Comprehensive writing guide for NEJM, Lancet, JAMA, BMJ, Annals of Internal Medicine, and other major medical journals.
Reviewed: 2026-07-20
Article-type instructions and reporting guidelines change. Verify every numeric limit with the journal's current author center.
Medical journals prioritize clinical relevance, patient outcomes, and evidence-based practice. Writing must be precise, evidence-focused, and directly applicable to clinical decision-making.
"Every sentence should help a clinician make better decisions for their patients."
Primary Goal: Communicate research findings that can improve patient care and clinical practice.
| Characteristic | Description |
|---|---|
| Evidence-focused | Appropriate hedging based on study design |
| Patient-centered | Focus on patient outcomes, not just biomarkers |
| Clinical | Emphasize practical applicability |
| Precise | Exact numbers, confidence intervals, NNT |
| Measured | Claims match evidence strength |
Most major medical journals require structured abstracts with labeled sections. This is one of the few venues where structured abstracts are expected.
Background: [Why this study was needed - 1-2 sentences]
Methods: [Study design, setting, participants, intervention,
main outcomes - 2-4 sentences]
Results: [Primary and key secondary outcomes with statistics -
3-5 sentences]
Conclusions: [Clinical implications, with appropriate hedging -
1-2 sentences]
| Journal | Abstract Limit |
|---|---|
| NEJM | 250 words |
| Lancet | 300 words |
| JAMA | 350 words |
| BMJ | 300 words |
| Annals | 325 words |
BACKGROUND
Type 2 diabetes is associated with increased cardiovascular risk, but
the effects of intensive glucose control on cardiovascular outcomes
remain uncertain.
METHODS
We randomly assigned 10,251 patients with type 2 diabetes and established
cardiovascular disease to receive intensive glucose-lowering therapy
(target HbA1c <6.0%) or standard therapy (target HbA1c 7.0-7.9%). The
primary outcome was a composite of nonfatal myocardial infarction,
nonfatal stroke, or death from cardiovascular causes.
RESULTS
After a median follow-up of 3.5 years, the primary outcome occurred in
352 patients (6.9%) in the intensive-therapy group and in 371 patients
(7.2%) in the standard-therapy group (hazard ratio, 0.90; 95% CI, 0.78
to 1.04; P=0.16). Severe hypoglycemia was more common with intensive
therapy (3.1% vs. 1.0%; P<0.001). All-cause mortality was similar
between groups (5.0% vs. 4.8%; hazard ratio, 1.04; 95% CI, 0.87 to 1.24).
CONCLUSIONS
In patients with type 2 diabetes and established cardiovascular disease,
intensive glucose lowering did not significantly reduce major
cardiovascular events compared with standard therapy and was associated
with increased severe hypoglycemia.
Match your language to your evidence strength.
| Study Design | Appropriate Language |
|---|---|
| Meta-analysis of RCTs | "Treatment X reduces mortality..." |
| Large RCT | "Treatment X reduced mortality in this trial..." |
| Small RCT | "Treatment X was associated with reduced mortality..." |
| Cohort study | "Treatment X was associated with lower mortality..." |
| Case-control | "Treatment X was associated with reduced odds of death..." |
| Cross-sectional | "Treatment X use was associated with lower mortality..." |
| Case series | "These cases suggest that treatment X may..." |
| Case report | "This case illustrates that treatment X can..." |
❌ Never say (unless RCT): "Treatment X prevents..." / "Treatment X causes..."
✅ Use for observational: "Treatment X was associated with..." / "Treatment X was linked to..."
✅ Use for RCTs: "Treatment X resulted in..." / "Treatment X reduced..."
| Certainty Level | Phrases |
|---|---|
| High | "demonstrates," "shows," "confirms" |
| Moderate | "suggests," "indicates," "supports" |
| Low | "may," "might," "could potentially" |
| Speculative | "it is possible that," "one interpretation is" |
Always report both absolute and relative measures.
❌ Incomplete: "Treatment reduced mortality by 50%"
✅ Complete: "Treatment reduced relative mortality by 50% (absolute risk reduction, 2.5 percentage points; number needed to treat, 40)"
Always include 95% confidence intervals.
❌ "The hazard ratio was 0.75"
✅ "The hazard ratio was 0.75 (95% CI, 0.62 to 0.91)"
Include NNT for clinically important outcomes:
"The intervention prevented one additional death for every 40 patients
treated (NNT=40; 95% CI, 28 to 67)."
Paragraph 1: Clinical Problem - Burden of disease (incidence, prevalence, mortality) - Impact on patients and healthcare system - Why this matters clinically
"Type 2 diabetes affects hundreds of millions of adults worldwide and is
a leading cause of cardiovascular disease, renal failure, and premature
death. Despite advances in glucose-lowering therapies, patients with
diabetes continue to face a two- to four-fold increased risk of
cardiovascular events compared with the general population."
Paragraph 2: Current Knowledge and Limitations - What treatments/approaches exist - What evidence gaps remain - Why more research was needed
Paragraph 3: Rationale and Objectives - Why this study was conducted - Clear statement of objectives/hypothesis - Primary outcome stated
"We therefore conducted a randomized, controlled trial to evaluate
whether intensive glucose-lowering therapy, compared with standard
therapy, would reduce major cardiovascular events in patients with
type 2 diabetes and established cardiovascular disease."
Medical methods sections follow reporting guidelines:
METHODS
├── Study Design
├── Setting and Participants
│ ├── Eligibility Criteria
│ └── Recruitment
├── Randomization and Blinding (for RCTs)
├── Interventions
├── Outcomes
│ ├── Primary Outcome
│ └── Secondary Outcomes
├── Sample Size Calculation
├── Statistical Analysis
├── Ethics Approval
└── Registration
Eligibility Criteria - List inclusion and exclusion criteria explicitly - Be specific (age ranges, disease definitions, lab values)
Primary Outcome - Define precisely, including timing of assessment - State how it was measured
Statistical Analysis - Pre-specified analysis plan - Handling of missing data - Subgroup analyses (pre-specified vs. exploratory)
We enrolled adults aged 40 years or older with type 2 diabetes (defined
as HbA1c ≥6.5% or use of glucose-lowering medication) and established
cardiovascular disease (previous myocardial infarction, stroke, or
revascularization procedure). Patients were excluded if they had an
HbA1c level below 7.5% or above 11.0%, estimated glomerular filtration
rate below 30 ml per minute per 1.73 m² of body-surface area, or a
cardiovascular event within the past 30 days.
Opening: Participant Flow - Screening, enrollment, randomization, follow-up, analysis - Reference CONSORT flow diagram
Baseline Characteristics - Table 1: Baseline demographics and clinical characteristics - Note any imbalances
Primary Outcome - Report first and prominently - Include point estimate, CI, P-value - State clinical significance
Secondary Outcomes - Report all pre-specified secondary outcomes - Be cautious about multiple comparisons
Adverse Events - Report serious adverse events systematically - Include deaths, hospitalizations, SAEs by category
Of 12,537 patients assessed for eligibility, 10,251 underwent
randomization: 5,128 were assigned to intensive therapy and 5,123 to
standard therapy (Figure 1). Baseline characteristics were similar
between groups (Table 1). Median follow-up was 3.5 years (interquartile
range, 2.8 to 4.2), with vital status available for 99.2% of patients.
The primary outcome occurred in 352 patients (6.9%) in the intensive-
therapy group and 371 patients (7.2%) in the standard-therapy group
(hazard ratio, 0.90; 95% confidence interval [CI], 0.78 to 1.04;
P=0.16). The absolute difference was 0.3 percentage points (95% CI,
-0.7 to 1.4). Results were consistent across pre-specified subgroups
(Figure 3).
Paragraph 1: Summary of Main Findings - Restate primary outcome result - State whether hypothesis was supported
Paragraphs 2-3: Interpretation and Context - How do findings compare with prior evidence? - What mechanisms might explain findings? - Clinical interpretation
Paragraph 4: Strengths - Study design features - Generalizability - Completeness of follow-up
Paragraph 5: Limitations - Be specific and thoughtful - Discuss how limitations might affect interpretation - Avoid generic statements
Final Paragraph: Conclusions and Implications - Clinical implications - Policy implications - Future research needs
Our study has several limitations. First, despite randomization, we
cannot exclude residual confounding from unmeasured factors. Second,
the open-label design may have introduced bias in outcome assessment
for subjective endpoints, though the primary outcome of death was
objective. Third, our findings may not generalize to patients without
established cardiovascular disease or to healthcare settings with
different resources. Fourth, the 3.5-year follow-up may have been
insufficient to detect cardiovascular benefits that emerge over
longer periods.
CONSORT 2025 uses a 30-item checklist and flow diagram covering: - Trial design, randomization, blinding - Participant flow (diagram required) - All outcomes with effect sizes and CIs - Harms and adverse events
22-item checklist for: - Cohort, case-control, cross-sectional studies - Setting, participants, variables, data sources - Bias assessment, sensitivity analyses
27-item checklist including: - Search strategy - Study selection process (diagram) - Risk of bias assessment - Synthesis methods
30 items for diagnostic accuracy studies
Standard format:
Intensive Therapy Standard Therapy
(N=5128) (N=5123)
Age — yr 63.4 ± 8.7 63.6 ± 8.5
Male sex — no. (%) 3389 (66.1) 3401 (66.4)
Body-mass index 32.1 ± 5.4 32.0 ± 5.3
HbA1c — % 8.3 ± 1.1 8.3 ± 1.0
Duration of diabetes — yr 10.2 ± 7.8 10.1 ± 7.6
Prior MI — no. (%) 2435 (47.5) 2411 (47.1)
Required for RCTs:
Assessed for eligibility (n=12,537)
│
├─► Excluded (n=2,286)
│ ├─ Not meeting criteria (n=1,854)
│ ├─ Declined to participate (n=389)
│ └─ Other reasons (n=43)
│
Randomized (n=10,251)
│
├─► Intensive therapy (n=5,128)
│ ├─ Lost to follow-up (n=52)
│ └─ Analyzed (n=5,076)
│
└─► Standard therapy (n=5,123)
├─ Lost to follow-up (n=48)
└─ Analyzed (n=5,075)
Standard presentation: - Survival curves with shaded confidence bands - Number at risk table below - Hazard ratio with 95% CI - Log-rank P-value
venue_writing_styles.md - Master style overviewjournals_formatting.md - Technical formatting requirementsreviewer_expectations.md - What medical reviewers seek