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ICD Code: 493. Asthma

ICD Code: 493. Article Review
Title: Kynyk JA et al; "Asthma, the Sex Difference." Current Opinion in Pulmonary Medicine; V.17; 2011; p6     DOI:10.1097/MCP.0b013e3283410038
      PREVALENCE BY GENDER: In general, the lifetime likelihood of developing asthma is about 10.5% greater in women than in men. When examined at specific time points, asthma is more common and more severe in prepubertal boys, with boys less than 18 years of age having a 54% higher rate of asthma than girls of the same age. However, the prevalence of asthma and its severity increases significantly in women after puberty, with asthma becoming more common in women by age 20 in the United States. As an example, 2009 estimates from the National Health Interview Survey in the United States demonstrate a prevalence of asthma in those younger than 15 years of age of 11.9% in boys and 7.7% in girls. In young adults aged 15-34 years, the pattern shifts, with a prevalence of 6.3% in men and 9.6% in women. The difference continues to widen in adults older than 35 years with a prevalence of 5.6% versus 10.1% in men and women, respectively. European studies evaluating the prevalence of asthma by age yield similar results. However, more recent studies suggest a narrowing of the gap in asthma prevalence during childhood. After menopause, the difference in asthma prevalence between men and women seems to narrow but does not disappear.
      MORTALITY: Sex-related differences in asthma mortality also exist, but the patterns are difficult to predict based on prevalence data alone. Ethnicity contributes further to the observed mortality differences between men and women, with black women experiencing the highest age-adjusted mortality from asthma in the United States.
      HOSPITALIZATION AND EXACERBATIONS: Age-related sex differences in hospitalized asthma patients have been well described. Patients hospitalized for asthma more than 15 years old are up to three times more likely to be female, whereas those hospitalized for asthma exacerbations at younger than 15 years of age are up to 2 times more likely to be male. Although the established differences in asthma prevalence between men and women likely contribute to these observations, it has been suggested that other factors should also be considered. There is conflicting data on whether length of hospital stay differs between men and women, but it appears that African American women suffer more severe exacerbations requiring intensive care unit (ICU) admissions then either men or white women.
      BRONCHIAL HYPERRESPONSIVENESS: A clinical hallmark of asthma is bronchial hyperresponsiveness (BHR) to nonspecific stimuli such as methacholine or histamine. Many population-based studies have revealed a greater prevalence of BHR in women than in men. Sex differences may reflect increased BHR to hyperventilation as a result of smaller airway caliber in women, or it may reflect an inherently different sensitivity to the stimulus. Collectively, these findings suggest that the increased dyspnea and other asthma symptoms in women compared to men may be due to exaggerated responses to asthma triggers or increased BHR, despite having similar baseline lung function.
      MENSTRUAL-LINKED ASTHMA: Of women of reproductive age with asthma, 20%-40% report worsening of asthma symptoms or a decrease in pulmonary function during the premenstrual or menstrual period. In some series, clinically significant changes in pulmonary function and asthma control related to these self-reported changes in symptoms are infrequent, but in others, menstrual-related changes in asthma symptoms are associated with increased healthcare utilization and near-fatal asthma episodes. Studies evaluating the effectiveness of oral contraceptives in blunting premenstrual worsening of asthma have been inconclusive.
      MENOPAUSE AND HORMONE REPLACEMENT THERAPY: The overall incidence of asthma in women decreases after menopause. However, in two large prospective studies, the use of postmenopausal hormone replacement was associated with an increased rate of newly diagnosed asthma in menopausal women. In data published from the Nurses’ Health Study, any use of postmenopausal hormone replacement therapy (HRT) was associated with approximately twice the risk of asthma when compared to postmenopausal women without exogenous hormone exposure, and HRT was associated with an increased risk of newly diagnosed asthma with a relative risk of 2.30 in current estrogen users, with lean women with a body mass index of 25 kg/m2 or less most affected. These data again highlight the importance of questioning women about changes in reproductive health, which may potentially impact the control of underlying asthma, or may contribute to a new diagnosis later in life.
      MANAGEMENT AND COMPLIANCE: Women with asthma are more likely to have a primary care physician than men, and studies suggest that they are also more likely to recognize asthma symptoms, seek medical care, and be prescribed systemic corticosteroids for acute symptoms despite being prescribed inhaled corticosteroids for asthma control at a similar rate.

Search Criteria: Text - Current Opinion in Pulmonary Medicine; V.17; 2011; p6