFU, 23 (20%) reported no LTFU, and 3 (3%) trials did not report on whether LTFU occurred. The median percentage of study participants lost to follow-up was 2% (interquartile range, 0.33%-5.3%). Only 10 trials (9%) had a low cluster of risk factors for impairment in trial quality. The percentage of trials losing statistical significance varied from 2% when the relative event incidence for LTFU between the randomized groups was 1 for the intervention arm and 1.5 for the control arm to 16% when the relative event incidence was 3 for the intervention arm and 1 for the control arm. Conclusions Almost 1 in 6 (16%) cardiovascular randomized trials published in leading journals may have a change in the primary outcome if plausible assumptions are made about differential event rates of participants lost to follow up. There is scope for improvement arising from LTFU in randomized trials in cardiovascular medicine. Registration URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42019121959.