Drawing the study schema
A protocol's study schema is a figure that shows the study design the text describes. It can be drawn with standard tools as a timeline of the study's periods, visits and treatment arms, with labelled icons for the elements that matter or repeat.
What a study schema is for
The content of clinical regulatory documents is usually governed by health agency guidelines that set the type of information to include and the format in which to present it. Most of that information is not necessarily suited to visualisation and can be difficult to translate into a figure other than a table or a graph. The study schema is a significant exception. It is a graphical description of the study design detailed in the text, it appears in the protocol and may later be included in the corresponding clinical study report or publication, and it gives the medical writer an opportunity to be creative. Drawn as an infographic, a schema can help readers better understand multiple layers of complex information.
A schema can show a complicated design. Examples are a first-in-human phase 1 study, which often doses several cohorts in sequence with single or multiple doses, multiple strengths of the study treatment or both, a study with several treatment periods, and an adaptive design.
Drawing a schema needs neither specialised graphic design abilities nor expensive software. A schema that adheres to the company brand and the standards of professional publication can be designed with standard tools such as Microsoft PowerPoint. Colour, shapes and icons can portray its timelines, dosage regimens, treatment arms, study periods and procedures.
Who reads the schema
The readers of clinical regulatory documents include regulatory agencies, health authorities and investigators, and also potential study participants and their caregivers, who may read protocols on regulatory websites because of the data disclosure requirements of the EMA and the FDA. These requirements mandate that protocols be shared on designated clinical trial websites. As a visual medium, the internet is transforming the way these protocols are communicated to a global audience. A schema drawn as an infographic helps an international audience understand the study design at a glance. If the study is later presented as a poster or a presentation at a scientific conference, a well-prepared schema gives the reader a rapid grasp of the design while saving space in the slide deck or poster.
The schema as a timeline
A study has a defined start and usually an end, so a timeline infographic is the most suitable way to represent its schema. A timeline conveys processes that run in sequence and in parallel at the same time. The visits from enrolment through the study are a sequential process, and the administration of study drug to patients in the different treatment arms is a parallel process. Both are easy to understand together when they are drawn as separate bars on one timeline, because the mind already has built-in assumptions about how to read and parse visual information:
- English is read from left to right, so the timeline begins on the left and proceeds to the right.
- Information is parsed from top to bottom, so the main stages of the study are described at the top.
What a timeline schema shows
One example schema shows a relatively simple fixed-duration, parallel-group study in which three doses of a drug were compared with placebo. The study is double-blind, with about 100 patients in each arm and 1:1:1:1 randomisation. The schema depicts the timepoints of the in-clinic visits and of the telephone contact during the study. Its timeline represents every significant milestone of the study:
- Main study periods: screening, the double-blind treatment period and follow-up appear as top-level headings, and every element of the infographic is placed under one of them.
- Periodic visits: small triangles mark the visits from visit 1 to visit 9, each visit in the double-blind treatment and follow-up periods is anchored to the week in which it occurs, and a unique colour links each visit with its week. Different colours can be used for the visits even where some visits share similar assessments and procedures.
- Visits of particular importance: flags mark such visits, for example visit 2, the baseline, and visit 8, the end of the treatment period or, for a patient who withdraws from the study, the early termination visit.
- Number and type of treatment arms: an arm discontinued for any reason can be marked, for example by an "X" on it, and the approximate number of patients planned for enrolment can be included.
- Start and end dates of treatment: vertical lines mark the start and end of the treatment period.
Icons
Icons increase an infographic's value as a communication tool. This matters particularly in clinical studies, because many late-phase studies are conducted in several countries and might need translation into the local language. Icons are a global visual language that transcends linguistic and cultural barriers. With icons, a writer can convey concepts in a visual language that everyone understands.
Some companies have their own icons, consistent with their brand and with patient perceptions. Collections of medical icons can also be found on websites such as SVG Repo, Dry Icons and Freepik. Many of these icons are open-source files that can be used in commercial projects without payment of royalties, and the icon file states whether the source must be acknowledged.
Icons can depict important or repeating elements of a study clearly and consistently. They can symbolise the main types of assessment or treatment: an icon of a tablet can depict an oral drug, and a syringe an injection. Icons can also represent inpatient and outpatient periods, which are especially critical in phase 1/2a studies.
One example schema with icons is of a study with a complex structure of multiple check points, patient interfaces and treatments, in which an oral treatment period is followed by randomisation to one of three treatment arms. Its patients are monitored with monthly in-clinic visits, and weekly telephone calls in the weeks between visits enquire about adverse events and concomitant medications. Another is of a phase 1 study with an oral treatment period, a washout and randomisation of patients to two treatment arms investigating different formulations of the study drug, in which icons depict inpatient and outpatient periods, pharmacokinetic assessments, pharmacodynamic assessments and electrocardiograms. A brief look at that schema shows a reader whether a treatment was given in a clinical trial unit or on an outpatient basis, and whether there were visits of particular importance, at which several key assessments were performed.
Labelling icons
An icon in an infographic should be described or labelled to avoid ambiguity in interpretation. Text used together with an icon enables double encoding, in which the reader processes the concept by its label and by its image. Double encoding facilitates memory, so a reader is more likely to recall an icon that is accompanied by text. Icons used repeatedly in an infographic should be labelled in a legend.