Resource Burden at Children’s Hospitals Experiencing Surge Volumes during the Spring 2009 H1N1 Influenza Pandemic

Resource Burden at Children’s Hospitals Experiencing Surge Volumes during the Spring 2009 H1N1 Influenza Pandemic

Marion R. Sills, MD, MPHMarion R. Sills, MD, MPH11; Matthew Hall, PhD; Matthew Hall, PhD22; Harold K. Simon, MD, MBA; Harold K. Simon, MD, MBA33; Evan S. Fieldston, MD, MBA, MSHP; Evan S. Fieldston, MD, MBA, MSHP44; Nicholas Walter, MD, MS; Nicholas Walter, MD, MS11; James E. Levin, MD, PhD; James E. Levin, MD, PhD55; ; Thomas V. Brogan, MDThomas V. Brogan, MD66; Paul D. Hain, MD; Paul D. Hain, MD77; Denise M. Goodman, MD, MS; Denise M. Goodman, MD, MS88; D.D. Fritch-Levens, RN, BSN; D.D. Fritch-Levens, RN, BSN33; Daniel B. Fagbuyi, MD; Daniel B. Fagbuyi, MD99; Michael B. Mundorff, MBA, MHSA; Michael B. Mundorff, MBA, MHSA1010; ;

Anne M. Libby, PhDAnne M. Libby, PhD11; Heather O. Anderson, PhD; Heather O. Anderson, PhD11; William V. Padula, MS; William V. Padula, MS11; Samir S. Shah, MD, MSCE; Samir S. Shah, MD, MSCE44

11Aurora, CO; Aurora, CO; 22Shawnee Mission, KS; Shawnee Mission, KS; 33Atlanta, GA; Atlanta, GA; 44Philadelphia, PA; Philadelphia, PA; 55Pittsburgh, PA; Pittsburgh, PA; 66Seattle, WA; Seattle, WA; 77Nashville, TN; Nashville, TN; 88Chicago, IL; Chicago, IL; 99 Washington, DC; Washington, DC; 1010Salt Lake City, UTSalt Lake City, UT

The authors have documented that they have no relevant financial relationships to disclose or conflicts-of-interest to resolve.The authors have documented that they have no relevant financial relationships to disclose or conflicts-of-interest to resolve.

Marion R. Sills, MD, MPHMarion R. Sills, MD, MPH11; Matthew Hall, PhD; Matthew Hall, PhD22; Harold K. Simon, MD, MBA; Harold K. Simon, MD, MBA33; Evan S. Fieldston, MD, MBA, MSHP; Evan S. Fieldston, MD, MBA, MSHP44; Nicholas Walter, MD, MS; Nicholas Walter, MD, MS11; James E. Levin, MD, PhD; James E. Levin, MD, PhD55; ; Thomas V. Brogan, MDThomas V. Brogan, MD66; Paul D. Hain, MD; Paul D. Hain, MD77; Denise M. Goodman, MD, MS; Denise M. Goodman, MD, MS88; D.D. Fritch-Levens, RN, BSN; D.D. Fritch-Levens, RN, BSN33; Daniel B. Fagbuyi, MD; Daniel B. Fagbuyi, MD99; Michael B. Mundorff, MBA, MHSA; Michael B. Mundorff, MBA, MHSA1010; ;

Anne M. Libby, PhDAnne M. Libby, PhD11; Heather O. Anderson, PhD; Heather O. Anderson, PhD11; William V. Padula, MS; William V. Padula, MS11; Samir S. Shah, MD, MSCE; Samir S. Shah, MD, MSCE44

11Aurora, CO; Aurora, CO; 22Shawnee Mission, KS; Shawnee Mission, KS; 33Atlanta, GA; Atlanta, GA; 44Philadelphia, PA; Philadelphia, PA; 55Pittsburgh, PA; Pittsburgh, PA; 66Seattle, WA; Seattle, WA; 77Nashville, TN; Nashville, TN; 88Chicago, IL; Chicago, IL; 99 Washington, DC; Washington, DC; 1010Salt Lake City, UTSalt Lake City, UT

The authors have documented that they have no relevant financial relationships to disclose or conflicts-of-interest to resolve.The authors have documented that they have no relevant financial relationships to disclose or conflicts-of-interest to resolve.

Background Objective

Methods

Results

Conclusions

Due to mild virulence and the predominance in children, the greatest burden during the spring 2009 novel H1N1 influenza (nH1N1) pandemic was experienced in emergency departments (ED) treating large numbers of children.

To describe the ED resource burden of the spring nH1N1 pandemic at children’s hospitals in the US by quantifying observed-to-expected (O:E) utilization.

Study Design and Data Source: ecological analysis of ED visits to children’s hospitals contributing data to the Pediatric Health Information System (PHIS)

Study Participants: all ED visits during April-July 2009 (calendar weeks 16-29) from 23 hospitals with ED data available continuously from January 2004-July 2009

Definitions• Influenza-like-illness (ILI): Used Electronic Surveillance System for the Early Notification of

Community-based Epidemics (ESSENCE) list of ICD-9 codes• Hospital surge period

•For each hospital, we fitted a time series curve to April-July for 2004-2008 and extrapolated the expected ED visits for each hospital-week in April-July, 2009•Defined upper 90% confidence limit on time-series as the hospital-specific surge threshold •Start and end of each surge for each hospital were defined by the first and last of 2 consecutive weeks with ED ILI visits above the hospital-specific surge threshold

• Influenza circulation period: Onset of the nH1N1 period for each CDC region began with the first week that any WHO/NREVSS lab specimen tested positive for nH1N1

Measures• Utilization Measures: ED and ED ILI visits, ED ILI admissions, ILI-related

medications/procedures• Severity Measures: APR-DRG severity levels for ED patients admitted to the hospital, deaths• Quality Measure: Any-cause ED revisits within one week for all ED visits and for ED ILI visits• For each utilization, severity, and quality measure, we derived the expected value for the 2009

study period, and calculated the observed to expected (O:E) proportion

Analysis • Frequency distributions for patient characteristics for all ED ILI visits were calculated • Hospital-level analysis

•Hospitals experiencing a surge (n=14): O:E proportion visits (all visits and ILI visits) during surge weeks (14 hospitals)•All Hospitals (n=23): O:E proportion visits (all visits and ILI visits) for the peak week and for calendar weeks 16-29 (14 weeks for 23 hospitals = 322 hospital-weeks)

• Aggregate analysis•Calculated the O:E for all utilization, severity and quality measures•Calculated O:E for ED visits and admission rates for surge hospital-weeks by patient characteristics

Affiliated with

University of Colorado Denver

•During the spring 2009 wave of the 2009 H1N1 influenza pandemic, pediatric EDs nationwide experienced a marked increase in visits.•Only a small minority of patients with ILI required ICU hospitalization. •Data from the CHCA research network represents national trends and may be useful for future pandemic planning.

Characteristics of ED ILI Patients and Observed-to-Expected (O:E) Proportion for Utilization MeasuresKey Findings:•Factors associated with an increased O:E proportion for ED

visits (p<0.05) included age 2-17 years, insurance, and asthma•No factors were associated with an increased O:E proportion for

ED admissionObserved (%) O:E Proportion

Week 16-29 ED visits ED admission rate Number of Visits 88,885 31,703 31,703Number of Hospitals 23 14 14Number of Hospital-Weeks 322 71 71Age

0 - <6 months 8,680 (9.8) 0.71** 0.786 - <24 months 31,126 (35) 0.86** 0.8324 - <60 months 22,677 (25.5) 1.15** 0.745 - < 9 years 13,211 (14.9) 1.45** 0.709 - <13 years 7,330 (8.2) 2.08** 0.7413 - <18 years 5,130 (5.8) 2.02** 0.41**

Female Gender 40,990 (46.1) 1.12** 0.66Race/ethnicity

White Non-Latino 18,456 (21.3) 0.72** 0.88 Black Non-Latino 28,459 (32.8) 0.77** 1.08

Latino 29,507 (34.1) 1.42** 0.62Asian 1,512 (1.7) 1.06 1.36Other 8,700 (10) 1.21** 0.46

RegionMiddle Atlantic 9,562 (10.8) 0.84** 0.63*North Central 28,828 (32.4) 1.54** 0.52*South Atlantic 19,041 (21.4) 1.76** 0.62South Central 14,203 (16) 1.44** 1.11West 1,7251 (19.4) 1.62** 0.73

InsurancePublic 55,804 (62.9) 1.29** 0.72

Private 23,460 (26.4) 1.73** 0.75None 9,518 (10.7) 0.16** 0.51

High Risk ConditionNeurological Disorders 998 (1.1) 0.78 0.93Asthma 8,582 (9.7) 1.51** 0.89

Other Chronic Respiratory 528 (0.6) 1.2 1.70Immune Deficiencies 520 (0.6) 0.16** 0.28*Cardiovascular Disease 582 (0.7) 0.48** 0.71Endocrine/Metabolic 516 (0.6) 0.85 0.52

* p<0.05** p<0.01

West (4)

South Central (5)

North Central (6)MiddleAtlantic (3)

South Atlantic (5)

Regions (Number of PHIS Hospitals/Region)

Observed and Expected Daily ED ILI visits from April-July 2009 for 14 Hospitals with Surge Weeks Key Finding: All surge EDs experienced a peak in ILI visits around week 17-18Dashed black series is expected 2009 based on 2004-2008 data Dashed vertical reference lines end a surge periodDotted black series is the 90% upper CI for expected based on 2003-2008 data Solid vertical reference lines start a surge periodSolid series is observed 2009 Y-axis indicates the number of ED ILI visits per dayShaded background indicates weeks of circulation of 2009 novel H1N1 influenza (WHO/NREVSS regional surveillance data)

Observed-to-Expected Proportion, April-July 2009 ED Visits

(Median, Interquartile Range)

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

ED Visits ED ILI Visits ED Visits ED ILI Visits

Surge Weeks (14 Hospitals) Peak Week (23 Hospitals)

Middle Atlantic

North Central

South Atlantic

South Central

West

Utilization, Severity and Quality Measuresfor ED ILI Visits (14 Hospitals, 71 Hospital-weeks)Key Findings•During surge weeks, EDs experienced 29% more visits,

and 51% more ILI visits, than expected (both, p<0.01)•Only 4.8% (70% of expected) of surge ILI patients were

admitted to non-ICU beds, 0.19% (44% of expected) 0.19% (44% of expected) were admitted to ICU beds, and 0.01% (5.0% of expected, p<0.01) received positive pressure ventilation.

Expected ObservedO:E

ProportionTotal ED Visits 82130 106330 1.29**Total ED Visits with ILI 21047 31703 1.51**Disposition [% of ED ILI visits]

Home 92.2 94.7 1.03**Admitted to Non-ICU 6.8 4.8 0.70**Admitted to ICU 0.42 0.19 0.44**Died in ED or hospital 0.00 0.04 - ***

APR-DRG severity level for ILI patients admittedMinor 28.7 27.5 0.96**Moderate 37.9 37.1 0.98**Major 9.6 10.7 1.11**Extreme 0.38 0.65 1.71**

Medications/procedures done in ED (or on 1st hospital day)Anti-influenza medication given 0.00 0.53 159.5**Positive pressure ventilation [%] 0.20 0.01 0.05**Influenza testing, patients discharged from ED [%]5.0 14.1 2.82**

Quality measures [%]Seven-day ED revisits (ILI) 5.0 3.9 0.79**Seven-day ED revisits (all) 4.3 4.0 0.94*

* p<0.05** p<0.01*** unable to calculate O:E due to insufficient numbers