Abstract
Less than 40% of potentially eligible patients receive implantable cardioverter-defibrillator therapy. Amongst those who do, there is a significant bias towards white males, researchers have found.
Discrepancy in heart defibrillator distribution disadvantages women and black people
Sudden cardiac death is a serious problem, killing 350,000 people in the USA every day. Implantable cardioverter-defibrillator (ICD) therapy, introduced approximately 20 years ago, was designed to treat those most at risk. However, two recent studies published in the Journal of the American Medical Association have highlighted that, despite the palpable benefits of ICD therapy, less than 40% of potentially eligible patients actually receive the treatment. In addition, there is a discrepancy in treatment between men and women, as well as with racial groups.
Adrian Hernandez, an author of both of the studies, has highlighted that this is not a novel concern. “In the mid 1990s, the Institute of Medicine noted that newer technologies and innovative therapies were more likely to be used in men versus women and in whites versus blacks consistently, and recommended that the health-care system needs to figure out how to deliver new therapies more efficiently and equitably”. He added, “This is a case example where we still haven't done that”.
The first of the two studies utilized Medicare patient data collected between 1991 and 2005. Patients for sudden cardiac death, aged 65 years or above, who fulfilled either primary or secondary prevention criteria, were analyzed. Of the primary prevention patients, men were shown to be 3.2-times more likely than women to receive ICD therapy and 2.4-times more likely in the secondary prevention cohort. In addition, when white and black patients were compared, the results demonstrated a bias towards the former.
“We're not talking about a small difference. The magnitude is striking”, commented Lesley Curtis of Duke University School of Medicine (NC, USA), also an author of the studies.
The second study considered primary prevention only and involved observational analysis of 13,034 patients admitted with heart failure and left ventricular ejection fraction of 30% or less who had been discharged alive. Results showed that only 35.4% of eligible patients received ICD treatment, with a significant difference between groups: 28.2% of black women received treatment compared with 29.8% of white women, while 33.4% of black men had ICD therapy compared with 43.6% of white men.
After researchers made the necessary adjustments for hospital factors and patient characteristics, it was found that, compared with white men, black men were 27% less likely to receive ICD, white women were 38% less likely and black women were 44% less likely, the lowest figure of all the groups.
There may be any number of reasons underlying these discrepancies. However, there is some consensus in the belief in education as a primary method for rectifying this inequity. Wojchiech Zareba, a professor of medicine at the University of Rochester Medical Center (NY, USA), explained, “We do not know the reason for the discrepancy but, in my view, one predominant reason is a lot of education needs to be done among physicians to convince them. People don't know enough and we should have more advertisements during the evening news on sudden cardiac death in women rather than on asthma drugs or breast cancer”.
A similar belief was voiced by Hernandez: “We need to promote awareness about the use of defibrillators, we need to figure out what are the barriers for use and, specifically, what are barriers for use in women and minorities and how to address these barriers”.
Sources: Curtis LH, Al-Khatib SM, Shea AM et al.: Sex differences in the use of implantable cardioverter-defibrillators for primary and secondary prevention of sudden cardiac death. JAMA 298(13), 1517–1524 (2007).
Hernandez AF, Fonarow GC, Liang L et al.: Sex and racial differences in the use of implantable cardioverter-defibrillators among patients hospitalized with heart failure. JAMA 298(13), 1525–1532 (2007).
in brief…
Patt DA, Duan Z, Fang S, Hortobagyi GN, Giordano SH: J. Clin. Onc. 25(25), 3871–3876 (2007). This observational study, using data obtained between 1992 and 2002, suggests that older women who receive adjuvant chemotherapy in the treatment of breast cancer are at an increased risk of developing acute myeloid leukemia. Of a total of 64,71 5 patients who were studied, 10,130 received adjuvant therapy and 54,585 did not. The age range of patients was 66–104 years (median: 75.6 years), with a mean follow-up time of 54.8 months. Researchers calculated the risk of developing acute myeloid leukemia after 10 years to be 1.8% in women who had been treated with chemotherapy, compared with 1.2% for those who had not undergone the treatment.
Prentice RL, Thomson CA, Caan B et al.: J. Natl Cancer Inst. 99(20), 1534–1543 (2007).
This randomized, controlled trial of 48,835 postmenopausal women, followed for an average of 8.1 years, suggests that a low-fat diet may lessen the risk of ovarian cancer. A total of 19,541 women completed dietary modification (DM), while 29,284 women continued with their usual diet. DM intervention aimed to reduce total fat consumption to 20% of energy intake while increasing intake of vegetables, fruits and grains. Incidence of invasive cancers was measured by weighted log-rank tests. The results demonstrated the DM cohort to be at a lower risk of ovarian cancer. The overall ovarian cancer hazard ratio was not statistically significant but did show a correlation with increase of intervention.
Neilson LM, Zhu J, Xie J et al.: Mol. Endrocrinol. 21 (9), 2218–2232 (2007).
This study suggests that inhibitors of Jak1 may be useful in the treatment of breast cancer, owing to the discovery of a new mode of action for prolactin signaling. Most breast cancers express a large number of prolactin receptors. Researchers discovered that prolactin receptor-induced tyrosine phosphorylation occured in breast cancer cell lines, including T47, MCF7 and SKBR3. However, in noncancerous breast epithelial lines, prolactin did not activate Jak1. The study showed that when Jak1 protein expression was experimentally disrupted in breast cancer cells, prolactin signaling through Stat3 and ERK was prevented. Previously, it has been thought that prolactin signaled only through Jak2. The discovery of a new prolactin signaling pathway suggests a mechanism in cancer cells that supports further tumor cell growth.
Study reveals association between panic attacks and myocardial infarction
Researchers from the Massachusetts General Hospital, Boston (MA, USA) have documented an association amongst postmenopausal women between panic attacks and risk of cardiovascular morbidity and mortality.
The study, published in the Archives of General Psychiatry, involved observation of 3369 healthy, postmenopausal women aged 51–81 years, with a mean follow-up of 5.3 years. A total of 10% had experienced panic attacks in the 6 months prior to the study.
Results of the study showed that experience of one or more panic attacks was associated with a fourfold increase in the risk of myocardial infarction, as well three-times the risk of having a heart attack or stroke. The risk of dying from any cause was doubled in those women who had experienced panic attacks.
‘These results suggest that panic anxiety is a marker for increased risk of cardiovascular morbidity and mortality among postmenopausal women’, conclude the study's authors. Source: Smoller JW, Pollack MH, Wassertheil-Smoller S: Panic attacks and risk of incident cardiovascular events among postmenopausal women in the Women's Health Initiative observational study. Arch. Gen. Psychiatry 64(10), 1153–1160 (2007).
Concerns raised over consequences of cesarean delivery
A new study, published in the British Journal of Obstetrics and Gynaecology, has investigated a number of risk factors involved in uterine rupture. Women who had previously undergone a cesarean delivery were highlighted as most at risk, exhibiting 50-times the rate of uterine rupture in subsequent vaginal births compared with women who had delivered vaginally.
Philip Steer, British Journal of Obstetrics and Gynaecology Editor in Chief, commented on why the risks resulting from cesarean births are such a concern: “The rate of Caesarean deliveries continues to increase in the developed world which means that a growing percentage of women will experience birth following a previous Caesarean section”.
“Although uterine rupture is a relatively rare occurrence, the consequences can be devastating”, warned Steer.
Melissa Kaczmarczyk of Emory University (GA, USA), a researcher involved in the study, concluded that the risks must be clearly laid out for patients and that careful management during labor is required for those at higher risk.
Source: Kaczmarczyk M, Sparén P, Terry P, Cnattingius S: Risk factors for uterine rupture and neonatal consequences of uterine rupture: a population-based study of successive pregnancies in Sweden. BJOG 114(10), 1208–1214 (2007).
If you have newsworthy information, please contact: Charlotte Barker, Commissioning Editor, Women's Health, Future Medicine Ltd, Unitec House, 2 Albert Place, Finchley Central, London N3 1QB, UK
Location of breast density gene is revealed
Increased mammographic density (MD) is a recognized risk factor for breast cancer, with scientists estimating the risk to be heightened by up to five-times. A study published in the American Association for Cancer Research has provided new evidence to suggest that the trait is genetically influenced.
In the first study of its kind, researchers examined DNA from 899 relatives, including 756 women and 133 men, from 89 different families. A genome-wide linkage scan was conducted to ascertain genes that may influence mammographic density. Compelling evidence of genetic influence on mammographic density was found, implicating a region of approximately 45 genes on chromosome 5p.
Initially, three regions of the genome were highlighted by DNA markers as having a potential association with MD. Researchers examined these regions further by including a number of additional, more densely spaced, markers, which led to the identification of the region on chromosome 5p. They believe that this region may be responsible for up to 22% of the variation in MD. ‘One or more of the 45 candidate genes in this region could explain a large proportion of mammographic breast density, and potentially, breast cancer’, stated study investivator Celine Vachon.
‘At this point, we have not identified a gene or genes for breast density but a promising location to investigate further’, she commented. ‘Identification of genes for breast density will improve our understanding of how breast density influences breast cancer development in women.’
If the gene is identified, there is scope for its role as a predictive marker. Scientists may be able to target the gene with agents able to reduce breast density, thereby reducing the risk of breast cancer.
The gene encoding the prolactin receptor, found within the region in question on chromosome 5p, has been highlighted as potentially contributing to breast density. Research conducted prior to this study has demonstrated an association, in postmenopausal women, between prolactin levels and mammographic density.
Source: Vachon CM, Sellers TA, Carlson EE et al.: Strong evidence of a genetic determinant for mammographic density, a major risk factor for breast cancer. Cancer Res. 67(17), 8412–8418 (2007).
Study suggests neuroprotective role of estrogen
Unilateral or bilateral oophorectomy, prior to onset of menopause, causes increased risk of dementia or cognitive impairment, recent research suggests. The study, reported in a recent issue of Neurology, took place over 37 years and followed 1500 women who had undergone the surgery.
Lead author of the study, Walter Rocca, from the Mayo Clinic in Rochester (MN, USA), hypothesized, “It's possible that estrogen has a protective effect on the brain and that a lack of estrogen due to ovary removal may increase a woman's risk of developing memory problems”.
The results of the study were age sensitive, with younger women more at risk than older women who had experienced oophorectomy. Rocca believes the results may imply a critical age window for neuroprotection by estrogen.
The authors found that dementia and cognitive impairment could be overcome in women who had bilateral oophorectomy prior to the age of 49 years if they were treated with estrogen until at least the age of 50 years. Conversely, previous studies in which patients began estrogen treatment at age 65 years have demonstrated an increased risk of dementia. This provides further reinforcement to the view that the neuroprotective role of estrogen is age dependant.
Source: Rocca WA, Bower JH, Maraganore DM et al.: Increased risk of cognitive impairment or dementia in women who underwent oophorectomy before menopause. Neurology 69(11), 1074–1083 (2007).
Pregnant women should not undergo routine thyroid screening, say ACOG
A committee opinion, issued by the American College of Obstetricians and Gynecologists (ACOG), has recommended against routine thyroid screening in pregnant women.
‘The issue has been whether thyroid screening should be a routine test during prenatal care’, commented Sarah J Kilpatrick, chair of ACOG's Committee on Obstetric Practice. ‘Some groups argue that identifying and treating asymptomatic hypothyroidism (subclinical hypothyroidism) will improve outcomes for pregnant women and their infants. With the information we have at this time, there isn't any proven health benefit.’
It is estimated that approximately 2–5% of women suffer from subclinical hyperthyroidism, a condition that exhibits no symptoms and maintains a normal level of thyroxine, although a mildly abnormal result is obtained for one test of thyroid function.
There has been some demand for routine screening of pregnant women, following several studies that suggest a relationship between subclinical hyperthyroidism and preterm delivery and impaired brain development in children. However, Kilpatrick refutes the need for this: ‘There just isn't any data that supports the routine screening of millions of pregnant women for subclinical hypothyroidism every year because the long-term effects are not certain and there is no evidence that any treatment would make a difference in the long run’.
The ACOG argue that, while those women diagnosed with thyroid disease should be treated during pregnancy and during the postpartum period, routine thyroid testing should only be conducted for women who fulfill specific criteria, namely: exhibition of symptoms for thyroid disease, a history of thyroid disease, or a history of diseases associated with thyroid disease, such as diabetes.
Source: ACOG Committee Opinion No. 381: Subclinical hypothyroidism in pregnancy. Obstet. Gynecol 110,959–960 (2007).