Rare Variant Genetics and Dilated Cardiomyopathy Severity: The DCM Precision Medicine Study

BACKGROUND

Dilated cardiomyopathy (DCM) can lead to advanced disease, defined herein as necessitating a durable left ventricular assist device or a heart transplant (LVAD/HT). DCM is known to have a genetic basis, but the association of rare variant genetics with advanced DCM has not been studied.

METHODS

We analyzed clinical and genetic sequence data from patients enrolled between 2016 and 2021 in the US multisite DCM Precision Medicine Study, which was a geographically diverse, multiracial, multiethnic cohort. Clinical evaluation included standardized patient interview and medical record query forms. DCM severity was classified into 3 groups: patients with advanced disease with LVAD/HT; patients with an implantable cardioverter defibrillator (ICD) only; or patients with no ICD or LVAD/HT. Rare variants in 36 DCM genes were classified as pathogenic or likely pathogenic or variants of uncertain significance. Confounding factors we considered included demographic characteristics, lifestyle factors, access to care, DCM duration, and comorbidities. Crude and adjusted associations between DCM severity and rare variant genetic findings were assessed using multinomial models with generalized logit link.

RESULTS

Patients' mean (SD) age was 51.9 (13.6) years; 42% were of African ancestry, 56% were of European ancestry, and 44% were female. Of 1198 patients, 347 had LVAD/HT, 511 had an ICD, and 340 had no LVAD/HT or ICD. The percentage of patients with pathogenic or likely pathogenic variants was 26.2%, 15.9%, and 15.0% for those with LVAD/HT, ICD only, or neither, respectively. After controlling for sociodemographic characteristics and comorbidities, patients with DCM with LVAD/HT were more likely than those without LVAD/HT or ICD to have DCM-related pathogenic or likely pathogenic rare variants (odds ratio, 2.3 [95% CI, 1.5-3.6]). The association did not differ by ancestry. Rare variant genetic findings were similar between patients with DCM with an ICD and those without LVAD/HT or ICD.

CONCLUSIONS

Advanced DCM was associated with higher odds of rare variants in DCM genes adjudicated as pathogenic or likely pathogenic, compared with individuals with less severe DCM. This finding may help assess the risk of outcomes in management of patients with DCM and their at-risk family members.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03037632.

Genetic Architecture of Dilated Cardiomyopathy in Individuals of African and European Ancestry

Importance

Black patients with dilated cardiomyopathy (DCM) have increased familial risk and worse outcomes than White patients, but most DCM genetic data are from White patients.

Objective

To compare the rare variant genetic architecture of DCM by genomic ancestry within a diverse population of patients with DCM.

Design

Cross-sectional study enrolling patients with DCM who self-identified as non-Hispanic Black, Hispanic, or non-Hispanic White from June 7, 2016, to March 15, 2020, at 25 US advanced heart failure programs. Variants in 36 DCM genes were adjudicated as pathogenic, likely pathogenic, or of uncertain significance.

Exposure

Presence of DCM.

Main Outcomes and Measures

Variants in DCM genes classified as pathogenic/likely pathogenic/uncertain significance and clinically actionable (pathogenic/likely pathogenic).

Results

A total of 505, 667, and 26 patients with DCM of predominantly African, European, or Native American genomic ancestry, respectively, were included. Compared with patients of European ancestry, a lower percentage of patients of African ancestry had clinically actionable variants (8.2% [95% CI, 5.2%-11.1%] vs 25.5% [95% CI, 21.3%-29.6%]), reflecting the lower odds of a clinically actionable variant for those with any pathogenic variant/likely pathogenic variant/variant of uncertain significance (odds ratio, 0.25 [95% CI, 0.17-0.37]). On average, patients of African ancestry had fewer clinically actionable variants in TTN (difference, -0.09 [95% CI, -0.14 to -0.05]) and other genes with predicted loss of function as a disease-causing mechanism (difference, -0.06 [95% CI, -0.11 to -0.02]). However, the number of pathogenic variants/likely pathogenic variants/variants of uncertain significance was more comparable between ancestry groups (difference, -0.07 [95% CI, -0.22 to 0.09]) due to a larger number of non-TTN non-predicted loss of function variants of uncertain significance, mostly missense, in patients of African ancestry (difference, 0.15 [95% CI, 0.00-0.30]). Published clinical case-based evidence supporting pathogenicity was less available for variants found only in patients of African ancestry (P < .001).

Conclusion and Relevance

Patients of African ancestry with DCM were less likely to have clinically actionable variants in DCM genes than those of European ancestry due to differences in genetic architecture and a lack of representation of African ancestry in clinical data sets.

Prevalence and Cumulative Risk of Familial Idiopathic Dilated Cardiomyopathy

Importance

Idiopathic dilated cardiomyopathy (DCM) aggregates in families, and early detection in at-risk family members can provide opportunity to initiate treatment prior to late-phase disease. Most studies have included only White patients, yet Black patients with DCM have higher risk of heart failure-related hospitalization and death.

Objective

To estimate the prevalence of familial DCM among DCM probands and the age-specific cumulative risk of DCM in first-degree relatives across race and ethnicity groups.

Design, Setting, and Participants

A family-based, cross-sectional study conducted by a multisite consortium of 25 US heart failure programs. Participants included patients with DCM (probands), defined as left ventricular systolic dysfunction and left ventricular enlargement after excluding usual clinical causes, and their first-degree relatives. Enrollment commenced June 7, 2016; proband and family member enrollment concluded March 15, 2020, and April 1, 2021, respectively.

Exposures

The presence of DCM in a proband.

Main Outcomes and Measures

Familial DCM defined by DCM in at least 1 first-degree relative; expanded familial DCM defined by the presence of DCM or either left ventricular enlargement or left ventricular systolic dysfunction without known cause in at least 1 first-degree relative.

Results

The study enrolled 1220 probands (median age, 52.8 years [IQR, 42.4-61.8]; 43.8% female; 43.1% Black and 8.3% Hispanic) and screened 1693 first-degree relatives for DCM. A median of 28% (IQR, 0%-60%) of living first-degree relatives were screened per family. The crude prevalence of familial DCM among probands was 11.6% overall. The model-based estimate of the prevalence of familial DCM among probands at a typical US advanced heart failure program if all living first-degree relatives were screened was 29.7% (95% CI, 23.5% to 36.0%) overall. The estimated prevalence of familial DCM was higher in Black probands than in White probands (difference, 11.3% [95% CI, 1.9% to 20.8%]) but did not differ significantly between Hispanic probands and non-Hispanic probands (difference, -1.4% [95% CI, -15.9% to 13.1%]). The estimated prevalence of expanded familial DCM was 56.9% (95% CI, 50.8% to 63.0%) overall. Based on age-specific disease status at enrollment, estimated cumulative risks in first-degree relatives at a typical US advanced heart failure program reached 19% (95% CI, 13% to 24%) by age 80 years for DCM and 33% (95% CI, 27% to 40%) for expanded DCM inclusive of partial phenotypes. The DCM hazard was higher in first-degree relatives of non-Hispanic Black probands than non-Hispanic White probands (hazard ratio, 1.89 [95% CI, 1.26 to 2.83]).

Conclusions and Relevance

In a US cross-sectional study, there was substantial estimated prevalence of familial DCM among probands and modeled cumulative risk of DCM among their first-degree relatives.

Trial Registration

ClinicalTrials.gov Identifier: NCT03037632.

[Association between LMNA mutation and familial and idiopathic dilated cardiomyopathy patients in Xinjiang]

OBJECTIVE

To explore the association between LMNA gene mutation and familiar dilated cardiomyopathy (DCM) (FDCM) and idiopathic DCM (IDCM) in Uygurs and Hans people in Xinjiang area.

METHODS

Peripheral blood samples were collected from 28 family member with FDCM and 123 sporadic patients with IDCM(56 Uygur patients and 67 Han patients), 80 Uygur and 80 Han people were chosen as normal controls. PCR was used to amplify the 12 exons of LMNA gene. The amplified products were sequenced and compared with the standard sequence in the NCBI to determine the mutation sites.

RESULTS

Transmission of the allele C and T of rs4641 was similar in Han FDCM patients. One new variation(c.1714C>T) located at exon 10 of LMNA gene was identified in 1 Han patient with IDCM, this mutation caused an amino acid substitution (R572C). In Uygurs people, rs553016 polymorphism was significant different between IDCM and control groups (P < 0.05). Logistic regression revealed that rs553016 was an independent risk factor for Uygurs patients with IDCM (OR = 3.178, P = 0.035).

CONCLUSIONS

LMNA rs4641 is not associated with FDCM of Hans people in Xinjiang while LMNA mutation is associated with IDCM and rs533106 polymorphism is an independent risk factor for Uygurs patients with IDCM.

Analysis of IL-17 gene polymorphisms in Chinese patients with dilated cardiomyopathy

Cardiomyopathy is one of the major causes of sudden death and/or progressive heart failure. Dilated cardiomyopathy (DCM), comprising 60% of the cases of identified cardiomyopathy, is the most common form of heart muscle disease. Interleukin 17 (IL-17) is a proinflammatory cytokine that has been implicated in the pathogenesis of various diseases. To evaluate the influence of IL-17A and IL-17F gene polymorphisms on the risk of DCM, a case-control study was conducted in a Chinese Han population. The TaqMan® SNP Genotyping Assay was used to genotype the SNP rs2275913 of IL-17A and SNP rs763780 of IL-17F in 288 DCM patients and 421 ethnicity-matched controls. No significant difference in genotypic and allelic frequencies between DCM patients and control subjects was observed. However, Results of stratified analysis revealed that rs763780 was associated with male DCM patients in a dominant genetic model (p=0.031, OR=1.83, 95% CI=1.04-3.22). Our results suggest that the tested two IL-17 SNPs, rs2275913 and rs763780, are not found to be associated with DCM in the Chinese population studied.

A meta-analysis of β1-adrenergic receptor gene polymorphisms in idiopathic dilated cardiomyopathy

Published data on the association between β1-adrenergic receptor gene polymorphisms and idiopathic dilated cardiomyopathy (IDCM) risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 12 case-control studies including 2642 cases and 3136 controls provided data on the association between β1-adrenergic receptor gene polymorphisms and susceptibility to IDCM. Overall, no significantly elevated risk was associated with Arg389Gly polymorphisms for all genetic models. In the subgroup analysis by ethnicity, no statistically increased risk was found for Gly389Gly versus Arg389Arg (OR 0.73; 95% CI 0.54-0.99; Ph=0.35) and Gly389Gly versus Arg389Arg+Arg389Gly (OR 0.75; 95% CI 0.55-1.01; Ph=0.52) among Europeans. Meanwhile, significantly increased risk was found among Asians based on the relatively small sample size. Further, significantly elevated IDCM risk was associated with Ser49Gly polymorphisms for all genetic models. When stratified by ethnicity, statistical association was found among Asians for Gly49Gly versus Ser49Ser (OR 4.56; 95% CI 1.36-15.23; Ph=0.10) and Gly49Gly versus Ser49Ser+Ser49Gly (OR 4.49; 95% CI 1.33-15.15; Ph=0.12), but not among Europeans. In summary, this meta-analysis suggests that no statistically increased risk was found between β1-adrenergic receptor gene polymorphisms and susceptibility to IDCM among Europeans.

Molecular and clinical characterization of a novel SCN5A mutation associated with atrioventricular block and dilated cardiomyopathy

BACKGROUND

Increased susceptibility to dilated cardiomyopathy has been observed in patients carrying mutations in the SCN5A gene, but the underlying mechanism remains unclear. In this study, we identified and characterized, both in vitro and clinically, an SCN5A mutation associated with familial progressive atrioventricular block of adult onset and dilated cardiomyopathy in a Chinese family.

METHODS AND RESULTS

Among 32 family members, 5 were initially diagnosed with atrioventricular block after age 30; 4 were studied, 3 of whom later developed dilated cardiomyopathy. We found a heterozygous single-nucleotide mutation resulting in an amino acid substitution (A1180V) in all studied patients and in 6 other younger unaffected members but not in 200 control chromosomes. When expressed with the beta1 subunit, the mutated channels exhibited a -4.5-mV shift of inactivation with slower recovery leading to a rate-dependent Na(+) current reduction and a moderate increase in late Na(+) current. Clinical study revealed that although QRS duration decreased with increasing heart rate in noncarrier family members, this change was blunted in unaffected carriers whose ECG and heart function were normal. Resting corrected QT interval of unaffected carriers was significantly longer than that of noncarriers, even though it was still within the normal range.

CONCLUSIONS

A1180V expresses a mild Na(+) channel phenotype in vitro and a corresponding clinical phenotype in unaffected mutation carriers, implying that A1180V caused structural heart disease in affected carriers by disturbing Na(+) influx and, hence, cellular Na(+) homeostasis. The high penetrance of A1180V suggests this phenotype as a high risk factor for dilated cardiomyopathy with preceding atrioventricular block.

Desmin mutations in a St. Petersburg cohort of cardiomyopathies

Several desmin mutations have been described over the past few years in patients with dilated and restrictive cardiomyopathy, often in association with distal myopathy. However, the role of desmin mutations as a cause of various types of cardiomyopathy is still undetermined. The aim of this study was to analyse the frequency of desmin mutations in patients with cardiomyopathy identified and diagnosed in the St. Petersburg area of Russia. We screened 98 patients with dilated, 40 with hypertrophic and 4 with restrictive cardiomyopathy. All exons of the desmin gene were amplified by PCR and studied by sequencing. Two out of 98 patients showed the presence of desmin gene mutations, not previously described in dilated cardiomyopathy. A novel IVS2-2A-->G splice site mutation, presumably causing skipping of exon 3, was detected in a case of familial right ventricular dilated cardiomyopathy. An A213V mutation was associated with a case of late onset dilated cardiomyopathy. No desmin mutations were found in patients with hypertrophic or restrictive cardiomyopathy. Desmin mutations should be considered a relatively rare cause of dilated cardiomyopathy in this specific geographic area.

Evidence of viral infection in the myocardium of American and Japanese patients with idiopathic dilated cardiomyopathy

Enteroviruses have been implicated in the pathogenesis of idiopathic dilated cardiomyopathy (IDC). Recently, the association of adenovirus or parvovirus with IDC has been reported. Viral infection in the myocardium of American and Japanese patients with end-stage IDC was evaluated. Myocardial specimens from 30 American patients with IDC and 47 Japanese patients with IDC were analyzed for the presence of cardiotropic viruses. The strand-specific detection of enteroviral ribonucleic acid (RNA) was performed to determine viral activity in hearts with IDC. Established reverse transcription-polymerase chain reaction (PCR) or PCR techniques were used to detect genomic sequences of influenza viruses, mumps virus, adenovirus, parvovirus, herpes simplex viruses, varicella-zoster virus, and Epstein-Barr virus. Enteroviral RNA was detected in 7 of the 30 American patients (23%) and in 15 of the 47 Japanese patients (32%). Minus-strand enteroviral RNA, an indicator of active enteroviral RNA replication, was demonstrated in 5 of 7 plus-strand-positive American patients (71%) and in 12 of 15 plus-strand-positive Japanese patients (80%). Sequence analysis revealed that the viruses detected were Coxsackie B viruses. No genomic sequences of other viruses were detected in the myocardium of either American or Japanese patients with IDC. Therefore, active group B Coxsackie virus RNA replication in the myocardium was demonstrated in a significant proportion of American and Japanese patients with end-stage IDC. There was no evidence of persistent infection by other viruses in hearts with IDC. Specific therapy should be designed for Coxsackie virus positive patients with IDC.

Low proportion of familial dilated cardiomyopathy in an arab population with a high prevalence of consanguineous marriages

In this study, 770/890 (87%) first-degree relatives from 108 families of hospitalized patients with idiopathic dilated cardiomyopathy (IDC) were screened using clinical examination, electrocardiography and echocardiography. Thirty percent of the patients were born to consanguineous parents. Familial dilated cardiomyopathy (FDC) was found in 7 (6.5%) families, which is lower than the earlier published figures of 20-25%. Patients with IDC were younger at presentation (p = 0.002) and were more often associated with parental consanguinity (p = 0.04). but the survival rates of familial patients did not differ significantly.

CONCLUSION

Despite the high prevalence of consanguinity, there was a low proportion of FDC in the study population. With the prospects of treatment of asymptomatic IDC to slow the progression of the disease, all family members of newly identified IDC patients should receive screening and counselling, with appropriate therapy where indicated.

Evidence for autosomal recessive inheritance of infantile dilated cardiomyopathy: studies from the Eastern Province of Saudi Arabia

Familial dilated cardiomyopathy is being increasingly recognized, but affected individuals <10 y are rarely identified. We describe the natural history of dilated cardiomyopathy and evaluate the mode of inheritance among infants of Arab descent from the Eastern Province of Saudi Arabia. We evaluated 55 consecutive cases of dilated cardiomyopathy in patients <10 y of age seen during a 5-y interval. Echocardiography was the primary diagnostic modality. The 55 cases represented 20% of the offspring of 41 families of Arab descent. In 19 families (46%), parents were first cousins; there was no obvious consanguinity in 22 families (54%). Age at presentation was <30 mo (95%) (range, 1 to 100 mo); males (38%) and females (62%) were affected. Patients died (25 patients, 46%), improved (15 patients, 27%), or recovered (15 patients, 27%). The left ventricular shortening fraction at diagnosis ranged from 5 to 28% and did not differ in those who died, improved, or recovered. Complex segregation analysis of the family data using the mixed model of inheritance showed that a model of recessive inheritance best fits the data. Recessively inherited dilated cardiomyopathy has been infrequently reported, perhaps because it may be difficult to recognize in other patient groups in which consanguineous marriage is uncommon and the number of children per family is small. In the setting of consanguineous marriage, homozygosity mapping should lead to identification of the gene(s) causing dilated cardiomyopathy in the families we studied.

Plasma and urinary selenium in Saudi Arabian patients with dilated cardiomyopathy

We measured selenium (Se) levels in the urine and blood plasma samples of 72 Saudi Arabian patients with dilated cardiomyopathy (DCM) and 70 control subjects of the same origin. To correct for differences in the hydration state of the subjects, the selenium concentration for each urine sample was normalized by dividing it by the concentration of creatinine (CREAT) in the same sample. The median (and range) of the values found for the concentration of Se in plasma, urine, and normalized concentration in urine for the control subjects was 1.306 (0.66-2.50) microM, 0.478 (0.05-2.00) microM, and 56.7 (10.6-426.5) microM Se/M CREAT, respectively, whereas, for the patients, it was 1.246 (0.53-2.45) microM, 0.39 (0.05-1.90) microM, and 75.1 (4.9-656.2) microM Se/M CREAT, respectively. Additionally, the patients were separated into three subgroups according to the severity of their disease state as judged by NYHA procedure, and were then compared to the control group. Only group 4 (the most severe state of the disease) had a significantly lower concentration of urinary Se than the control group. However, the difference became nonsignificant when normalized for CREAT levels. There was no significant difference in the plasma Se levels between the controls and any of the patient groups. As the plasma Se in the control group and in the DCM patients both fell on the low end of the "normal" range, with the patients being marginally lower than the controls, there is no firm evidence from this study to suggest that Se is related to the high incidence rate of DCM found in Saudi Arabia.

Effect of race in the response to metoprolol in patients with congestive heart failure secondary to idiopathic dilated or ischemic cardiomyopathy

We sought to determine the effect of race in response to metoprolol in patients with dilated cardiomyopathy. We found no difference in exercise, hemodynamic, and neurohormonal responses to metoprolol based on race in patients with cardiomyopathy.

What explains black-white differences in survival in idiopathic dilated cardiomyopathy? The Washington, DC, Dilated Cardiomyopathy Study

We have found race to be an independent predictor of mortality in a preliminary analysis of data from an ongoing study of patients with idiopathic dilated cardiomyopathy. Our previous, analyses, however, were based on only 12 to 24 months of follow-up. In the present analysis, which is based on up to 5 years of follow-up, we extended our earlier observations and examined whether other socioeconomic factors account for the association with race. A total of 128 patients from five Washington, DC, area hospitals were included in the analysis. One hundred three (80.5%) of the patients were black and 25 (19.5%) were white. The black patients were less likely to have private health insurance, less educated on average, and more likely to have a household income < or = $15,000. No racial differences were found in cardiac medication usage, with the exception of beta blockers and antiarrhythmics. The cumulated survival among black patients at 12 and 60 months was 71.5% and 39.1%, respectively, compared with 92% and 31.4% among whites. Age, ventricular arrhythmias, and ejection fraction were significant predictors of survival in univariate analysis. The univariate association with black race was of borderline significance. In multivariable analysis using the proportional hazards model, age and ejection fraction were significant independent predictors of survival. The association with ventricular arrhythmias was of borderline significance. The association with black race, which was statistically nonsignificant, was diminished even further by adjustment for income and type of health insurance. Thus, the previously reported association with black race may be accounted for by socioeconomic factors related to access to health care.

HLA antigens in an Omani population with dilated cardiomyopathy

We have investigated the frequency of HLA antigens in 50 Omanis with idiopathic dilated cardiomyopathy to establish whether there are ethnic/racial differences in the reported HLA associations with this disease. There were no statistically significant HLA-A, B, C, DR or DQ antigen frequency differences between the patients and 247 healthy Omanis. THe reported association of HLA-DR4 with idiopathic dilated cardiomyopathy in the Caucasian population does not apply to the Omanis. This confirms the heterogeneity of this disease and points to ethnic/racial origins as important factors when examining the HLA association. This is particularly pertinent as HLD-DR4 has been strongly linked to autoantibody formation in idiopathic dilated cardiomyopathy in Caucasians. The lack of any HLA antigen association in Omanis would argue against the proposed HLA-linked autoimmune pathology of idiopathic dilated cardiomyopathy.

Lack of association between insertion/deletion polymorphism of the angiotensin-converting enzyme gene and end-stage heart failure due to ischemic or idiopathic dilate cardiomyopathy in the Chinese

Homozygosity for the deletion allele of the angiotensin-converting enzyme gene (DD) has been associated with a variety of cardiovascular diseases, including ischemic and idiopathic dilated cardiomyopathy, in Caucasians. In this study of 104 Chinese patients with end-stage heart failure due to idiopathic dilated or ischemic cardiomyopathy, the DD genotype frequency was low (12% and 11%, respectively) and was not seen more often than in a control group of 183 subjects without cardiac disease (13%). Therefore, in the Chinese, the DD genotype is less common than in Caucasians and does not appear to be associated with the development of either ischemic or idiopathic dilated cardiomyopathy.

DNA typing of HLA class II genes in Japanese patients with dilated cardiomyopathy

HLA class II genes (DRB, DQA, DQB, DPA, and DPB) were typed at the DNA level using polymerase chain reaction/sequence-specific oligonucleotide probe analysis in 78 unrelated patients with DCM and 336 unrelated healthy controls to elucidate the HLA alleles or HLA haplotypes associated with DCM. The frequencies of DRB1*1401 (15.4% v 4.5%, RR = 3.90, P < 0.0005, Pc < 0.03), DQB1*0503 (14.1% v 5.4%, RR = 2.93, P < 0.007) and DRB1*1401-DQB1*0503 haplotype (11.5% v 1.5%, RR = 8.24, P < 0.00001, Pc < 0.01) were increased in the DCM patients. The frequency of HLA-DRB1*1101 (9.0% v 3.0%, RR = 3.26, P < 0.02) also was increased in the patients. In addition, the frequencies of DQB1*0604 and DPB1*0401 were increased in the DRB1*1401 and DRB1*1101 negative patients. In contrast, the frequencies of DQB1*0303 (19.2% v 30.7%, RR = 0.55, P < 0.05) and DRB1*0901-DQB1*0303 haplotype (16.7% v 29.8%, RR = 0.49, P < 0.02) were decreased in the DCM group. Disease susceptibility to DCM in the Japanese population, thus, may be controlled in part by a gene (or genes) in close linkage disequilibrium with DRB1*1401-DQB1*0503, DRB1*1101-DQB1*0301, and DQB1*0604-DPB1*0401 haplotypes, while the resistance to DCM may be associated with the DRB1*0901-DQB1*0303 haplotype.

Predictors of mortality from idiopathic dilated cardiomyopathy in 356,222 men screened for the Multiple Risk Factor Intervention Trial

Possible predictors of mortality from idiopathic dilated cardiomyopathy were studied in 356,222 men who were screened as part of the Multiple Risk Factor Intervention Trial. The vital status of each member of this cohort was ascertained through 1986. Death certificates were obtained from state health departments and coded by a trained nosologist. Individuals with a history of myocardial infarction were excluded. A total of 206 deaths due to idiopathic dilated cardiomyopathy occurred in the cohort of 356,222 men after an average of 12 years of follow-up. The age-specific rates of mortality from idiopathic dilated cardiomyopathy increased from 0.10 per 10,000 person-years among men aged 35-39 years to 1.16 per 10,000 person-years among men aged 55-57 years. The proportional hazards model was used to obtain adjusted estimates of relative risks. Statistically significant, independent associations were observed with cigarettes smoked per day (p < 0.001), diastolic blood pressure (p < 0.001), and diabetes mellitus (relative risk (RR) = 2.97, p < 0.001). Black race was also associated with an increased risk of death from idiopathic dilated cardiomyopathy (RR = 1.59 and p = 0.045 without adjustment for income; RR = 1.58 and p = 0.058 with adjustment for income). No association was found with serum cholesterol or income. The information about possible risk factors obtained in this study may contribute to future preventive programs for idiopathic dilated cardiomyopathy.

Black-white differences in idiopathic dilated cardiomyopathy: the Washington DC dilated Cardiomyopathy Study

We conducted an epidemiologic study to examine the extent to which differences in purported risk factors account for black-white differences in risk of idiopathic dilated cardiomyopathy. We examined associations with race and other factors by comparing newly diagnosed cases (N = 122), ascertained from five Washington DC area hospitals, with neighborhood controls (N = 234) identified using a random digit dialing technique. We matched the cases and controls on sex and 5-year age intervals and analyzed the data using conditional logistic regression methods. We found that blacks were at increased risk for idiopathic dilated cardiomyopathy (relative odds = 2.6, 95% confidence interval = 1.6-4.3). The increased risk for blacks could not be explained by income, educational attainment, alcohol consumption, cigarette smoking, or history of hypertension, obesity, diabetes, or asthma. We also observed a possible interactive effect between black race and hypertension.