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