Pain, Psychiatric Disorders, and Disability Among Veterans With and Without Polytrauma
Condition: Chronic Pain
MeSH terms: Chronic Pain; Multiple Trauma; Mental Disorders; Problem Behavior
Study type: Observational

Summary: 
      We believe information to be obtained from this proposed study will prove critical for
      planning future VA healthcare strategies and developing effective and efficient treatments
      targeting pain and emotional adjustment difficulties among individuals with polytrauma and
      returning Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) personnel. More
      specifically, this study will be the first to provide systematic data regarding pain and
      emotional problem prevalence, course, associated impairments, risk factors, and barriers to
      care and community reintegration among returning OEF and OIF service members with and without
      polytrauma.
    

Detailed description: 
      Design Overview: This clinically-oriented study will utilize an observational cohort design
      to compare cross sectional baseline samples of polytrauma and non-polytrauma OEF/OIF military
      personnel from two sites (Minneapolis and Tampa VAs) over three time points (baseline and 6
      and 12 months post-enrollment). With the relatively large sample sizes employed in this
      study, cross sectional baseline sampling of existing patients and a longitudinal design will
      allow us to evaluate associations between injury time and the onset of pain and emotional
      distress symptoms. The employment of two of the four existing PRCs as study sites will
      facilitate recruitment of sufficient study participants and will enhance the generalizability
      of the results. The multiple time points allow us to track the course of pain, emotional
      problems, and associated disabilities over a 12-month period, and to identify the onset of
      any new pain or emotional symptoms in participants during the 12-month monitoring period.
      Most of the study procedures and measures have been utilized in our prior clinical and
      research efforts with these patient populations. Subjects and Sampling Strategy: Two
      non-stratified samples of participants will be recruited at each study site. A polytrauma
      injury group (PTR) will be comprised of between 150 and 200 inpatients or former inpatients
      returning for additional rehabilitation care to the Minneapolis and Tampa PRCs (ns = 75-100
      at each site). PTR subjects will be subdivided into those with combat polytrauma ( 60% based
      on current data) and those with non-combat polytrauma ( 40%) for selected subsequent
      analyses. A comparison group of between 300 and 400 non-polytrauma OEF/OIF service members
      (NPTR) will be sampled randomly from the pool of all veterans on the Minneapolis and Tampa
      OEF/OIF patient registries (ns = 150-200 at each site). This latter group will be
      dichotomized into those with pain (NPTR-P; approximately 42 - 50% based on our previous
      research) and those without (NPTR-NP) for later analyses. Sample Size Determination: The
      above sample sizes were based on analyses powered to detect significant ( .05) differences in
      the proportions of pain and PTSD present in the sample cohorts at baseline (H1). For pain,
      using estimates of pain disorder prevalence among polytrauma (80%) and non-polytrauma (46%)
      service members based on pain complaint frequencies found in our prior studies,1, 34 and
      group sizes of 150 (polytrauma) and 300 (non-polytrauma), associated power would approach
      1.0. For PTSD, utilizing the same sample sizes and prior research-based estimates of PTSD
      prevalence rates of 48% (polytrauma) and 32% (non-polytrauma), power to detect a difference
      between the groups would approach .91. If time allows, we will recruit up to a maximum of 200
      PTR and 400 NPTR participants to counter any reduced power due to attrition during the
      12-month follow up, to increase the precision of our estimates of the12-month incidence of
      pain and emotional symptoms in previously symptom-free individuals, and to retain adequate
      power for subgroup analyses. Inclusionary Criteria - a) PTR group. To participate in the
      study, PTR subjects must: 1) have been deployed to Iraq or Afghanistan between October 2001
      and the present; 2) meet the VA definition of polytrauma injury; 3) receive medical clearance
      to participate from their attending physician; 4) be able to provide a valid self-report of
      pain level using the 0-10 Numeric Rating Scale; 5) fluency in verbal and written English; 6)
      attain a Rancho Los Amigos 35(a scale of cognitive impairment routinely used in PRCs) level
      of 6 (moderate impairment) or greater; and 7) be competent to provide full informed consent.

      Individuals who do not attain Rancho levels exceeding 5 during treatment will not be eligible
      for participation as in our experience they will be incapable of providing full informed
      consent or reliable pain scores and will be unable to complete the study self report
      measures. These criteria were selected to maximize generalizability while minimizing the
      probability of including polytrauma participants unable to provide valid self-report data.
      Based on our prior work in this area,1, 34 approximately 70% of PRC patients will attain
      Rancho levels of 6 or greater and be able to provide valid pain scores during treatment.

      Participants may be enrolled at any point during their treatment provided they meet the above
      criteria. The rationale for allowing enrollment throughout treatment stems from some of the
      special characteristics of the PTR group. More specifically, polytrauma inpatients often are
      admitted on large doses of opioid analgesics which may limit their ability to provide
      reliable self-reports of pain, particularly if they also have experienced a TBI. As the
      opioid dosages are titrated in order to promote increased involvement in rehabilitation, they
      may be more able to provide valid pain ratings. Secondly, the cognitive function of soldiers
      with significant cognitive limitations typically improves substantially during treatment,1,
      34 sometimes dramatically. If we were to limit participation only to those able to provide
      valid self-reports of pain or other symptoms at the time of admission we would restrict the
      pool of potential participants and substantially reduce the generalizability and clinical
      utility of the study. Because we are not focusing on treatment effects, and because we are
      using a cross-sectional baseline sampling approach and will be controlling for time since
      injury, this approach will not bias the obtained data. b) NPTR group. Criteria for NPTR
      participation include: 1) deployment to Iraq or Afghanistan between October 2001 and the
      present; 2) fluency in verbal and written English; 3) ability to provide a valid self-report
      of pain level using the 0-10 Numeric Rating Scale; and 4) competency to give full informed
      consent. This comparison group will include participants who do not meet polytrauma criteria
      and be sampled from all eligible members of the registries of both participating VA
      facilities. Participants who meet the above criteria will be enrolled for one-year. Women and
      minorities will be recruited to the extent that they are present in the associated
      participant pools, but will not be oversampled. Participants will receive a token payment of
      $30 following each completed assessment session in order to defray their travel expenses and
      time investments. Estimated Participation Rates and Participant Pool Size. Based on our
      experience in recruiting participants for prior chronic pain, polytrauma, and OEF/OIF studies
      or clinical evaluations, we anticipate that at least 80% of those who meet the study criteria
      will agree to participate. Therefore, in order to meet our minimum recruitment goals we will
      need at least 280 individuals with polytrauma (280 X 67% able to provide pain ratings X 80%
      participation rate = 150). In the past 12 months, a total of 490 individuals have been
      admitted or returned to the Minneapolis (n=289) and Tampa (n=201) PRCs, suggesting a more
      than adequate pool of participants with polytrauma. Minimum recruitment goals for OEF/OIF
      soldiers without polytrauma will require a participant pool of at least 376 individuals (376
      X 80% participation rate = 300). As of May 1st, 2007, there are 3723 OEF/PIF returnees on the
      Minneapolis OEF/OIF registry, and 4099 on the Tampa patient registry.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Two non-stratified samples of participants will be recruited at each study site. A
        polytrauma injury group (PTR) will be comprised of between 150 and 200 inpatients or former
        inpatients returning for additional rehabilitation care to the Minneapolis and Tampa PRCs
        (ns = 75-100 at each site). PTR subjects will be subdivided into those with combat
        polytrauma (60% based on current data) and those with non-combat polytrauma (40%) for
        selected subsequent analyses. A comparison group of between 300 and 400 non-polytrauma
        OEF/OIF service members (NPTR) will be sampled randomly from the pool of all veterans on
        the Minneapolis and Tampa OEF/OIF patient registries (ns = 150-200 at each site). This
        latter group will be dichotomized into those with pain (NPTR-P; approximately 42 - 50%
        based on our previous research) and those without (NPTR-NP) for later analyses.
      
Keywords: chronic pain; combat injuries; pain assessment; multiple traumas; rehabilitation