Gender Differences and Prevalen

Pain in OEF/OIF OEF/OIF Veterans Veterans

Sally Haskell, MD

Cynthia Brandt, MD, MPH

E ir n K b re s, MD, MPH

Melissa Skanderson, MSW

Robert Kerns, PhD

Joseph Goulet, PhD, MS

HSR&D Cyber Seminar, Nov 19th, 2009
A project project of The Women

Veteran’s Cohort Study

Cynthia Brandt, MD,MPH, PI

Sa yll Has e , k ll MD Co‐PI

Amy Justice, MD, PhD, Co‐PI

Erin Krebs, MD, MPH, Indiana site PI

Joseph Goulet, PhD, MS, lead statistician statistician

Douglas Leslie, PhD, econometrician

Kristin Mattocks, PhD, co‐investigator

Robert Kerns, PhD, co‐investigator

VA HSR&D grant DHI 07‐065‐1
Background

• P i a n is f tl requently report de by V t e erans of war• Operation Desert Shield/Desert Shield/Desert Storm• Operation Enduring Freedom/ q Ira i Freedom
Pain is more common in women

• In civilian populations women more commo

specific pain syndromes:

– Migraines– Oral‐facial pain– Fibromyalgia– Abdominal pain– More severe and longer lasting lasting pain
Gender Differences in

Pain among Veterans

• VA CT study of pain in female Veteran prim

patients found a higher prevalence of pain 

than a similar study in male veterans ( %) 50 

• Another study of health related quality of l

over 18 000 , veterans with ment l a illness f 

o

females had lower scores on the SF‐36 physcomponent summary (indicating worse sym

were more lik l e y to report th t a they were li 

li

lot" in activities of daily living, and had mor

than males
The p p ro ortion of women in the

military, and using VA, is increasin

• At present, 15% of Active Military, 17% of Nation

Guard/Reserves, and 20% of new recruits are wo

• OEF/OIF women are using the VHA in record num• Women are now among the fastest growing segm

new VHA users with as many as 44% of women rfrom Iraq and Af h i g an stan el i ect ng to use the VH

compared to 11% in prior eras.
OEF/OIF Women at risk

for pain.

• OEF/OIF female Veterans are younger,• More likely to identify as racial minorities,• Less likely to be married than male counter• Hi hg prevalence of ment l a h lth ea di d sor ers

• High rates of exposure to combat trauma.

• High rates of exposure exposure to sexual trauma.
Pain screening part of routine

health assessment at VA

• Previous studies have not assessed whethe

pain varies by sex.

• No study has reported whether women

returning returning from war have more severe or

persistent pain than their male counterpart

• Understanding the epidemiology of pain in

female Veterans will be essential as the VA

plans pain treatment treatment services. services.
Hypothesis:

• Our study was designed to assess the

prevalence of pain by gender in Veterans se

in the VA in the first year after deployment deployment 

OEF‐OIF.

• We hypothesized that Female Veterans will 

more overall pain, more moderate‐severe pand more persistent persistent pain than their male

counterparts.
Methods

• Study population from VA’s OEF/OIF roster

– Roster contains information on U.S. Military per

discharged from 10/1/2001 10/1/2001‐11/30/2007 11/30/2007

– Who enrolled for VA services before January 1, 

– N=406,802 at the time of this analysis

• Analytic sample limited to:

– Veterans Veterans who had at least 1 visit to a VA clinic li

obtain pain scores (e.g. primary care, women’s c

– And at least one year of observation after enrol
Data Sources

• Roster includes information on Veteran’s se

DOB, race, education, marital status, rank,branch of service service, and deployment deployment start an

end dates.

• Data on eligible visits, ICD‐9 codes, and pai

scores ascertained from VA Corporate DataWarehouse (CDW).
Pain numeric rating scale

• At each visit, Veterans are asked to rate their 

pain intensity on a scale of 0–10, where 0 is n

and 10 is the worst possible pain

• The score is recorded along with vital signs.• We retained only scores recorded at outpatie

visits.

• We retained the highest scores on a day.
Definitions

• Pain was defined as assessed if the Veteran had 

valid pain score in the 1 year observation perio

• Among Veterans who were assessed, Any Pain 

defined as a score ≥ 1.

• Among those with Any Pain, Moderate‐Severe 

was defined as a score ≥ 4.

• Persistent pain was defined as 3 or more scores

recorded in at least 3 different months.
Haskell SG, Brandt C, Krebs EE, Skanderson M, Kerns R, Goulet JL. Pain am

Operations Enduring Freedom and Iraqi Freedom: Do Women and Men Differ? 

Oct;10(7):1167-73 .
Statistical analyses

• Chi square to examine bivariate relationships.• T‐tests or nonparametric tests as appropriate f

continuous variables.

• Poisson Poisson regression regression to calculate calculate relative relative risks an

95% confidence intervals.

– demographic variables significant in bivariate analys

were entered into the mutlivariable model as covari
Demographics of OEF/OIF Veterans using VA i

first year post deployment

N=153,212 Female 

n=18,481

Male 

n=134,731

P va

Age mean (SD) Age mean (SD) 30.2 (8.8) 30.2 (8.8) 32.6 (9.8) 32.6 (9.8) 

Race

Black 30.3% 14.2% Hispanic 10.8% 11.8%White 52.9% 68.8%Other 3.3% 2.6%unknown 2 7%. 2 5%.

Education

Less than HS 1.4% 1.5% High School High School 69 6%. 74 6%.College 28.7% 24.0%

Marital Status 

Married 31.8% 50.1%Never married 57.9% 44.5%
Service Characteristics

Female 

n=18,481

Male 

n=134,731

P val

8, 8 3,3

Branch <

Army 78.9% 76.1%Air Force 10.3% 6.6%Marines 2.9% 11.2%Navy 7 8%. 6 1%.

Rank <

Enlisted 91 4%. 91 8%.Officer 8.0% 7.0%Warrant 0.6% 1.2%
Distribution of Pain score
Results

• The analytic sample consisted of 153,212

Veterans

• Pain was assessed in 59.7% of sample

– Among those assessed, 43.3% reported any pain

• Among those with any p , ain 63.2% reported mod

severe pain.

• 20.6% met our definition definition of persistent persistent pain
Pain Assessment and Pain Charact

by Sex

Female 

n=18,481

Male 

n=134,731

P va

Pain Assessment Pain Assessment 60.1% 59.6% 

Any pain Any pain 38.1% 44.0% 

Moderate pain Moderate pain 68 0%. 62 6%. Persistent pain Persistent pain 18.0% 21.2% 
Results of regression model

(relative risks)

Variable Variable Assessed Assessed

RR 95% CI)

Any pain

RR (95%CI)

Moderate Pain

RR (95%CI)

Per

RR 95% CI) RR (95%CI) RR (95%CI) R

R

Female 0.98 (0.96, 1.00) 0.89 (0.86, 0.92) 1.05 (1.01, 1.09) 0.9Male Ref. Ref. Ref. Age 1.00 ( ) 1.00, 1.00) 1.00 ( ) 1.00, 1.00) 1.00 ( ) 1.00, 1.00) 1Divorced 1.05 (1.02, 1.08) 1.00 (0.96, 1.04) 1.00 (0.95, 1.06) 0

Never married 1.10 (1.08, 1.12) 0.88 (0.86, 0.90) 0.98 (0.95, 1.01) 0

Married Ref. Ref. Ref. Black 1.00 (.098, 1.02) 0.97 (0.94, 1.00) 1.22 (1.18, 1.26) 1Hispanic 1 07 (1 05 1 10) 1.07 (1.05, 1.10) 0 92 (0 90 0 95) 0.92 (0.90, 0.95) 1 01 (0 97 1 05) 1.01 (0.97, 1.05) 0 

0

Other 1.05 (1.01, 1.09) 0.97 (0.91, 1.03) 1.09 (1.01, 1.17) 0

Unknown 0.92 (0.88, 0.96) 0.97 (0.90, 1.03) 1.16 (1.07, 1.25) 1

White Ref. Ref. Ref. 

Also controlled for education, branch, and rank
Summary

• Our findings document a lower prevalence of

reported pain in women compared with men in 

first year post‐deployment, deployment, after adjusting adjusting for o

demographic factors.

• In those with pain, women were more lk l i e y to

report moderate‐severe pain

– But women had a lower prevalence of moderate‐s

pain overall.

• Persistent Persistent pain was also less common in wome
Unexpected findings

• Lower prevalence of pain in women is an unexpected

finding.

• Does this reflect gender differences in exposure to

combat trauma and injury?

• Does OEF‐OIF training/service training/service change usual gender

differences in pain outcomes?

• Are OEF‐OIF women less likely to complain complain of pain?

• Are barriers to VA care different for women/men

Veterans with pain?
Limitations

1. Accuracy of pain numeric rating sca2. Evaluation is limited to patients see

Clinics.
Conclusions

• Among OEF/OIF Veterans seen in VA outpat

clinics within 1 year of last deployment, wefound that women Veterans Veterans had a lower

prevalence of pain.

• Understanding gender differences in pain is 

important step in VA Pain research and willhelp guide planning planning, resource resource allocation allocation, an

policy for women Veterans and OEF/OIFVeterans of both sexes.
Next Steps

• What is the trajectory of pain in OEF/OI

women/men Veterans over time?

• What are the specific specific pain related related diagn

diagn

women compared to men?

• Is there a difference in comp y lexit of pa

syndromes in women/men?

• What about the co‐occurrence of MST a

association with chronic chronic pain?

• Are there gender specific differences in 

treatment?
Thank you

• Joseph Goulet@va gov Joseph.Goulet@va.gov• Sally Haskell@va gov Sally.Haskell@va.gov