Sex Differences in 30-Day Readmission Risk among Young Patients with Acute Myocardial Infarction Medstar Washington Hospital Center November 4th 2015 Rachel Dreyer, PhD Yale University School of Medicine Center for Outcomes Research and Evaluation (CORE)

Disclosures Statement of Financial Interest I, Rachel Dreyer, DO NOT have any relevant financial relationships to disclose at this time.

1. Background and Objectives Photo credits: Flickr user Dan_DC

Young women are still virtually invisible in cardiology Photo credits: Flickr user JimCodePoet, Huaweioz, AHA Go Red Campaign

The barrier of small numbers at any single institution… Photo credits: Flickr user Bart Luyckx

% In-hospital Mortality Young Women with AMI Have Higher In-Hospital Mortality NRMI 1994-1998 N=38,478 (40% women) 24.2 21.8 21.5 Sex-Age Interaction: P<0.001 19.1 18.4 14.4 % In-hospital Mortality 2.9 10.7 9.5 8.2 7.4 5.7 4.1 2.9 Vaccarino V et al. N Engl J Med 1999;341:217-225.

Australia Europe USA Canada China

Photo credits: Flickr user Casitalboga

Readmission Photo credits: Michael S. Helfenbein

No data on young women

Study Objectives To evaluate sex differences in the rate, timing and principal diagnoses of 30-day readmission following AMI To examine the association of sex with 30-day readmissions To assess whether or not there is an age-sex interaction We hypothesized that younger women (<65 years) have a higher risk of readmission than younger men, even following extensive adjustment for covariates, and similar timing of readmission, as well, and a broad range of readmission diagnoses.

2. Methods Photo credits: Flickr user Dan_DC

Data Source & Study Population Healthcare cost and Utilization Project (HCUP) - State Inpatient Dataset (SID) for California (Jan 07 – Nov 09) Administrative dataset of 42,518 patients (26% women) with acute myocardial infarction (AMI) Inclusion criteria: 18-65 years of age Principal discharge diagnosis of AMI Defined by ICD-9-CM diagnostic codes of “410.xx” with exclusion of codes 410.X2, consistent with the Medicare AMI readmission measure

Exclusion Criteria Exclusion criteria: Left against medical advice Transferred to another facility Died in Hospital Non California residents (as subsequent readmissions may not have been captured in the state inpatient dataset) We considered only the 1st readmission within 30-days of the index admission, as used by the CMS criteria for reporting hospital readmission performance Planned hospitalizations were excluded

Statistical Analyses Sex differences assessed via χ² and Wilcoxon Rank Sum tests We assessed the timing of the first unplanned readmission by day (0-30) after discharge, and the principal readmission diagnoses within 30 days A cox proportional hazards model was utilized to assess the association between sex and risk of unplanned 30-day readmission for AMI. We sequentially adjusted for the following: Socio-demographics Cardiovascular risk factors/conditions/procedures Other co-morbidities Length of stay Discharge disposition In the final model we tested the interaction between age and sex on 30-day readmission

3. Results Photo credits: Flickr user Dan_DC

Socio-Demographics on Presentation Characteristics Women (N=11,215) Men (N=31,303) Socio-Demographics (%)* Age (Mean±SD) White Black Hispanic Other Private health insurance Medicare Medicaid 54±7.5 53% 13% 21% 47% 16% 20% 14% 53±7.6 57% 6% 58% 10% 11% 19% *All P values <0.001 Dreyer et al. Circulation. 2015;4:557-564.

Cardiovascular Risk Factors on Presentation Characteristics Women (N=11,215) Men (N=31,303) Cardiovascular Risk factors (%)* Acute coronary syndrome Congestive Heart failure Diabetes and complications Stroke Anterior AMI Angina pectoris Valvular/Rheumatic heart disease Arrhythmias 10% 12% 44% 1% 16% 9% 6% 5% 32% 0% 18% 14% 4% *All P values <0.001 Dreyer et al. Circulation. 2015;4:557-564.

Co-morbidities on Presentation Characteristics Women (N=11,215) Men (N=31,303) Co-morbidities (%)* Chronic obstructive pulmonary disease Pneumonia Asthma Renal failure Cancer History of infection Vascular/circulatory disease Fluid/electrolyte/acid-base disorders Dementia/Senility Major Psychiatric disorders Drug/alcohol abuse 16% 9% 8% 11% 3% 6% 14% 5% 10% 1% 2% 4% 7% *All P values <0.001 Dreyer et al. Circulation. 2015;4:557-564.

Discharge Disposition Characteristics Women (N=11,215) Men (N=31,303) LOS/Primary Discharge Disposition (%)* Length of stay (Mean±SD) Routine (home) Transfer (Skilled nursing facility/Intermediate care) Home health care Alive but place unknown 4.9±6.4 87% 5% 7% 0.3% 4.4±5.6 90% 3% 6% 0.2% *All P values <0.001 Dreyer et al. Circulation. 2015;4:557-564.

30-Day Readmission Rate in Young Patients with AMI Close to 2-fold higher risk of readmission N=4,775 30-Day All-Cause Readmissions (1,736 women) Dreyer et al. Circulation. 2015;4:557-564.

30-Day Readmission Rate in Young Patients Stratified by Age Men Women Dreyer et al. Circulation. 2015;4:557-564.

30-Day Readmission Rate in Young Patients Stratified by Race Men Women Dreyer et al. Circulation. 2015;4:557-564.

30-Day Readmission Rate in Young Patients Stratified by Payer Status Men Women Dreyer et al. Circulation. 2015;4:557-564.

Timing of Readmission Per Day (0-30) Post AMI Dreyer et al. Circulation. 2015;4:557-564.

Principal Readmission Diagnoses for Cardiac Causes Characteristics Women (N=11,215) Men (N=31,303) Readmission for cardiac diagnosis (%) Heart failure Myocardial infarction UA/other acute ischemic heart disease Chronic angina/CAD* Other congenital heart/hypertensive disease Arrhythmias/conduction disorders Chest pain* Syncope* Acute stroke/TIA Other peripheral vascular disease 55% 13% 8% 3% 6% 2% 11% 0% 1% 59% 12% 9% *P value <0.01 Dreyer et al. Circulation. 2015;4:557-564.

Principal Readmission Diagnoses for Non-Cardiac Causes Characteristics Women (N=11,215) Men (N=31,303) Readmission for noncardiac diagnosis (%) Pleural effusion/pneumothorax COPD* Pneumonia UTI and urinary system* Renal disorders/renal failure Anemia Diabetes mellitus and its complications Septicemia/shock Hip fracture Gastrointestinal hemorrhage 44% 0% 2% 3% 4% 1% 40% *P value <0.001 Dreyer et al. Circulation. 2015;4:557-564.

Independent Association of Sex on 30-Day Readmission Dreyer et al. Circulation. 2015;4:557-564.

Discussion of Findings 4. Conclusion and Discussion of Findings Photo credits: Flickr user Dan_DC

Summary of Key Findings We observed nearly a 2-fold greater risk of readmission in younger women with AMI in comparison to younger men The association of sex persists even following adjustment for extensive covariates, and does not vary by age The timing of 30-day readmission was similar between sexes, and both sexes were vulnerable for a wide range of unrelated causes for readmission, a pattern consistent with the post-hospital syndrome The key finding is that the pattern was similar in women and men, but the rate was substantively higher in women Dreyer et al. Circulation. 2015;4:557-564.

Discussion Appreciate that younger women (<65 years) represent a unique phenotype and have a higher risk for 30-day readmission Research efforts should be focused on identifying risk factors or opportunities in care that differ between groups and that may mediate the observed disparities- to inform effective interventions A need for continued focus on safe discharge planning and early ambulatory intervention post discharge for AMI There is an opportunity to focus on young women, a high risk group, who are inherently more unaware of the prevalence of CAD Dreyer et al. Circulation. 2015;4:557-564.

Women’s Cardiac Health 5. New Frontiers: Women’s Cardiac Health Photo credits: Flickr user marionzetta

Re-hospitalization (%) Young Women with AMI Have Higher 12-month Readmission TRIUMPH AMI Registry 2005-2008 N=1414 (28% women) Re-hospitalization (%) Dreyer R et al. 2015. In progress.

Contact: rachel.dreyer@yale.edu Thank you Contact: rachel.dreyer@yale.edu @DreyerRachel