21 KiB
21 KiB
Data Presentation in Clinical Reports
Tables for Clinical Data
Table Design Principles
General guidelines:
- Clear, concise title describing table contents
- Column headers with units
- Row labels aligned left, data aligned appropriately (numbers right, text left)
- Footnotes for abbreviations, statistical notation, special cases
- Consistent decimal places (typically 1-2 for percentages, 1-3 for continuous variables)
- Consistent formatting throughout document
Title placement:
- Above table
- Numbered sequentially (Table 1, Table 2, etc.)
- Descriptive enough to stand alone
Footnote symbols (in order):
- *, †, ‡, §, ||, ¶, #
- Or use superscript letters (a, b, c...)
- Or use superscript numbers if not confused with references
Demographic and Baseline Characteristics Table
Purpose: Describe study population at baseline
Standard format:
Table 1. Baseline Demographics and Clinical Characteristics
Characteristic Treatment Group Control Group Total
(N=150) (N=145) (N=295)
─────────────────────────────────────────────────────────────────────────
Age, years
Mean (SD) 64.2 (8.5) 63.8 (9.1) 64.0 (8.8)
Median (IQR) 65 (58-71) 64 (57-70) 64 (58-71)
Range 45-82 43-85 43-85
Sex, n (%)
Male 95 (63.3) 88 (60.7) 183 (62.0)
Female 55 (36.7) 57 (39.3) 112 (38.0)
Race, n (%)
White 110 (73.3) 105 (72.4) 215 (72.9)
Black/African American 25 (16.7) 28 (19.3) 53 (18.0)
Asian 10 (6.7) 8 (5.5) 18 (6.1)
Other 5 (3.3) 4 (2.8) 9 (3.0)
BMI, kg/m²
Mean (SD) 28.5 (4.2) 28.1 (4.5) 28.3 (4.4)
Baseline HbA1c, %
Mean (SD) 8.9 (1.2) 9.0 (1.3) 9.0 (1.2)
Disease duration, years
Median (IQR) 6 (3-10) 5 (3-9) 6 (3-10)
Prior medications, n (%)
Metformin 135 (90.0) 130 (89.7) 265 (89.8)
Sulfonylurea 45 (30.0) 42 (29.0) 87 (29.5)
Insulin 20 (13.3) 18 (12.4) 38 (12.9)
─────────────────────────────────────────────────────────────────────────
SD = standard deviation; IQR = interquartile range; BMI = body mass index;
HbA1c = hemoglobin A1c
Key elements:
- Sample size for each group (N=)
- Continuous variables: mean (SD), median (IQR), range
- Categorical variables: n (%)
- No p-values for baseline comparisons (debated but generally not recommended)
Efficacy Results Table
Purpose: Present primary and secondary endpoint results
Example:
Table 2. Primary and Secondary Efficacy Endpoints at Week 24
Endpoint Treatment Control Difference P-value
(N=150) (N=145) (95% CI)
──────────────────────────────────────────────────────────────────────────────────
Primary Endpoint
Change in HbA1c from baseline, %
Mean (SE) -1.8 (0.1) -0.6 (0.1) -1.2 <0.001
95% CI (-2.0, -1.6) (-0.8, -0.4) (-1.5, -0.9)
Secondary Endpoints
Change in FPG, mg/dL
Mean (SE) -42.5 (3.2) -15.2 (3.4) -27.3 <0.001
95% CI (-48.8, -36.2) (-21.9, -8.5) (-36.4, -18.2)
% achieving HbA1c <7%
n (%) 78 (52.0) 25 (17.2) - <0.001
95% CI (43.9, 60.1) (11.4, 24.5)
Change in body weight, kg
Mean (SE) -3.2 (0.4) -0.5 (0.4) -2.7 <0.001
95% CI (-4.0, -2.4) (-1.3, 0.3) (-3.8, -1.6)
──────────────────────────────────────────────────────────────────────────────
SE = standard error; CI = confidence interval; HbA1c = hemoglobin A1c;
FPG = fasting plasma glucose
Statistical presentation:
- Point estimates with measures of precision (SE or CI)
- p-values (consider adjustment for multiplicity)
- Effect size (difference or ratio) with 95% CI
- Significance level noted (e.g., p<0.05, p<0.01, p<0.001)
Adverse Events Table
Purpose: Summarize safety data
Example:
Table 3. Summary of Adverse Events
Event Category Treatment Control P-value
(N=150) (N=145)
n (%) n (%)
──────────────────────────────────────────────────────────────────────────
Any adverse event 120 (80.0) 95 (65.5) 0.004
Treatment-related adverse events 85 (56.7) 42 (29.0) <0.001
Serious adverse events 12 (8.0) 8 (5.5) 0.412
Adverse events leading to 8 (5.3) 4 (2.8) 0.257
discontinuation
Deaths 0 (0.0) 1 (0.7) 0.492
Common adverse events (≥5% in any group)
Nausea 45 (30.0) 12 (8.3) <0.001
Diarrhea 38 (25.3) 10 (6.9) <0.001
Headache 22 (14.7) 18 (12.4) 0.568
Hypoglycemia 18 (12.0) 5 (3.4) 0.007
Dizziness 12 (8.0) 8 (5.5) 0.412
──────────────────────────────────────────────────────────────────────────
Adverse events coded using MedDRA version 24.0
Key elements:
- Overall AE summary
- Serious AEs highlighted
- Deaths reported
- Common AEs (typically ≥5% or ≥10% threshold)
- MedDRA coding indicated
Laboratory Abnormalities Table
Shift tables showing changes from baseline:
Table 4. Laboratory Values Meeting Predefined Criteria for Abnormality
Laboratory Parameter Treatment Control
(N=150) (N=145)
n (%) n (%)
──────────────────────────────────────────────────────────────────────────
ALT >3× ULN 8 (5.3) 3 (2.1)
AST >3× ULN 5 (3.3) 2 (1.4)
Total bilirubin >2× ULN 2 (1.3) 1 (0.7)
Creatinine >1.5× baseline 12 (8.0) 5 (3.4)
Hemoglobin <10 g/dL 3 (2.0) 2 (1.4)
Platelets <100 × 10³/μL 1 (0.7) 0 (0.0)
──────────────────────────────────────────────────────────────────────────
ULN = upper limit of normal; ALT = alanine aminotransferase;
AST = aspartate aminotransferase
Patient Disposition Table (CONSORT Format)
Table 5. Patient Disposition
Disposition Treatment Control Total
(N=150) (N=145) (N=295)
────────────────────────────────────────────────────────────────────────────
Screened - - 425
Randomized 150 145 295
Completed study 135 (90.0) 130 (89.7) 265 (89.8)
Discontinued, n (%) 15 (10.0) 15 (10.3) 30 (10.2)
Adverse event 8 (5.3) 4 (2.8) 12 (4.1)
Lack of efficacy 2 (1.3) 5 (3.4) 7 (2.4)
Lost to follow-up 3 (2.0) 4 (2.8) 7 (2.4)
Withdrawal of consent 2 (1.3) 2 (1.4) 4 (1.4)
Included in efficacy analysis
ITT population 150 (100) 145 (100) 295 (100)
Per-protocol population 142 (94.7) 138 (95.2) 280 (94.9)
Included in safety analysis 150 (100) 145 (100) 295 (100)
────────────────────────────────────────────────────────────────────────────
ITT = intent-to-treat
Figures for Clinical Data
Figure Design Principles
General guidelines:
- Clear, concise caption/legend below figure
- Numbered sequentially (Figure 1, Figure 2, etc.)
- Axis labels with units
- Legible font size (minimum 8-10 point)
- High resolution (300 dpi for print, 150 dpi for web)
- Color-blind friendly palette
- Black and white compatible (use different symbols/patterns)
Figure caption:
- Describes what is shown
- Explains symbols, error bars, statistical annotations
- Defines abbreviations
- Provides context for interpretation
CONSORT Flow Diagram
Purpose: Show patient flow through randomized trial
Assessed for eligibility (n=425)
│
┌─────────────────────┴─────────────────────┐
│ │
Excluded (n=130) │
• Not meeting inclusion criteria (n=85) │
• Declined to participate (n=32) │
• Other reasons (n=13) │
│
Randomized (n=295)
│
┌───────────────────────────────┴───────────────────────────────┐
│ │
Allocated to Treatment (n=150) Allocated to Control (n=145)
• Received allocated intervention (n=148) • Received allocated intervention (n=143)
• Did not receive allocated intervention (n=2) • Did not receive allocated intervention (n=2)
Reasons: withdrew consent before treatment Reasons: withdrew consent before treatment
│ │
┌───────────┴────────────┐ ┌──────────────┴─────────────┐
│ │ │ │
Lost to follow-up (n=3) Discontinued (n=12) Lost to follow-up (n=4) Discontinued (n=11)
• Adverse events (n=8) • Adverse events (n=4)
• Lack of efficacy (n=2) • Lack of efficacy (n=5)
• Withdrew consent (n=2) • Withdrew consent (n=2)
│ │
Analyzed (n=150) Analyzed (n=145)
• ITT analysis (n=150) • ITT analysis (n=145)
• Per-protocol analysis (n=142) • Per-protocol analysis (n=138)
• Excluded from analysis (n=0) • Excluded from analysis (n=0)
Kaplan-Meier Survival Curve
Purpose: Show time-to-event data
Elements:
- X-axis: Time (weeks, months, years)
- Y-axis: Probability of event-free survival (0 to 1 or 0% to 100%)
- Separate curves for each treatment group
- Censored observations marked (often with vertical tick marks)
- Number at risk table below graph
- Median survival time indicated
- Log-rank p-value
- Hazard ratio with 95% CI
Caption example:
Figure 1. Kaplan-Meier Curves for Overall Survival
Kaplan-Meier estimates of overall survival in the treatment and control groups.
Tick marks indicate censored observations. Number at risk shown below graph.
Log-rank p<0.001. Median survival: Treatment 24.5 months (95% CI: 22.1-26.8),
Control 18.2 months (95% CI: 16.5-20.1). Hazard ratio 0.68 (95% CI: 0.55-0.84).
Forest Plot
Purpose: Display subgroup analyses or meta-analysis results
Elements:
- Point estimates (squares or diamonds)
- Size of symbol proportional to precision (inverse variance) or sample size
- Horizontal lines showing 95% CI
- Vertical line at null effect (HR=1.0, OR=1.0, or difference=0)
- Subgroup labels on left
- Effect size values on right
- Overall estimate (if meta-analysis)
- Heterogeneity statistics (I², p-value)
Caption example:
Figure 2. Forest Plot of Treatment Effect by Subgroup
Effect of treatment vs. control on primary endpoint across pre-specified subgroups.
Squares represent point estimates; horizontal lines represent 95% confidence intervals.
Square size is proportional to subgroup sample size. Overall effect shown as diamond.
p-value for interaction testing heterogeneity of treatment effect across subgroups.
Box Plot
Purpose: Show distribution of continuous variable
Elements:
- Box: IQR (25th to 75th percentile)
- Line in box: Median
- Whiskers: Extend to most extreme data point within 1.5 × IQR
- Outliers: Points beyond whiskers (often shown as circles)
- X-axis: Groups or time points
- Y-axis: Continuous variable with units
Scatter Plot with Regression
Purpose: Show relationship between two continuous variables
Elements:
- X-axis: Independent variable
- Y-axis: Dependent variable
- Individual data points
- Regression line (if appropriate)
- Regression equation
- R² value
- P-value for slope
- 95% confidence interval for regression line (optional, shown as shaded area)
Spaghetti Plot
Purpose: Show individual trajectories over time
Elements:
- X-axis: Time
- Y-axis: Outcome variable
- Individual patient lines (often semi-transparent)
- Mean trajectory (bold line)
- Separate colors for treatment groups
Bar Chart
Purpose: Compare proportions or means across groups
Elements:
- Clear separation between bars
- Error bars (SEM or 95% CI)
- Y-axis starts at 0 (do not truncate for bar charts)
- Group labels on X-axis
- Value labels on Y-axis with units
- Statistical significance indicated (p-values or asterisks)
Avoid:
- 3D bar charts (distort perception)
- Excessive decoration
- Truncated Y-axis for bars
Line Graph
Purpose: Show changes over time
Elements:
- X-axis: Time (with consistent intervals)
- Y-axis: Outcome variable
- Separate lines for each group (different colors/patterns)
- Data points marked (circles, squares, triangles)
- Error bars at each time point (SE or 95% CI)
- Legend identifying groups
- Grid lines (optional, light gray)
Histogram
Purpose: Show distribution of continuous variable
Elements:
- X-axis: Variable (divided into bins)
- Y-axis: Frequency or density
- Appropriate bin width (not too few, not too many)
- Overlay normal distribution curve (if testing normality)
Special Considerations for Clinical Data
Presenting Proportions
Numerator and denominator:
- Always provide both: 25/100 (25%)
- Not just percentage (25%)
Percentages:
- No decimal places if n<100
- 1 decimal place if n≥100
- Never report >1 decimal place for percentages
Confidence intervals for proportions:
- Wilson score interval or exact binomial (better than Wald for small samples)
- Always report with percentage
Presenting Continuous Data
Measures of central tendency:
- Mean for normally distributed data
- Median for skewed data or ordinal data
- Report both if distribution unclear
Measures of dispersion:
- Standard deviation (SD): Describes variability in data
- Standard error (SE): Describes precision of mean estimate
- 95% Confidence interval: Preferred for inferential statistics
- Interquartile range (IQR): With median for skewed data
- Range: Min to max
When to use each:
- Descriptive statistics → Mean (SD) or Median (IQR)
- Inferential statistics → Mean (95% CI) or Mean (SE)
- Never use ± without specifying SD, SE, or CI
Presenting P-values
Reporting guidelines:
- Report exact p-values to 2-3 decimal places (p=0.042)
- For very small p-values, use p<0.001 (not p=0.000)
- Do not report as "NS" or "p=NS"
- For non-significant results, report exact p-value (p=0.18, not p>0.05)
- Specify two-tailed unless pre-specified one-tailed
- Correct for multiple comparisons when appropriate
- Report significance threshold used (α=0.05 is standard)
Avoid:
- p<0.05 (report exact value)
- p=0.00 (impossible)
- Multiple decimal places (p=0.04235891)
Statistical Significance Indicators
Options:
- Report p-values in table
- Use asterisks with legend:
- *p<0.05
- **p<0.01
- ***p<0.001
- Use confidence intervals (preferred)
Confidence Intervals
Reporting:
- 95% CI is standard
- Format: (lower limit, upper limit)
- Or: lower limit to upper limit
- Or: lower limit-upper limit
Interpretation:
- If CI for difference excludes 0 → significant
- If CI for ratio excludes 1 → significant
- Width of CI indicates precision
Missing Data
Indicate clearly:
- Footnote explaining missing data
- State clearly if analysis is complete case
- Describe imputation method if used
- Report amount of missing data per variable
Decimal Places and Rounding
General rules:
- Report to level of measurement precision
- Consistent decimal places within table
- Round p-values to 2-3 decimal places
- Round percentages to 0-1 decimal place
- Round means/medians to 1-2 decimal places
- Include appropriate significant figures
Software for Creating Figures
Statistical software:
- R (ggplot2) - highly customizable
- GraphPad Prism - user-friendly for biomedical
- SAS, Stata, SPSS - comprehensive statistical packages
- Python (matplotlib, seaborn) - flexible and powerful
General graphics software:
- Adobe Illustrator - professional publication-quality
- Inkscape - free vector graphics editor
- PowerPoint - basic graphs, easy to use
- BioRender - biological schematics and figures
Color Schemes
Color-blind friendly palettes:
- Avoid red-green combinations
- Use blue-orange, blue-yellow
- Include shape/pattern differences
- Test figures in grayscale
Recommended palettes:
- ColorBrewer (designed for data visualization)
- Viridis (perceptually uniform)
- IBM Color Blind Safe Palette
Image Quality Standards
Resolution:
- 300 dpi for print publication
- 150 dpi for web/screen
- Vector graphics (PDF, SVG) preferred for graphs
File formats:
- TIFF or EPS for print
- PNG for web
- PDF for vector graphics
- JPEG acceptable for photographs (high quality)
Image editing:
- No manipulation that alters data
- Only acceptable adjustments: brightness, contrast, color balance applied to entire image
- Document all adjustments
- Provide original images if requested
This reference provides comprehensive guidance for presenting clinical data in tables and figures following best practices and publication standards. Use these guidelines to create clear, accurate, and professional data presentations.