Publishing and Presenting Clinical Research 2013

Week Three

Richard Grant, MD

Amy J. Markowitz, JDamyjmarkowitz@alum.wellesley.edu

415-307-0391

Most research = a simple finding

A > B

Weight of experimental rats > Weight of control rats

Bone density with TT genotype > Bone density with tt genotype

Survival after surgery > Survival with medical therapy

Health care in UK > Health care in US

Never lose sight of this

Today's agenda

• Review from last week

• Results

• Tables and Figures

• Your stuff

Lessons from Abstract Homework

• Too short

• Too wordy, but not results-y or explanatory

• Lack of clarity with the objective or aim

• Conclusions were simply recaps, lacking synthesis or insights to move the reader vertically

• Proofreading was sketchy

Results

• Do not confuse data with information

• Too much just obscures the important stuff

• All results must have methods; all methods must have results

• Results in the results section (only)

– Do not present new results in the discussion

Statistics: The Cinematic Analogy

• Title: My Research Question

• Starring: Effect Size

• Supporting roles for:– The effect size’s Confidence Interval– If needed, Adjusted Analyses

• Cameo appearance by: P value

Do not write a manuscript around a significant P value

• People born on Tuesdays who were married in May were 10% more likely to have ulcerative colitis than expected (P < 0.03).

The Order of Presentation: I

• Descriptive results– Who, what they were like, what happened to

them, who vanished, etc.

• Main analytic findings– An English sentence that you want everyone

to remember• “Three-year-old girls were nicer than 3-year-old

boys, but the reverse was true by age six.”

The Order of Presentation: II

• Variations on the theme– Alternate outcomes, predictors, and

definitions – Excluding (or including) selected subjects– Multivariate analyses

• Sometimes essential for main results, however

• Other interesting stuff– Anecdotes, oddities, weird sub-groups– What made a variable “drop-out” of a model– Projected cost-effectiveness

Results, Style Thereof: I

• Treat your tables and figures like pictures in an art museum, and use the text like an knowledgeable docent– Tell the reader what to look for

• Use sub-headers to “warn” the reader

Results, Style Thereof: II

• Avoid:– The results of our analysis are demonstrated

in Figure 1.– Table 2 shows the multivariate model.

Results, Style Thereof: III

• Think parentheses:– Blood pressure declined with time in both men

and women (Figure 1).– After adjusting for age, sex, race, and

household income, education remained a significant predictor of mortality (Table 2). Each additional year of schooling was associated with a 15% decrease in survival.

Tables-1• Descriptive title• Must make sense on its own• Think about the rows and columns

– Side-by-side comparisons are best– Combine tables if rows or columns are repeated

• Avoid repetition

Tables-2

• Avoid excess digits

• Provide units for all measurements

• Put rows for categorical variables in a meaningful order (usually descending frequency)

• Numbers for categorical variables should add to 100%

• Proofread!!!

Comparison of Selected Characteristics of the Two Groups of Subjects.

Characteristic Group I Group II P

Male 74/112 = 66% 33/68 = 49% *

Female 28/112 = 34% 35/68 = 51% *

CHD 77/112 = 69% 50/68 = 74% NS

Cost in dollars $29,323 ± $13,358

$31,482 ± 16,552

NS

Age (years) 0.5 ± 0.5 0.6 ± 0.4 NS

Premature 92/112 = 82% 43/68 = 63% *

<32 weeks 47% 41% NS

<28 weeks 18% 3% *

*p < 0 .05. NS = nonsignificant.

A yucky table

What is wrong with this table?

Pediatrics, Apr 2009; 123: 1108 - 1115

Interpreting Coefficients

What do these coefficients mean?

Pediatrics, Nov 2008; 122: 1051

Figures

• Sketch first to ensure the point is clear

• Label (axes, lines, bars, N’s at risk, etc.)

• Remember reviewers and editors

Mean (closed circle), median (horizontal line), 25th to 75th percentile (box), and range (whiskers) of creatinine clearance by age.

An informative figure and legend

36 die or dropout

2311 subjects contacted

691 ineligible135 refuse

1485 agree to participate

RANDOMIZATION

735 intervention 750 control

36 die or dropout

699 complete study 709 complete study

Sampling scheme for the study.

Another

Figures: Reconsider

• Light on data

• Pie charts

• 3-D graphs

• “Fake” data

• Lines that cross

Annual rates of myocardial infarction per 1000 by sex.

Wastes ink

Annual rates of myocardial infarction per 1000 by sex.

Wastes more ink

Causes of neuropathy in 112 primary care patients.

Pies = good in bakeries

Annual risk of hepatoma by age and alcohol consumption.

3D = hard to read

Annual risk of hepatoma by age and alcohol consumption.

A better version

Mortality as a function of age and sex.

Makes modeled results look too real

Mortality modeled as a function of age and sex. Error bars indicate 95% confidence intervals for modeled risk.

Legend informs the reader

Figure 1. Frequency investigational studies are ordered by general pediatricians in the work-up of prenatally detected hydronephrosis after birth.