The C523A β2 Adrenergic Receptor Polymorphism Associates with Markers of Asthma Severity in African Americans

Our goal was to explore associations between β₂ adrenergic receptor polymorphisms and markers of asthma severity in African American and Caucasian patients with asthma. Polymorphisms at loci ?1023, ?654, ?47, 46, 79, 491, and 523 were genotyped and haplotypes were imputed in 143 African Americans and 336 Caucasians. C523A genotype associated with percentage of African Americans (but not of Caucasians) having an asthma exacerbation: AA, AC, and CC genotypes were 17, 29, and 40%, respectively (p = 0.018). Symptom scores, pulmonary function, and rescue inhaler use paralleled exacerbation prevalence. We conclude the 523 A allele modifies asthma severity in African Americans.     

Differing Reports of Asthma Symptoms in African Americans and Caucasians

Objective. This pilot study explores the reported symptoms in African Americans and Caucasians with asthma. Methods. Asthma patients in an inner-city pulmonary clinic were given a brief questionnaire of asthma symptoms and the BORG scale, followed by spirometry. Results. African Americans were less likely to report nocturnal awakenings (67% vs. 100%; p = 0.037), complain of dyspnea (33% vs. 75%; p = 0.038), or experience chest pain (13% vs. 75%; p = 0.002) than Caucasians. Conclusions. This is the first study to demonstrate that there are clinically significant differences in the reporting of asthma symptoms between African Americans and Caucasians.     

Single-nucleotide polymorphisms in tumor necrosis factor receptor genes: definition of novel haplotypes and racial/ethnic differences

OBJECTIVE: To characterize allele frequencies of known single-nucleotide polymorphisms (SNPs) in tumor necrosis factor receptor (TNFR) genes in African Americans with rheumatoid arthritis (RA), healthy African Americans, and healthy Caucasians. METHODS: One TNFRSF1B SNP (196 G/T) that influences susceptibility to familial RA in Caucasians and 3 SNPs in the 5' flanking region of the TNFRSF1A gene (-609G/T, -580A/G, and -383A/C) were genotyped in 108 African Americans with RA, 62 healthy African Americans, and 59 healthy Caucasians. RESULTS: There were no differences in TNFRSF1A allele frequencies between African Americans with RA and healthy African Americans. Allele frequencies were strikingly different, however, between healthy African Americans and healthy Caucasians: 0.13 versus 0.42 for -609T, 0.49 versus 0 for -580G, and 0.14 versus 0 for -383C. We identified 4 novel haplotypes defined by the 3 TNFRSF1A SNPs, the distribution of which was markedly different in healthy Caucasians and healthy African Americans (P = 0.000001 by chi-square test-. The frequencies of the TNFRSF1B 196 genotypes were similar in African Americans with RA and healthy African Americans but differed between healthy African Americans and healthy Caucasians (P = 0.05). CONCLUSION: Although we observed no associations between known TNFR SNPs or haplotypes and RA, significant racial differences were observed at both loci. Comparison of these data with other published frequencies of TNFRSF1A and TNFRSF1B genotypes according to race suggests that the distribution in African American, Caucasian, and Asian populations differs significantly. These striking racial/ethnic differences in TNFR SNP frequencies may influence the likelihood of familial RA, severe disease, or response to TNF inhibitors and may have important evolutionary implications.     

Treatment of chronic hepatitis C virus in African Americans with genotypes 2 and 3

Previous studies have documented that sustained virologic response (SVR) is significantly reduced in African Americans with chronic HCV genotype 1 following treatment with interferon and ribavirin when compared with Caucasians. The specific aim of the present retrospective study was to assess virologic response to interferon and ribavirin in African Americans with HCV genotypes 2 and 3. A review of our database identified 42 African Americans and 334 Caucasians with HCV genotypes 2 and 3. Patients coinfected with hepatitis B or human immunodeficiency virus, chronic renal failure, and recipients of an organ transplant were excluded. Thirty of the African Americans were treated with either standard interferon or peginterferon and ribavirin as initial treatment for chronic HCV. Ninety of the 334 Caucasians were matched to the African Americans with regards to genotype, cirrhosis, treatment regimen, sex, age, and body weight for comparison of virologic response. The proportion of patients with HCV genotype 2 was significantly greater (P < 0.001) in African Americans compared with Caucasians (81%vs 52%). End-of-treatment virologic response was observed in 94% of Caucasians compared with 80% in African Americans (P= 0.036). SVR was observed in 82% and 57% of Caucasians and African Americans, respectively (P= 0.012). Similar results were observed when patients who had been treated with only peginterferon and ribavirin were assessed. These results suggest that African Americans have a global defect in their ability to eradicate HCV infection following treatment with interferon and ribavirin which transcends across all genotypes.     

Single‐nucleotide polymorphisms in tumor necrosis factor receptor genes: Definition of novel haplotypes and racial/ethnic differences

Objective

To characterize allele frequencies of known single‐nucleotide polymorphisms (SNPs) in tumor necrosis factor receptor (TNFR) genes in African Americans with rheumatoid arthritis (RA), healthy African Americans, and healthy Caucasians.

Methods

One TNFRSF1B SNP (196 G/T) that influences susceptibility to familial RA in Caucasians and 3 SNPs in the 5′ flanking region of the TNFRSF1A gene (‐609G/T, ‐580A/G, and ‐383A/C) were genotyped in 108 African Americans with RA, 62 healthy African Americans, and 59 healthy Caucasians.

Results

There were no differences in TNFRSF1A allele frequencies between African Americans with RA and healthy African Americans. Allele frequencies were strikingly different, however, between healthy African Americans and healthy Caucasians: 0.13 versus 0.42 for ‐609T, 0.49 versus 0 for ‐580G, and 0.14 versus 0 for ‐383C. We identified 4 novel haplotypes defined by the 3 TNFRSF1A SNPs, the distribution of which was markedly different in healthy Caucasians and healthy African Americans (P = 0.000001 by chi‐square test‐. The frequencies of the TNFRSF1B 196 genotypes were similar in African Americans with RA and healthy African Americans but differed between healthy African Americans and healthy Caucasians (P = 0.05).

Conclusion

Although we observed no associations between known TNFR SNPs or haplotypes and RA, significant racial differences were observed at both loci. Comparison of these data with other published frequencies of TNFRSF1A and TNFRSF1B genotypes according to race suggests that the distribution in African American, Caucasian, and Asian populations differs significantly. These striking racial/ethnic differences in TNFR SNP frequencies may influence the likelihood of familial RA, severe disease, or response to TNF inhibitors and may have important evolutionary implications.

     

Influence of race in heart failure and cardiac transplantation: mortality differences are eliminated by specialized,comprehensive care

BACKGROUND: Differences in mortality are thought to exist between African Americans and Caucasians with heart failure. These differences may be due to a variety of factors, including differences in disease process, socioeconomic status, and access to health care. Additionally, little data exist on racial differences between these two groups after cardiac transplantation. This study examines a single center, urban experience in treating African Americans and Caucasians with heart failure and after cardiac transplantation. We hypothesize that treatment in a specialized, comprehensive heart failure/cardiac transplantation program results in similar survival between African Americans and Caucasians. METHODS: We retrospectively reviewed the Rush Heart Failure and Cardiac Transplant Database from July 1994 to August 2000. Variables analyzed in the cardiomyopathy patients included survival (until death, placement of left ventricular assist device or cardiac transplantation), number of hospitalizations per year, length of stay per year, and utilization of outpatient resources. Follow-up period was from initial visit to death, transplantation, or implantation of left ventricular assist device. In those who underwent cardiac transplantation, we examined rejection rates (cellular and humoral), rejection burden, hospitalization data, and 5-year survival. A subgroup bridged to cardiac transplantation with a left ventricular device was also analyzed. RESULTS: Seven hundred thirty-four cardiomyopathy patients were identified: 203 were African Americans and 531 were Caucasians. The etiology of cardiomyopathy was more commonly ischemic in Caucasians as compared to non-ischemic in African Americans (P <.01). African Americans had more admissions to the hospital per year compared with Caucasians, 1.2 +/- 2.1 versus.5 +/- 1.1 (P <.01) with longer length of stay per year, 1.4 +/- 25.2 days versus 4.4 +/- 14.3 days (P <.01). Utilization of outpatient resources was significantly higher in African Americans compared with Caucasians with more use of continuous inotropes (13% versus 6%, P <.01), intermittent inotropes (11% versus 5%, P <.01), and home nursing after hospital discharge (52% versus 32% of hospital discharges, P <.01). Survival by Kaplan-Meier analysis was comparable between the two groups (mean survival 1,470 +/- 72 days in African Americans versus 1521 +/- 46 days in Caucasians, log rank test [P =.6]). During this time, 30 African Americans and 73 Caucasians underwent cardiac transplantation. Fifty-three were bridged to transplantation with a left ventricular assist device (20 African Americans, 33 Caucasians). There were no differences in 5-year survival by Kaplan-Meier analysis despite higher peak preoperative panel reactive antibody levels in African Americans versus Caucasians (12% +/- 30% compared with 5% +/- 15%, P =.04), more overall treated rejection episodes per year in the African Americans (P <.01), as well as more posttransplant hospitalizations (2.2 +/- 1.2 times per year as compared with 1.7 +/- 2.1 times per year, P =.04). CONCLUSION: Delivery of care to heart failure patients in a comprehensive, specialized program results in similar survival regardless of race despite higher utilization of inpatient and outpatient resources. The finding that, after cardiac transplantation, African Americans do not have higher mortality rates, despite having higher rates of rejection overall and more hospitalizations, further supports the hypothesis that optimal care can improve outcomes despite unfavorable baseline clinical characteristics.     

24-Hour ambulatory blood pressure response to combination valsartan/hydrochlorothiazide and amlodipine/hydrochlorothiazide in stage 2 hypertension by ethnicity: the EVALUATE study

Several studies reported racial/ethnic differences in blood pressure (BP) response to antihypertensive monotherapy. In a 10-week study of stage 2 hypertension, 320/25 mg valsartan/hydrochlorothiazide (HCTZ) reduced ambulatory BP (ABP) significantly more effectively than 10/25 mg amlodipine/HCTZ. Results (post hoc analysis) are described in Caucasians (n=256), African Americans (n=79), and Hispanics (n=86). Compared with clinic-measured BP (no significant treatment-group differences in ethnic subgroups), least-squares mean reductions from baseline to week 10 in mean ambulatory systolic BP (MASBP) and mean ambulatory diastolic BP (MADBP) favored valsartan/HCTZ over amlodipine/HCTZ in Caucasians (-21.9/-12.7 mm Hg vs -17.6/-9.5 mm Hg; P=.0004/P<.0001). No treatment-group differences in MASBP/MADBP were observed in African Americans (-17.3/-10.6 vs -17.9/-9.5; P=.76/P=.40) or Hispanics (-17.9/-9.7 vs -14.2/-7.2; P=.20/P=.17). Based on ABP monitoring, valsartan/HCTZ is more effective than amlodipine/HCTZ in lowering ABP in Caucasians. In African Americans and Hispanics, both regimens are similarly effective.     

Effect of race on outcomes after allogeneic hematopoietic cell transplantation for severe aplastic anemia

We compared outcomes after hematopoietic cell transplantation in patients of African American (n = 84) and Caucasian (n = 215) descent with severe aplastic anemia. African Americans and Caucasians were matched for age, donor–recipient human leukocyte antigen match, graft type, and transplantation year. The median follow‐up of surviving patients was 5 years. In multivariate analysis, overall mortality risks were higher for African Americans compared to Caucasians (relative risk 1.73, P = 0.01). The 5‐year probabilities of overall survival adjusted for interval from diagnosis to transplantation, and performance score was 58% for African Americans and 73% for Caucasians. The day‐100 cumulative incidence of grade III–IV, but not grade II–IV acute graft‐versus‐host disease (GVHD), was higher in African Americans compared to Caucasians (29% vs. 13%, P = 0.006). Although the 5‐year cumulative incidence of chronic GVHD was not significantly different between the racial groups, African Americans were more likely to have extensive chronic GVHD compared to Caucasians (72% vs. 49%, P = 0.06). Survival differences between Caucasians and African Americans can be attributed to multiple factors. Our data suggest that some of the observed survival differences between Caucasians and African Americans may be explained by higher rates of acute GVHD and severity of chronic GVHD. Am. J. Hematol. 89:125–129, 2014. © 2013 Wiley Periodicals, Inc.     

Ethnic disparities among patients with systemic lupus erythematosus in South Carolina

OBJECTIVE: To evaluate whether ethnic disparities in mortality exist among hospitalized patients with systemic lupus erythematosus (SLE) in South Carolina, USA. METHODS: Administrative data were obtained on all SLE patients (ICD-9 code 710.0) hospitalized in South Carolina between 1996 and 2003. An SLE-specific comorbidity index validated as a predictor of hospital mortality was used as a measure of overall comorbidity. Cox proportional hazards models were used to compare mortality rates between Caucasians and African Americans. Post-hoc analyses focused on determining whether disparities were present across different risk strata. RESULTS: Of 6521 hospitalized patients with SLE (5728 female, 793 male), 1280 (19.6%) died. Annual mortality rates were 21.9% among Caucasians and 25.0% among African Americans. The comorbidity index score was significantly higher among African Americans [median 2.0 (interquartile range 0.0-4.0)] versus Caucasians [median 0.0 (IQR 0.0-3.0); p < 0.0001, Wilcoxon rank-sum test]; however, even after multivariate adjustment, African Americans had a 15% increased mortality risk (hazard ratio 1.15, 95% CI 1.02-1.29, p = 0.013). The disparity was strongest among those with less comorbidity (HR 1.39, 95% CI 1.05-1.81, p = 0.017). Among patients with low comorbidity index scores (n = 3485), the annual mortality rate was 8.1% among Caucasians and 9.7% among African Americans. No ethnic differences in mortality were seen for patients with higher comorbidity. CONCLUSION: In South Carolina, ethnic disparities in SLE mortality exist, predominantly among those with the least illness severity. Studies are planned to help clarify whether access and quality of care play a role.     

Sequence, haplotype, and association analysis of ADRbeta2 in a multiethnic asthma case-control study

RATIONALE: The comprehensive evaluation of gene variation, haplotype structure, and linkage disequilibrium is important in understanding the function of beta2-adrenergic receptor gene (ADRbeta2) on disease susceptibility, pulmonary function, and therapeutic responses in different ethnic groups with asthma. OBJECTIVES: To identify ADRbeta2 polymorphisms and haplotype structure in white and African American subjects and to test for genotype and haplotype association with asthma phenotypes. METHODS: A 5.3-kb region of ADRbeta2 was resequenced in 669 individuals from 429 whites and 240 African Americans. A total of 12 polymorphisms, representing an optimal haplotype tagging set, were genotyped in whites (338 patients and 326 control subjects) and African Americans (222 patients and 299 control subjects). RESULTS: A total of 49 polymorphisms were identified, 21 of which are novel; 31 polymorphisms (frequency > 0.03) were used to identify 24 haplotypes (frequency > 0.01) and assess linkage disequilibrium. Association with ratio (FEV1/FVC)2 for single-nucleotide polymorphism +79 (p < 0.05) was observed in African Americans. Significant haplotype association for (FEV1/FVC)2 was also observed in African Americans. CONCLUSIONS: There are additional genetic variants besides +46 (Gly16Arg) that are important in determining asthma phenotypes. These data suggest that the length of a poly-C repeat (+1269) in the 3' untranslated region of ADRbeta2 may influence lung function, and may be important in delineating variation in beta-agonist responses, especially in African Americans.     

Platelet functional implications of glycoprotein Ibalpha polymorphisms in African Americans

The platelet glycoprotein Ibalpha is crucial in the binding of platelets to Von Willebrand Factor within areas of high stress. A single nucleotide polymorphism of GP Ibalpha gives rise to the Ko(a) (HPA-2b) and the -5C Kozak polymorphism. The presence of these polymorphisms has been associated with an increased risk for atherothrombotic disease. The Ko(a) polymorphism has been shown to have a higher prevalence in African Americans compared to American Caucasians. However, very little is known regarding any functional consequences of these platelet polymorphisms in African Americans. We assessed the prevalence of the Ko and -5C Kozak polymorphisms in a population of both African American and American Caucasian patients with and without CAD and determined whether there were platelet functional consequences in both groups. We studied 99 patients of which 22 were African American and 77 were American Caucasian. Aggregations were performed and shear induced platelet plug formation was tested using a platelet function analyzer. The HPA-2b allele was significantly higher in African Americans when compared to Caucasians (P = 0.001). Genotype frequencies of the -5C Kozak polymorphism were not significantly different between the two groups. We found no differences in platelet aggregation in African Americans who were either heterozygous or homozygous for the HPA-2b allele or the -5C Kozak allele when compared to American Caucasians of the same category. We found no significant differences in PFA-100 testing. We conclude from our study that these polymorphisms do not lead to altered platelet function in African Americans.     

The frequency of the cholesteryl ester transfer protein-TaqI B2 allele is lower in African Americans than in Caucasians

Cholesteryl ester transfer protein (CETP) mediates the exchange of cholesteryl ester for triglyceride between high density lipoprotein (HDL) and very low density lipoprotein. The B2 allele of the TaqIB polymorphism located in the first intron of the CETP gene occurs with an allele frequency of about 0.40 in Caucasians and is associated with decreased CETP levels and activity and with higher HDL-cholesterol (HDL-C) levels in this racial group. We hypothesized that the higher levels of HDL-C seen in African Americans compared with Caucasians could be in part explained by a higher frequency of the TaqI B2 allele. We determined the distribution of this polymorphism in a total of 395 African Americans and 362 Caucasian ascertained as two independent cohorts: one of healthy volunteers (NORM) and the other of patients undergoing cardiac catheterization (CATH). Of the 244 NORM-African Americans studied, 56% were B1B1, 37% B1B2 and 7% B2B2, compared with the 224 NORM-Caucasians of which 33% were B1B1, 45% B1B2 and 22% B2B2. In the CATH-African American group (n=151) 51% were B1B1, 41% B1B2 and 8% B2B2 compared with 35% CATH-Caucasians B1B1, 54% B1B2 and 11% B2B2. The frequency of the B2 allele in the Caucasian subjects in both cohorts was similar to that reported in the literature. The frequency of the B2 allele was significantly lower in African Americans than in Caucasians in the NORM group (0.26 vs 0.44; chi(2)=36.5, P<0.001) and in the CATH group (0.28 vs 0.38, chi(2)=4.7, P=0.01). Carriers of the B2 allele had higher HDL-C levels compared with B1B1 subjects in Caucasians (NORM: 57 vs 53 mg/dl, P=0.035; CATH: 47 vs 42 mg/dl, P=0.049) and in CATH-African Americans (48 vs 43 mg/dl, P=0.028), but not in NORM-African Americans (55 vs 54 mg/dl, P=0.494). There were no other significant associations between this polymorphism and other lipids and lipoproteins in the subjects studied. These results suggest that, in contrast to our hypothesis, the B2 allele of the TaqIB polymorphism is less frequent in African Americans compared with Caucasians and that this polymorphism is unlikely to contribute to the higher levels of HDL-C reported in the African American population.     

Transferrin receptor-2 (TFR2) mutation Y250X in Alabama Caucasian and African American subjects with and without primary iron overload

Most cases of hemochromatosis are associated with mutations of the HFE gene on Ch6p. In southern Italy and central Alabama, the percentages of patients with hemochromatosis who have "atypical" HFE genotypes (defined as lack of C282Y homozygosity, C282Y/H63D compound heterozygosity, or H63D homozygosity) are relatively great. A mutation of the transferrin receptor-2 gene (TFR2; exon 6, nt 750 C --> G, replaces TAC with stop signal TAG; Y250X) on Ch7q22 was recently identified in two Sicilian families with HFE mutation-negative hemochromatosis. We wanted to estimate the frequency of this mutation in persons from central Alabama. We evaluated Caucasian hemochromatosis probands with atypical HFE genotypes and African Americans with primary iron overload. We also studied control Caucasians, including persons of southern Italian/Sicilian heritage, and control African Americans. Analysis of genomic DNA was performed using a PCR-sequence-specific priming assay and positive control specimens from Sicilian hemochromatosis subjects heterozygous and homozygous for Y250X. Among Alabama subjects, this allele was not detected in 113 Caucasians, including 21 hemochromatosis probands with atypical HFE genotypes and 92 normal control subjects (including 27 of southern Italian/Sicilian descent). In African Americans, Y250X was not detected in 20 index cases with primary iron overload or in 274 unrelated control subjects. We conclude that Y250X is uncommon in Caucasians with hemochromatosis associated with atypical HFE genotypes, in African Americans with primary iron overload, and in the general Caucasian and African American population subgroups in central Alabama.     

African Americans with genotype 1 treated with interferon for chronic hepatitis C have a lower end of treatment response than Caucasians

African Americans as a group have a higher incidence of chronic hepatitis C (CHC) than Caucasians but are often under‐represented in clinical trials used to define response rates to interferon therapy. The aim of this study was to compare African Americans with Caucasians with respect to end‐of‐treatment response to interferon. This retrospective study had 61 African Americans and 49 Caucasians with CHC. All patients were treated for at least 12 weeks with interferon‐α2b (Intron A) thrice weekly. End‐of‐treatment response was defined as three consecutive nondetectable HCV RNA measurements at least 1 month apart. Sustained response was defined as a negative serum HCV RNA 6 months after end of treatment. Of the 110 patients, 19 achieved an end‐of‐treatment response (17%) but only four achieved a sustained response (4/110=4%). Of the patients achieving a sustained response, one was genotype 1 (male Caucasian), three were genotype 2/3 with four patients having no follow‐up information. The end‐of‐treatment response was 7% for patients with genotype 1 and 71% for genotype non‐1 (P < 0.005 for genotype non‐1). The end‐of‐treatment response was significantly higher in Caucasians (14/49=31%) compared with African Americans (5/61=8%; P < 0.05). A lower response rate in African Americans with genotype 1 in contrast to Caucasians was the primary reason for the difference in end‐of‐treatment response (1/45=2% vs. 5/33=15%, P < 0.05). Hence, interferon treatment resulted in a poor sustained response rate in the group of patients representative of the urban populations with the highest prevalence of hepatitis C. A genotype other than type 1 was the strongest predictor of end‐of‐treatment response in patients treated but over 86% of patients in this urban clinic were genotype 1. Caucasians were more likely to respond than African Americans, especially in patients with genotype 1.     

The association of race and ethnicity with disease expression in male US veterans with rheumatoid arthritis

OBJECTIVE: To examine the association of race/ethnicity with measures of disease activity and severity among male US veterans with rheumatoid arthritis (RA). METHODS: Measures of disease activity and severity were examined in a group of US veterans (n = 573) with RA, comparing measures in African American men (n = 79) with Caucasian men (n = 494). Dichotomous variables were compared using logistic regression while continuous variables were examined using linear regression, adjusting for the effects of age, disease duration, and smoking status. RESULTS: Compared to Caucasians, African Americans were slightly younger (65.0 vs 67.1 yrs; p = 0.09) at enrollment and had a similar age at disease onset (50.5 vs 50.6 years; p = 0.98). After adjusting for age, disease duration, and smoking status, there were no differences based on race/ethnicity in rheumatoid factor positivity, the presence of radiographic changes, physical functioning, swollen joint counts, Disease Activity Score (DAS28), or global well-being scores. In contrast, African Americans were about 50% less likely than Caucasians with RA to have subcutaneous nodules (adjusted OR 0.51, 95% CI 0.30-0.86) and had lower tender joint counts (p = 0.007), associations that were attenuated and not significant with further adjustment for collection site. CONCLUSION: With the possible exception of lower rates of rheumatoid nodules and lower tender joint counts in African Americans, there is little evidence to support the existence of important racial/ethnic differences in RA disease expression between African American and Caucasian men.     

Differential effects of ramipril on ambulatory blood pressure in African Americans and Caucasians

BACKGROUND: On average, angiotensin-converting enzyme inhibitors produce less office blood-pressure lowering in African Americans compared with Caucasians. Past studies did not compare daytime and nighttime ambulatory blood-pressure responses to angiotensin-converting enzyme inhibitors in African Americans and Caucasians. METHODS: We measured the office and ambulatory blood-pressure response to 8 weeks of a fixed dose of 10 mg daily of the angiotensin-converting enzyme inhibitor ramipril in a cohort of 72 African Americans and 89 Caucasians. RESULTS: Ramipril lowered age-adjusted daytime ambulatory systolic blood pressure 6 mm Hg and diastolic blood pressure 3 mm Hg less in African Americans compared with Caucasians (both P=.02). This difference persisted after adjusting for baseline blood pressure, body mass index, urine sodium and potassium, plasma aldosterone, and other covariates. Despite the difference in mean response, there was a 72% overlap in daytime blood-pressure response to ramipril between African Americans and Caucasians. Among Caucasians, ramipril lowered systolic blood pressure 2 mm Hg less during nighttime compared with daytime, whereas among African Americans, blood pressure lowering was equivalent during day and night. Nighttime blood-pressure response to ramipril did not differ significantly between African Americans and Caucasians. CONCLUSIONS: Ramipril was more effective in lowering daytime blood pressure in Caucasians compared with African Americans, but appreciable differences in response did not persist at night. Despite the small difference in mean response between groups, the majority of African Americans and Caucasians had a similar blood-pressure response to a fixed dose of ramipril.     

Racial differences in the influence of body size on ambulatory blood pressure in youths

BACKGROUND: African Americans have higher night-time blood pressures than Caucasians do despite their having similar daytime blood pressures. It is well established that body size is related to casual blood pressure. OBJECTIVE: To examine the influence of body size on racial differences in patterns of ambulatory blood pressure. METHODS: Ambulatory blood pressure recordings were performed on 292 healthy children and adolescents (148 African Americans and 144 Caucasian) aged 10-18 years (mean 13+/-2 years). These blood pressures were related to height, weight, body surface area, and body mass index in separate regression models that also included race, sex, and age as factors. RESULTS: The race-by-height interaction was significant for night-time systolic blood pressure (P<0.02), with a significant relationship for African Americans (P<0. 0001), but not for Caucasians. The race-by-weight interaction was significant for night-time systolic blood pressure (P<0.04), also with a greater relationship for African Americans (P<0.0001) than for Caucasians (P<0.03). In addition, the race-by-weight interaction was significant for night-time diastolic blood pressure (P<0.04), with a significant relationship for African Americans (P<0.01), but not for Caucasians. Finally, the race-by-body-surface-area interaction was significant for night-time diastolic blood pressure (P<0.05), again with a significant relationship for African Americans (P<0.02) but not for Caucasians. CONCLUSION: Differences in the relationship between body size and blood pressure contribute to the racial differences in patterns of ambulatory blood pressure and should be considered when evaluating patterns of blood pressure in African American youths.     

Predictive factors associated with severity of asthma exacerbations

Several factors have been accused for asthma exacerbations, however, very few studies have evaluated whether different factors predict severity of asthma exacerbation. We aimed to determine the predictive factors for severity of asthma exacerbation. Retrospective analysis of data on 93 patients visited our emergency-department because of asthma exacerbation was reviewed. Hospitalization in intensive care unit and/or intubation because of asthma was accepted as the criteria for severe exacerbation. Logistic regression analysis estimated the strength of association of each variable, potentially related to severe asthmatic exacerbation, with severe/very severe as compared to mild/moderate asthmatic exacerbation. Independent variables included in the analysis were age, sex, smoking history, inhaler steroid using, compliance with medication, chronic asthma severity, presence of additional atopic diseases, prick test positivity, provocative factors, number of short-acting beta(2)-agonist using, number of visits to emergency department for asthma over one year period, previous severe exacerbation, pulmonary functions, and blood eosinophil count. 20 were severe/very severe and 73 mild/moderate asthmatic exacerbation. Frequent using of short-acting beta(2)-agonist (OR= 1.5, 95% CI= 1.08-5.3, p= 0.003), noncompliance with medication (OR= 3.6, 95% CI= 1.3-9.9, p= 0.013), previous severe asthmatic exacerbation (OR= 3.8, 95% CI= 1.48-10.01, p= 0.005) and recent admission to hospital (OR= 2.9, 95% CI= 1.07-8.09, p= 0.037) were found to be predictive factors for severe asthmatic exacerbation. Different predictive factors, in particular frequent using of short-acting beta(2)-agonist and noncompliance with medication may be associated with severe asthma exacerbations compared to milder exacerbations. This suggests different mechanisms are responsible for severity of asthma exacerbation.     

Long QT Syndrome in African‐Americans

Background: We evaluated the risk factors and clinical course of Long QT syndrome (LQTS) in African‐American patients. Methods: The study involved 41 African‐Americans and 3456 Caucasians with a QTc ≥ 450 ms from the U.S. portion of the International LQTS Registry. Data included information about the medical history and clinical course of the LQTS patients with end points relating to the occurrence of syncope, aborted cardiac arrest, or LQTS‐related sudden cardiac death from birth through age 40 years. The statistical analyses involved Kaplan‐Meier time to event graphs and Cox regression models for multivariable risk factor evaluation. Results: The QTc was 29 ms longer in African‐Americans than Caucasians. Multivarite Cox analyses with adjustment for decade of birth revealed that the cardiac event rate was similar in African‐Americans and Caucasians with LQTS and that beta‐blockers were equally effective in reducing cardiac events in the two racial groups. Conclusions: The clinical course of LQTS in African‐Americans is similar to that of Caucasians with comparable risk factors and benefit from beta‐blocker therapy in the two racial groups. Ann Noninvasive Electrocardiol 2010;15(1):73–76