Investigating the Relationship between Psychopharmacological Treatments and Change in Body Mass Index (BMI), in a Clinical
Sample of Child and Adolescent Psychiatric Outpatients
Robert J. Love, D.O., M.S.1,3; Ashley S. Love, D.P.H.2; Rachel Ballard, M.D.1; Thomas L., Matthews, M.D.1; Michelle S. Guchereau,
Guchereau, M.D.1,3
1
Department of Psychiatry, University of Texas Health Science Center at San Antonio; 2 Department of Health and Kinesiology, University of Texas at San Antonio; 3Department of Psychiatry, Wilford Hall Medical Center
ABSTRACT
Objective: To determine if any associations would be observed between change in BMI/BMI Z-score, psychotropic medication
administration, and several potentially confounding variables in clinical sample of child and adolescent psychiatric outpatients.
Method: Retrospective analyses of 250 charts of patients who received treatment in an outpatient clinic during 18 month period
prior to these analyses were performed. Of these charts, 204 contained adequate follow-up information. Multiple comparisons were
performed using repeated measures analyses of covariance.
Result: There was significant change in BMI (p=.05), but not a statistically significant change in BMIZ-score on all the children
from baseline to follow-up. The mean and median number of days on stable regimen was 721.7 and 460.5 respectively. There were
no statistically significant effects on the change in BMI/BMI Z-score that were revealed when comparison was performed with:
age; gender; class of psychotropic medication used (including: atypical antipsychotic, antidepressant, mood stabilizer, and
stimulant medications); total number of medications; total time of exposure; or exposure to psychotropic medication prior to
observation period.
Conclusions: After comparing the changes in BMI/BMI Z-score between patients differentiated by various parameters, we did not
find any statistically significant associations between any of these factors and change in BMI/BMI Z-score.
INTRODUCTION
Background:
Background: The
Therelationship
relationshipbetween
betweenbody
bodymass
massand
andaffective
affectivedisorders
disordersvaries
variesbetween
betweengenders
gendersand
andacross
acrossthe
thelifespan.
lifespan.
Causal
Causalrelationships
relationshipsthat
thatmay
mayexist
existbetween
betweenobesity,
obesity,psychiatric
psychiatricdisorders,
disorders,and
andpharmacological
pharmacologicaltreatment
treatmentfor
foraffective
affectivedisorders
disorders
are
not
clearly
defined.
In
adult
psychiatric
patients,
previous
investigations
have
shown
potential
associations
between
are not clearly defined. In adult psychiatric patients, previous investigations have shown potential associations betweenobesity
obesity
and
andaffective
affectivedisorders.
disorders. (1-3).
(1-3). However,
However,ininchildren,
children,the
therelationship
relationshipbetween
betweenobesity
obesityand
andpsychiatric
psychiatricillness
illnessisisless
lesswell
well
established.
established. Longitudinal,
Longitudinal,prospective,
prospective,population-based
population-basedstudies
studiesindicate
indicatethat
thatdepression
depressionininchildren
childrenmay
maypredict
predictfuture
futureobesity
obesityoror
accompany
chronic
obesity.
Cross
sectional
studies
of
large
populations
show
weaker
correlation,
but
previous
studies
have
accompany chronic obesity. Cross sectional studies of large populations show weaker correlation, but previous studies have
suggested
suggestedthat
thatclinically
clinicallyreferred
referredgroups
groupsofofobese
obesepatients
patientshave
havehigh
highrates
ratesofofpsychopathology
psychopathology(4),
(4),and
andchronically
chronicallymentally
mentallyill
ill
children
childrenhave
haveelevated
elevatedrates
ratesofofoverweight
overweight(5).
(5). Still,
Still,the
thepresence
presenceororabsence
absenceofofaatrue
truerelationship
relationshipbetween
betweenoverweight
overweightand
and
affective
affectivedisorders
disordersremains
remainsunclear.
unclear. Large
Largecross-sectional
cross-sectionalstudies
studiesofofadolescent,
adolescent,children,
children,and
andyoung
youngadults
adultsshow
showlittle
littlecorrelation
correlation
between
betweenobesity
obesityand
andpsychopathology
psychopathology(6,
(6,7).
7).
Significance:
Significance: The
Theenormity
enormityofofthe
theissue
issueofofepidemic
epidemicobesity
obesityininthe
theUS
UScannot
cannotbe
beoverstated.
overstated. Other
Otherresearchers
researchershave
havepredicted
predicted
that
thatthe
thecurrent
currenthealth
healthcare
caresystem
systemwill
willincreasingly
increasinglybe
beoverwhelmed
overwhelmedwith
withindividuals
individualswho
whorequire
requiretreatments
treatmentsfor
forobesity
obesityrelated
related
health
healthconditions,
conditions,and
andthat
thatthe
themedical
medicalcommunity
communitymust
mustemplace
emplaceconcerted
concertedinitiatives
initiativestotoprevent
preventand
andtreat
treatobesity
obesity(8).
(8). Recent
Recent
estimates
estimatesofofthe
thedirect
directcost
costofofobesity
obesityand
andphysical
physicalinactivity
inactivityare
arestaggering.
staggering. Obesity-related
Obesity-relatedhealth
healthcare
carecosts
costshave
havebeen
beenstated
statedtoto
be
beapproximately
approximately9.4%
9.4%ofofthe
theUS
UShealth
healthcare
careexpenditures
expenditures(9).
(9). There
Therehas
hasbeen
beenaadramatic
dramaticrise
riseininthe
theprevalence
prevalenceofofobesity
obesityininthe
the
United
UnitedStates
Stateswhich
whichspans
spansacross
acrossall
allage
ageand
andethnic
ethnicgroups,
groups,and
andexists
existsamong
amongboth
bothmen
menand
andwomen
women(10).
(10). AAparticularly
particularly
worrisome
worrisomefact
factisisthat
thatthe
theprevalence
prevalencerates
ratesamong
amongchildren
childrenhave
havedoubled
doubledininthe
thepast
pasttwo
twodecades,
decades,suggesting
suggestingthat
thatthe
thecurrent
current
incidence
of
obesity
in
adults
does
not
fully
reflect
the
severity
of
obesity-related
problems
we
will
see
in
the
next
few
decades
incidence of obesity in adults does not fully reflect the severity of obesity-related problems we will see in the next few decades
(10).
(10). When
Whenconsidering
consideringthat
thatobesity-related
obesity-relatedhealth
healthcare
carecosts
costshave
havemore
morethan
thantripled
tripledininthis
thiscountry
countryduring
duringthe
thepast
past20
20years
yearsand
and
were
wereestimated
estimatedatat$127
$127million
millioninin1997
1997toto1999,
1999,the
thecost
costofoftreating
treatingobesity
obesityrelated
relatedproblems
problemsare
arelikely
likelygoing
goingtotobe
beoverwhelm
overwhelm
health
healthcare
caresystem
system(11).
(11).
Clinical
ClinicalRelevance:
Relevance: The
Theimpact
impactofofpharmacological
pharmacologicaltreatment
treatmentof
ofchildhood
childhoodpsychiatric
psychiatricdisorders
disorderson
onbody
bodymass
massisisunknown.
unknown.
However,
However,weight
weightgain
gainhas
hasbeen
beenassociated
associatedwith
withpsychopharmacological
psychopharmacologicaltreatment
treatmentininadults.
adults. Childhood
Childhoodobesity
obesityisisaasignificant
significant
and
andgrowing
growingproblem,
problem,and
andgiven
giventhat
thatnumerous
numerousstudies
studieshave
havesuggested
suggestedthat
thatpsychopharmacological
psychopharmacologicaltreatments
treatmentsmay
maybe
beassociated
associated
with
weight
gain,
it
seems
exceedingly
important
that
further
investigations
be
made
in
this
area.
Given
the
lack
of
certainty
with weight gain, it seems exceedingly important that further investigations be made in this area. Given the lack of certainty
regarding
regardingthe
theinteraction
interactionbetween
betweenpsychopharmacological
psychopharmacologicalintervention
interventionand
andthe
thedevelopment
developmentofofobesity,
obesity,this
thisstudy
studywas
wasundertaken
undertaken
totoattempt
attempttotoidentify
identifythe
thepresence
presenceororabsence
absenceofofan
anassociation
associationbetween
betweenpsychopharmacological
psychopharmacologicaltreatment
treatmentand
andthe
thedevelopment
development
ofofobesity
obesityininaapopulation
populationofofchild
childand
andadolescent
adolescentpsychiatric
psychiatricoutpatients.
outpatients.
METHOD
Subjects: The study population consisted of 250 adolescent patients who were treated to the Child Clinic Center in San
Antonio, TX, during 1996-2005. Of the 250 adolescent patients, 204 had adequate follow-up information. All of these patients
underwent a semi-structured psychiatric interview at their initial visit and received a physical examination including height and
weight measurements according to the standard procedure of the clinic. The primary diagnoses of the children were attentiondeficit/hyperactivity disorder (ADHD). This study was approved by the Institutional Review Board of University of Texas
Health Science Center at San Antonio, TX.
Database: Each patient’s admission record was reviewed to extract variables including date of birth, gender, date of
measurement, height in inches, weight in pounds, psychotropic and non-psychotropic medications, psychiatric diagnosis,
family history of psychiatric conditions, and start and finish date of stable drug regiment. The total duration of the stable drug
regiment was calculated by subtracting the start date of stable drug regiment from the finish date. Nutstat module of Epi Info
was used to calculate Body Mass Index (BMI), BMI percentile, and BMI Z-score (Division of Public Health Surveillance and
Informatics, 2003). Birth date, date of measurement, sex, height, and weight were imported into this program for baseline and
follow-up visits.
Statistical Analyses: Statistical Package for Social Sciences (SPSS) Version 14 was used to analyze the data. Retrospective
analyses of 204 patients, who received treatment in an outpatient clinic and had complete follow-up information, were
performed. Univariate and bivariate analyses were conducted. Multiple comparisons were performed using repeated measures
analyses of covariance. A series of repeated measures analyses of covariance to determine the main effects of gender, type of
psycho medicine, and duration of stable medication on BMI Z-score.
Table 1. Characteristics of Sample at Baseline by Gender
16
Boys
(n=154)
10.34(3.44)
20.13 (5.99)
14
Age (y)
BMI (kg/m2)
Girls
(n=50)
9.85 (2.98)
19.71(5.28)
Z-Score of BMI
0.37 (1.05)
0.21 (5.49)
8
6
BMI percentile
RESULTS
ChangesininAnthropometric
AnthropometricMeasures
Measuresover
overTime:
Time: There
Therewas
wassignificant
significantchange
changeininBMI
BMI(p=.05)
(p=.05)but
butnot
notaastatistically
statistically
Changes
significantchange
changeininBMI
BMIZ-score
Z-scoreon
onall
allthe
thechildren
childrenfrom
frombaseline
baselinetotofollow-up.
follow-up. There
Therewere
wereno
nostatistically
statisticallysignificant
significant
significant
effectson
onthe
thechange
changeininBMI
BMIZ-score
Z-scorethat
thatwere
wererevealed
revealedwhen
whencomparison
comparisonwas
wasperformed
performedwith
withthe
thefollowing
followingfactors:
factors:family
family
effects
psychiatrichistory,
history,gender,
gender,and
andclass
classofofpsychotropic
psychotropicmedication
medicationused
used(including:
(including:atypical
atypicalantipsychotic,
antipsychotic,antidepressant,
antidepressant,
psychiatric
moodstabilizer,
stabilizer,and
andstimulant
stimulantmedications)
medications)while
whilecontrolling
controllingfor
forage,
age,gender,
gender,and
andtotal
totalnumber
numberofofmedications
medications(Figure
(Figure1).
1).
mood
Whenuse
useofofmultiple
multiplemedications
medicationsfrom
fromdiffering
differingclasses
classeswas
wascontrolled
controlledfor,
for,there
therewere
werestill
stillno
nodifferential
differentialassociations
associations
When
revealedtotoexist
existbetween
betweenclass
classofofmedication
medicationand
andchange
changeininBMI
BMIZZscore
score(Figure
(Figure2).
2). There
Therewas
wasalso
alsono
nodifferences
differencesininchange
change
revealed
BMIZZscore
scorewhen
whenpatients
patientswho
whohad
hadbeen
beenexposed
exposedtotopsychotropic
psychotropicmedication
medicationprior
priortotoobservation
observationperiod
periodwere
werecompared
compared
ininBMI
withsubjects
subjects(new
(newpatients)
patients)who
whowere
werenot
nottaking
takingany
anymedications
medicationsprior
priortotothe
theperiod
periodofofobservation
observation(Figure
(Figure3).
3).
with
10
59.17
65.85
Mean days on Stable Regimen*
489.60 (460.12)
722.93 (733.35)
Median days on Stable Regimen
344.50
459.00
0.98 (.94)
1.11 (.97)
10.0
12.3
-2
% on antidepressant
22.0
23.3
-4
% on mood stabilizer
4.0
9.5
% Stimulant medications
42.0
43.6
% Family psych history
50.0
36.9
Mean of Total number of
medications
% on atypical
Initial BMI_Z
Final BMI_Z
4
2
0
Atypical
n = 10
Stimulant
SSRI
n = 16
n = 75
Figure 2: Comparison of change in BMI –Z score when use of multiple medications from
differing classes was controlled for. Mood stabilizers were removed
removed from analysis due to lack
(and loss to follow up) of patients treated with mood stabilizer monomono-therapy in this population
* Significant at p<.05
BaselineDemographic
DemographicCharacteristics:
Characteristics: The
Themean
meanage
ageofofall
allsubjects
subjectswas
was9.97
9.97(3.01)
(3.01)years
yearsand
and21.8%
21.8%ofofthe
thesample
samplewere
were
Baseline
females. About
About39.7%
39.7%ofofthe
thesample
samplehad
hadfamily
familymembers
membersdiagnosed
diagnosedwith
withpsychiatric
psychiatricconditions.
conditions. The
Themean
meanand
andmedian
median
females.
numberofofdays
dayson
onstable
stableregimen
regimenwas
was721.7
721.7and
and460.5
460.5respectively.
respectively. The
Themean
meaninitial
initialBMI
BMIz-score
z-scoreofof19.96
19.96(5.76)
(5.76)was
was
number
equivalenttotoaaBMI
BMIpercentile
percentileofof64.1.
64.1. There
Therewas
wasno
nodifference
differenceofofbaseline
baselinedemographic
demographiccharacteristics
characteristicsby
bygender
gender(Table
(Table1).
1).
equivalent
Bothsexes
sexeshad
hadequivalent
equivalentpercentage
percentageofoffamily
familypsychiatric
psychiatrichistory
historyand
andsimilar
similarfrequencies
frequenciesofofprior
priorpsychotropic
psychotropicmedication.
medication.
Both
Baseline
BMI,
BMI
Z-scores,
and
BMI
percentiles
were
similar
for
both
male
and
female
patients.
Mean
number
of
days
on
Baseline BMI, BMI Z-scores, and BMI percentiles were similar for both male and female patients. Mean number of days on
stabledrug
drugregimen
regimenwere
weresignificantly
significantlyhigher
higheramong
amongboys
boysthan
thangirls
girls(p<.05).
(p<.05). There
Therewas
wasno
nosignificant
significantcorrelation
correlationbetween
between
aastable
theBMI
BMIZ-score
Z-scoreand
andthe
thefactors
factorsmentioned
mentionedabove.
above.
the
12
8
30
26
22
18
14
10
6
2
-2
7
6
5
Initial BMI
4
Initial BMI_Z
Final BMI
3
Final BMI_Z
2
1
0
Atypical
n = 27
Stimulant
n = 102
SSRI
n =33
Mood
-1
Prior meds
n = 158
n = 19
Figure 1: Comparison of baseline and final BMI differentiated by class of
medication prescribed without change for minimum period of 3 months.
months. (This
analysis was uncontrolled for concomitant medications)
No prior Meds
n = 71
Figure 3: Comparison of baseline and final BMI – Z score, between patients who had been
treated with medications prior to the stable period of observation
observation and those who were not
previously on medications.
CONCLUSION
Discussion: We
Wecompared
comparedaagroup
groupofofpatients
patientsdifferentiated
differentiatedby
byvarious
variousparameters
parameters(including
(includingclass
classofofmedication,
medication,prior
priormedication
medicationexposure,
exposure,duration
durationofoftreatment,
treatment,gender,
gender,age,
age,and
andfamily
familyhistory),
history),but
butfound
foundno
nostatistically
statisticallysignificant
significantassociations
associationsbetween
betweenany
anyofofthese
thesefactors
factorsand
andchange
changeininBMI
BMIororBMI
BMIZ-score.
Z-score.
Discussion:
Limitations:No
Nomatched
matchedcontrols
controlsininthis
thisnaturalistic
naturalisticretrospective
retrospectiveanalysis
analysisusing
usingconvenience
conveniencesample.
sample. Unequal
Unequalnumbers
numbersofofmales
malesand
andfemales.
females. Relatively
Relativelysmall
smallsample
samplesize
sizemay
maybe
beunderpowered
underpoweredtotodetect
detectsmall
smallbut
butrelevant
relevanteffect.
effect.No
Norecord
recordofofethnicity
ethnicityof
ofindividual
individualsubjects
subjectswas
wasavailable,
available,so
soethnicity
ethnicitycould
couldnot
notbe
becontrolled
controlled
Limitations:
forchildren
childrenwith
withdifferent
differentethnicity/race
ethnicity/racemay
mayshow
showdifferent
differentgrowth
growthpatterns.
patterns. Because
Becausethis
thisstudy
studywas
wasretrospective
retrospectiveand
andnaturalistic
naturalisticwe
wewere
wereunable
unabletotocontrol
controlthe
theway
wayininwhich
whichmedications
medicationswere
wereprescribed.
prescribed. AAlarge
largeportion
portionofofthe
theavailable
availabledata
datawas
wasunusable
unusabledue
duetotoaahigh
highfrequency
frequencyofofmedication
medicationchanges
changesininthis
thispopulation.
population.
for
ClinicalImplications:
Implications: Our
Ourresults
resultssuggest
suggestthat
thatthe
thelink
linkbetween
betweenpsychotropic
psychotropicmedications
medicationsand
andweight
weightgain
gainmay
maynot
notbe
beas
assignificant
significantas
asexpected.
expected.While
Whilethis
thisstudy
studymay
mayhave
havebeen
beenunderpowered
underpoweredtotoidentify
identifyaaclinically
clinicallyrelevant
relevanteffect,
effect,the
theuse
useofofBMI
BMIZZscore
scorerather
ratherthan
thanBMI
BMIallowed
allowedus
ustotocontrol
controlfor
forindividual
individualgrowth
growthand
andallowed
allowed
Clinical
theavoidance
avoidanceofofmisidentification
misidentificationofofnormal
normalgrowth/weight
growth/weightgain
gainas
asaamedication
medicationeffect.
effect. Larger
Largerscale
scaleprospective
prospectivestudies
studiesare
areneeded
neededtotobetter
betterassess
assessthe
theinteraction
interactionbetween
betweenpsychotropic
psychotropicmedication
medicationand
andweight
weightgain
gainininthis
thispopulation
population
the
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