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Incidence, Mortality, and Racial Differences in Peripartum Cardiomyopathy

Somjot S. Brar, MDa,*, Steven S. Khan, MDa,c, Gagandeep K. Sandhu, MDa,Michael B. Jorgensen, MDa,c, Neil Parikh, BSa, Jin-Wen Y. Hsu, PhDb,

and Albert Yuh-Jer Shen, MDa,c

There are no large population-based studies on the incidence and prognosis of peripartumcardiomyopathy (PC). Between 1996 and 2005, there were 241,497 deliveries within theSouthern California Kaiser healthcare system. Among these, we identified 60 cases of PCby searching for an International Classification of Diseases, Ninth Edition diagnosis ofheart failure (HF) and detailed chart review. PC was confirmed if all of the followingcriteria were satisfied: (1) left ventricular ejection fraction <0.50, (2) met the Framinghamcriteria for HF, (3) new symptoms of HF or initial echocardiographic diagnosis of leftventricular dysfunction occurred in the month before or in the 5 months after delivery, and(4) no alternative cause of HF could be identified. The overall incidence of PC was 1 in4,025 deliveries. The incidence in whites, African-Americans, Hispanics, and Asians was 1of 4,075, 1 of 1,421, 1 of 9,861, and 1 of 2,675 deliveries, respectively. The incidence of PCwas greatest in African-Americans, which was 2.9-fold higher compared with whites (p �0.03) and 7-fold that of Hispanics (p <0.001). With a mean follow-up of 4.7 years, thefreedom from all-cause death was 96.7% by the Kaplan-Meier method. In conclusion, thislarge population-based study highlights important racial differences in the incidence of PC.We observed the lowest incidence of PC in Hispanics and the highest in African-Americans.Our findings also suggest that the current mortality associated with PC may be less thanreported in older series, perhaps because of the high utilization of modern HF

therapy. © 2007 Elsevier Inc. All rights reserved. (Am J Cardiol 2007;100:302–304)

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eripartum cardiomyopathy (PC) is a cardiomyopathy ofnclear etiology occurring between 1 month before and 5onths after delivery. The reported incidence has variedidely1,2 and may be in part related to the population

tudied and also to biases associated with case identifica-ion. For example, a higher prevalence has been reported infrican-Americans and in certain regions of the world.3,4

he incidence in other ethnicities remains less clear. Theeported survival from PC has also varied greatly, rangingrom 18% to 56% in different series.5–7 These estimates mayuffer from significant biases in patient identification whereicker women are more likely to be identified as having PC.

omen with a benign course and rapid recovery may beess likely to be identified in these estimates. We thereforedentified cases of PC in a large multiethnic, insured popu-ation in Southern California to evaluate possible racialifferences in the incidence and prognosis of PC.

ethods and Results

he Peripartum Cardiomyopathy research project is a studyesigned to determine the incidence, predictors, and out-omes of women with this rare disorder in the Kaiser Per-anente Southern California health plan. The region is

aKaiser Permanente, Los Angeles and bKaiser Permanente, Pasadena,nd cUCLA School of Medicine, Los Angeles, California. Manuscripteceived October 25, 2006; revised manuscript received and acceptedebruary 17, 2007.

*Corresponding author: Tel: 323-783-4915; fax: 323-783-5509.

tE-mail address: SBrar@cvri.org (S. Brar).

002-9149/07/$ – see front matter © 2007 Elsevier Inc. All rights reserved.oi:10.1016/j.amjcard.2007.02.092

thnically diverse with whites, Hispanics, Asians, and Af-ican-Americans well represented.

By searching electronic hospitalization databases, wedentified all women hospitalized with heart failure (HF) 6onths before or 9 months after a delivery between January

, 1996 and December 31, 2005. HF was initially screenedor by International Classification of Diseases, 9th Revi-ion, Clinical Modification (ICD-9-CM) codes 428.0, 428.1,28.4, 428.9, 425.4, and 425.9. Women who met theseriteria underwent a detailed review of their medical recordo confirm the diagnosis of PC.

PC was confirmed if all of the following criteria wereatisfied: (1) ejection fraction �0.50, (2) met the Framing-am criteria for HF, (3) new symptoms of HF or initialiagnosis of left ventricular dysfunction occurred in theonth before or in the 5 months after delivery, and (4) no

ther cause of HF could be identified. This definition isonsistent with that described by the National Heart, Lung,nd Blood Institute workshop recommendations on PC.8

Death was confirmed from hospital administrative data-ases and/or MORTLINK. The latter is a database of deathsn residents of California maintained by the state. Race andthnicity data was obtained from birth certificates and waself-reported.

We calculated the incidence of PC for each race/ethnic-ty. Comparisons between groups were performed usingnalysis of variance or chi-square test as appropriate. Aaplan-Meier survival analysis was performed. Follow-upegan at the delivery date and cases were censored for lossf health plan membership or the end of the study period. Avalue �0.05 was considered significant. The analysis for

his study was generated using SAS statistical software,

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303Cardiomyopathy/Peripartum Cardiomyopathy

ersion 9.1 (SAS Institute Inc., Cary, North Carolina). Thetudy was approved by the institutional review board.

Between January 1, 1996 and December 31, 2005 thereere 248,841 women who delivered in the Southern Cali-

ornia Kaiser healthcare system. We excluded 6,984 caseshat were not health plan members and therefore did notave follow-up data. This resulted in a study cohort of41,497 women. The initial search using HF codes identi-ed 240 cases within the period of interest. After detailedhart review of all available records, 60 were confirmed toave PC by the previously described criteria. In the remain-ng patients, 35% did not have evidence of HF or did noteet the Framingham criteria, 25% met all criteria for PC

xcept the ejection fraction was �0.50, 20% had previousardiac disorders (e.g., dilated cardiomyopathy, hypertro-hic cardiomyopathy, myocardial infarction, valvular heartisease, or previous heart transplantation), and 18% hadoncardiac disorders, such as pulmonary embolism, pulmo-ary hypertension, hyperthyroidism, or sepsis. In contrast toprevious report, we identified only 3 cases (2%) with

nexplained HF outside of the PC time frame.9 Among the80 excluded patients, there were 6 deaths, resulting in aortality of 2.5% during the study period. To identify cases

f PC where death occurred before delivery, we reviewed andditional 122,517 cases with a positive urine or serumregnancy test. However, there were no additional cases ofF meeting criteria for PC.In the 60 confirmed PC cases, the mean age was 33 � 7

ears. The mean ages for whites, African-Americans, His-anics, and Asians was 33 � 6, 32 � 8, 35 � 5, and 31 �years, respectively (p � 0.47). The mean ejection fractionas 0.32 � 0.10 as assessed by either echocardiogram,yocardial perfusion imaging, or multiple-gated acquisition

cans.The race/ethnicity composition of the 241,437 health

lan members without PC was 49% Hispanic, 27% white,1% Asian, 10% African-American, and 3% other races.mong the PC cohort, 28% were African-American, 27%hite, 20% Hispanic, 17% Asian, and 8% other. The inci-ence of PC in whites, African-Americans, Hispanics, and

igure 1. Kaplan-Meier estimates of survival for the non-PC cohort (n �41,437) and PC cohort (n � 60).

sians was 1 of 4,075, 1 of 1,421, 1 of 9,861, and 1 of W

,675, respectively. The incidence of PC among African-mericans was 2.9-fold that of whites (p � 0.03) and 7-fold

hat of Hispanics (p �0.001).With a mean follow-up of 4.7 years, a Kaplan-Meier

nalysis showed 96.7% survival in the PC cohort (Figure 1)t the end of the study period. There were 2 deaths in the PCroup during the study period and 393 in the 241,437omen without PC. Of the 2 deaths in the PC cohort, 1erson died 5 months after delivery; she was diagnosed andreated for a deep venous thrombosis 3 months prior. Theecond patient died 4.5 years after delivery from respiratoryailure, presumably asthma related. Her left ventricularunction had recovered, ejection fraction by echocardiogra-hy the day before death was 0.59. No patients underwentardiac transplantation during the study period.

iscussion

n this large community-based population the overall incidencef PC was 1 in 4,025 births in the Southern California region,ut there was substantial variability between races. The inci-ence was highest in African-Americans and lowest in His-anics. The variation in incidence by ethnicity may help ex-lain, in part, the wide range reported in the literature.owever, what remains unclear is the reason for these differ-

nces. It is possible that environmental or genetic influencesay be partially responsible for the differences observed.Our data also suggest that the mortality from PC may be

ess than previously reported. The reasons for the higherortality reported in previous studies is not clear, but it is

ossible that estimates may have been biased by preferentialdentification of women with more advanced disease. Ourrocess of screening by ICD-9-CM codes followed by in-ividual chart review of all potential cases may have al-owed identification of less sick patients. However, anotherossible explanation is that our population consisted pre-ominantly of insured members of a prepaid health plan.his may have improved their access to health care re-ources after delivery and contributed to improved out-omes. The observed mortality of 3.3% in this study wasomparable to the 2.1% reported recently by Mielniczuk etl10 using the National Hospital Discharge Survey.

Several limitations of our study should be noted. UsingCD-9-CM codes for patient screening may have missedome cases of PC that were not properly coded. A secondimitation is that the study population consisted of membersf a prepaid insurance plan in which both the very poor andhe very rich may be under-represented. This may alter theisk factor mix for PC as well as the long-term prognosis.inally, due to active computer-driven reminders to care-ivers, in this system patients with HF are all flagged fornitiation of angiotensin-converting enzyme inhibitors, an-iotensin receptor blockers, and � blockers. At 30 days afterC diagnosis, angiotensin-converting enzyme inhibitors (orngiotensin receptor blockers) and �-blocker utilization was8% and 55%, respectively. The medical therapy of theseatients may therefore not reflect medical therapy in lesslosely monitored care settings.

In conclusion, this large population-based study high-ights important racial differences in the incidence of PC.

e observed the lowest incidence of PC in Hispanics and

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304 The American Journal of Cardiology (www.AJConline.org)

he highest in African-Americans. Our findings also suggesthat the current mortality associated with PC may be lesshan reported in older series, perhaps due in part to hightilization of modern HF therapy.

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