The relationship of sex to asthma prevalence, health care utilization, and medications in a large managed care organization

Sex differences in hospital admissions from emergency departments in asthmatic adults: a population-based study

BACKGROUND

Women represent the majority of adult patients hospitalized for asthma. Analyzing the course of emergency department (ED) visits before hospital admission can help understanding of the mechanisms behind the excess of hospitalizations in women.

OBJECTIVE

To investigate sex differences in hospital admission rates in adult patients with asthma visiting EDs in Ontario.

METHODS

Asthmatic patients 18 to 55 years old who visited Ontario EDs between April 1, 2003, and March 31, 2004, were identified using the Canadian Institute for Health Information's National Ambulatory Care Reporting System. The generalized estimating equations for binary outcome were used to model rates of hospital admission with sex, age, and triage (severity) score as covariates. Analysis was further stratified by the ED volume.

RESULTS

Women represented 62.2% of all ED visits. They were on average older than men, but both groups had similar distributions of triage scores. Female patients accounted for more hospital admissions than male patients (7.4% vs 4.5%). After adjusting for age and triage score, women were more likely to be admitted than men (odds ratio, 1.64; 95% confidence interval, 1.41-1.90). The interaction found between sex and triage level indicates that hospitalized women may have less severe asthma than hospitalized men. Analysis by ED volume did not significantly alter the results.

CONCLUSION

The higher admission rates in women may be related to sex differences in the subjective perception of dyspnea, management of asthma by ED physician, or inadequate ambulatory care strategies in women and thus merit further investigation.

Risk areas for pediatric acute care: asthma differs from upper and lower respiratory illness

OBJECTIVE

To determine if emergency department utilization for pediatric respiratory illness varies across small geographic jurisdictions within a large urban city.

DESIGN

A retrospective analysis of Maryland Health Services Cost Review Commission Emergency Department discharge data.

SETTING/PATIENTS

All non-neonatal, Baltimore City residents <18 years old with valid diagnoses admitted and discharged from emergency departments (ED) in the state of Maryland from April 1, 1997 to December 31, 2000 (n=245,339).

MAIN OUTCOME MEASURES

Crude and adjusted ED visit rates for asthma, upper and lower respiratory illnesses (per 1000 population). To evaluate the effect of geography on pediatric ED visit rates, odds of an asthma ED visit, URI, or LRI vs. non-respiratory ED visit were compared across regions of the city.

RESULTS

We determined that residential areas with high ED utilization rates for upper and lower respiratory illnesses, as well as non-respiratory illnesses correlate with regions of high ED utilization for asthma, even after adjusting for race, gender and age of the population. The regions with high odds ratios that an ED visit was for asthma were different from those with high ORs for URI and LRI after also controlling for poverty.

CONCLUSIONS

This suggests that poverty accounts for high utilization of the ED in urban settings, but suggests that environmental exposures that increase the risk of ED care for asthma differ from those that lead to URI and LRI.

Women with asthma: a review of potential variables and preferred medical management

OBJECTIVES

To summarize the potential variables that contribute to the increased risk of asthma in women, outline therapeutic strategies that address these variables, and review current treatment recommendations for both pregnant and nonpregnant women with asthma.

DATA SOURCES

Literature searches (MEDLINE and cross-references) were performed using the keywords asthma and women in combination with the terms compliance, depression, emergency department, hormones, menstruation, mortality, National Asthma Education and Prevention Program, osteoporosis, pregnancy, prevalence, smoking, and treatment. Searches were limited to human studies with data published before 2005.

STUDY SELECTION

The author selected relevant articles for inclusion in this review.

RESULTS

Fluctuations in sex hormones, menstruation, pregnancy, obesity, depression, medication nonadherence, and smoking may contribute to increased asthma symptoms or severity in women. Asthma control may be improved if physicians address conditions and behaviors associated with asthma variability and severity in women. Notably, asthma must be managed aggressively in pregnant women, because uncontrolled asthma can lead to perinatal complications. Asthma treatment in women is optimized through patient and physician adherence to national guideline recommendations, including provision of patient education and asthma action plans.

CONCLUSIONS

Multiple variables throughout the female life cycle may influence asthma control. Successful asthma management requires an ongoing partnership between the patient and her physician to address physiologic (eg, sex hormones, pregnancy, obesity, depression) and nonphysiologic (eg, smoking, medication nonadherence) factors that may contribute to decreased asthma control.

Effect of gender, age, and severity of asthma attack on patterns of emergency department visits due to asthma by month and day of the week

OBJECTIVE

To examine the pattern and strength of seasonal fluctuations in emergency department (ED) visits due to asthma, by month and day of the week, by the patient's age, gender, and severity of asthma attack.

METHODS

Time series analysis of ED visits was conducted among patients with asthma aged from 18 to 55 years who visited Ontario EDs between April 1, 2001 and March 31, 2004. Autoregressive regression models with months and days of the week as predictors were fitted for (1) all patients; (2) females and males separately; (3) each combination of gender and age group, and (4) each combination of gender and level of severity. The strength of seasonality in each group of patients was estimated from the R2-statistic derived from autoregression models.

RESULTS

For all patient groups, the highest number of ED visits occurred in October and December, and on Sundays and Mondays. Month of January and Fridays were associated with a decreased number of visits. The strength of seasonality was similar in men and women (R2 = 0.52), was the highest in young patients and decreased with age, in men more rapidly than in women. Severe cases of asthma attacks exhibited weaker seasonality (R2 = 0.30) compared to mild (R2 = 0.45) or moderate (R2 = 0.53) cases.

CONCLUSION

The strength of seasonal patterns of asthma ED visits is influenced by age and the severity of attack, and to a lesser extent, gender. Understanding the significance of seasonal precipitants of asthma in different patients subgroups could lead to better management strategies.

Effect of fetal sex on airway lability in pregnant women with asthma

The authors investigated the association between sex of the fetus and maternal airway lability among pregnant women with asthma. Data were prospectively collected among 702 pregnant women with a diagnosis of asthma who were recruited in southern New England between 1997 and 2000 and followed through pregnancy. Peak expiratory flow lability, defined as percent daily maximum minus the minimum divided by the mean, was assessed at enrollment and at 21, 29, and 37 weeks' gestation. There was a -9.9 percent (95 percent confidence interval: -19.4, -0.4) difference in airway lability observed between women carrying female fetuses and those carrying male fetuses. This difference persisted throughout pregnancy. Among pregnant asthmatic women, carrying a female fetus is associated with worse maternal asthma, as assessed by greater airway lability, than is carrying a male fetus.

Sex Differences in the Presentation and Course of Asthma Hospitalizations

OBJECTIVE

To distinguish between differences in prevalence, asthma severity, and treatment to explain sex-related differences in hospitalized asthma patients.

DESIGN

Medical record review.

SETTING

Thirty US hospitals as part of the University HealthSystem Consortium Asthma Clinical Benchmarking Project.

PATIENTS

A random sample of patients aged 2 to 54 years and admitted to the hospital for acute asthma from 1999 to 2000.

MEASUREMENTS

Demographics, medical history, initial oxygen saturation, initial peak expiratory flow (adults), initial pulmonary index (children), emergency department course, length of hospital stay, and discharge plans.

RESULTS

The cohort included 606 pediatric (aged 2 to 17 years) and 680 adult (aged 18 to 54 years) inpatients. The sex ratio varied significantly by age: 40% were girls 2 to 17 years of age, and 68% were women 18 to 54 years of age p < 0.001). Among children, girls did not differ from boys according to asthma history, pulmonary index scores, or hospital length of stay. Among adults, women were more likely to have a primary care provider (90% vs 73%, p < 0.001) but did not differ according to asthma history or recent medication use. Women had a higher mean initial PEF compared to men (43% of predicted vs 36% of predicted, p < 0.001) and higher median initial oxygen saturation (95% vs 93%, p = 0.002) but did not differ by hospital length of stay. No sex differences in discharge regimens were identified in children or adults.

CONCLUSIONS

Among US inpatients with acute asthma, male children are more common than female children, while women are more common in adults. The results in children are probably explained by prevalence differences, since no sex differences were seen in markers of asthma severity or treatment. In adults, increased symptoms in response to a given level of airway obstruction in women may contribute to the female predominance in asthma hospitalizations.

Relation between phase of the menstrual cycle and asthma presentations in the emergency department

BACKGROUND

The phase of the menstrual cycle is thought to influence the course of asthma in women. One recent study reported a large increase in exacerbations during the perimenstrual phase, while another found a preovulatory increase. A study was undertaken to determine the relation between phase of the menstrual cycle and acute asthma in patients presenting to the emergency department (ED).

METHODS

All women aged 18-54 years presenting with a diagnosis of acute asthma exacerbation were considered for enrollment in the study. Women who were pregnant, postmenopausal, following hysterectomy, with a >28 day menstrual cycle or incomplete reproductive history were excluded. The 792 eligible women were classified by menstrual phase based on both date of symptom onset and date of ED visit.

RESULTS

When classified by date of symptom onset, 28% were preovulatory (days 5 to 11), 25% were periovulatory (days 12 to 18), 21% were postovulatory (days 19 to 25), and 27% were perimenstrual (days 26 to 4; p = 0.03). When classified by date of ED visit, 28% were preovulatory, 22% were periovulatory, 22% were postovulatory, and 27% were perimenstrual (p = 0.004). Using either approach, there were no significant differences in demographic factors or in asthma severity of women in the various menstrual phase groups.

CONCLUSION

Acute asthma exacerbations do not markedly increase during the perimenstrual phase. The results support the suggestion that both preovulatory and perimenstrual phases are actual triggers of asthma exacerbation in some women, or that these two phases serve as "co-factors" that worsen other recognised triggers of acute asthma.

Sex differences among children 2-13 years of age presenting at the emergency department with acute asthma

Hospitalization rates for asthma have been reported to be higher in males than females in children under age 15, but it is not clear whether this disparity reflects gender differences in prevalence, severity, or treatment. We performed a prospective cohort study as part of the Emergency Medicine Network. Patients aged 2-13 years who presented to the emergency department (ED) with acute asthma underwent a structured interview in the ED and another by telephone 2 weeks later. Of 1,602 patients, 61% (95% CI, 59-64%) were boys. Girls were slightly older than boys, although no material differences existed in acute presentation, chronic asthma characteristics, ED treatment, or ED course. There was no difference in admission rates for boys or girls (20% vs. 22%; P = 0.48). This finding persisted when adjusting for other factors in a multivariate logistic regression model. No sex differences were observed for relapse or ongoing exacerbation on univariate or multivariate analysis. These data suggest that asthma is not inherently more severe in boys with asthma compared to girls, and that the increased rate of hospitalizations in boys under age 13 is due to differences in prevalence, not severity.

Is there a causative role for tetanus toxoid vaccination in the development of allergy-like symptoms and in the increasing prevalence of atopic diseases?

Allergic diseases are a worldwide health problem. They mainly affect people living in developed countries where an increasing prevalence of allergy symptoms has been recorded in the last 20-30 years. The cause of this increase is still disputed, and, among others, the "hygiene hypothesis" supported the concept that relevant changes in lifestyle could have a relationship with the phenomenon. More recently the recorded parallel increase in autoimmune diseases has suggested to consider the "hygiene hypothesis" as a cause of a more general disregulation of the immune system leading to both allergy and to autoimmunity. Here are reported a series of observations, evidence, and data from the literature leading to a different hypothesis. The key points are: (1) the presence of two subsets of patients having allergy symptoms based on an IgE-mediated mechanism or not; (2) the positive results obtained with the autologous serum skin test in either cutaneous or respiratory affected subjects, mainly in children and adult females; (3) the presence of IgG autoantibodies against the alpha-chain of the high affinity IgE receptor (FcepsilonRIalpha) in non-IgE-mediated urticaria and even in respiratory subjects; (4) the cross-reactivity between epitopes of the tetanus toxoid molecule and the FcepsilonRIalpha detected by means of an alpha-chain affinity purified IgG fraction; (5) the positive skin reactivity obtained using IgG anti-tetanus toxoid preparations in allergic and non-allergic volunteers. The presence of IgG autoantibodies actively generated by the population-based vaccination with tetanus toxoid could induce both mediator release from activated mast cell and Th2 cytokine production early in life. There are epidemiological evidences that tetanus toxoid vaccination could be linked with an increased tendency to have allergy symptoms. The different epidemiological distribution of non-IgE-mediated symptoms, mainly affecting young infants would be in agreement with the present hypothesis. The prevalent mother-to-child relationship in terms of risk for allergy symptoms could be explained with the trans-placenta transfer of IgG. A similar transfer could also take place through the mother milk during breast feeding. It may thus be hypothesized that the increased prevalence of allergic diseases could be caused by the generalized tetanus toxoid immunization procedure, progressively extended to most of the countries worldwide in the last 30-40 years. Both the induction of non-IgE-mediated symptoms caused by the mast cell activation via the anti-FcepsilonRIalpha IgG and the long lasting Th2 inflammation of affected tissues would be the inducing mechanisms. This hypothesis would re-configure part of the allergic diseases as a Th2 phenotypic expression of an autoimmune disease.