Arterial oxygen saturation in Tibetan and Han infants born in Lhasa, Tibet

BACKGROUND

Reduced oxygen availability at high altitude is associated with increased neonatal and infant mortality. We hypothesized that native Tibetan infants, whose ancestors have inhabited the Himalayan Plateau for approximately 25,000 years, are better able to maintain adequate oxygenation at high altitude than Han infants, whose ancestors moved to Tibet from lowland areas of China after the Chinese military entered Tibet in 1951.

METHODS

We compared arterial oxygen saturation, signs of hypoxemia, and other indexes of neonatal wellbeing at birth and during the first four months of life in 15 Tibetan infants and 15 Han infants at 3658 m above sea level in Lhasa, Tibet. The Han mothers had migrated from lowland China about two years previously. A pulse oximeter was placed on each infant's foot to provide measurements of arterial oxygen saturation distal to the ductus arteriosus.

RESULTS

The two groups had similar gestational ages (about 38.9 weeks) and Apgar scores. The Han infants had lower birth weights (2773 +/- 92 g) than the Tibetan infants (3067 +/- 107 g), higher concentrations of cord-blood hemoglobin (18.6 +/- 0.8 g per deciliter, vs. 16.7 +/- 0.4 in the Tibetans), and higher hematocrit values (58.5 +/- 2.4 percent, vs. 51.4 +/- 1.2 percent in the Tibetans). In both groups, arterial oxygen saturation was highest in the first two days after birth and was lower when the infants were asleep than when they were awake. Oxygen saturation values were lower in the Han than in the Tibetan infants at all times and under all conditions during all activities. The values declined in the Han infants from 92 +/- 3 percent while they were awake and 90 +/- 5 percent during quiet sleep at birth to 85 +/- 4 percent while awake and 76 +/- 5 percent during quiet sleep at four months of age. In the Tibetan infants, oxygen saturation values averaged 94 +/- 2 percent while they were awake and 94 +/- 3 percent during quiet sleep at birth and 88 +/- 2 percent while awake and 86 +/- 5 percent during quiet sleep at four months. Han infants had clinical signs of hypoxemia--such as cyanosis during sleep and while feeding--more frequently than Tibetans.

CONCLUSIONS

In Lhasa, Tibet, we found that Tibetan newborns had higher arterial oxygen saturation at birth and during the first four months of life than Han newborns. Genetic adaptations may permit adequate oxygenation and confer resistance to the syndrome of pulmonary hypertension and right-heart failure (subacute infantile mountain sickness).

Prognosis for South Asian and white patients newly admitted to hospital with heart failure in the United Kingdom: historical cohort study

OBJECTIVES

To compare patterns of admission to hospital and prognosis in white and South Asian patients newly admitted with heart failure, and to evaluate the effect of personal characteristics and comorbidity on outcome.

DESIGN

Historical cohort study.

SETTING

UK district health authority (population 960,000).

PARTICIPANTS

5789 consecutive patients newly admitted with heart failure.

MAIN OUTCOME MEASURES

Population admission rates, incidence rates for first admission with heart failure, survival, and readmission rates.

RESULTS

When compared with the white population, South Asian patients had significantly higher age adjusted admission rates (rate ratio 3.8 for men and 5.2 for women) and hospital incidence rates (2.2 and 2.9). Among 5789 incident cases of heart failure, South Asian patients were younger and more often male than white patients (70 (SD 0.6) v 78 (SD 0.1) years and 56.5% (190/336) v 49.3% (2494/5057)). South Asian patients were also more likely to have previous myocardial infarction (10.1% (n = 34) v 5.5% (n = 278)) or concomitant myocardial infarction (18.8% (n = 63) v 10.7% (n = 539)) or diabetes (45.8% (n = 154) v 16.2% (n = 817), all P < 0.001). A trend was shown to longer unadjusted survival for both sexes among South Asian patients. After adjustment for covariables, South Asian patients had a significantly lower risk of death (hazard ratio 0.82, 95% confidence interval 0.68 to 0.99) and a similar probability of death or readmission (0.96, 0.81 to 1.09) compared with white patients.

CONCLUSIONS

Population admission rates for heart failure are higher among South Asian patients than white patients in Leicestershire. At first admission South Asian patients were younger and more often had concomitant diabetes or acute ischaemic heart disease than white patients. Despite major differences in personal characteristics and risk factors between white and South Asian patients, outcome was similar, if not better, in South Asian patients.

Outcomes by Gender in the African-American Heart Failure Trial

OBJECTIVES

Previous trials testing isosorbide dinitrate/hydralazine (I/H) were performed in all-male study cohorts, and thus the efficacy of I/H in women was unknown; 40% of the A-HeFT (African-American Heart Failure Trial) cohort were women. We therefore compared outcomes by gender and treatment.

BACKGROUND

Fixed-dose combined I/H significantly reduced mortality and heart failure hospitalizations and improved quality of life in 1,050 black patients with heart failure treated with background neurohormonal blockade. Previous trials testing I/H were done in all-male study cohorts, and thus the efficacy of I/H in women was unknown.

METHODS

Baseline characteristics and medications were compared between men and women by I/H and placebo treatment. Survival, time to first heart failure hospitalization, change in quality of life, and event-free survival were compared by gender and treatment.

RESULTS

At baseline, women had lower hemoglobin and creatinine levels; less renal insufficiency; and higher body mass indexes, diabetes prevalence, and systolic blood pressures; but worse quality of life scores. All-cause mortality was lower in women than in men treated with I/H but without significant treatment interaction by gender. The primary composite score, which weighted mortality, first heart failure hospitalization, and change in quality of life at 6 months, was similarly improved by I/H in men and women. First heart failure hospitalization and event-free survival (time to death or first heart failure hospitalization) were similarly improved in both genders.

CONCLUSIONS

Fixed-dose I/H improved heart failure outcomes in both men and women in A-HeFT. The I/H significantly improved the primary composite score and event-free survival as well as reduced the risk of first heart failure hospitalizations similarly in both genders. The I/H had a slightly greater mortality benefit in women, but without a significant treatment interaction by gender.

Prevalence of self-reported heart failure among US adults: results from the 1999 National Health Interview Survey

OBJECTIVE

The objective of the present study was to determine the prevalence of self-reported heart failure among US adults.

METHODS

Data from the 1999 National Health Interview Survey were analyzed. A total of 30,801 sampled adults aged >or=18 years were given a list of major medical conditions, which included heart failure (HF), and asked if they had ever been told by a doctor or other health professional that they had any of the conditions. Analyses were conducted with the use of SUDAAN software to account for the complex sample design.

RESULTS

An estimated 2.4 million adults had been told by a doctor or other health professional that they had HF. The prevalence of self-reported HF for age groups 18 to 39, 40 to 64, 65 to 74, and 75 to 105 years were 0.1%, 1.1%, 3.6%, and 5.5%, respectively. HF was most prevalent among ever-smokers, obese persons, and persons aged >or=65 years. No difference was found in the prevalence of self-reported HF between black and white persons. The most common comorbid conditions for those with HF were hypertension, coronary heart disease, and diabetes. Compared with those without HF, the elderly persons with HF were 8 times as likely to have severe mobility difficulties and 2 to 3 times as likely to have severe depression. Half of the elderly persons with HF had been hospitalized, visited an emergency room, or had >10 clinic visits in the past year. Black patients were more likely than white patients to have been unable to pay for prescription medicine and to have seen a medical specialist during the past year.

CONCLUSIONS

This nationally representative survey indicates that an estimated 2.4 million adults had been told by a doctor or other health professional that they had heart failure. Black patients with HF were less likely than white patients to have received the needed care.

Isosorbide dinitrate and hydralazine hydrochloride: a review of efficacy and safety

In the USA alone, there are over 5,000,000 people diagnosed with heart failure. A disproportionate number of African-Americans are affected by this disease, with increased morbidity and mortality, yet they are tremendously under-represented in clinical trials. Several drugs have been approved for use in heart failure based on clinical trials, with percentages of African-American subjects as low as 1%. In the African-American Heart Failure Trial the use of BiDil, a drug combining isosorbide dinitrate and hydralazine hydrochloride, demonstrated a 43% decrease in overall mortality and a 39% decrease in first hospitalization. The combination consists of 20 mg of isosorbide and 37.5 mg hydralazine hydrochloride in a fixed dose that functions as a nitric oxide enhancer and an antioxidant, and helps to prevent tolerance to the prolonged use of nitrate. The hemodynamic effects of the combination drug in heart failure includes increased cardiac output. The US Food and Drug Administration approved the combination of isosorbide dinitrate based on the African-American Heart Failure Trial. Further clinical trials utilizing isosorbide dinitrate will hopefully determine the benefit of this combination in a larger population, including caucasians and other racial/ethnic groups.

Drug development and the importance of ethnicity: lessons from heart failure management and implications for hypertension

Heart failure is a common condition, associated with both poor prognosis and poor quality of life. In contrast to all other cardiovascular diseases, the prevalence of heart failure is increasing in the western world, and is likely to continue to do so as the population ages. In the UK, a significant proportion of patients with heart failure come from South Asian and African Caribbean ethnic groups. A large body of evidence exists that there may be epidemiological and pathophysiological differences between patients with heart failure from different ethnic groups. Treatments such as ACE inhibitors, which are now part of standard heart failure therapy, have an evidence base consisting of trials in patients of almost exclusively white ethnicity. Such treatments may not be equally effective in patients from other ethnic groups. This review will discuss the current evidence for heart failure management with respect to ethnicity, and consider the implications for future drug development and implications for antihypertensive therapy.

Efficacy of community-based multidisciplinary disease management of chronic heart failure

INTRODUCTION

A multidisciplinary disease management (DM) programme in chronic heart failure (CHF) improves clinical outcome. The efficacy of such a programme in a heterogeneous Asian community is not well established. Therefore, we undertook the evaluation of the efficacy of the multidisciplinary community-based DM CHF programme.

METHODS

This was a prospective study involving 154 patients (54 percent male) with a primary diagnosis of CHF, New York Heart Association functional class III/IV CHF, with left ventricular ejection fraction (LVEF) less than 40 percent. The mean age was 65 +/- 12 years and mean LVEF was 27 +/- 9 percent. We evaluated CHF hospitalisation, quality of life, activity status and quality of care (percentage of patients who received ACE inhibitors/angiotensin receptor blockers (ARB) and beta blockers after a period of six months.

RESULTS

At six months, there was improvement in the quality of life and activity status (p < 0.001). ACE inhibitors/ARB were maintained in 97 percent of the patients and there was an increased usage of beta blockers (p-value equals 0.001). The rate of CHF hospitalisation was reduced by 68 percent (p-value is less than 0.001) and there was no mortality.

CONCLUSION

The multidisciplinary DM of CHF in a heterogeneous Asian community showed significant improvement in quality of life, quality of care and reduction in CHF hospitalisation.

[Neuromyelopathy in the population of Noir-marron of Saint-Laurent du Maroni in French Guiana]

The neurological observations have been reported at André Bouron Hospital of Saint-Laurent du Maroni and at General Hospital of Cayenne during a period of 5 years. All patients belonged to the "Noir Marron" ethnic group and lived in the area of Saint-Laurent. There were six women and four men, aged 15-35 years. Neurological symptoms were isolated or associated to other organ failure. Neurological manifestations included retrobulbar optic neuropathy, spastic paraparesis, sensitive ataxia and cerebellar ataxia, psychiatric symptoms were observed. Other organs affected were cardiovascular, digestive, cutaneous or endocrinologic (thyroid). Diet consist mainly in cassava. Thiamin deficiency has been observed several times. Improvement of neurological deficits following thiamin administration points towards Thiamin as an etiological factor. Ethnological specificity of Saint-Laurent area may explain that such neurological manifestation have not been observed in the rest of the department.

Heart failure hospitalisations and deaths in New Zealand: patterns by deprivation and ethnicity

AIM

To examine the association between socioeconomic deprivation and heart failure outcomes in Maori and non-Maori New Zealanders.

METHODS

Retrospective analysis of heart failure mortality and hospital admissions among Maori and non-Maori aged 45 year and older assigned to small area deprivation (NZDep91/96) during the period 1988-1998.

RESULTS

Deprivation was associated with an increase in risk of heart failure deaths and hospitalisations for both Maori and non-Maori. Within all socioeconomic strata, this risk was higher for Maori than non-Maori.

CONCLUSION

Socioeconomic deprivation was associated with an increased chance of death and hospitalisation from heart failure in New Zealand. Maori disparities in heart failure outcomes do not simply reflect differences in deprivation, however, and further studies are needed to explain the influence of other determinants such as lifecourse and lifestyle exposures, neighbourhood characteristics, access to medical care, and racism.

Examining healthcare disparities in a disease management population

OBJECTIVES

To examine whether racial disparities in healthcare exist in a heart failure population and to estimate the impact of disease management (DM) on any identified disparities.

STUDY DESIGN

Before-after cohort study.

PATIENTS AND METHODS

A total of 2619 high-risk heart failure patients (2129 whites and 490 blacks) who participated in a DM program for at least 90 days between July 2001 and July 2003 were examined. Analysis was stratified by sex and age (< 65 years and > or = 65 years). Functional status as measured by the New York Heart Association (NYHA) classification system and mental and physical quality of life (QOL) as measured by the 8-Item Short-Form Health Survey were used to assess disparities between races.

RESULTS

At baseline, 33.7% of black versus 44.3% of white older women and 32.6% of black versus 48.5% of white older men were at NYHA level I or II (P < .01 and P = .005, respectively). At the most current measurement, the differences between the cohorts disappeared. Results were similar for the younger male, but not the younger female, cohort. The only QOL disparities at baseline were in favor of blacks. Both races had significant increases in mean mental and physical QOL scores (P < .001) after involvement in the DM program.

CONCLUSIONS

Disparities in QOL were not observed between blacks and whites at baseline or over the course of the study. Disparities in functional status at baseline disappeared over time, implying that DM may help reduce disparities and maintain equity in healthcare outcomes.