Associations between Delivery Hospital Obstetric Service Level and Selected Maternal and Perinatal Outcomes for High Risk Women Open Access

Vanderlaan, Jennifer (2017)

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Despite recent calls for implementation of new definitions of graduated hospital levels of obstetric service to reduce maternal mortality and morbidity, associations between such an intervention and delivery outcomes remain untested. The purpose of this project is to investigate the association between the American Hospital Association's (AHA) graduated levels of obstetric service and delivery outcomes for women at high obstetric risk to provide evidence for policy makers tasked with making decisions about updating regional perinatal systems. Using the three delays framework, this project hypothesized improved outcomes at hospitals with the highest level of obstetric service.

This project first addressed the lack of a gold standard for identifying a sample of women at high obstetric risk in epidemiological data by demonstrating that a recently proposed obstetric comorbidity index allowed creation of a sample resulting in a lower likelihood of misclassification bias. The project then used a sample of women at high obstetric risk to test associations between maternal and perinatal delivery outcomes and delivering at hospitals with different levels of obstetric service as defined by the AHA.

The analyses did not provide evidence to support the hypothesis of improved outcomes for women at high risk delivering at hospitals with the highest level of obstetric service and instead found reduced odds of extended length of stay at hospitals with lower levels of obstetric service. These findings suggest the AHA system of designating levels of obstetric service may not stratify hospitals by resources that improve care and introduces questions about the validity of assumptions that the resources that provide safe care for women at high risk are limited to hospitals with the highest level of obstetric service. In addition, this project identified problems with using the metric for extended length of stay as a measure of resource use.

Table of Contents

Abstract ii

Acknowledgements iv

Contents vii

List of Figures x

List of Tables xi

Abbreviations xii

Chapter 1: Introduction 1

Background 1

Limitations and Benefits of Levels of Service 4

Importance of estimating effect of service levels 6

Purpose 8

Project Description 9

Specific Aims 9

Aim One. 9

Aim two. 9

Aim Three. 10

Setting 10

Significance 11

Theoretical Framework 11

Assessing High Obstetric Risk 13

Assessing Hospital Obstetric Service Level 15

Evaluating Effect of Delivery Hospital Obstetric Level 16

Limitations 19

Chapter Two: Net benefit analysis of obstetric high risk sample selection Methods 22

Abstract 22

Background 24

Purpose 25

Methods 25

Setting & Participants 25

Variables & Data Sources 26

High-Risk Identification Models 26

Predicted Outcome. 28

Analysis 29

Results 30

Participants 30

Model Characteristics 32

Main Results 33

Discussion 33

Limitations 34

Implications 35

Funding 36

Chapter Three: Associations between delivery hospital level of obstetric service and maternal delivery outcomes 37

Abstract 37

Background 39

Objectives 39

Methods 39

Setting 40

Participants 40

Variables and Data Sources 41

Control of Bias 43

Statistical Methods 44

Results 44

Participants 44

Descriptive Data 45

Outcome Data 45

Main Results 46

Other Analyses 46

Discussion 47

Limitations and Generalizability 49

Implications 50

Funding 51

Chapter Four: Associations between delivery hospital level of obstetric service and Neonatal delivery outcomes 52

Abstract 52

Background 54

Objectives 54

Methods 54

Setting 54

Participants 55

Variables & Data Sources 55

Predictor 57

Control Variables 57

Statistical Methods 58

Results 59

Descriptive Data 60

Outcome Data 60

Main Results 61

Discussion 63

Limitations and Generalizability 64

Implications 65

Conclusion 66

Funding 66

Chapter Five: Conclusion 68

Review of Objective and Aims 68

Aim One 68

Aim Two 69

Aim Three 70

Advances in Study 71

Interpretation 74

Limitations 77

Generalizability 78

Implications 79

Conclusion 82

Appendicies 83

Appendix 1: Georgia Regional Perinatal Centers and Perinatal Regions 83

Appendix 2: Bed size and AHA Obstetrical Service Level of Delivery Hospitals in Georgia Maternal Child Health Repository, 2008-2012 84

Appendix 3: Capabilities of Health Care Providers in Hospitals Delivering Basic, Specialty and Subspecialty Care 87

Appendix 4: ICD Codes used for conditions included in the Obstetric Comorbidity Index 90


Appendix 5: ICD Codes for conditions included in the New Zealand Transfer Guidelines 91

References 94

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