Original research reports typically cover various study types, such as randomized trials, intervention studies, cohort and case-control studies, epidemiologic assessments, and other observational research. They may also include surveys with high response rates and studies on screening and diagnostic tests. It is mandatory to specify the study type. Each manuscript should clearly define the objective or hypothesis and provide details on the design and methods, including the study type, setting, dates, and information about participants (e.g., inclusion/exclusion criteria, participation or response rates). For studies involving data, authors should describe the sources and selection criteria. Additionally, manuscripts should outline the key features of any interventions, the main outcome measures, and the study’s primary results.

A thorough discussion should place the findings in the context of relevant published literature and address any study limitations. Conclusions should be supported by the results and include implications for clinical practice or health policy. The data presented in research reports must be original, up-to-date, and relevant (refer to Timeliness of Data). Authors must also follow the appropriate EQUATOR Reporting Guidelines for their study type.

A structured abstract is required for submission (see guidelines for Abstracts for Reports of Original Data). Authors must also include a list of 3 Key Points summarizing the most important findings (see Key Points guidance). Manuscripts should not exceed 3000 words of text (excluding the abstract, tables, figures, acknowledgments, references, and any online-only material) and may contain no more than 6 tables and/or figures combined.

Abstract Guidelines for Research Articles:

The abstract should be a concise summary of no more than 350 words, adhering to the following structured format. Authors may use phrases rather than complete sentences for brevity. Each section of the abstract should address the following content:
Importance:
This section should introduce the clinical or research significance of the study. Authors should explain why the research question or topic is important to the field.

• Example: "Obesity is a leading cause of cardiovascular diseases, yet interventions targeting dietary patterns remain underutilized in primary care."

Objective:
Clearly state the main objective(s) of the study. If more than one objective is being addressed, specify the primary goal and outline any key secondary objectives. Include any a priori hypotheses, if applicable.

• Example: "To evaluate whether a low-carb diet reduces the incidence of hypertension in adults aged 40-60."

Design:
Provide a brief description of the study design, including its type (e.g., randomized controlled trial, cohort, case-control, survey, etc.). State the time period when the study was conducted and the duration of follow-up, if relevant.

• Example: "Randomized controlled trial conducted between 2020 and 2023 with a 12-month follow-up."

Setting:
Indicate the location and context in which the research was conducted.

• Example: "Multicenter study conducted in five urban primary care clinics in the United States."

Participants:
Describe the study population, including eligibility criteria, key demographics, and selection procedures (e.g., random sample, convenience sample). Report the number of eligible participants and how many actually participated in the study.

• Example: "Adults aged 40-60 with no history of cardiovascular disease were recruited. Of 500 approached, 450 enrolled and 400 completed follow-up."

Intervention(s) or Exposure(s):
For intervention studies, describe the interventions, including their type and duration. For observational studies, specify the exposures being investigated.

• Example: "Participants followed either a low-carb or standard diet for 12 months."

Main Outcome(s) and Measure(s):
Identify the primary outcome(s) measured in the study as defined prior to data collection. Include how these outcomes were measured and any tools or methods used.

• Example: "The primary outcome was systolic blood pressure change measured at baseline and after 12 months using a standardized sphygmomanometer."

Results:
Present the key findings, including demographic information (e.g., age, sex distribution), the number of participants, and a summary of the main outcomes. Provide numerical data when possible, with indicators of uncertainty such as confidence intervals and p-values.

• Example: "Among 400 participants (50% female, mean age 52), systolic blood pressure decreased by a mean of 5.2 mm Hg (95% CI, 2.4-8.0; P = .01) in the low-carb group compared with controls."

Conclusions and Relevance:
State the primary conclusions supported by the study results and highlight their clinical or research relevance. Address how the findings may influence practice or policy. Avoid overgeneralization or unsupported speculation.

• Example: "A low-carb diet modestly reduces blood pressure in middle-aged adults, supporting its use in primary care for hypertension management."

Trial Registration:
For clinical trials, provide the trial registration number, registry name, and URL.

• Example: "Registered with ClinicalTrials.gov: NCT00012345."

Clinical Trial

These manuscripts report various types of clinical trials, including Randomized Clinical Trials, Parallel-Design Double-blind Trials, Crossover Trials, Equivalence and Non-inferiority Trials, Cluster Trials, and Non-randomized Clinical Trials.

According to the ICMJE, a clinical trial is defined as any research project that prospectively assigns human participants to intervention or comparison groups to study the cause-and-effect relationship between an intervention and a health outcome. These interventions can include, but are not limited to, drugs, surgical procedures, medical devices, behavioral treatments, educational programs, dietary interventions, quality improvement measures, and changes in care processes. All manuscripts reporting clinical trials, including those that focus on secondary exploratory or post hoc analysis, must provide the following:

• A copy of the original trial protocol, including the complete statistical analysis plan and any amendments. It is recommended to use the SPIRIT reporting guidelines when preparing the original protocols (refer to Protocols).
• A CONSORT flow diagram.
• A completed trial checklist.
• Registration in an appropriate public clinical trial registry (see Trial Registration requirements).
• A Data Sharing Statement indicating whether the data will be shared or not. Specific questions on data sharing are included during manuscript submission. 

For additional guidance on reporting different types of trials, such as Randomized Clinical Trials, Parallel-Design Double-blind Trials, Crossover Trials, Equivalence and Non-inferiority Trials, Cluster Trials, and Non-randomized Clinical Trials, refer to the Study Types section.

Each manuscript should clearly describe the objective or hypothesis; study design and methods, including the setting and dates, patient or participant characteristics (with inclusion and exclusion criteria), data sources, and selection methods. It should also outline the key features of the interventions; the primary and secondary outcome measures as outlined in the trial protocol; the main results; a discussion section placing the results in the context of existing literature and addressing limitations; and the study’s conclusions.

A structured abstract is required, and trial registration details (registry name, trial ID, and URL) must be included at the end of the abstract. For more details, refer to the Abstracts for Reports of Original Data guidelines. Additionally, authors must provide a list of 3 Key Points summarizing the key findings (see Key Points guidance). The manuscript should not exceed 3000 words of text (excluding abstract, tables, figures, acknowledgments, references, and supplemental material). A maximum of 6 tables and/or figures is allowed, with 50 to 75 references.

The subtitle of the manuscript should include the phrase "A Randomized Clinical Trial" or, for non-randomized studies, "A Non-randomized Clinical Trial." For further details on clinical trial reporting, refer to the AMA Manual of Style.

Protocols Submission Guidelines

Authors submitting manuscripts reporting clinical trials must provide the full trial protocol, including the complete statistical analysis plan, as part of their submission. If the protocol is in a non-English language, it must be translated into English. This submission should include the original, approved protocol and statistical analysis plan, along with any amendments made to either document. A summarized version, previously published in another journal, is not acceptable. Upon acceptance of the manuscript, the protocol and statistical analysis plan will be published as a supplementary document. Furthermore, any clinical trial that has commenced randomization must be registered in an appropriate public registry (see Trial Registration requirements). Authors should follow the SPIRIT Reporting Guidelines when preparing their protocol.

CONSORT Flow Diagram and Checklist
Manuscripts reporting results of randomized clinical trials must include the CONSORT flow diagram, which outlines the progress of participants through each stage of the trial. Additionally, authors are required to complete and submit the CONSORT checklist along with the manuscript submission.

Figure: Profile of a Randomized Clinical Trial (example showing patient flow)