terminated-trials-analysis-study

Overview

A repository for analysing ClinicalTrials.gov registered trials with a "Terminated" status, using functions from the terminated-trials-study package.

Part 1

Description

This part focuses on processing historical entries related to ClinicalTrials.gov registered terminated trials and relies on 'cthist' package developed by BG Carlisle. For following part 1, refer to the 01_analyse-data-terminated.R.

Input

The dataset used for processing should include trial ID (nctid) of ClinicalTrials.gov registered trials with recruitment status ('recruitment_status') specified as "Terminated" in the registry.

Dependencies:

The 'cthist' package is utilised to obtain historical entries for the terminated trials
The Following Two functions are employed from the 'terminatedtrialsstudy' R package :

The duration_of_trial function calculates the number of days the trial was ongoing until termination, referred to as "trial_days."
The degree_of_enrollment function calculates the percentage of enrollment achieved for a particular terminated trial, known as "enrollment_percentage."

Output

The output dataset generated by this script includes the following variables for each terminated trial:

variable	description
nctid	Trial ID
why_stopped	Reason for trial termination
has_summary_result_ctgov	Boolean indicating the availability of summary results on ClinicalTrials.gov for the trial
start_date	Date when the trial was initiated
stop_date	Date when the trial's overall status was first updated to "Terminated" in the registry
trial_days	Number of days the trial was ongoing until termination calculated as `stop_date - start_date`
anticipated_enrollment	Expected number of participants that the trial aimed to enrol
actual_enrollment	Observed number of participants actually enrolled
enrollment_percentage	Percentage of enrollment achieved until termination, `(achieved enrollment / anticipated enrollment) * 100`

Note

At the dataset level, the total number of trial days is calculated by summing the trial days values for all trials total_trial_days = sum of trial days for all trials
At the dataset level, the average degree of enrollment is calculated by summing the degree of enrollment values for all trials and dividing it by the total number of trials: average_degree_of_enrollment = (Sum of Degree of Enrollment) / (Number of Trials)

Part 2 (dataset specific)

Description (summary result reporting)

Bi-directional cross-registration checks will be performed using two approaches:

Cross-registration from ClinicalTrials.gov to EUCTR: The IntoValue dataset will be used to identify cross-registrations between the ctgov (ClinicalTrials.gov) registry and the EUCTR (European Union Clinical Trials Register) registry. The cross-registration dataset will be utilized to find EUCTR cross-registrations for the corresponding NCT IDs.
Cross-registration from EUCTR to ctgov: EUCTR IDs associated with German UMC leads will be extracted from a JSON dataset, maintained in the euctr-tracker-data repository. The dataset will further be analyzed to identify additional identifiers in the protocol and result pages of the EUCTR registry. The combine_info function, sourced from a forked version of the "euctrscrape" repository by Delwen Franzen and originally created by BG Carlisle, will be used for this purpose. From the extracted additional identifiers, NCT IDs found in the original IntoValue dataset will be identified, thus obtaining cross-registered data from both sources.

Once the cross-registered data is obtained, the EUCTR IDs will be checked to determine if the corresponding trials had results posted in the registry using the get_euctr_results.R function from the 'terminatedtrialsstudy' package.

Input

The EUCTR trial IDs sourced from bi-directional cross-registration checks

Dependencies

The forked version of the 'euctrscrape' package is utilised to find additional identifiers in the protocol and results section of EUCTR ids and these identifiers are matched to nctids in the original dataset.
get_euctr_result_link.R function: This function retrieves the result link if the result were posted for EUCTR entry, otherwise returns 'No result found'.

Output

The output variable generated for each ClinicalTrails.gov registered trial:

variable	description
nctid	Trial ID
crossreg_euctr_ids	Cross-registered EUCTR ids for ClinicalTrials.gov registered trial
is_crossreg_euctr	Boolean indicating whether or not the 'nctid' has cross-registration in EUCTR
has_summary_result_euctr	Boolean indicating the availability of summary results on the EUCTR registry for the trial
link	Link to available result section page

References

Carlisle BG. Analysis of clinical trial registry entry histories using the novel R package cthist. PLoS One. 2022;17(7):e0270909. https://doi.org/10.1371/journal.pone.0270909

DeVito NJ, Goldacre B. Trends and variation in data quality and availability on the European Union Clinical Trials Register: A cross-sectional study. Clinical Trials. 2022;19(2):172-183. https://doi.org/10.1177/17407745211073483

bgcarlisle / terminated-trials-analysis-study Goto Github PK