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SCI: Pressure Ulcers (2007)

Citation:

Krause JS, Broderick L. Patterns of recurrent pressure ulcers after spinal cord injury: identification of risk and protective factors 5 or more years after onset.  Arch Phys Med Rehabil. 2004;85:1257-1264.

PubMed ID: 15295750
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To identify risk and protective factors associated with a history of recurrent pressure ulcers and persons who do not have a pattern of recurrent pressure ulcers among participants with spinal cord injury.
Inclusion Criteria:
  • etiology of traumatic SCI
  • 18 years of age or older
  • at least 5 years postinjury
  • nonambulatory (American Spinal Cord Injury Association grades A-C)
Exclusion Criteria:
Ambulatory participants were excluded because of diminished likelihood of developing pressure ulcers.
Description of Study Protocol:

Recruitment

All potential participants were selected from outpatient records of a large specialty hospital in the southeastern United States.  The participants were selected from the Model Spinal Cord Injury Systems (MSCIS) catchment areas, the MSCIS registry, and general outpatient records.

Design

  • Cross-sectional design in which cover letters were sent to participants before the mailing of the questionnaires.  4-6 weeks after the initial letter the participants were sent an initial packet of information. Nonrespondents were sent a second packet of information, followed by a telephone call.  A third mailing was initiated to all nonrespondents who continued to state a willingness to participate.  Participants were offered $20 to participate in the study and were made eligible for drawings totalling $1500.
  • Questions about pressure ulcer history, completion of the Zuckerman-Kuhlman Personality Questionnaire, the Multi-Dimentional Health Locus of Control Scale, several questions from the Behavioral Risk Factor Surveillance System, the Older Adult Health and Mood Inventory, and questions regarding the participants eating and nutritional habits and risk behaviors were solicited.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable):  Not Applicable

Statistical Analysis

  • Descriptive statistics were obtained for each pressure ulcer variable.
  • Pressure ulcer history was analyzed in relation to other pressure ulcer variables to assist in determining the consistency of the overall presure ulcer rating.
  • The primary pressure ulcer history outcome variable was cross-tabulated with several dichotomous or dichotomized pressure ulcer variables, including current status, pressure ulcers in the past year, and ever having had a pressure ulcer-related surgery.
  • These analyses were used to eliminate cases with incongruent responses.
  • Logistic regression was used to identify the risk and protective behaviors and psychologic variables that were significantly associated with recurrent pressure ulcer history. Biographic and demographic variables were entered into the equaton first, including age of onset, years post-injury, injury level, ASIA score, gender, and ethnicity.  Each behavioral predictor and psychologic trait was evaluated one at a time during univariate analyses.

 

Data Collection Summary:

Timing of Measurements

 A mail survey was used to obtain information from participants

Dependent Variables

  • Never having a pressure ulcer since SCI
  • Pressure ulcer immediately after SCI with few if any after that point
  • Occurence of pressure ulcers every couple of years
  • Occurence of pressure ulcer at least once a year
  • Occurence of pressure ulcer on an almost constant basis

Independent Variables

  •  15 risk and 7 protective variables and 9 proxy variables to include tobacco use, alcohol consumption, nutrition, depressive symptoms

Control Variables

Biographic and injury-related variables were entered into the first stage of the logistic regression analysis as statistical controls.

Description of Actual Data Sample:

Initial N:

1391 were selected from the MSCIS registry, 826 participants met the criteria

Attrition (final N):  826 particpants, 633 had a pressure ulcer history that could be classified as either recurrent or nonrecurrent.

Age:

Mean age was 30.4 years of age at the time of injury and 40.8 years of age at the time of the study.

Ethnicity: 74.9% Caucasian, other ethnicities were not reported

Other relevant demographics:

The average number of years of education was 13.1 years.

Anthropometrics 

Location:

Southeastern United States

Summary of Results:

 

Variables

ß

SE

OR

Confidence interval (95%)

Protective factors

       

employed

 -0.77

 .30

0.46*

0.26-0.84

healthy lifestyle

 -0.43

.12

0.65♦

0.51-0.83
eat healthy diet  -0.26 .12   0.77*  0.62-0.97
eat vegetables  -0.10 .05  0.90*  0.82-0.99 
self-reported fitness  -0.58 .13   0.56♦  0.43-0.72
exercise compaared with others  -0.48 .11   0.62♦  0.49-0.78
planned exercise  -0.22 .08  0.80♦  0.71-0.91 
SCI specific protective factors        
regular skin checks  0.18 .15   1.19  0.90-1.58
regular weight checks  0.07 .12  1.07  0.84-1.37 
drink water regularly  -0.22 .12  0.80  0.83-1.02 
trun regularly in bed  -0.14  .11 0.87  0.71-1.01 
Risk factors        
smoking        
currently smoking  0.40 .24  1.49  0.92-2.41 
smoke 100+ cigarettes  1.10 .35  3.00^   1.52-5.94
Alcohol        
CAGE (last 12 mo)  -0.03 .15   0.97  0.72-1.30
CAGE (ever)  -0.14 .13  0.87  0.67-1.13 
5+ drinks on 1 occasion  0.02 .03  1.02  0.96-1.07 
Prescription medication use        
treatment for depression  0.08 .10  1.09  0.89-1.33 
treatment for sleep  0.25 .10  1.29*   1.06-1.57
treatment for pain  0.14 .10  1.15  0.95-1.40 
treatment for spasticity  -0.05 .08  0.96  0.81-1.12 
Proxy variables        
QAHMI  0.10 .24  2.7♦  1.69-4.35
impulsive sensation seeking  0.02 .01  1.02  0.99-1.04 
neuroticism/anxiety  0.04 .01  1.05♦ 1.02-1.07 
aggression/hostility  0.02 .01  1.02  0.99-1.04 
activity  0.00 .01  1.00   0.88-1.02
sociablility  0.01 .01  1.01  0.99-1.03 
internal health LOC  -0.02 .01  0.98*  0.95-0.99 
Chance LOC  -0.01 .01  0.99  0.97-1.02 
Powerful others LOC  0.03 .01  1.03*   1.00-1.06

 *p<.05; ^p<.01; ♦p<.001; LOC = Locus of control

Lifestyle, exercise, and diet were protective behaviors for recurrent ulcers

None of the protective behaviors usually recommended during inpatient rehabilitation specifically to prevent ulcers (skin checks, weight shifts) were associated with pressure ulcer history.

2 risk behaviors were identified (number of cigarettes smoked, use of medications for sleep) were related to pressure ulcer history.

Other Findings

  • 75.5% of participants were men
  • 74.9% Caucasian, 55% had cervical injuries, 37% reporting not movement or sensation below the level of injury,
  • 36% reported sensation only, and 26% reported some movement below the level of injury
  • 70% of participants failed to report recurrent pressure ulcer (never had any or had them only immediately after SCI onset)
  • 13% reported a clear pattern of recurring pressure ulcers of 1 or more per year.

 

Author Conclusion:
Investigations that promote fitness, exercise, general activity, and avoidance of high-risk activities (heavy smoking, and sensation seeking) may be successful in reducing the risk for recurrent pressure ulcers. Pressure ulcer history is a more viable measureof pressure ulcer ooutcomes than measures taken at a single point in time (current), over a brief period (1 year), or in those relying on critical events occurring at any time since SCI onset.
Funding Source:
University/Hospital: Medical University of South Carolina, Crawford Research Institute
Reviewer Comments:
All data were cross-sectional in nature, therefore difficult to identify the extent to which the risk and protective factors correlated with pressure ulcer outcomes as opposed to leading to recurrent pressure ulcers.  All data were self-reported which may result in inconsistencies. The lack of longitudinal design did not allow an evaluation of behaviors that are recommended to avoid pressure ulcer. The cross-sectional design does not assess whether people only start performing behaviors after recurrent problems.  Participants self-reported their pressure ulcer history and then classified themselves into one of five groups.  Discrepancies were noted and 28 cases needed to be eliminated from the analyses. 
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes