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ORIGINAL RESEARCH
Factors Associated With Pressure Ulcers in Individuals
With Spina Bifida
Sunkyung Kim, PhD,
a
Elisabeth Ward, RN, MPH,
b
Brad E. Dicianno, MD,
c
Gerald H. Clayton, PhD,
d
Kathleen J. Sawin, PhD, CPNP-PC, FAAN,
e,f
Patricia Beierwaltes, DNP, CPNP,
g,h
Judy Thibadeau, RN, MN,
a
National Spina Bifida
Patient Registry
From the
a
Division of Human Development and Disability, National Center on Birth Defects and Developmental Disabilities, Centers for Disease
Control and Prevention, Atlanta, GA;
b
Carter Consulting, Inc., Atlanta, GA;
c
Department of Physical Medicine and Rehabilitation, University of
Pittsburgh Medical Center, Pittsburgh, PA;
d
Department of Physical Medicine and Rehabilitation, University of Colorado Denver and Children’s
Hospital Colorado, Aurora, CO;
e
College of Nursing, University of Wisconsin-Milwaukee, Milwaukee, WI;
f
Children’s Hospital of Wisconsin,
Milwaukee, WI;
g
Children’s Hospital of Michigan, Detroit, MI; and
h
Wayne State University, Detroit, MI.
Abstract
Objective: To describe factors associated with pressure ulcers in individuals with spina bifida (SB) enrolled in the National Spina Bifida Patient
Registry (NSBPR).
Design: Unbalanced longitudinal multicenter cohort study.
Setting: Nineteen SB clinics.
Participants: Individuals with SB (NZ3153) enrolled in 19 clinic sites that participate in the NSBPR.
Interventions: Not applicable.
Main Outcome Measures: Pressure ulcer status (yes/no) at the annual visit between 2009 and 2012.
Results: Of 3153 total participants, 19% (nZ603) reported ulcers at their most recent annual clinic visit. Seven factorsdlevel of lesion,
wheelchair use, urinary incontinence, shunt presence, above the knee orthopedic surgery, recent surgery, and male sexdwere significantly
associated with the presence of pressure ulcers. Of these factors, level of lesion, urinary incontinence, recent surgery, and male sex were included
in the final logistic regression model. The 3 adjusting variablesdSB type, SB clinic, and age groupdwere significant in all analyses (all P<.001).
Conclusions: By adjusting for SB type, SB clinic, and age group, we found that 7 factorsdlevel of lesion, wheelchair use, urinary incontinence,
shunt presence, above the knee orthopedic surgery, recent surgery, and male sexdwere associated with pressure ulcers. Identifying key factors
associated with the onset of pressure ulcers can be incorporated into clinical practice in ways that prevent and enhance treatment of pressure ulcers
in the population with SB.
Archives of Physical Medicine and Rehabilitation 2015;96:1435-41
ª2015 by the American Congress of Rehabilitation Medicine
Spina bifida (SB) is a neural tube defect that occurs when the
spinal column of a developing fetus does not close properly in
utero. It affects approximately 3.1 individuals per 10,000 children
and adolescents in 10 regions of the United States according to a
population-based study.
1
Myelomeningocele is the most severe
form of SB, in which the vertebrae and spinal canal do not close
before birth. Meningocele and lipomyelomeningocele are milder
forms. Resulting sequelae of an open neural tube defect may
include impairments in mobility, cognition, urinary and fecal
continence, and an accumulation of secondary conditions, which
may require numerous medical and surgical interventions
throughout the life span.
2
Pressure ulcers result from prolonged pressure to soft tissue,
skin, and muscle. They may occur in individuals who have
Ward is consultant to Centers for Disease Control and Prevention.
Supported by the National Center on Birth Defects and Developmental Disabilities, Centers for
Disease Control and Prevention, Atlanta, GA (grant no. 1UO1DDD000744.01). The findings and
conclusions in this report are those of the authors and do not necessarily represent the official
position of the Centers for Disease Control and Prevention.
Disclosures: none.
0003-9993/15/$36 - see front matter ª2015 by the American Congress of Rehabilitation Medicine
http://dx.doi.org/10.1016/j.apmr.2015.02.029
Archives of Physical Medicine and Rehabilitation
journal homepage: www.archives-pmr.org
Archives of Physical Medicine and Rehabilitation 2015;96:1435-41
impairments in sensation or motor function. Each year, more than
2.5 million people develop pressure ulcers in the United States.
3
Between 1999 and 2005, the overall pressure ulcer prevalence
rate was 15% for hospitalized individuals in 9 international
pressure ulcer surveys,
4
and 4% in hospitalized children in 2003.
5
In individuals with SB, skin wounds are reported as one of the
primary diagnoses associated with hospitalizations.
6
Pressure ul-
cers can lead to serious complications such as infection, sepsis, leg
amputation, and even death.
The annual prevalence rate of pressure ulcers and other causes
of skin breakdown in individuals with myelomeningocele reported
in the literature for all ages is between 15% and 77%,
7-11
and in
adults with SB it is 34%,
12
a much higher rate than in the general
population. The wide variations in the rates may be attributed to
the differences in population age and inclusion criteria over
different studies.
Although there are many published articles describing risk
factors for skin breakdown including pressure ulcers, there has
been a lack of studies focusing exclusively on this topic in the
population with SB. A recent cohort study over a 13-year period
found that age, wheelchair use, bare feet, obesity, and reduced
executive functioning are key risk factors for wound develop-
ment.
13
Another small questionnaire-based study of 87 adults with
myelomeningocele showed a higher prevalence of pressure ulcers
in individuals with memory deficits, Chiari II malformation, and
sensory deficit.
14
For young adults with myelomeningocele, the
number of ulcers has also been found to be associated with motor
and educational level.
15
Understanding factors associated with pressure ulcers in this
population is critical to help them maintain or improve their
health. Using results from a prospective study with an adequate
sample size will provide a scientific basis to help influence clinical
care. This study aims to explore factors associated with pressure
ulcers in individuals enrolled in the National Spina Bifida Patient
Registry (NSBPR) in the United States between 2009 and 2012.
Methods
Study population
The sample is composed of participants with SB from 19 clinic
sites who participated in the NSBPR between 2009 and 2012.
After institutional review board approval and obtaining informed
consent/assent from parents and patients, the clinics collected
longitudinal data on individuals with SB.
16
At the initial visit,
basic demographic and diagnostic information as well as infor-
mation on surgical procedures were collected from each patient.
At the initial visit and each subsequent annual visit, information
on insurance status, anthropometric measurements, surgeries and
procedures, education and employment, and treatments and out-
comes was also collected. Depending on when a patient was
enrolled, a patient may have had from 1 to 4 submitted annual
reports. By the end of 2012, a total of 3738 participants were
enrolled in the NSBPR. Of these, 585 participants aged <2 years
at enrollment were excluded because mobility status is variable in
this age group and for this reason they were not typically evalu-
ated as a cohort. The final analytical data set was composed of
3153 participants’ 5593 annual reports (see supplemental tables
S1 and S2, available online only at http://www.archives-pmr.org/).
Variables
SB type and level of lesion
Participants were classified into 2 SB types: myelomeningocele or
non-myelomeningocele, which included the diagnoses of menin-
gocele, lipomyelomeningocele, or fatty filum. Each patient’s level
of lesion was determined on their both right and left sides on the
basis of the presence of antigravity strength of muscle groups: hip
flexors, quadriceps, dorsiflexors, and plantar flexors. The func-
tional level of lesion was classified into 5 categoriesd1, sacral, 2,
low-lumbar, 3, mid-lumbar, 4, high-lumbar, and 5, thoracic in the
order of increasing severitydand used as a continuous variable
(1e5) in the analysis. For asymmetric level of lesions, the higher
spinal level (ie, more severe) was selected.
Pressure ulcer status
At each annual visit, participants were asked if there have been
any pressure ulcers in the past 12 months or since the previous
clinic visit.
Surgeries
Six surgical types were considered as potential factors. Chiari II
decompression and shunt placement surgeries that occurred from
birth to the time of the annual visit were considered as (history)
binary indicators. Orthopedic, urology, and tethered cord release
surgeries that occurred from the 12 months before enrollment to
the time of each annual visit were considered as (partial history)
binary indicators. Orthopedic surgeries were divided into 2 cate-
gories: above the knee and below the knee. Procedures addressing
scoliosis, kyphosis, hip flexion contracture, and hip subluxation/
dislocation were classified as above the knee procedures.
Correction of knee flexion contracture, external tibial torsion,
ankle valgus deformity, equinus contracture, clubfoot deformity,
congenital vertical talus, and congenital deformity of foot were
considered as below the knee procedures. Lastly, to consider the
effect of recent hospitalization on pressure ulcers, a summary
variable reflecting any recent surgery since the previous annual
visit was also created as a binary variable (yes/no).
Bladder/bowel incontinence
Participants were asked if they were wet during the day with or
without interventions for bladder incontinence and if they expe-
rienced involuntary stool leakage for bowel incontinence. If they
responded yes to either question, they were assigned to the in-
continence group for bladder and bowel, respectively.
Ambulatory ability
Participants were grouped into 4 ambulatory categories and then
regrouped into 2 groups: community ambulators or wheelchair
users. Community ambulators were defined as those who are able
to walk indoors and outdoors for most of their activities regardless
of whether they use assistive device or braces. Individuals in this
group could use a wheelchair, but only for long trips in the
List of abbreviations:
CI confidence interval
GEE generalized estimating equation
NSBPR National Spina Bifida Patient Registry
OR odds ratio
QIC quasi-likelihood information criteria
SB spina bifida
1436 S. Kim et al
www.archives-pmr.org
community. Otherwise, individuals were classified as wheel-
chair users.
Insurance type, age group, and race/ethnicity
Medicaid, Medicare, and state high-risk health care plans were
classified into public insurance, and all other types of insurance
were classified as private. Participants were classified into 1 of 3
groups at each annual visit: group 1 included patients aged 2 to
<10 years, group 2 included patients aged 10 to 20 years, and
group 3 included patients aged >20 years; age group was treated
as a continuous variable (Groups 1e3) in the analysis. With regard
to race/ethnicity, participants were classified into non-Hispanic
white, non-Hispanic black, Hispanic or Latino, or Asian.
Data analysis
The study population was described by their general characteris-
tics at the most recent annual clinic visit. To examine any asso-
ciation between pressure ulcer status and a candidate factor,
multiple logistic regressions were run treating pressure ulcer status
as a dependent variable and any given factor as a primary inde-
pendent variable by using all data. SB type, SB clinic, and age
groups were adjusted in the analyses, as we assumed that the
variation of ulcers would be explained by SB types, ages, and the
unobserved clinic level effects; for example, clinics may treat
wounds differently or have a patient population that differs
significantly from that in other clinics. We note that a clinic with a
sample of size nZ42 was set as the reference. To account for
repeated measurements per patient over multiple years, general-
ized estimating equation (GEE) analysis was performed with a
compound symmetry correlation structure. The GEE is robust for
the misspecification of the covariance structure and is more effi-
cient for large sample sizes compared to the number of repeated
measures. For the factors that had significant associations (P<.05)
in the analyses, the adjusted prevalence of pressure ulcers was
calculated over various age groups by SB type.
In addition, we developed the final model to select the joint
model, balancing model complexity, and model fit by applying
quasi-likelihood information criteria (QIC).
17
The QIC method is
a model selection method for GEE models. Including all the
significant factors initially, the final model was developed as the
one that led to the smallest QIC by comparing several GEE
candidate models. All data analyses were performed with SAS
version 9.3.
18,a
Results
Pressure ulcer prevalence
The final analytical data set was composed of 3153 participants
with at least 1 completed initial and annual visit report forms.
During the study period, 1036 pressure ulcers occurred in 825
participants (26%). Table 1 lists the general characteristics of
participants by pressure ulcer status at the most recent annual
clinic visit. Approximately 19% (nZ603) of participants reported
a pressure ulcer in the past 12 months. The myelomeningocele
group had a higher prevalence of pressure ulcers. The prevalence
of pressure ulcers increased with a higher level of lesions, grad-
ually increasing from 7% (nZ63) in participants with sacral level
lesions to 31% (nZ169) in participants with thoracic level lesions.
In comparison with community ambulators, wheelchair users had
an 11% higher prevalence of pressure ulcers. Participants with
bladder incontinence were 1.1% more likely to experience pres-
sure ulcers than did participants with bowel incontinence, and
overall, ulcers were more common in participants with any in-
continence. The prevalence of pressure ulcers was higher in those
with a history of neurologic and orthopedic surgeries, non-
Hispanic black participants, men, those aged 10 years, and
those with public insurance only. The mean age was 6.32.1 years
for patients aged 2 to <10 years, 14.92.8 years for patients aged
10 to 20 years, and 27.88.8 years for patients aged >20 years.
The location of ulcers was most frequent in the areas of the
foot, lower limb, or posterior pelvis for all age groups and SB
types (fig 1). Participants with myelomeningocele had more ulcers
than did participants with non-myelomeningocele. Although par-
ticipants aged 2 to <10 years had more ulcers on the lower limb
than on the posterior pelvis, those aged 10 years had more ulcers
on the posterior pelvis than on the lower limb.
Pressure ulcer factors
The results of multiple logistic regression using the GEE are
summarized in table 2. Adjusting for SB type, SB clinic, and age
groups, the factors significantly associated with pressure ulcers
were level of lesion, ambulation status, bladder incontinence,
shunt placement, above the knee orthopedic surgery, recent sur-
gery, and male sex. For each increase in the functional level of
lesion, the odds of pressure ulcers were increased by 34%
(P<.001). The odds were 74% higher (P<.001) in wheelchair
users and 22% higher (PZ.02) in participants with bladder in-
continence. The odds of a pressure ulcer were increased by 49%
(P<.001) in participants with a history of shunt placement and by
53% (PZ.02) in participants with a history of above the knee
orthopedic surgery. In men, the odds were 17% (PZ.04) higher
than those in women. No significant associations were found be-
tween pressure ulcer and bowel incontinence, Chiari II decom-
pression, urology surgery, tethered cord release, below the knee
orthopedic surgery, race/ethnicity, or insurance type. The 3
adjusting variablesdSB type, SB clinic, and age groupsdwere all
significant in all analyses (data not shown). To facilitate the
interpretation of these results, we illustrated the adjusted preva-
lence of the pressure ulcer status for the 7 significantly associated
factors by their values (yes/no) from the fitted model over various
age groups in figure 2. Overall, the prevalence of pressure ulcers in
participants with myelomeningocele was higher than that in par-
ticipants with non-myelomeningocele. Also, as the age increased
within both myelomeningocele and non-myelomeningocele
groups, the prevalence of pressure ulcers increased gradually.
For example, in wheelchair users with myelomeningocele, the
pressure ulcer prevalence was 29% in the age group of 2 to 10
years, 42% in the age group of 10e20 years, and 55% in the age
group of >20 years. In their peers with non-myelomeningocele
conditions, the pressure ulcer prevalence was 18%, 27%, and
39%, respectively. In participants with myelomeningocele with
shunt placement, the adjusted prevalence of pressure ulcers was
7% higher in the age group of 2 to 10 years, 9% higher in the age
group of 10 to 20 years, and 10% higher in the age group of >20
years as compared with those who were not shunted.
Our final model included level of lesion, urinary incontinence,
recent surgery, and male sex, adjusting for SB type, SB clinic, and
age groups (see table 2). Higher level of lesion and male sex
including SB type, age group, and SB clinic were still significantly
associated with pressure ulcers (all P<.05): the odds of pressure
Pressure ulcers in individuals with spina bifida 1437
www.archives-pmr.org
ulcer were 55% higher for the myelomeningocele group (odds
ratio [OR], 1.55; 95% confidence interval [CI], 1.17e2.04) and
68% higher for one age group increase (OR, 1.68; 95% CI, 1.48e
1.92) (not shown in table 2). The ORs for 18 clinics versus the
referred clinic are presented in figure 3 (ORs, 0.08e1.16). The
ORs excluding 1.00 in the 95% CI are significant.
Discussion
Pressure ulcers were more common in individuals with a higher level
of lesions in the study, which is consistent with the findings of
Ottolini et al.
13
In general, higher lesion levels are generally asso-
ciated with higher degrees of paralysis and sensory loss, which may
explain the higher rates of pressure ulcers. Wheelchair use was also
associated with ulcers, which is not surprising because prolonged
sitting and immobility may predispose to pressure ulcers. Among
demographic factors, male sex was associated with the occurrence of
pressure ulcers. Similar findings for higher riskof ulcers in men were
reported among palliative home care clients,
19
adults in acute care
hospitals,
20
and individuals with spinal cord injury,
21
where a higher
level of care requirements
19
and poor nutrition
20
compared to women
were discussed as possible reasons. After neurological surgeries, we
found that ulcers were more likely to occur in the shunted group.
13
Bladder incontinence was another factor associated with ulcers,
whereas bowel incontinence was not. Work by others has suggested
that urinary incontinence may be a more accurate predictor than fecal
incontinence in individuals with spinal cord injury,
22,23
and it has
been well demonstrated that incontinence and moisture are strongly
associated with pressure ulcers. For orthopedic surgeries, only above
the knee procedures were related to ulcers. Although the interactions
of mobility status, orthopedic surgery, bracing, and pressure ulcers
are likely quite complex, it is possible that individuals undergoing
orthopedic procedures above the knee are more vulnerable to pres-
sure ulcers because their mobility may be more limited than those
who have procedures exclusively below the knee. Any recent surgery
was also related to ulcers. This may indicate a hospital-acquired
pressure ulcer related to some posthospitalization circumstance.
This cannot be clearly explained using these data because the date of
the pressure ulcer occurrence was unknown.
Interestingly, a few studies reported that shunt, wheelchair use,
sex,
14
and level of lesion
24
were not associated with pressure ul-
cers in individuals with SB, which was in contrast to our findings
Table 1 Sample distribution of factors at the most recent
annual clinic visit by pressure ulcer status
Factor n (%)
Pressure Ulcer Status
Yes No
3153 (100) 603 (19.1) 2550 (80.9)
SB type
Myelomeningocele 2566 (81.4) 553 (21.5) 2013 (78.5)
Others 587 (18.6) 50 (8.5) 537 (91.5)
Level of lesion*
Sacral 886 (28.1) 63 (7.1) 823 (92.9)
Low-lumbar 565 (17.9) 89 (15.8) 476 (84.3)
Mid-lumbar 867 (27.5) 215 (24.8) 652 (75.2)
High-lumbar 285 (9.0) 67 (23.5) 218 (76.5)
Thoracic 550 (17.4) 169 (30.7) 381 (69.3)
Wheelchair use
Yes 1421 (45.1) 360 (25.3) 1061 (74.7)
No 1732 (54.9) 243 (14.0) 1489 (86.0)
Incontinence
Urinary
Yes 1851 (58.7) 375 (20.3) 1476 (79.7)
No 1302 (41.3) 228 (17.5) 1074 (82.5)
Stool
Yes 1662 (52.7) 319 (19.2) 1343 (80.8)
No 1491 (47.3) 284 (19.1) 1207 (81.0)
Neurologic surgery
Chiari II
decompression
y
Yes 235 (7.5) 64 (27.2) 171 (72.8)
No 2918 (92.6) 539 (18.5) 2379 (81.5)
Shunt
y
Yes 2077 (65.9) 473 (22.8) 1604 (77.2)
No 1076 (34.1) 130 (12.1) 946 (87.9)
Tethered cord
release
z
Yes 142 (4.5) 31 (21.8) 111 (78.2)
No 3011 (95.5) 572 (19.0) 2439 (81.0)
Orthopedic surgery
z
Above the knee
Yes 120 (3.8) 35 (29.2) 85 (70.8)
No 3033 (96.2) 568 (18.7) 2465 (81.3)
Below the knee 211 (6.7) 50 (23.7) 161 (76.3)
Yes
No 2942 (93.3) 553 (18.8) 2389 (81.2)
Urology surgery
z
Yes 285 (9.0) 60 (21.0) 225 (79.0)
No 2868 (91.0) 543 (18.9) 2325 (81.1)
Recent surgery
Yes 649 (20.6) 149 (23.0) 500 (77.0)
No 2504 (79.4) 454 (18.1) 2050 (81.9)
Race/ethnicity
Non-Hispanic white 2059 (65.3) 413 (20.1) 1646 (79.9)
Non-Hispanic black 256 (8.1) 59 (23.1) 197 (76.9)
Hispanic or Latino 651 (20.7) 103 (15.8) 548 (84.2)
Asian 130 (4.1) 14 (10.8) 116 (89.2)
Unknown 57 (1.8) 14 (24.6) 43 (75.4)
Sex
Male 1494 (47.4) 299 (20.0) 1195 (80.0)
Female 1659 (52.6) 304 (18.3) 1355 (81.7)
Table 1 (continued )
Factor n (%)
Pressure Ulcer Status
Yes No
Age group (y)*
2e<10 1177 (37.3) 144 (12.2) 1033 (87.8)
10e20 1420 (45.0) 321 (22.6) 1099 (77.4)
>20 556 (17.6) 138 (24.8) 418 (75.2)
Insurance type
Public 2066 (65.5) 414 (20.0) 1652 (80.0)
Private 1087 (34.5) 189 (17.4) 898 (82.6)
NOTE. Values are n (%). The mean ages for each age group were
6.32.1, 14.92.8, 27.88.8y in an order.
* Treated as a continuous variable in the main analysis.
y
Any surgery history from birth to the last annual visit.
z
Any surgery history from enrollment to the last annual visit.
1438 S. Kim et al
www.archives-pmr.org
of this study. However, these studies may lack the statistical power
to reveal the risk factors for ulcers because of small sample sizes
(nZ87 or 66), and the lack of significance in small studies should
not be considered as evidence that the factors are not a risk factor.
In all analyses, we adjusted for SB type, age groups, and SB
clinic, and these estimates were all statistically significant. As
expected, individuals with myelomeningocele are more limited
in their ambulation than those of the non-myelomeningocele
group; pressure ulcers were more prevalent in those with
myelomeningocele.
11,25
The significant relation of the age to
pressure ulcers corresponds with findings of a previous study,
26
but in our study, ulcers are most common in adults aged >20
years, not in adolescents. Interestingly, the SB clinic is significant,
possibly because of clinical variations in diagnosis, skin inspec-
tion, patient/parent education, and pressure ulcer treatments. For
example, in some clinics, skin care specialists may check the
patients during their regular visit, but in other clinics, ulcers may
be reported by patients only when asked by clinicians.
Fig 1 Count (#) of pressure ulcers by location for myelomeningocele (top) and others (bottom) at the most recent annual clinic visit.
Table 2 OR (95% CI) from multiple logistic regression models and the final model, controlling for SB type, SB clinic, and age groups
Factor
Multiple Logistic Regression Models Final Model
OR (95% CI) POR (95% CI) P
Level of lesion 1.34 (1.27e1.43) <.001 1.34 (1.26e1.42) <.001
Wheelchair use 1.74 (1.47e2.06) <.001 NA
Urinary incontinence 1.22 (1.04e1.43) .02 1.15 (0.98e1.35) .09
Stool incontinence 1.05 (0.90e1.23) .51 NA
Chiari II decompression 1.08 (0.83e1.40) .57 NA
Tethered cord release 1.21 (0.85e1.73) .29 NA
Shunt 1.49 (1.17e1.90) <.001 NA
Above the knee orthopedic surgery 1.53 (1.06e2.20) .02 NA
Below the knee orthopedic surgery knee 1.23 (0.93e1.63) .14 NA
Urology surgery 1.24 (0.97e1.60) .09 NA
Recent surgery 1.26 (1.06e1.49) .01 1.18 (0.99e1.40) .06
Race/ethnicity NA
Non-Hispanic white Reference NA NA
Non-Hispanic black 0.97 (0.72e1.30) .84 NA
Hispanic or Latino 0.91 (0.72e1.16) .44 NA
Asian 0.96 (0.59e1.55) .85 NA
Sex: male 1.17 (1.00e1.37) .04 1.18 (1.01e1.39) .04
Public insurance 1.15 (0.97e1.36) .11 NA
Abbreviation: NA, not applicable.
Pressure ulcers in individuals with spina bifida 1439
www.archives-pmr.org
Study limitations
Our study has several limitations. First, participants were not
asked to record exact dates of their surgeries and pressure ulcers;
therefore, some surgical procedures potentially occurred after
participants developed pressure ulcers, although all occurred in
the same year. Second, although pressure ulcers reported by a
participant and by examination are different entities, we could
not separate these from our data. Third, although long-term
prospective data are well suited to address causality of the fac-
tors, we could review NSBPR data only over a 4-year period at
this time. However, annual data continue to be collected up to
2019 (the currently funded period of this longitudinal data
collection) including exact dates of the surgical procedures
extracted from medical records, so the risk factors for ulcers may
be better understood in a future analysis. Fourth, the impact of
mobility category on pressure ulcers was assessed with only
wheelchair use, whereas orthoses and other devices can also
cause pressure or shear that can lead to ulcers. Fifth, we did not
distinguish between factors related to initial ulcers versus those
related to recurrence of ulcers. Ulcer recurrences were previ-
ously found in 53% of individuals with SB.
13
We al so did n ot
distinguish between factors related to multiple ulcers. We expect
that future studies with more (longitudinal) data will address
these issues better. Sixth, the prevalence of pressure ulcers is
possibly underestimated for the general population with SB
because participants may not report their ulcers during an annual
visit unless they were routinely examined by clinicians. Finally,
we did not adjust for multiple testing such as Bonferroni
correction because this study was exploratory in nature and we
did not posit a strong assumption of no association between
pressure ulcers and a factor.
Conclusions
Recent pressure ulcers were present in 19% of the total sample at
the mean age of 14 years, present in 22% for myelomeningocele
and 9% for non-myelomeningocele. Factors with statistically
significant associations with pressure ulcers were level of lesion,
wheelchair use, urinary incontinence, presence of shunt, recent
surgery, and male sex. Of these, level of lesion, urinary inconti-
nence, recent surgery, and sex were also included in the final
model. Approximately 75% to 85% of individuals born with SB
are now surviving into adulthood, likely owing to advances in
medical and surgical care.
27,28
This elevates the importance of
Fig 2 Adjusted prevalence (%) of pressure ulcers by associated factors over various age groups for myelomeningocele (top) and others
(bottom), adjusting SB clinic. Adjusted prevalence was calculated using GEE analysis. Each model included the factor of interest, age group, SB
type, and SB clinic.
Fig 3 OR (95% CI) for SB clinics in the final model.
1440 S. Kim et al
www.archives-pmr.org
dealing with the morbidity associated with pressure ulcers in a
longer living population. When considering prevention and treat-
ments for pressure ulcers, more importance should be placed on
the factors identified in these models of association.
Supplier
a. SAS Institute Inc.
Keywords
Pressure ulcer; Rehabilitation; Risk factors; Spinal cord injuries
Corresponding author
Sunkyung Kim, PhD, Division of Human Development and
Disability, National Center on Birth Defects and Developmental
Disabilities, Centers for Disease Control and Prevention, 1600
Clifton Rd NE, Mailstop E88, Atlanta, GA 30333. E-mail address:
wox0@cdc.gov.
Acknowledgments
We thank all members of the National Spina Bifida Patient Reg-
istry (NSBPR) Coordinating Committee who have participated in
the development of the NSBPR: William Walker, MD, Seattle
Children’s Hospital; Kathryn Smith, RN, DrPH, Children’s Hos-
pital Los Angeles; Kurt Freeman, PhD, ABPP, Oregon Health &
Science University; Pamela Wilson, MD, Children’s Hospital
Colorado; Kathleen Sawin, PhD, CPNP-PC, FAAN, Children’s
Hospital of Wisconsin; Jeffrey Thomson, MD, Connecticut Chil-
dren’s Medical Center; Heidi Castillo, MD, Cincinnati Children’s
Hospital Medical Center; Timothy Brei, MD, Riley Hospital for
Children; David Joseph, MD, Children’s Hospital of Alabama;
Elaine Pico, MD, Children’s Hospital and Research Center at
Oakland; Mitul Kapadia, MD, University of California, San
Francisco; Robin Bowman, MD, Ann & Robert H. Lurie Chil-
dren’s Hospital of Chicago; John Wiener, MD, Duke University;
Paula Peterson, PNP, Primary Children’s Medical Center; Mark
Dias, MD, Pennsylvania State University, Hershey Medical Cen-
ter; Karen Ratliff-Schaub, MD, Nationwide Children’s Hospital;
Brad Dicianno, MD, University of Pittsburgh; James Chinarian,
MD, Wayne State University; and The Spina Bifida Association.
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Pressure ulcers in individuals with spina bifida 1441
www.archives-pmr.org
Supplemental Table S1 The number of participants by their
total number of clinic visits
Total Number of Clinic Visits n
1 1728
2 629
3 577
4 219
Total 3153
Supplemental Table S2 The number of participants at their
each annual visit between 2009 and 2012
Year of Annual Visit n
2009 697
2010 1134
2011 1380
2012 2382
Total 5593
1441.e1 S. Kim et al
www.archives-pmr.org
