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Pediatric retropharyngeal abscesses: A national perspective Lina Lander a , Sam Lu b , Rahul K. Shah c, * a Department of Epidemiology, University of Nebraska Medical Center, Omaha, NE, United States b University of Arkansas Medical School, Little Rock, AR, United States c Division of Otolaryngology, Children’s National Medical Center, George Washington University Medical School, 111 Michigan Avenue, NW, Washington, DC 20010, United States Received 30 June 2008; received in revised form 28 August 2008; accepted 2 September 2008 Available online 15 October 2008 International Journal of Pediatric Otorhinolaryngology (2008) 72, 1837—1843 www.elsevier.com/locate/ijporl KEYWORDS Resource utilization; Outcomes; Patient quality; Retropharyngeal abscesses; Kids’ Inpatient Database (KID); Healthcare Cost and Utilization Project (HCUP) Summary Objectives: To determine the resource utilization and national variation in the management of pediatric retropharyngeal abscesses. Methods: The Kids’ Inpatient Database (KID) 2003 was analyzed. International Classification of Diseases, Ninth Revision code 478.24 was the inclusion criteria. Results: One thousand three hundred and twenty-one admissions with retrophar- yngeal abscess were sampled from the KID in 2003; there were no deaths. The mean age of patients was 5.1 years (S.D. 4.4 years); 63% were male. Of all admissions, 563 (43%) patients underwent surgical drainage of their infection; surgical patients had longer length of stays and total charges than patients managed medically. The average state spending per admission varied from $5126 (Utah) to $27,776 (California). There was seasonal variation in admissions with the highest percentage of admissions occurring in March (10.7%) and lowest in August (3.8%). Indicators of increased resource utilization included age (older patients), increased length of stay, non- elective admission, discharge quarter, and number of other diagnoses on record. There is a statistically significant decrease in the length of stay and total charges in patients admitted in the Midwest compared to other regions of the country. Conclusions: This study demonstrates national demographics and normative data on a commonly treated pediatric disease process, retropharyngeal space infections. The average demographic of such a patient is a 5-year-old male from an urban location admitted in a non-elective fashion via the emergency department. The mean total charges were $16,377; 90% of admissions had total charges less than $28,511. Patients who underwent surgical procedures had mean total charges of $22,013. There exists significant national variation in resource utilization for this commonly treated disease process. # 2008 Elsevier Ireland Ltd. All rights reserved. * Corresponding author. Tel.: +1 202 476 3852; fax: +1 202 476 5038. E-mail addresses: [email protected], [email protected] (R.K. Shah). 0165-5876/$ — see front matter # 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2008.09.001

Pediatric retropharyngeal abscesses: A national perspective

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Page 1: Pediatric retropharyngeal abscesses: A national perspective

Pediatric retropharyngeal abscesses: A nationalperspective

Lina Lander a, Sam Lu b, Rahul K. Shah c,*

aDepartment of Epidemiology, University of Nebraska Medical Center, Omaha, NE, United StatesbUniversity of Arkansas Medical School, Little Rock, AR, United StatescDivision of Otolaryngology, Children’s National Medical Center, George WashingtonUniversity Medical School, 111 Michigan Avenue, NW, Washington, DC 20010, United States

Received 30 June 2008; received in revised form 28 August 2008; accepted 2 September 2008Available online 15 October 2008

International Journal of Pediatric Otorhinolaryngology (2008) 72, 1837—1843

www.elsevier.com/locate/ijporl

KEYWORDSResource utilization;Outcomes;Patient quality;Retropharyngealabscesses;Kids’ InpatientDatabase (KID);Healthcare Cost andUtilization Project(HCUP)

Summary

Objectives: To determine the resource utilization and national variation in themanagement of pediatric retropharyngeal abscesses.Methods: The Kids’ Inpatient Database (KID) 2003 was analyzed. InternationalClassification of Diseases, Ninth Revision code 478.24 was the inclusion criteria.Results: One thousand three hundred and twenty-one admissions with retrophar-yngeal abscess were sampled from the KID in 2003; there were no deaths. The meanage of patients was 5.1 years (S.D. 4.4 years); 63% were male. Of all admissions, 563(43%) patients underwent surgical drainage of their infection; surgical patients hadlonger length of stays and total charges than patientsmanagedmedically. The averagestate spending per admission varied from $5126 (Utah) to $27,776 (California). Therewas seasonal variation in admissions with the highest percentage of admissionsoccurring in March (10.7%) and lowest in August (3.8%). Indicators of increasedresource utilization included age (older patients), increased length of stay, non-elective admission, discharge quarter, and number of other diagnoses on record.There is a statistically significant decrease in the length of stay and total charges inpatients admitted in the Midwest compared to other regions of the country.Conclusions: This study demonstrates national demographics and normative data on acommonly treated pediatric disease process, retropharyngeal space infections. Theaverage demographic of such a patient is a 5-year-old male from an urban locationadmitted in a non-elective fashion via the emergency department. The mean totalcharges were $16,377; 90% of admissions had total charges less than $28,511. Patientswho underwent surgical procedures had mean total charges of $22,013. There existssignificant national variation in resource utilization for this commonly treated diseaseprocess.# 2008 Elsevier Ireland Ltd. All rights reserved.

* Corresponding author. Tel.: +1 202 476 3852; fax: +1 202 476 5038.E-mail addresses: [email protected], [email protected] (R.K. Shah).

0165-5876/$ — see front matter # 2008 Elsevier Ireland Ltd. All rights reserved.doi:10.1016/j.ijporl.2008.09.001

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1838 L. Lander et al.

1. Introduction

Retropharyngeal space infections are one of themore commonly treated disease processes atpediatric hospitals. Despite the prevalence of thisdisease process, little national data exists describ-ing treatment variations and outcomes. Advancesin imaging modalities as well as increasing potencyof antibiotics, tempered by the emergence ofdrug-resistant organisms have changed the mor-bidity, mortality, and treatment algorithms asso-ciated with the management of retropharyngealspace infections and retropharyngeal abscesses(RPA) [1].

The nuances of RPA make these infections achallenge to manage. Effective and well-describedstrategies include solo or combination therapieswhich include intravenous antibiotics, needleaspiration, long-term intravenous antibiotics, andsurgical drainage [2—6]. Given the variety of man-agement options, the potential for morbidity andmortality, and the relatively high frequency of RPAin the realm of pediatrics, we hypothesize thatthere would be treatment variations in managingRPA; further we believe that from a national per-spective, important trends and findings aboutresource utilization for this commonly manageddisease could be identified.

Examining a frequently managed disease processsuch as RPAs from a national perspective facilitatesdiscussion about treatment trends and furtherenables individual practices and hospitals to bench-mark themselves to this data. It is helpful to com-pare lengths of stay and mortality rates of patientsadmitted for RPA across states and institutions.National aggregate sampled data, such as thosepresented in this paper, however, are the first stepsfor introspective evaluation of one’s practice.Large, national database sets allow generalizationson the treatment of a specific disease while simul-taneously facilitating the breakdown of the analysisinto meaningful pieces. Our group has performedsimilar analyses to evaluate pediatric subglotticstenosis [7] and another common infectious process,pediatric mastoiditis [8]. Those analyses revealedsignificant national variations in the management ofthese disease processes.

2. Methods

Institutional review board approval was obtainedfor this study. The source of the data is from theKids’ Inpatient Database (KID), Healthcare Costand Utilization Project (HCUP), Agency for Health-care Research and Quality [9]. The KID 2003 data-

base serves as the only all-payer, pediatricdatabase of inpatient hospital stays from theyear 2003. Developed by Agency for HealthcareResearch and Quality (AHRQ), the KID is one mem-ber of a family of databases in the Healthcare Costand Utilization Project (HCUP) [9]. The KID pro-vides researchers and physicians an objective toolin evaluating national trends in the managementand resource utilization of pediatric diseases. TheKID has been increasingly utilized as a researchtool to establish normative data and assist inpredicting parameters of high resource utilization[10—19].

The KID is an inpatient database consisting of astratified random sample of 2,984,129 unweighteddischarges from 3438 hospitals distributed across36 states (Arizona, California, Colorado, Connecti-cut, Florida, Georgia, Hawaii, Illinois, Indiana,Iowa, Kansas, Kentucky, Maryland, Massachusetts,Michigan, Minnesota, Missouri, North Carolina,Nebraska, New Hampshire, New Jersey, Nevada,New York, Ohio, Oregon, Rhode Island, South Car-olina, South Dakota, Tennessee, Texas, Utah, Vir-ginia, Vermont, Washington, West Virginia, andWisconsin). The sampled cohort includes pediatricdischarges from community, non-rehabilitationhospitals in the United States in 2003. The Amer-ican Hospital Association definition of communityhospitals includes academic medical centers andspecialty hospitals such as obstetrics/gynecology,ear nose throat, orthopedic, and pediatric hospi-tals. Excluded from the KID are federal hospitals,long-term hospitals, psychiatric hospitals, alcohol/chemical dependency treatment facilities, andhospital units within institutions, such as prisons.Of the participating hospitals, the KID sampled 10%of uncomplicated, in-hospital births and 80% ofcomplicated, in-hospital births and other pediatriccases from each hospital.

Patients less than 21 years of age and dischargedwith a diagnosis of retropharyngeal abscess (RPA) —International Classification of Diseases, NinthRevision, Clinical Modification (ICD-9-CM) codeof 478.24 — were included in this study. Eachadmission included in the KID database containsup to 15 diagnoses. Inclusion into the study samplerequired the presence of RPA as one of the 15available diagnoses. RPA, however, was not foundin any patients as the eleventh through fifteenthdiagnoses.

Total hospital charges accrued during hospitali-zation were used as a surrogate for resource utiliza-tion. Rationale for this has been detailedextensively in previous studies [10,17,18]. Simplelinear regression was fit to evaluate the effect of thepotential predictors on increased total hospital

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Pediatric retropharyngeal abscesses: A national perspective 1839

charges (Table 1). The p-value <0.05 indicated asignificant predictor of increased total charges.Multivariate regression model was fit to determinewhich factors were associated with increased totalcharges in a multivariate model (Table 2).

Table 1 Demographics of patients with RPA with p-valuebaseline)

Variablea

Age (years), older patients have higher total charges

GenderMale (n = 825, 62.5%)Female (n = 455, 34.4%)

Length of stay (days), longer stay has higher total chargesNumber of diagnosesNumber of procedures performed during admissionMean total charges

Source of admissionEmergency room (n = 802, 61.2%)Another hospital (n = 117, 8.9%)Another facility (n = 15, 1.1%)Routine/birth/other (n = 364, 27.6%)

Admission typeElective admission (n = 140, 10.6%)Non-elective admission (n = 1157, 87.6%)

Disposition of patientRoutine (n = 1204, 91.1%)Short-term hospital (n = 52, 3.9%)Home health care services (n = 43, 3.3%)

Discharge quarter1st (n = 438, 33.2%)2nd (n = 352, 26.6%)3rd (n = 200, 15.1%)4th (n = 316, 23.9%)

Primary payerMedicaid (n = 450, 34.1%)Private insurance (n = 750, 56.8%)Self-pay (n = 52, 3.9%)Other (n = 49, 3.7%)

Patient location (urban/rural)Large metropolitan area (n = 794, 60.1%)Small metropolitan area (n = 364, 27.6%)Micropolitan area (n = 91, 6.9%)Non-urban (n = 53, 4.0%)

Hospital locationRural (n = 66, 5.0%)Urban (n = 1182, 89.5%)

NACHRI hospital typeNot identified as a children’s hospital (n = 503, 38.1%)Children’s general hospital (n = 370, 28.0%)Children’s unit in a general hospital (n = 340, 25.7%)

Hospital teaching statusTeaching hospital (n = 268, 20.3%)

Patients with an RPA that underwent surgical drai-nage of the infection were also analyzed, inclusioncriteria included the patient having ICD-9 procedurecode 28.0 (incision and drainage of tonsil and peri-tonsillar structures, drainage (oral) (transcervical)

from univariate analysis (total charges was used as the

Mean p-Value

5.06 0.0379

0.8412$16,490$16,170

4.27 <0.00012.63 <0.00011.21 <0.0001$16,377 N/A

0.0047$16,700 —$23,916 0.0255$29,677 0.1269$12,865 0.0629

0.0136$9959$17,188

<0.0001$15,684 —$11,091 0.3101$38,072 <0.0001

0.1239$14,095 —$16,682 0.2678$20,747 0.0170$16,434 0.3312

0.7047$17,815 —$15,702 0.2789$14,290 0.4621$16,722 0.8243

0.0338$18,251 —$14,737 0.0890$10,913 0.0422$9139 0.0491

0.0213$7382$17,060

0.2313$15,322 —$16,025 0.7603$19,244 0.0971

0.1295$13,820

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1840 L. Lander et al.

Table 1 (Continued )

Variablea Mean p-Value

Non-teaching hospital (n = 980, 74.2%) $17,294

Median household income quartile 0.3536$1—35,999 (n = 290, 22.0%) $15,609 —$36,000—44,999 (n = 301, 22.8%) $13,670 0.4039$45,000—59,000 (n = 353, 26.7%) $17,616 0.3699$60,000+ (n = 346, 26.2%) $16,232 0.7819

Hospital region 0.0025Northeast (n = 238, 18.0%) $18,649 —Midwest (n = 348, 26.3%) $10,718 0.0038West (n = 300, 22.7%) $18,619 0.9916South (n = 420, 31.8%) $18,176 0.8577

Race 0.9170White (n = 494, 37.4%) $17,865 —Black (n = 155, 11.7%) $16,944 0.7911Hispanic (n = 147, 11.1%) $20,176 0.5146Asian/Pacific Islander (n = 27, 2.0%) $22,716 0.5157Other (n = 50, 3.8%) $22,027 0.4576

Bold typeface with p-value <0.05 is considered to be a statistically significant predictor of increased total charges.a Note some variables do not total to 1321 as some data elements were missing from the KID.

of: parapharyngeal abscess, peritonsillar abscess,retropharyngeal abscess, tonsillar abscess).

3. Results

There were 1321 admissions sampled from 36 stateswith a diagnosis of pediatric RPA in the KID 2003.Therewere nomortalities in the sampled admissions.

The average total charges per admission was$16,377 (S.D. $32,637, range $859 to $728,351);90% of admissions had charges less than $28,511.RPA admissions were found in all 36 states with 5states (California, Texas, Florida, New York, andOhio) accounting for over 40% of all admissions.There is significant variation in the number of admis-sions per state and costs per state as well as themonths of admission (Figs. 1 and 2).

Table 2 Indicators for increased resource utilization of Rcharacteristics of patients

Variable Regression coef

Age 286.1(41.6, 5Gender �1542.8 (�3804Race �722.0 (�1532Elective type of admission �5828.6 (�1167Length of stay 6327.7 (6096.6Type of admission 3426.0 (845.6,Discharge quarter 1067.5 (136.5,Hospital location �2158.9 (�6902Number of diagnoses on record �875.7 (�1502Number of procedures on record 531.9 (�340.Model R2 = 0.85, p < 0.0001.

Themeanpresenting age at time of admissionwithan RPA was 5.1 years (S.D. 4.4). Males represented adisproportionate number of admissions compared tofemales, 64.6% versus 35.4%, respectively.

A summary of pertinent variables and their asso-ciation with total charges is presented in Table 1.

Male patients had a slightly higher, but not sta-tistically significant, mean charge than femalepatients. There were geographic variations inadmissions and resource utilization with the Southregion having the highest percentage of RPA admis-sions (32%) and the Midwest having the lowest lengthof stay and total charges (Table 3). The length ofstay was the highest in the South (5 days), but thehighest total charges per RPA admission, however,occurred in the North.

An analysis of patients that underwent surgicaldrainage for their infections is found in Table 4. There

PA admissions in a multivariate analysis of admission

ficient (95% CI) p-Value Partial R 2

30.6) 0.0219 0.00707.0, 717.3) 0.1806 0.00242.1, 88.1) 0.0806 0.004112, 14.3) 0.0506 0.00515, 6558.8) <0.0001 0.795896006.5) 0.0093 0.009081998.4) 0.0247 0.00679.4, 2584.6) 0.3719 0.00108.0, �249.3) 0.0062 0.010065, 1404.3) 0.2317 0.00193

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Pediatric retropharyngeal abscesses: A national perspective 1841

Fig. 1 Distribution of reported admissions of RPAs in KID by month. Total admissions for a respective month appear atthe top of individual bar graphs.

Fig. 2 Total charges per admission by state in which the patient received care. The solid line graphically represents theoverall mean total charge of $16,377 for all RPA cases. Total admissions for a respective state appear at the top of eachbar graph (note: only states that had more than 10 admissions sampled are included in this graph).

were fewer surgical compared to non-surgical admis-sions; on average, total charges was almost twice ashigh for surgical admissions (p < 0.0001) (Table 4).Further, surgical admissions involved longer lengthsof stay (4.8 versus 3.9 days) (p < 0.0001).

4. Discussion

This series is the first to examine the variation andoutcomes associated with pediatric retropharyngealspace infections on a national scale. Despite theprevalence of this disease process, normative,aggregate, and national data are lacking. In thisseries of patients, the average demographics ofpatients that develop RPAs include male childrenwith an average age of 5 years. Most patients were

hospitalized for 4.3 days (S.D. 4.7) and did not havesignificant concomitant diagnoses (on average 2.6diagnoses at time of admission). The majority ofadmissions occurred in urban, non-teaching hospi-tals and over 50% admissions were paid with privateinsurance. As to be expected, there is no correlationbetween race and increased total charges.

Variables associated with increased totalcharges, or resource utilization, in the managementof pediatric RPAs included: older patients, longerlength of stay, number of diagnoses on admission,number of procedures performed during the hospi-talization, patients transferred from another hospi-tal, those necessitating home health care services,patients from large metropolitan areas, thoseadmitted to urban hospitals, and those admittedregions of the United States other than the Midwest.

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1842 L. Lander et al.

Table 3 Comparison of patient characteristics by admission region (n = 1321)

Treatment Northeast Midwest West South p-Value *

Admissions, n (%) 238 (18%) 349 (26%) 312 (24%) 422 (32%) <0.0001Length of stay (days),

mean, S.D.4.8 (3.4) 3.5 (2.7) 3.9 (3.2) 5.0 (7.0) <0.0001

Total charges,mean, S.D.

18648.8 (23000.7) 10718.2 (8624.0) 18619.0 (25139.6) 18176.1 (49693.0) 0.0025

Surgical procedureperformed, n (%)

93 (7%) 165 (12%) 137 (10%) 168 (13%) 0.1169

Treated at teachinghospital, n (%)

202 (15%) 254 (19%) 227 (17%) 311 (24%) <0.0001

Treated at urbanhospital, n (%)

228 (17%) 280 (21%) 294 (22%) 394 (30%) 0.2518

* p-Values as determined by chi-square test for nominal variables and analysis of variance for continuous variables.

Table 4 Comparison of surgical and non-surgical RPA treatments (n = 1321)

Treatment Non-surgical Surgical drainage p-Value *

Admissions, n (%) 758 (57%) 563 (43%) <0.0001Length of stay (days), mean, S.D. 3.9 (4.2) 4.8 (5.4) 0.0002Total charges, mean, S.D. $12,198 ($24,645) $22,013 ($40,368) <0.0001Treated at teaching hospital, n (%) 554 (42%) 440 (33%) 0.0060* p-Values as determined by chi-square test for nominal variables and analysis of variance for continuous variables.

It was of interest that one region of the countrywould have significantly lower total charges thanthe other three (Table 3). Further analysis ofpatients admitted in the Midwest compared to therest of the country revealed that these patientsstayed a statistically significantly shorter time inthe hospital and accrued approximately $8000 lessin total charges. The rate of surgical admissions andadmissions to teaching hospitals in the Midwest wasapproximately similar to the other regions of thecountry. The reason for the large differencebetween the Midwest and other regions deservesfurther investigation, however it is beyond thescope of the KID analysis.

Several additional demographic characteristicsidentified in thisnational samplingofadmissionsweresurprising, including an average age of 5.1 years,which is older than previously reported [2—4]. Thedisproportionate number of admissions of male com-paredto femalepatients (64.5%versus 34.5%, respec-tively), however, mirrors past findings [3—5].

A study by Schweinfurth found no fluctuations inRPA hospitalizations as a function of the seasons [6].We observed markedly higher incidences of RPAsduring the winter months (defined as December,January and February) and spring months (March,April and May) versus the summer (June, July andAugust) and fall (September, October and November)months (Fig. 1). Approximately 33.2% (n = 399) ofadmissions occurred in the winter followed closelyby31.2%(n = 375) in thespring.This is rather intuitive

asmost children do have upper respiratory infectionsor other viral infections during the colder months.

The majority of patients were admitted fromemergency rooms; however, patients admitted from‘‘another hospital’’ had higher total charges relativeto other admissions sources. It may be that patientstransferred from another hospital are sicker (hencethe rational for the transfer of care) and eventuallyneed more interventions. Perhaps better triage orproper initial identification of a hospital suitable intreating RPAs may alleviate excessive inter-hospitaltransfers and increased economic-burdens for thisdisease process.

An overwhelming number of hospital admissionsresulted from non-elective admissions (n = 1157,87.6%) at a mean total charges of $17,188 versuselective admissions (n = 140, 10.6%) with mean totalcharges of $9959. Patients who become ill to thepoint where treatment and admission becomesurgent will have a more complicated hospital coursethan an elective admission. This was shown in ouranalysis with the difference in costs between elec-tive and non-elective admissions. Primary care,emergency room, and triage physicians need to becognizant of the standard of care for treating deepneck space infections; perhaps applications of algo-rithms such as suggested by Kirse and Roberson mayprove to be cost-efficient in addition to optimizingpatient care [1].

Comparison of patients that underwent surgicaldrainage of the RPA compared to non-surgical

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Pediatric retropharyngeal abscesses: A national perspective 1843

intervention revealed a longer length of stay andcharges for surgical patients. A statistically signif-icant proportion of patients underwent non-surgi-cal treatment at teaching institutions compared tothose that were operated upon at teaching hospi-tals; it may be that these institutions are moreapt to try conservative measures prior to surgicaldrainage.

The limitations of using a national databaseshould be highlighted. First, the data is an averageof admissions and it is expected that an individualhospital and physician will have slightly differentmeans for the variables presented. Further, not allstates are included in the KID, which somewhatlimits the scope of the database and an ability tomake generalizations.

5. Conclusions

This study demonstrated national demographics andnormative data on a commonly treated pediatricdisease process, retropharyngeal space infections.The average demographic of such a patient is a 5-year-old male from an urban location admitted in anon-elective fashion via the emergency depart-ment. In a multivariate analysis, significant indica-tors of total charges include older patients, longerlength of stay, discharge quarter, and number ofdiagnoses on record. There is significant variationbetween states and regions of the United States,with the Midwest having a statistically lower totalcharges and length of stay than other areas of thecountry. Data from this study will enable individualhospitals and physicians to compare themselves inan attempt to provide high quality and cost-effec-tive care on a macrolevel. Furthermore, periodicstudies of RPAs on a national level will allow identi-fication of emerging changes in the demographics ofthis infectious process.

References

[1] D.J. Kirse, D.W. Roberson, Surgical management of retro-pharyngeal space infections in children, Laryngoscope 111(August (8)) (2001) 1413—1422.

[2] B. Dodds, A.J. Maniglia, Peritonsillar and neck abscesses inthe pediatric age group, Laryngoscope 116 (June (6)) (1988)887—889.

[3] J.M. Coticchia, G.S. Getnick, R.D. Yun, J.E. Arnold, Age-,site-, and time-specific differences in pediatric deep neckabscesses, Arch. Otolaryngol. Head Neck Surg. 130 (February(2)) (2004) 201—207.

[4] J.W. Thompson, P. Reddix, S.R. Cohen, Retropharyngealabscess in children: a retrospective and historical analysis,Laryngoscope (June (6 Pt. 1)) (1998) 589—592.

[5] S.S. Lee, R.H. Schwartz, R.S. Bahadori, Retropharyngealabscess: epiglottitis of the new millennium, J. Pediatr.138 (March (3)) (2001) 435—437.

[6] J.M. Schweinfurth, Demographics of pediatric head and neckinfections in a tertiary care hospital, Laryngoscope 116(June (6)) (2006) 887—889.

[7] R.K. Shah, L. Lander, S.S. Choi, G.H. Zalzal, Resource uti-lization in the management of subglottic stenosis, Otolar-yngol. Head Neck Surg. 138 (February (2)) (2008) 233—241.

[8] J.L. Acevedo, L. Lander, U.K. Shah, R.K. Shah, Existence ofImportant Variations in the United States in the Treatment ofPediatric Mastoiditis, Arch. Otolaryngol. Head Neck Surg., inpress.

[9] HCUP Kids’ Inpatient Database (KID), Healthcare Cost andUtilization Project (HCUP), Agency for Healthcare Researchand Quality, Rockville, MD, 2003, www.hcup-us.ahrq.gov/kidoverview.jsp, accessed March 15, 2007.

[10] J.A. Connor, K. Gauvreau, K.J. Jenkins, Factors associatedwith increased resource utilization for congenital heartdisease, Pediatrics 116 (September (3)) (2005) 689—695.

[11] J.G. Berry, T.A. Lieu, P.W. Forbes, D.A. Goldmann, Hospitalvolumes for common pediatric specialty operations, Arch.Pediatr. Adolesc. Med. 161 (January (1)) (2007) 38—43.

[12] E.R. Kokoska, T.M. Bird, J.M. Robbins, S.D. Smith, J.M. Corsi,B.T. Campbell, Racial disparities in the management ofappendicitis, J. Surg. Res. 137 (January (1)) (2007) 83—88.

[13] G.H. Cosper, M.S. Hamann, A. Stiles, D.K. Nakayama,Hospitalcharacteristics affect outcomes for common pediatric surgi-cal conditions, Am. Surg. 72 (August (8)) (2006) 739—745.

[14] M.A. Malek, A.T. Curns, R.C. Holman, T.K. Fischer, J.S.Bresee, R.I. Glass, et al., Diarrhea- and rotavirus-associatedhospitalizations among children less than 5 years of age:United States, 1997 and 2000, Pediatrics 117 (June (6))(2006) 1887—1892.

[15] J.R. Meurer, E.M. Kuhn, G. Varghese, J.S. Yauck, P.M. Layde,Charges for childhood asthma by hospital characteristics,Pediatrics 102 (December (6)) (1998) E70.

[16] D.S. Smink, S.J. Fishman, K. Kleinman, J.A. Finkelstein,Effects of race, insurance status and hospital volume onperforated appendicitis in children, Pediatrics 115 (April (4))(2005) 920—925.

[17] A.J. Schneier, B.J. Shields, B.A. Hostetler, H. Xiang, G.A.Smith, Incidence of pediatric traumatic brain injury andassociated hospital resource utilization in the United States,Pediatrics 118 (August (2)) (2006) 483—492.

[18] D. Merenstein, B. Egleston, M. Diener-West, Lengths of stayand costs associated with children’s hospitals, Pediatrics 115(April (4)) (2005) 839—844.

[19] S.L. Guthery, C. Hutchings, M. Dean, C. Hoff, Nationalestimates of hospital utilization by children with gastroin-testinal disorders: analysis of the 1997 Kids’ Inpatient Data-base, J. Pediatr. 144 (May (5)) (2004) 589—594.

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