(1)Batra P, Fridman M, Leng M, Gregory KD

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Batra P, Fridman M, Leng M, Gregory KD. Emergency department care in the postpartum period: California births, 2009–2011.

Obstet Gynecol 2017; 130.

The authors provided this information as a supplement to their article.

Appendix 1. Medicare Severity-Diagnosis Related Group (MS-DRG) Codes for Live Birth MS-DRG Associated diagnosis

765 Cesarean section with CC/MCC 766 Cesarean section without CC/MCC

767 Vaginal delivery with sterilization and/or dilation and curettage

768 Vaginal delivery with operating room procedure except sterilization and/or dilation and curettage

774 Vaginal delivery with complicating diagnoses 775 Vaginal delivery without complicating diagnoses

*CC – Complication or comorbidity

†MCC – Major complication or comorbidity

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Appendix 2. Diagnosis and Procedure Codes for Severe Maternal Morbidity (United States Centers for Disease Control and Prevention)

Severe Maternal Morbidity Indicator

Diagnosis (DX) or Procedure (PR)

International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9) Code(s)

Acute myocardial infarction

DX 410.xx

Acute renal failure DX 584.5, 584.6, 584.7, 584.8, 584.9, 669.3x Adult respiratory distress

syndrome

DX 518.5 (until September 2011), 518.51,

518.52, 518.53 (since October 2011), 518.81 518.82 518.84 799.1

Amniotic fluid embolism DX 673.1x

Aneurysm DX 441.xx

Cardiac arrest/ventricular fibrillation/ventricular flutter

DX 427.41, 427.42, 427.5

Disseminated

intravascular coagulation

DX 286.6, 286.9, 666.3x

Eclampsia DX 642.6x

Heart failure/arrest during surgery or procedure

DX 669.4x, 997.1

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Puerperal cerebrovascular disorders

DX 430, 431, 432.x, 433.xx, 434.xx, 436, 437.x, 671.5x, 674.0x, 997.02

Pulmonary edema/acute heart failure

DX 518.4, 428.1

Severe anesthesia complications

DX 668.0x, 668.1x, 668.2x

Sepsis DX 038.xx, 995.91, 995.92, 670.2x (after

October 1, 2009)

Shock DX 669.1x, 785.5x, 995.0, 995.4, 998.0x

Sickle cell disease with crisis

DX 282.62, 282.64, 282.69

Air and thrombotic embolism

DX 415.1x, 673.0x, 673.2x

673.3x, 673.8x

Blood transfusion PR 99.0x

Conversion of cardiac rhythm

PR 99.6x

Hysterectomy PR 68.3x-68.9

Temporary tracheostomy PR 31.1

Ventilation PR 93.90, 96.01-96.05

Delete: 96.04, 96.7x

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Data from Centers for Disease Control and Prevention (CDC) Pregnancy Mortality Surveillance System. Available at: http://www.cdc.gov/reproductivehealth/MaternalInfantHealth/PMSS.html.

Retrieved December 19, 2016.

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Appendix 3. Diagnosis and Procedure Codes for Antepartum Complications Health Condition International Classification of Diseases,

Ninth Revision, Clinical Modification (ICD-9) Code(s)

Code Definition

Diabetes 648.8x Gestational diabetes

250.0x-250.9x; 648.80 Chronic diabetes

Hypertension 642.3x-642.6x Gestational hypertension

401.xx-405.xx; 642.0x-652.2x, 642.7x Chronic hypertension

642.9x Unspecified hypertension

Heart disease 648.5x; 645.xx-747.xx Congenital heart disease 414.xx, 416.xx, 417.xx, 424.xx, 429.xx Other heart disease

410.xx +POA^† , 411.xx + POA Acute myocardial infarction (MI)

413.xx + POA Angina

415.xx + POA Acute pulmonary heart

disease

420.xx+ POA Acute pericarditis

421.xx + POA Acute/subacute pericarditis

422.xx+ POA Acute myocarditis

423.xx + POA Other pericardial

425.xx + POA Cardiomyopathy

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426.xx + POA Conduction disorders

427.xx + POA Dysrhythmias

428.xx + POA Heart failure

35.xx-37.xx; 39.xx Operations on heart and pericardium (procedure codes)

Mental health diagnoses

296.0x, 296.2x- 296.8x, 298.0x, 300.4x, 311.xx

Mood disorders

300.0x, 300.2x, 300.3x, 308.0x, 309.81 Anxiety disorders

309.xx Adjustment disorders

291.xx, 292.xx, 303.xx-305.xx, 648.3x Substance use disorders

295.xx, 297.xx Psychotic disorders

293.0x, 293.1x Cognitive disorders

307.1x, 307.50-307.54 Eating disorders Obesity Body mass index (BMI) ≥ 30 kg/m2 (as

noted on birth certificate) or 278.xx

Reprinted with permission from Fridman M, Greene NH, Korst LM, Lawton E, Ibrahim SEJ, Griffin F, et al. Evaluating the effect of maternal health conditions on severe maternal morbidity adjusting for emergent cesarean delivery: A mediation analysis approach. J Epidem Res

2016;2(2):36-48.

†POA: Present on admission

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Appendix 4. Cluster-Adjusted Bivariate Comparisons of Training and Validation Samples

Characteristic Training sample

(N=535,616) N (%)

Validation sample (N=535,616) N(%)

P-value (cluster- adjusted chi-square tes)

Age <20 44,285 (8.3) 44,640 (8.3) 0.31

20-34 390,394 (72.9) 390,081 (72.8)

>35 100,954 (18.8) 100,874 (18.8)

Race or ethnicity

White 201,328 (37.6) 200,765 (37.5) 0.12

Black 37,761 (7.1) 38,217 (7.1)

Hispanic 115,173 (21.5) 116,075 (21.7)

Asian/Pacific Islander 68,953 (12.9) 68,541 (12.8) Native American/

Eskimo/Aleutian

2,569 (0.5) 2,527 (0.5)

Cesarean delivery 177,420 (33.1) 177,490 (33.1) 0.87

Insurance Private 304,532 (56.9) 304,045 (56.8) 0.18

Medicaid 212,501 (39.7) 213,183 (39.8)

Severe maternal morbidity at birth 8,142 (1.5) 8,306 (1.6) 0.19

Pregnancy with antepartum complications 139,254 (26.0) 139,198 (26.0) 0.89

Length of stay (days) 2.60* 2.61* 0.43^†

Income (dollars) $62,585* $62,496* 0.05^†

Any ED visit in the 90 days following delivery discharge

44,372 (8.3) 44,301 (8.3) 0.79

*Mean (continuous variable)

†Cluster-adjusted t-test – 2 samples

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Appendix 5: Receiver operating characteristic (ROC) curve* validation sample (N=535,616). *This ROC curve was constructed using the predicted probabilities of postpartum emergency department use in the validation sample, as calculated using the regression model built on the training sample. The area under the curve is 0.95, suggesting that the training model was accurate in predicting postpartum emergency department use in the validation sample.

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Appendix 6. Frequency of Primary and Secondary Outcomes by Patient Characteristics (Covariates; N=1,071,232)

Characteristic (categorical) At least 1 ED* visit within 90 days of delivery discharge – N

(%)

>3 ED* visits within 90 days of delivery discharge – N(%)

Age <20 12,102 (1.1) 871 (0.0)

Age 20-34 65,417 (6.1) 3,911 (0.4)

Age >35 11,154 (1.0) 388 (0.0)

White 31,390 (2.9) 2,038 (0.2)

Black 10,423 (0.9) 782 (0.0)

Hispanic 21,951 (2.0) 1,241 (0.1)

Asian/Pacific Islander 5,714 (0.5) 129 (0.0)

Native

American/Eskimo/Aleutian

509 (0.0) 35 (0.0)

Cesarean delivery 35,813 (3.3) 2,252 (0.2)

Medicaid insurance 33,400 (3.1) 3,946 (0.4)

Severe maternal morbidity 2,369 (0.2) 208 (0.0)

Antepartum complication 29,557 (2.8) 2,142 (0.2)

1^st income quartile 27,128 (2.5) 1,906 (0.2)

2^nd income quartile 24,860 (2.3) 1,529 (0.1)

3^rd income quartile 20,617 (1.9) 1,103 (0.1)

4^th income quartile 15,082 (1.4) 565 (0.1)

*ED: Emergency Department