Readmissions as a measure of quality for neonatal intensive care units (NICU)

and outpatient practices

SA Lorch1, JH Silber1, GE Escobar2, D Small3

1 Center for Outcomes Research, Dept of Pediatrics, The Children’s Hospital of Philadelphia

2 Perinatal Research Center, Kaiser Permanente Medical System, Oakland, CA

3 Dept of Statistics, The Wharton School

Background

• There is increased interest in measuring the quality of inpatient care by insurers, public agencies, and patients.

• One proposed measure: risk-adjusted readmission rates

Conceptual Framework

Poor inpatient quality of care

Incomplete Evaluation or Management of Condition

Increased Readmission Rates

Prior Work

• Conflicting data in literature– Ashton (1995): Meta-Analysis, 13 studies

• OR 1.55 for readmission if care received at hospital with sub-standard quality

• Wide range of metrics and time frame for readmissions

– More recent literature did not find this association

• Congestive Heart Failure• Myocardial Infarction

Conceptual Framework

Poor inpatient quality of care

Incomplete Evaluation or Management of Condition

Increased Readmission Rates

Illness Severity Quality of Outpatient Facility

Goals of Study

• Aim 1: Determine the role of NICUs in predicting variations in risk-adjusted readmission rates

• Aim 2: Determine how this role changes when site of outpatient care is accounted for

• Aim 3: Define characteristics of facilities associated with high risk-adjusted readmission rates

Patient Population

• 5 Northern California Kaiser Permanente hospitals

• 1998-2001• Gestational age < 32 weeks at

delivery• Survive to hospital discharge• Received care at 1 of 32 outpatient

clinics affiliated with the Kaiser Permanente health system

Exclusion Criteria

• Major congenital anomalies

• Need for home ventilation

• Loss to follow-up within 1 year of discharge– Typically from leaving the Kaiser

system

Study Definitions• Readmission

– Any unplanned rehospitalization within specified time period

• Ambulatory-care Sensitive Condition– Any readmission for condition “sensitive” to

care provided in outpatient setting• Pneumonia• Asthma• Cellulitis• Failure-to-Thrive

• Time Frame: 0-1 month; 0-3 months; 3-12 months

Data Collection

• Neonatal data– Neonatal Minimal Data Set: prospective

collection of 250 clinical variables, including• Maternal history• Birth history• Complications occurring in NICU

• Outpatient data– Cost Management Information System tracked

all resources used in the outpatient setting, including

• medications and laboratory studies• readmissions, outpatient visits, and emergency room

visits– Demographic data used to define area-level

socioeconomic data based on zip code

Facility Characteristics

• Outpatient facility assigned to child based on site of usual care for well-child visits.

• Characteristics:– Use of oral albuterol (poor quality)– Use of inhaled albuterol for asthma symptoms

(good quality)– Use of antibiotics for viral illness (poor quality)

• Facilities divided into high or low quality for each characteristic.

Statistical Analysis

• Multivariable poisson regression models

• 2 sets of models– Fixed NICU effects included alone (Aim 1)– Random outpatient effects added to the

fixed NICU effects (Aim 2)

• Random outpatient effects accounts for smaller numbers of patients at a given outpatient center.

Demographics

• 892 infants at 5 NICUs and 32 outpatient facilities• Each NICU discharged to 9-17 outpatient facilities• Each outpatient facility received infants from 1-3

NICUs• Gestational Age 29.5 ± 2.2 wks• Racial/Ethnic Distribution:

– 45.5% White non-Hispanic– 20.5% Hispanic– 11.2% Black– 22.8% Asian or Multi-Racial

• 16.6% with BPD, 1.8% with NEC

Timing of Readmissions

Time of Readmissions

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12

Months after Discharge

Nu

mb

er o

f R

ead

mis

sio

ns

All Readmissions: Medical Factors

0-1 mos 0-3 mos 3-12 mos

Gestational Age

< 26 wks 8.65*** 5.43** 2.80***

27-28 wks 6.48*** 3.36** 1.98**

29-30 wks 6.17*** 2.79** 1.00

31-32 wks Reference Reference Reference

NEC 2.43

3.55*** 2.60*

BPD 2.20* 1.17 1.21

Home on oxygen 0.75 1.36 1.39

All values report incident rate ratios for the given risk factor * P < 0.05; ** P < 0.01; *** P < 0.001

All Readmissions: Sociodemographic Factors

0-1 mos 0-3 mos 3-12 mos

Each sibling at home 1.13 1.06 1.34***

Median Area Income, per $10,000

0.98 1.03 0.95

Racial/Ethnic Status Reference Reference Reference

Asian/Other 1.01 0.84 0.99

Black 1.15 1.53 1.18

Hispanic 1.22 0.79 0.91

White Reference Reference Reference

Maternal Age < 18 yrs 1.24 0.70 1.65

Male Sex 0.96 1.21 1.14

All values report incident rate ratios for the given risk factor * P < 0.05; ** P < 0.01; *** P < 0.001

All Readmissions: NICU and Outpatient Facilities

0-1 mos 0-3 mos 3-12 mos

NICU measured alone

NICU Variation 0.24 0.02 < 0.001

NICU measured with outpatient facility

NICU Variation 0.25 0.10 0.07

Outpatient Facility Variation

1.00 1.00 0.011

Example of Attributable Variation: All readmissions 0-3 months

Area of each circle represents the proportional amount of variation attributed to each group of factors.

Patient

NICU

Program

ACS Readmissions: Medical Factors

0-1 mos 0-3 mos 3-12 mos

Gestational Age

< 26 wks 15.66*** 7.43*** 2.89**

27-28 wks 15.32*** 3.13** 1.72

29-30 wks 21.01*** 3.79*** 0.72

31-32 wks Reference Reference Reference

NEC 2.44 2.25 2.80***

BPD 2.10 1.12 1.78

Home on oxygen 0.59 1.33 0.81

All values report incident rate ratios for the given risk factor * P < 0.05; ** P < 0.01; *** P < 0.001

ACS Readmissions: Sociodemographic Factors

0-1 mos 0-3 mos 3-12 mos

Each sibling at home 1.04 1.27* 1.43***

Median Area Income, per $10,000

0.96 0.99 0.90

Racial/Ethnic Status Reference Reference Reference

Asian/Other 1.44 0.97 0.80

Black 1.31 1.91 1.13

Hispanic 1.21 0.80 1.03

White Reference Reference Reference

Maternal Age < 18 yrs 1.35 0.64 2.64

Male Sex 0.54 0.84 0.68

All values report incident rate ratios for the given risk factor * P < 0.05; ** P < 0.01; *** P < 0.001

ACS Readmissions: NICU and Outpatient Facilities

0-1 mos 0-3 mos 3-12 mos

NICU measured alone

NICU Variation 0.63 0.06 < 0.001

NICU measured with outpatient facility

NICU Variation 0.63 0.24 0.41

Outpatient Facility Variation

0.50 1.00 < 0.001

Oral Albuterol Inhaled Albuterol Viral antibiotics

Facility Characteristics and Readmissions

0.5

11

.52

2.5

33

.54

Inci

dent

Ra

te R

atio

All 0-1 All 0-3 All 3-12 ACS 0-1 ACS 0-3 ACS 3-12

Limitations

• Data from one health system– NICUs and outpatient facilities with

different practices and outcomes

• No direct information on family income and socioeconomic status

• Cohort more homogeneous than other NICUs, especially academic centers

Conclusions

• Patient-level factors were the primary determinants for readmissions after NICU discharge.

• NICU measured alone:– Significant variations between sites.

• NICU measured with outpatient facilities:– No independent variation between NICUs

Conclusions

• Outpatient facility characteristics associated with poor quality are also associated with higher readmission rates:– High oral albuterol use: 0-3 mos and 3-12 mos– High antibiotic use: 3-12 mos

• Time frame does matter when examining readmission rates.

Implications for Policy

• Readmission rates appear to measure the quality of outpatient facilities, not inpatient hospitals.

• Associations with NICU typical sites of outpatient care to which a NICU discharges.

Acknowledgements

• Funded by MCHB R40 MC00238

• Thanks to Marla Gardner and John Greene at Northern California Kaiser Permanente health system.

Why Study NICUs and Premature Infants?

• Prematurely-born infants are uniformly admitted to NICUs.

• Relatively consistent discharge practices based on development of physiologic skills and weight gain.

• Readmission rates after discharge are high, but do not occur in all patients.– Allows for variation among NICUs and

outpatient settings

Deficits in Literature

• Many conditions do not have validated admission criteria

• Wide variations in time frame– Which time frames are valid?

• No control for site of outpatient care• Ignoring these factors may lead to

faulty assessment of the care provided by inpatient services, such as neonatal intensive care units (NICUs)