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ICD Code: 493. Asthma



ICD Code: 493. Article Review
Title: Bauer BA et al; "Incidence and Outcomes of Asthma in the Elderly: A Population-Based Study in Rochester, Minnesota." Chest; V.111; No.2; 2/97; p303
      STUDY DESIGN: Asthma occurs more frequently in the elderly than is usually appreciated and may, therefore, be underdiagnosed and undertreated. The objective of this study was to estimate the incidence of asthma in an elderly population and to describe the clinical characteristics, use of health services, and long-term survival of persons with onset of asthma after 65 years of age. The authors recently identified a population-based incidence cohort of 3622 Rochester, Minnesota, residents with the diagnosis of asthma or symptoms compatible with the diagnosis of asthma. This cohort included 102 residents with onset of asthma at age 65 years or older. This community-based study used a linked medical diagnostic index and reviewed the medical records of all providers of care to all elderly patients in the community. Explicit criteria were used to identify all patients with asthma, independent of diagnosis assigned by the patient's physician. Also, because the authors not only looked at diagnosed cases of asthma but also symptom complexes compatible with the diagnosis of asthma, they were able to avoid the previously reported labeling bias whereby men are more likely to be labeled as having emphysema, while women are more likely to be labeled as asthmatic.
      PATIENT CHARACTERISTICS: All Rochester, Minnesota, residents age 65 years or older who met criteria for onset of definite or probable asthma from 1964 through 1983 were included. After review of all medical records of previously identified elderly Rochester residents with asthma, the authors identified 98 residents with onset of asthma at age 65 years or older (46 men and 52 women). 62% were in the 65- to 74-year age range, 31% were in the 75- to 84-year age range, and 7% were age 85 years or older. 52 received all of their care from the Mayo Clinic and affiliated hospitals, while 46 additionally received at least some of their care from the Olmsted Medical Group and its affiliated hospital.
      INCIDENCE: The overall age- and sex-adjusted incidence was 95 per 100,000. The age-adjusted incidence was 126 per 100,000 for male subjects and 74 per 100,000 for female subjects. The age-specific incidence rates declined with age from 103 per 100,000 in those aged 65 to 74 years, to 81 per 100,000 in those aged 75 to 84 years, to 58 per 100,000 in those over 85. Analysis showed that the incidence of asthma was significantly higher in male subjects. The apparent decrease in the incidence of asthma with older age was not statistically significant, and the apparent difference in the decrease by sex was not significant. The incidence of asthma in the elderly in Rochester did not change during the years 1964 to 1983.
      UTILIZATION: Elderly patients with asthma had high utilization of health services for asthma, other respiratory illnesses (predominantly bronchitis and pneumonia), and other illnesses. During the follow-up period, the medical records documented that 80% of patients had one or more ambulatory visits for asthma, 40% had unscheduled ambulatory visits for asthma, 22% had an emergency department visit for asthma, and 42% had a hospitalization for asthma.
      SURVIVAL: There were 850 person-years of observation available for the 98 elderly asthmatics. Survival was 95% at 1 year, 72% at 5 years, and 57% at 10 years. Overall observed survival was not significantly different from expected survival.
      DISCUSSION: This study indicates that asthma can begin late in life at an incidence rate comparable to the incidence rates previously reported in young and middle-aged adults in the community studied. Of note was the large number of patients whose very first asthmatic symptoms were preceded immediately by or concomitant with an upper respiratory tract infection, suggesting an infectious trigger for at least some asthma in the elderly population. There was no increased risk of death in adults with onset of asthma after age 65 years. Asthma needs to be distinguished from chronic obstructive pulmonary disease (COPD), interstitial lung disease, bronchiectasis, cardiac disease, upper airway obstruction, pulmonary embolism, bronchogenic carcinoma, aspiration, and gastroesophageal reflux. The authors had sufficient clinical and diagnostic information on the patients to reliably exclude each of these conditions with the exception of COPD.

Search Criteria: Text - Chest; V.111; No.2; 2/97; p303