antenatal hospital encounters and preterm delivery, ma 2002-2008

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Antenatal Hospital Encounters and Preterm Delivery, MA 2002-2008

Lizzie Harvey, MPHCDC/CSTE Applied Epidemiology FellowMassachusetts Department of Public HealthJune 5, 2012

HDiop

How about Antenatal Hospitalization and Preterm Delivery for the Title? It's simpler. feel free to take or leave this suggestion...I am not married to it..

Background

• MA Infants born <32 weeks gestation made up 1.5% of the birth population but accounted for 63.8% of infant deaths in 2008

• <32 weeks infants have an infant mortality rate (IMR) of 195 deaths/1,000 live births – MA IMR is 5.0 deaths/1,000 live births

HDiop

You are comparing the less than 32 weekers to the state overall? You may want to compare them to term babies instead if you're making the case for preterm. Preterms are included in the overall IMR...

Research Priorities

• Prematurity is a research priority– IOM Report: “Preterm Birth:

Causes, Consequences, and Prevention”

– March of Dimes: • Prematurity Research Initiative • “Healthy Babies are worth the wait”

campaign

– ASTHO Presidential Challenge

HDiop

Lauren announced the following at the MPQC Summit:

Infections

Maternal Behaviors

INCREASED RISK OF

PREMATURE DELIVERY

Bacterial vaginosis

Chronic Disease

Chronic Hypertension

Anemia Stress

Diabetes

Family History

Maternal lbw

Black race

Family hx ofPreterm birth

Chorioamnionitis

Trichomonasis

Maternal ObstetricHistory

Prior pretermbirth

Short cervix

Multiplepregnancies

Low BMI

↑ Maternal age

Pre eclampsia

Obesity

Low maternal Weight gain

Maternal smoking

Drug dependency

Asthma poorlycontrolled

Cervicalincompetence

Placental Abruption

Protective

Progesteronefor prior PTD

Neighborhood Factors

Lower SES

Physical Abuse duringpregnancy

Stress

High unemployment

Conceptual Model for Premature Delivery

Research Gaps

• <32 week population– Low percentage of births– High IMR

• Potential for intervention– Course of pregnancy– Hospital encounters

Research Question

• In deliveries <32 weeks, are there patterns among antenatal hospital encounters and adverse pregnancy outcomes?– Demographic characteristics– Timing of hospital encounters – Number of hospital encounters– Diagnosis codes of hospital encounters

Methods

• Definitions:– Adverse outcome: Any delivery with a fetal

death or infant death occurring before 1 year post-delivery

– Hospital Encounters:• Emergency Department (ED)• Observational Stay (OS)• Hospital Discharge (HD)

Methods: PELL Data System

Early Intervention

Linked birth-infant deaths

Child and Mother deaths

Birth Defects Registry

WIC

Birth Certificate

(HD) Birth Mothers

Fetal Death

(HD) Birth Child

Emergency Department

Census 2000 Data

(and 2010 data)

CORE

Geocoded birth data

Observational StaysOther Future Datasets: All

Payers Data, School, NICU, Medicaid

Contextual Data

Pregnancy-associated deaths

Non-birth Hospital Discharge

Newborn Hearing Screening

Vital and Health Status Data

Program Participation Data

Health Services Utilization Data w/ diagnosis codes & charges

1998-2008

875,708 births

Cancer Registry

ART Clinic Data

Databases to be added to system

PRAMS

Methods: PELL Data System

Linked birth-infant deaths

Birth Certificate

Fetal Death

Emergency Department

CORE

Observational Stays

Non-birth Hospital Discharge

Vital and Health Status Data

Health Services Utilization Data w/ diagnosis codes & charges

2002-2008

Methods

• Exclusion criteria:– ≥32 weeks gestation delivery– Missing gestational age– HD, OS, or ED admission date outside

conception and delivery date– Delivery hospitalization records

• Analysis on SAS 9.2:– Frequency distributions– Logistic regressions

HDiop

This should not be an exclusion criteria, you are only excluding the delivery hospitalization

Results—Data Merging

567,323Births, FD, ID

11,226 <32 wks

554,603 ≥ 32 weeks1,494 missing GA

9,330 DELIVERIES

Code by adverse deliveryOutcome and delete

multiples

Sorted and merged by child unique identifier

Sorted and merged by mother unique delivery identifier

Results—Data Merging

Final datasets: 1) 9,330 unique deliveries

2) 11,744 duplicate deliveries with every prenatal hospitalization

9,330DELIVERIES

32,360HD

9,330DELIVERIES

252,853ED

9,330DELIVERIES

118,482OS

10,423DEL+ED

9,788OS

9,661HD

7,013NON-ENC.

4,013ED ENC.

7,788NON-ENC.

2,048OS ENC.

Deleted non-prenatal hospitalization encounters by GA, delivery date and hospitalization admission date

7,695NON ENC.

2,064HD ENC.

1,635DEL. w/ HD

1,542DEL. w/ OS

2,317DEL. w/ ED

Merged back to delivery records by unique identifier to capture non-encounters

Demographics by DeliveryCharacteristic % N (9,330)

Race

Hispanic

Non-Hispanic White

Non-Hispanic Black

API

AI/Other

15.1

60.0

17.7

5.7

3.4

1393

5351

1636

527

299

Maternal Age

<20 years

20-34 years

35+ years

9.0

65.7

25.3

835

6124

2358

Nativity

US born

PR

Foreign born

68.9

3.5

27.6

6230

6550

2492

Maternal Education

<HS

HS+

14.4

80.4

1343

8846

Prenatal Care

Adequate Plus

Adequate

Intermediate

Inadequate

80.6

5.4

1.2

3.1

7523

502

112

285

Characteristic % N

Gestational Age

≤20 weeks

21-24 weeks

25-28 weeks

29-31 weeks

6.1

21.6

28.7

43.6

568

2015

2677

4070

Delivery Method

Vaginal

VBAC

Primary C-section

Repeat C-section

50.9

2.6

37.0

9.1

4746

240

3456

848

Plurality

Singletons

Twins

Triplets+

80.9

17.1

2.0

7552

1596

182

Payer

Private

Public

Self-care

Free care

52.0

41.1

1.2

1.2

4849

3837

112

115Note: % and N do not always equal to 9330 due to missing information in some categories

Initial Results

• Exposure: Antenatal hospitalization– 44.0% of deliveries <32 weeks had at least one

non-delivery antenatal hospital encounter

• Outcome: Adverse pregnancy outcome– 31.2% of deliveries <32 weeks with at least one

non-delivery antenatal hospitalizations had an adverse outcome

– 34.4% of all deliveries <32 weeks had an adverse outcome

Results: Demographic Characteristics, Hospital Encounters and Adverse

Outcomes

Univariate Analysis

Demographics by Any Hospitalization

Characteristic % Hosp % Non-Hosp

Race

Hispanic

Non-Hispanic White

Non-Hispanic Black

API

AI/Other

50.3

42.6

48.2

35.5

37.8

49.8

57.4

51.8

64.5

62.2

Maternal Age

<20 years

20-34 years

35+ years

49.8

44.6

40.5

50.2

55.4

59.5

Nativity

US born

PR

Foreign born

45.9

56.9

38.6

54.1

43.1

61.4

Maternal Education

<HS

HS+

49.2

43.6

50.8

56.4

Prenatal Care

Adequate Plus

Adequate

Intermediate

Inadequate

45.6

46.2

41.1

34.7

54.4

53.8

58.9

65.3

Characteristic % Hosp % Non-Hosp

Gestational Age

≤20 weeks

21-24 weeks

25-28 weeks

29-31 weeks

36.3

42.0

44.1

45.9

63.7

58.0

55.9

54.1

Delivery Method

Vaginal

VBAC

Primary C-section

Repeat C-section

41.0

45.0

46.9

49.3

59.0

55.0

53.1

50.7

Plurality

Singletons

Twins

Triplets+

42.9

47.9

52.7

57.1

52.1

47.3

Payer

Private

Public

Self-care

Free care

41.7

52.0

31.3

42.6

58.3

48.0

68.8

57.4

Variations by Type of Hospital Encounter

p<0.0001 p<0.0001 p=0.20 p<0.0001

Variations by Type of Hospital Encounter

p<0.0001 p<0.0001p<0.0001 p<0.0001

Univariate Analysis

Demographics by Adverse Outcome

Characteristic % Adverse % Non-Adverse

Race

Hispanic

Non-Hispanic White

Non-Hispanic Black

API

AI/Other

35.8

31.4

38.3

32.4

41.5

64.2

68.6

64.7

67.9

58.5

Maternal Age

<20 years

20-34 years

35+ years

39.2

34.4

32.5

60.8

65.6

67.5

Nativity

US born

PR

Foreign born

30.7

22.5

38.5

69.3

77.5

61.5

Maternal Education

<HS

HS+

35.0

30.8

65.0

69.2

Prenatal Care

Adequate Plus

Adequate

Intermediate

Inadequate

30.7

25.9

34.8

44.9

69.3

74.1

65.2

55.1

Characteristic % Adverse % Non-Adverse

Gestational Age

≤20 weeks

21-24 weeks

25-28 weeks

29-31 weeks

92.1

79.8

25.7

9.7

7.9

20.2

74.3

90.3

Delivery Method

Vaginal

VBAC

Primary C-section

Repeat C-section

51.9

53.8

13.8

13.7

48.1

46.3

86.2

86.3

Plurality

Singletons

Twins

Triplets+

35.1

32.4

24.6

64.9

67.6

75.4

Payer

Private

Public

Self-care

Free care

34.7

34.9

61.6

40.0

65.3

65.1

38.4

60.0

Bivariate Analysis

p=0.004 p<0.0001 p<0.0001 p<0.0001

Adjusted models controlled for: race/ethnicity, education, maternal age, gestational age at delivery, plurality, payer source, method of delivery, prenatal care, nativity

Odds Ratios

Other Demographic aORs for Adverse Outcomes

• Race/Ethnicity: – Black: 0.79 (0.66-0.93) vs. NH white

• Gestational age:– <25 weeks: 33.9 (29.1-39.5) vs. 29-31 weeks– 25-28 weeks: 3.61 (3.13-4.15) vs. 29-31 weeks

• Plurality:– Twins: 1.61 (1.37-1.90) vs. Singletons

• Payer:– Self-care: 1.81 (1.08-3.02) vs. Private

• Delivery Method:– Vaginal: 4.34 (3.78-5.00) vs. Primary c-section– VBAC: 4.61 (3.26-6.53) vs. Primary c-section

• Nativity:– PR 0.72 (0.59-0.87) vs. US-born– Foreign 1.06 (1.01-1.12) vs. US-born

Results: Timing of Hospital Encounters and Adverse

Outcomes

Variation in Timing of Encounters

Timing Indicators of Adverse Outcomes

Results: Number of Hospital Encounters and Adverse

Outcomes

Number and Duration of Visits: HD Encounters

P<0.0001

Mean # visits= 1.26

Mean Length of Stay/visit= 4.07 days

Number and Duration of Visits: OS Encounters

P<0.0001

Mean # visits= 1.33

Mean Length of Stay/visit= 0.39 days

Number and Duration of Visits: ED Encounters

P=0.0095

Mean # visits= 1.73

Mean Length of Stay/visit= 3.40 hours

No Increased Odds of Adverse Outcomes with Increased ED

Encounters

Results: Diagnosis Codes and Adverse Outcomes

HD Diagnosis Codes

Top 10 Principal Diagnosis Codes with No Adverse Outcomes

1. Threatened premature labor

2. Cervical incompetence

3. Hemorrhage from placenta previa

4. Other conditions, mother, complicating preg/childbirth

5. Mild/NOS pre-eclampsia

6. Premature separation of placenta

7. Premature rupture of membranes

8. Other congenital or acquired abnormality of the cervis

9. Transient hypertension

10. Delayed delivery after spontaneous rupture of membranes

Top 10 Principal Diagnosis Codes with Adverse Outcomes




4. Threatened abortion



7. Delayed delivery after spontaneous rupture of membranes

8. Premature separation of placenta

9. Hyperemesis gravidum with metabolic disturbance

10. Unspecified hemorrhage in early pregnancy

OS Diagnosis Codes





4. Unspecified antepartum hemorrhage




8. Transient hypertension

9. Other threatened labor

10. Severe pre-eclampsia









8. Twin pregnancy

9. Intrauterine death


ED Diagnosis Codes





4. Mild hyperemesis gravidarum

5. Other specified complications of pregnancy

6. Abdominal pain; unspecified site

7. Infections of genitourinary tract in pregnancy

8. Headache, Facial pain, Pain in head NOS


10. Asthma (bronchial) (allergic NOS)





4. Mild hyperemesis gravidarum

5. Other specified complications of pregnancy

6. Infections of genitourinary tract in pregnancy


8. Abdominal pain

9. Headache, Facial pain, Pain in head NOS,

10. Sprains/strains; neck, Anterior longitudinal (ligament), cervical, Atlanto-axial (joints), Atlanto-occipital (joints), Whiplash injury

• 44% of all <32 wk deliveries had ≥1 hospital encounter– Of these deliveries, almost 1/3 will have an adverse

outcome

• Type of hospital encounter matters:– Deliveries with ≥ 1 ED encounter have a 16% greater

risk of adverse outcomes than those with no encounter

– OS and HD encounters are protective against adverse outcomes, with 29% and 32% decreased risk, respectively

Conclusions

• Demographic:– Gestational age is the driver of poor outcomes– Black mothers and PR born mothers have decreased odds of adverse outcomes– Twins, Self-care payment, and vaginal delivery have increased odds of adverse

outcomes• Timing:

– Deliveries with adverse outcomes will present sooner in pregnancy with each type of hospital encounter than those without

– Women present sooner in the ED than OS or HD• Number:

– HD and OS both have decreased odds of adverse outcomes with each additional visit

– No increased risk of adverse outcomes with each additional ED visit• Diagnosis:

– HD: Cervical incompetence, threatened premature labor, PROM – OS: Cervical incompetence, hemorrhage, threatened abortion– ED: Infections, hemorrhage, sprains/strains

Conclusions

• Expand study population

• Further refinement of diagnosis coding

• Consult with clinicians – Share data by type of hospitalization– Feedback on potential interventions

• Exploration of costs associated with hospital utilization

Next Steps

Acknowledgements

• Hafsatou Diop, MD, MPH• Xiaohui Cui, PhD• Milton Kotelchuck, PhD, MPH• Maria Vu, MPH• Emily Lu, MPH• Karin Downs, RN, MPH

• CDC/CSTE Fellowship

References• CDC Premature Birth:

– http://www.cdc.gov/Features/PrematureBirth/• IOM Report:

– National Research Council. Preterm Birth: Causes, Consequences, and Prevention. Washington, DC: The National Academies Press, 2007.

• PELL Data System:– https://sph.bu.edu/index.php/Maternal-a-Child-Health/Pregnancy-to-Early-Life-

Longitudinal-Linkage-bPELLb/menu-id-452.html• MA Death Statistics:

– http://www.mass.gov/eohhs/docs/dph/research-epi/death-report-08.pdf• March of Dimes:

– http://www.marchofdimes.com• ASTHO Presidential Challenge:

– http://www.astho.org/t/pres_chal.aspx?id=6484

Thank you

Contact Information:[email protected]

antenatal hospital encounters and preterm delivery, ma 2002-2008

Documents

preterm birth

payers data

preterm delivery

delivery records

antenatal hospitalization

w edmerged

antenatal hospital encounters

unique deliveries2