This article was downloaded by: [Northeastern University]On: 06 October 2014, At: 17:53Publisher: RoutledgeInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,UK

Children's Health CarePublication details, including instructions forauthors and subscription information:http://www.tandfonline.com/loi/hchc20

Development of a ScreeningInstrument of Adherence inPediatric Sickle Cell DiseaseKellie A. Hilker , Sara Sytsma Jordan , Scott Jensen ,T. David Elkin & Rathi IyerPublished online: 07 Jun 2010.

To cite this article: Kellie A. Hilker , Sara Sytsma Jordan , Scott Jensen , T. DavidElkin & Rathi Iyer (2006) Development of a Screening Instrument of Adherence inPediatric Sickle Cell Disease, Children's Health Care, 35:3, 235-246, DOI: 10.1207/s15326888chc3503_3

To link to this article: http://dx.doi.org/10.1207/s15326888chc3503_3

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all theinformation (the “Content”) contained in the publications on our platform.However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness,or suitability for any purpose of the Content. Any opinions and viewsexpressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of theContent should not be relied upon and should be independently verified withprimary sources of information. Taylor and Francis shall not be liable for anylosses, actions, claims, proceedings, demands, costs, expenses, damages,and other liabilities whatsoever or howsoever caused arising directly orindirectly in connection with, in relation to or arising out of the use of theContent.

This article may be used for research, teaching, and private study purposes.Any substantial or systematic reproduction, redistribution, reselling, loan,sub-licensing, systematic supply, or distribution in any form to anyone isexpressly forbidden. Terms & Conditions of access and use can be found athttp://www.tandfonline.com/page/terms-and-conditions

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

CHILDREN’S HEALTH CARE, 35(3), 235–246Copyright © 2006, Lawrence Erlbaum Associates, Inc.

Development of a ScreeningInstrument of Adherence in

Pediatric Sickle Cell Disease

Kellie A. HilkerBehavioral Psychology

Kennedy Krieger Institute

Sara Sytsma Jordan Department of Psychology

University of Southern Mississippi

Scott Jensen and T. David ElkinDepartment of Psychiatry and Human Behavior

University of Mississippi Medical Center

Rathi IyerDepartment of Pediatrics

University of Mississippi Medical Center

This study evaluated the initial psychometric properties of the Self CareInventory–Sickle Cell (SCI-SC), a brief measure of adherence to health behaviorsfor pediatric sickle cell patients. Ninety-nine parents completed the measure regard-ing their child’s behavior. Factor analysis of the measure yielded three meaningfulfactors accounting for 64% of the variance in the measure, including General HealthBehavior, Sickle Cell Management, and Pain Management. Internal consistency ofthe SCI-SC was very good at .88. With further validation, the SCI-SC could be amethod of evaluating baseline adherence and changes in adherence following anintervention.

Correspondence should be sent to Kellie Hilker, Behavioral Psychology, Kennedy KriegerInstitute, 707 North Broadway, Baltimore, MD 21205. E-mail: hilker@kennedykrieger.org

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

Adherence to recommended health behaviors has been studied for many chronicchildhood illnesses, such as diabetes, asthma, and HIV, using a variety of meth-ods, including interviews, questionnaires, drug assays, pill counts, diaries, andestimates provided from medical staff and patients (Gil et al., 2001; Harris et al.,2000; Klinnert, McQuaid, & Gavin, 1997; Rapoff, 1999). Research in these spe-cific disease areas has moved beyond assessment of adherence to targeting behav-iors at improving the child’s adherence to medical requirements (Costa, Rapoff,Lemanek, & Goldstein, 1997; Wysocki, Greco, Harris, Bubb, & White, 2001).However, the literature on adherence in pediatric sickle cell disease (SCD) haslagged behind that of other chronic illnesses.

According to practice guidelines published by the National Heart, Lung, andBlood Institute (2002), pediatric SCD patients should engage in a variety of healthbehaviors, including adhering to the immunization schedule at regular health carevisits, taking prophylactic penicillin (for children 5 years of age and younger),counseling to monitor nutrition deficiencies and folic acid supplementation, avoid-ing strenuous exercise, avoiding extreme temperatures, getting adequate rest, andmaintaining adequate hydration. Chen, Cole, and Kato (2004) comprehensivelyreviewed psychosocial interventions for pain and adherence in pediatric and adultSCD. The review highlighted the benefit of cognitive–behavioral coping strategiesto manage pain, including calming self-statements, deep breathing, and imagery,and underscored the paucity of research in the area of self-care behaviors for SCD.Their recommendations for future studies include measurement and intervention ofthe full range of adherence behaviors for SCD patients.

Past studies of SCD have typically examined, and thus measured, only one ortwo self-care behaviors (e.g., pain coping strategies, medication adherence) and, inthe process, have utilized various reporting techniques to assess improvement in alimited number of behaviors. Daily pain diaries have provided valuable informationregarding the use of pain coping skills (Gil et al., 2001). This method could bebroadened to measure behaviors in addition to coping strategies; however, it is timeintensive, and this method could not be used for screening for identification forintervention, because information regarding the child’s adherence would not beavailable until after a specified monitoring period. The Coping StrategiesQuestionnaire (Gil, Abrams, Phillips, & Keefe, 1989; Gil, Williams, Thompson, &Kinney, 1991) asks about specific strategies, such as rest and fluid intake, to assessbehavior when faced with a pain crisis. However, the respondents report on behav-ior during pain crises, not ongoing self-care. Berkovitch et al. (1998) used theMedication Events Monitoring System, a bottle that monitors bottle openings, toassess adherence to prophylactic penicillin and assess the effectiveness of a multi-component intervention to target increased adherence to this self-care behavior.Although this may be useful for monitoring adherence for one specific self-carebehavior for young children, after age 5, children are not routinely prescribed prophy-lactic penicillin. Thus, a more comprehensive approach is needed.

236 HILKER, JORDAN, JENSEN, ELKIN, IYER

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

Other researchers have taken a different approach and developed measuresthat assess concepts associated with adherence, including the Sickle CellSelf-Efficacy Scale (Edwards, Telfair, Cecil, & Lenoci, 2000), a brief mea-sure assessing adults’s perception of managing their care, and the ChronicIllness Assessment Interview for Sickle Cell Disease (Lenoci, Telfair, Cecil, &Edwards, 2002), which consists of three factors that are hypothesized to be asso-ciated to self-care in SCD: personal satisfaction and perceived control, feelingconcerned and worried, and feeling supported. In addition to these measuresbeing geared toward adult care, neither survey queries directly about self-carebehaviors.

Only one study to date has evaluated the breadth of adherence and self-carebehaviors required of pediatric SCD patients (Barakat, Smith-Whitley, &Ohene-Frempong, 2002). Researchers used two methods to assess adherence inthis population: medical staff ratings of the child’s overall adherence to prescribedregimens and a parent-derived list of all sickle-cell-related health care activitiesperformed by the families. Parents’ opinions about the care of their children diag-nosed with SCD also have been investigated using parent interview methodology.Ievers-Landis et al. (2001) reported specific areas that parents find problematic inSCD care. The most challenging areas for parents included medication provision,behaviors surrounding appropriate nutrition, efforts to minimize pain episodes,and handling psychosocial issues related to SCD. Parents indicated that problemswith medication provision, nutrition, and minimizing pain occurred on averagemore than once a month.

Although both studies provide valuable information on adherence and healthissues important to parents, no standardized measure of these concerns wasutilized. Medical staff ratings of adherence in pediatric conditions may over-estimate adherence, and one overall score will miss performance of individ-ual self-care behaviors (Rapoff, 1999). Interviewing parents about adherencebehaviors is a widely used method for identifying problematic areas associatedwith adherence, but this methodology can be susceptible to shortfalls in relia-bility and validity. It may be more beneficial to ask patients about standardized,individual behaviors that are involved in self-care for SCD patients. Moreover,a brief measure would be clinically useful and could contribute to increasedacceptability among the parents of patients and clinical staff. A measure thathas been evaluated thoroughly with this population could contribute to clinicalservices, target specific areas for intervention, allow for longitudinal tracking ofchanges in adherence behaviors, and advance systematic research in this popu-lation. Thus, the purposes of this study were to develop a brief measure ofself-care and adherence behaviors, to evaluate the factor structure and internalconsistency of this newly developed measure, to provide descriptive informa-tion on parental responses on the measure for the entire sample, and to examineadherence ratings across age groups.

ADHERENCE 237

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

METHOD

Participants

A total of 146 parents attending a regularly scheduled appointment at the PediatricSickle Cell Clinic at a major university medical center were approached for partic-ipation. One hundred seven (73%) agreed to participate; however, 8 participantswere not included in the analyses because of incomplete information. Thus, analy-ses were based on a final sample of 99. Parents of children ages 5 to 20 wererecruited with an average age of 10.85 (SD = 3.77). Ninety-one percent of the par-ticipants were mothers, with fathers composing the rest of the participants. Themajority of participants had male children attending the clinic (59.6%). The major-ity (approximately 86%) of sample had the HbSS genotype. The average socioeco-nomic index as calculated by the Hollingshead (1975) Four Factor Index was 29.Thus, the study participants represented a lower socioeconomic sample.

Measures

Self Care Inventory–Sickle Cell. The Self Care Inventory–Sickle Cell(SCI-SC) is a novel parent-report measure of adherence behaviors for SCD caredeveloped at our institution. The purpose of the measure is to identify childrenwith poor medical adherence who may be at increased risk for SCD-related com-plications and who may benefit from intervention to increase adherence behav-iors. Parents are asked to rate, on a 5-point scale, how well their child followsdoctor’s orders for 18 self-care behaviors and 1 additional item pertaining tosleep. The scale for the main 18 items ranges from 1 (never do it) to 2 (sometimesfollows recommendations but mostly not) to 3 (follows recommendations about ½of the time) to 4 (usually does this as recommended) to 5 (always does this as rec-ommended without fail). Thus, higher scores indicate better performance of thatbehavior as reported by the parent. Parents also can indicate if the item is notapplicable for their child. This response format was borrowed from the Self CareInventory for Diabetes (La Greca, Follansbee, & Skyler, 1990; Weinger, Butler,Welch, & La Greca, 2005). Adherence is reported for the past month. For thesleep item, parents were asked to report the number of hours of sleep the childsleeps each night, with response choices ranging from less than 8 to greater than11. Items included in the measure were behaviors identified as important adher-ence behaviors engaged in by SCD patients and health concerns identified byparents in past studies utilizing interview methodology (Barakat et al., 2002;Ievers-Landis et al., 2001). Input from medical staff also was used in the finaldecision of what items to include in the measure.

Demographics questionnaire. A brief demographics questionnaire alsowas completed by parents. Information obtained included the child’s age, grade in

238 HILKER, JORDAN, JENSEN, ELKIN, IYER

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

school, race, and sex. Information on parent education and occupation also wasobtained to estimate socioeconomic status (Hollingshead, 1975).

Procedure

All procedures were approved by the Institutional Review Board of the participat-ing institution. After informed consent was obtained, parents completed the SCI-SCand a demographic questionnaire prior to a regularly scheduled follow-up appoint-ment in the pediatric SCD clinic. Chart reviews were conducted to obtain the totalnumber of doctor’s visits in the past year. Descriptive characteristics of the initialSCI-SC item set were evaluated. Then the core 18 items were factor analyzed andevaluated for reliability and validity.

RESULTS

Descriptive Information

A majority of parents indicated that their children always told them when theywere in pain (75%). In general, items measuring SCD management were endorsedas occurring most frequently; for instance, 86% of parents indicated that their childusually or always took medication given by the doctor, took pain medicine rightwhen the pain started, and rested when tired. Items assessing general healthybehavior and pain management strategies were endorsed as occurring less fre-quently; for example, 39% of parents indicated that their child avoided junk food,and 35% of parents reported that their child used distraction or imagery when inpain half of the time or less. Although average adherence ratings for each itemwere fairly high (e.g., a score of 4 or 5), there was a wide range of scores for partic-ipants. For the item “eaten a healthy diet,” 35% of parents gave a rating of 3 orlower. Thus, more than one third of parents reported that their children never,sometimes, or about half of the time eat a healthy diet. Scores of 3 or lower on anygiven item may possibly serve as a red flag for intervening with the family.

Principal Components Analysis

Descriptive information on individual items retained is presented in Table 1. Aprincipal components analysis with promax oblique rotation was conducted on 18items of the SCI-SC. An oblique rotation was selected on the basis of our theorythat the factors would be correlated with one another. Four factors emergedwith eigenvalues greater than unity. The scree test clearly indicated that the firstthree factors accounted for the greatest proportion of variance (Cattell, 1966).Thus, a three-factor solution was examined. Individual items were systematically

ADHERENCE 239

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

excluded until only items with pattern coefficients greater than 0.5 on a factor andless than 0.5 are on all other factors were retained, reducing the instrument to 13items. (See Table 2 for pattern coefficients.) The results from the analyses con-ducted on this 13-item scale yielded a three-factor solution, accounting for 63.9%of the variance.

The first factor, General Health Behavior (GHB), includes six items evaluatinghow well the child maintains adequate hydration, sleep requirements, and ahealthy diet. The second factor, Sickle Cell Management (SCM), consists of fourself-care behaviors that are important for pediatric SCD patients (e.g., folic acidadherence, taking medications given by the doctor, and avoiding extreme tempera-tures). Finally, the third factor, Pain Management (PMT), assesses the use of threepain management techniques.

The component correlation matrix, representing intercorrelations among thethree principal components or factors, is provided in Table 3. These moderatecorrelations suggest nonindependence of factors, in that aspects of general healthybehavior show considerable overlap with aspects of SCD management. These find-ings support use of an oblique rotation.

Reliability

Item–total correlations. Corrected item–total correlations were calculatedfor each item composing the Total scale and ranged from .22 to .72 (Mdn = .63);

240 HILKER, JORDAN, JENSEN, ELKIN, IYER

TABLE 1Self Care Inventory–Sickle Cell: Descriptive Information for Total Scale Items

Item M SD

1. Taken medication given by the doctor. 4.59 0.812. Eaten a balanced diet of vegetables, fruits, lean meats, and dairy foods. 3.87 1.053. Avoided very warm or cold temperatures. 4.09 1.054. Drank at least 8 glasses of water a day. 3.65 1.247. Told you when he/she is in pain. 4.56 0.958. Taken folic acid supplements. 4.54 0.979. Used deep breathing to relax when in pain. 3.83 1.33

11. Tried to do other activities or think about other things to distract 3.35 1.38him/herself when in pain.

12. Drank enough water to keep healthy. 4.00 1.1613. Got enough sleep. 4.16 1.0614. Used distraction or imagery when in pain. 3.15 1.3315. Eaten a healthy diet. 3.73 1.0516. Taken pain medication right when the pain starts. 4.51 0.90

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

they are provided in Table 2. Item–total correlations were slightly stronger whencalculated by factor, ranging from .43 to .77. This suggests independence of factors,as items are more strongly correlated with other items within a factor than with allitems in the scale. Interitem correlations between all possible combinations ofthe 13 items ranged from –.05 to .79 (M = .36). Interitem correlations calculated byfactor were stronger, ranging from .33 to .71.

Internal consistency. Coefficient alpha, a measure of internal consistency,was very good for the Total scale (α = .88) and ranged from acceptable to verygood for the three subscales: GHB (α = .87), SCM (α = .81), and PMT (α = .71).

ADHERENCE 241

TABLE 2Self-Care Inventory–Sickle Cell Pattern Matrix

CorrectedFactor 1: General Factor 2: Sickle Factor 3: Pain Item–Total

Item Health Behavior Cell Management Management Correlation

12. .935 −.098 −.049 .687. .784 −.093 −.230 .474. .764 .006 −039 .63

13. .736 .086 .034 .652. .716 −.025 .245 .72

15. .610 .107 .204 .688. −.225 .988 −.027 .481. .015 .845 .029 .64

16. .361 .558 −.044 .673. .283 .528 −.042 .53

11. −.144 −.080 .892 .2214. −.064 .070 .863 .449. .160 −.034 .621 .40

Eigenvalue after rotation 4.94 3.85 2.67

Note. Pattern coefficients in boldface represent primary loadings on a factor.

TABLE 3Component Correlation Matrix

Component 1 2 3

1. GHB —2. SCM .587 —3. PMT .349 .240 —

Note. GHB = General Health Behavior; SCM = Sickle Cell Management; PMT = PainManagement.

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

Validity

Construct validity. Initial evaluation of the construct validity of the SCI-SCwas estimated through correlation with an indirect measure of adherence, totalnumber of doctor visits in the past year. Results indicated a significant, modestinverse relationship, r(95) = –.27, p < .01, suggesting that children with poor SCDadherence required more frequent doctor visits. As predicted, correlations betweenthe SCM and PMT subscales of the SCI-SC were more strongly related (rs = –.34and –.23, respectively, p < .05), than the GHB subscale, r(95) = –.07, p > .05, ns.These findings provide initial evidence in support of the validity of the SCI-SC.

Age Analyses

Given that a pediatric SCD program routinely cares for a wide age range of patients,as indicated by the range of patients in the current sample (5–20 years), furtherexploratory analyses were conducted to examine the relationship of age toresponses on the SCI-SC. Three age groups were created: school age (5–8, n = 37),preteen (9–12, n = 29), and teen (13–20, n = 33). Items retained from the principalcomponents analysis were examined. For each item, the percentage of parents whoendorsed a rating of 3 or lower (i.e., indicated that the child engaged in that self-carebehavior half of the time or less) was calculated. Second, correlations wereconducted between age and factor scores for the SCI-SC.

Data for each item are presented in Table 4. Of the items on the PMT factor,the teen group had a lower percentage on Item 9 (utilizing deep breathing), indi-cating that fewer school-age and preteen children were reported as utilizing

242 HILKER, JORDAN, JENSEN, ELKIN, IYER

TABLE 4Age/ Item Data: Percentages of Parents Stating Half of the Time or Less

Item School Age Preteen Teen

1. 3 14 152. 20 43 233. 9 26 294. 15 38 437. 0 14 258. 0 28 119. 37 37 17

11. 46 41 4612. 16 29 2913. 6 22 3014. 54 50 4815. 23 46 5416. 3 14 16

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

this skill. For the SCM factor, three of the four items had increasing percentageswith increasing age (Items 1, 16, and 3); for example, for Item 3 (avoidingextreme temperatures), 9% of school-age children were reported as adhering tothis self-care behavior half of the time or less. This number increased to 26% and29% for the preteen and teen groups, respectively. A similar pattern was noted fora majority of items on the GHB factor (Items 4, 7, 12, 13, and 15). For Item 4,drinking eight glasses of water, the percentage for the school-age group (15%)increased to 43% for the teen group. Thus, with older age groups parents reportedlower rates of adherence to self-care behaviors.

Correlations between age and the individual factors of the SCI-SC were calcu-lated. A modest but significant negative relationship was found between age andthe SCM factor (r = –.25, p < .05). For older children, lower scores wereobserved, reflecting lower adherence to SCD management self-care behaviors.The relationship between age and the GHB factor approached significance (r =–.19, p >.05). Finally, the correlation between age and the PMT factor was notsignificant (r = .01, p > .05).

DISCUSSION

Overall, promising results for the SCI-SC were found. This is the first study thathas attempted to develop a parent-report measure of adherence and self-carebehaviors necessary for pediatric SCD patients. It also represents an attempt toconstruct a brief, reliable, and clinically useful adherence tool. The measureyielded three factors: (a) General Health Behavior, including six items assessingwater intake, sleep, and diet; (b) Sickle Cell Management, composed of fouritems that evaluate self-care activities important to SCD patients; and (c) PainManagement, consisting of three items assessing how frequently children usepain management strategies. Furthermore, the estimates of validity and reliabilityprovide initial support for the SCI-SC.

Exploratory analyses evaluating age also yielded some interesting results. Amodest correlation between age and the SCM factor was observed. With increasingage, parents reported lower adherence to self-care behaviors such as avoidingextreme temperatures and taking folic acid and other medications. This trend ofdecreased adherence with progression into adolescence has been observed in otherpediatric chronic illnesses, such as diabetes (Thomas, Peterson, & Goldstein, 1997).The correlations with the other two factors were not significant; however, the corre-lation between age and the GHB factor approached significance. This relationshipwas in the expected direction (e.g., with increased age, decreased adherence). Alarger sample size may be needed to further evaluate potential age group differ-ences. Behaviors associated with the PMT factor represent more complex skills thatmay develop over the course of adolescence, and with success, the adolescent may

ADHERENCE 243

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

be more willing to perform these self-care behaviors. Again, a larger sample sizemay help in evaluating this relationship. Perhaps other estimates of developmentalstatus besides chronological age would provide insight into changes in adherenceover time (De Civita & Dobkin, 2004). Furthermore, the percentages of parentswho reported that children were adherent to the self-care behaviors half of the timeor less underscored the importance of investigating this issue further. For manyitems, the adolescent group had a higher percentage of adherence difficulties asreported by parents. This provides information on potential areas for intervention toimprove adherence to these self-care behaviors.

Using multiple informants to assess adherence may provide more insight intothe issue of adherence as a child develops. Adolescents with SCD could easilycomplete this measure and provide a different perspective. Because of increasedindependence and responsibility during adolescence, adolescent self-report is animportant area to evaluate in the future, and validation with adolescents may be afuture goal for research with this measure. In addition, it would be helpful iffuture studies provide multiple methods of evaluating these behaviors, whichcould include correlation to a 24-hr recall of the self-care behaviors important forSCD. Finally, an association with various measures of health status or diseaseseverity may provide strong validity for use of this measure in both clinical andresearch settings.

Limitations of this study include a small sample size representing patientsfrom a limited geographical region and lower socioeconomic status. Examinationof the scale directions may be slightly confusing for parents if their physiciansdo not explicitly order some of these behaviors; however, the use of theresponse “not applicable” was relatively infrequent, ranging from 3% to 13% ofthe sample, depending on the item. It may be beneficial to gauge adherence toexplicitly ordered prescriptions made by the child’s physician. Last, the SCI-SCrelies solely on parent report. Although using parents as informants on a briefquestionnaire is efficient and inexpensive, this method may be affected by socialdesirability in the clinic setting.

The SCI-SC has many potential uses, including inclusion in systematicresearch on pediatric SCD. Future research will be focused on validating theSCI-SC, which may be beneficial in future pediatric SCD research projects andimproved clinical services to these patients.

IMPLICATIONS FOR PRACTICE

An additional goal of developing a measure of this type is the utility for healthcare practitioners. Administration of the SCI-SC at the onset of a health care visitmay provide useful information for practitioners to focus on while meeting withpatients. The SCI-SC is a brief measure that can be completed in a short amount

244 HILKER, JORDAN, JENSEN, ELKIN, IYER

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

of time and may identify families in need of additional evaluation and possiblyservices from the medical staff or pediatric psychology. With further validation,the SCI-SC may be useful in tracking adherence over time and assessing potentialimprovements after an intervention.

REFERENCES

Barakat, L. P., Smith-Whitley, K., & Ohene-Frempong, K. (2002). Treatment adherence in childrenwith sickle cell disease: Disease-related risk and psychosocial resistance factors. Journal ofClinical Psychology in Medical Settings, 9, 201–209.

Berkovitch, M., Papadouris, D., Shaw, D., Onuaha, N., Dias, C., & Olivieri, N. F. (1998). Trying toimprove compliance with prophylactic penicillin therapy in children with sickle cell disease. BritishJournal of Clinical Pharmacology, 45, 605–607.

Cattell, R. B. (1966). The scree test for the number of factors. Multivariate Behavioral Research, 1,245–276.

Chen, E., Cole, S. W., & Kato, P. M. (2004). A review of empirically supported psychosocial interven-tions for pain and adherence outcomes in sickle cell disease. Journal of Pediatric Psychology, 29,197–209.

Costa, I. G. D., Rapoff, M. A., Lemanek, K., & Goldstein, G. L. (1997). Improving adherence to med-ication regimens for children with asthma and its effect on clinical outcome. Journal of AppliedBehavior Analysis, 30, 687–691.

De Civita, M., & Dobkin, P. L. (2004). Pediatric adherence as a multidimensional and dynamic con-struct, involving a triadic partnership. Journal of Pediatric Psychology, 29, 157–169.

Edwards, R., Telfair, J., Cecil, H., & Lenoci, J. (2000). Reliability and validity of a self-efficacy instru-ment specific to sickle cell disease. Behaviour Research and Therapy, 38, 951–963.

Gil, K. M., Abrams, M. R., Phillips, G., & Keefe, F. J. (1989). Sickle cell disease pain: Relation ofcoping strategies to adjustment. Journal of Consulting and Clinical Psychology, 57, 725–731.

Gil, K. M., Anthony, K. K., Carson, J. W., Redding-Lallinger, R., Daeschner, C. W., & Ware, R. E.(2001). Daily coping practice predicts treatment effects in children with sickle cell disease. Journalof Pediatric Psychology, 26, 163–173.

Gil, K. M., Williams, D. A., Thompson, R. J., & Kinney, T. R. (1991). Sickle cell disease in childrenand adolescents: The relation of child and parent pain coping strategies to adjustment. Journal ofPediatric Psychology, 16, 643–663.

Harris, M. A., Wysocki, T., Sadler, M., Wilkinson, K., Harvey, L. M., Buckloh, L. M., et al. (2000).Validation of a structured interview for the assessment of diabetes self-management. DiabetesCare, 23, 1301–1304.

Hollingshead, A. B. (1975). Four factor index of social status. New Haven, CT:Yale University. Ievers-Landis, C. E., Brown, R. T., Drotar, D., Bunke, V., Lambert, R. G., & Walker, A. A. (2001).

Situational analysis of parenting problems for caregivers of children with sickle cell syndromes.Journal of Developmental & Behavioral Pediatrics, 22, 169–178.

Klinnert, M. D., McQuaid, E. L., & Gavin, L. A. (1997). Assessing the Family Asthma ManagementSystem. Journal of Asthma, 34, 77–88.

La Greca, A. M., Follansbee, D., & Skyler, J. S. (1990). Developmental and behavioral aspects ofdiabetes management in youngsters. Children’s Health Care, 19, 132–139.

Lenoci, J. M., Telfair, J., Cecil, H., & Edwards, R. R. (2002). Self-care in adults with sickle celldisease. Western Journal of Nursing Research, 24, 228–245.

National Heart, Lung, and Blood Institute. (2002). Management and therapy of sickle cell disease(NIH Publication No. 02-2117). Bethesda, MD: National Institutes of Health.

ADHERENCE 245

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014

Rapoff, M. A. (1999). Adherence to pediatric medical regimens. New York: Kluwer Academic/Plenum.

Thomas, A. M., Peterson, L., & Goldstein, D. (1997). Problem solving and diabetes regimen adher-ence by children and adolescents with IDDM in social pressure situations: A reflection of normaldevelopment. Journal of Pediatric Psychology, 22, 541–561.

Weinger, K., Butler, H. A., Welch, G. W., & La Greca, A. M. (2005). Measuring diabetes self-care: Apsychometric analysis of the Self-Care Inventory—Revised with adults. Diabetes Care, 28,1346–1352.

Wysocki, T., Greco, P., Harris, M. A., Bubb, J., & White, N. H. (2001). Behavior therapy for familiesof adolescents with diabetes: Maintenance of treatment effects. Diabetes Care, 24, 441–446.

246 HILKER, JORDAN, JENSEN, ELKIN, IYER

Dow

nloa

ded

by [

Nor

thea

ster

n U

nive

rsity

] at

17:

53 0

6 O

ctob

er 2

014