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D L Hahn

Publications and source records attributed to D L Hahn.

At least 37 records · Page 2Linked to original sources
PubMed1996

Association of Chlamydia pneumoniae IgA antibodies with recently symptomatic asthma.

To determine whether recently diagnosed adult-onset asthma is associated with serologic evidence of chronic Chlamydia pneumoniae infection, we performed a case-control study in a primary care clinic of cases with asthma (25 adults reporting first symptoms of asthma within 2 years of enrollment) and 45 concurrently enrolled sex and age (+/- 10 years) matched non-asthmatic controls with normal pulmonary function. C. pneumoniae-specific IgA, IgG and IgG4 antibodies, and circulating immune complexes (CIC) were measured by microimmunofluorescence testing. Results showed that frequencies of IgG titres > or = 16 (92%), IgG4 titres > or = 16 (20%) and CIC > or = 4 (60%) in asthma patients were not significantly different from those of controls. However, asthmatics had a significantly higher prevalence of C. pneumoniae-specific IgA titres > or = 10 (72% of cases vs 44% of controls, P < 0.05). After adjustment for the effects of age, sex and smoking, the odds ratio for an association of IgA and asthma was 3.7 (95% confidence interval 1.2-11.5). We conclude that recently symptomatic reversible airway obstruction in adults is associated with the presence of C. pneumoniae-specific IgA antibodies, a proposed indicator of chronic respiratory C. pneumoniae infection.

Adult↗
PubMed1995

Treatment of Chlamydia pneumoniae infection in adult asthma: a before-after trial.

BACKGROUND: Some diseases previously believed to be noninfectious, eg, peptic ulcer disease, are now known to be caused by chronic infection. Recently, chronic Chlamydia pneumoniae infection has been suggested as a cause for adult-onset asthma. The purpose of this study was to determine whether antichlamydial treatment would affect the natural history of this disease. METHODS: An open-label, before-after treatment trial was performed in a community-based, primary care office. Forty-six patients (mean age 47.7 years; range 17 to 78) with moderate to moderately severe, stable, chronic asthma were treated a median of 4 weeks (range 3 to 9) with oral doxycycline (100 mg twice daily), azithromycin (1000 mg once weekly), or erythromycin (1000 mg daily). Post-treatment pulmonary function and asthma symptoms were compared with baseline values. Follow-up was an average of 6 months (range 1.5 to 36) post-treatment. RESULTS: Four patients with C pneumoniae respiratory tract infection developed chronic asthma, which disappeared after treatment in each case. Of the remaining 42 seroreactive patients who were treated a mean of 6 years after the development of chronic asthma, one half had either complete remission or major clinical improvement (3 and 18 patients, respectively). This improvement was significantly more likely to occur in patients with early disease (P = .01) and before the development of fixed obstruction (P < .01). CONCLUSIONS: Antimicrobial therapy appeared to "cure" or significantly improve asthma in approximately one half of treated adults, and the response pattern was consistent with chlamydial pathogenesis. C pneumoniae infection in asthma may be clinically important and should be investigated further.

Adolescent↗
PubMed1995

Infectious asthma: a reemerging clinical entity?

BACKGROUND: In the primary care setting, patients often report that their asthma began after an acute respiratory infection such as bronchitis, pneumonia, or an influenza-like illness ("infectious asthma"). Preceding respiratory illnesses such as bronchitis and pneumonia are also epidemiologic correlates of asthma in both children and adults. These associations suggest the possibility that respiratory infection is involved in the initiation of asthma in addition to the already acknowledged role of infection in asthma exacerbations. The purpose of this study was to investigate whether a history of infectious asthma influenced clinical and pulmonary function characteristics of patients with chronic asthma. METHODS: Conducted in a community-based primary care practice, this is a clinical descriptive study of 92 middle-class patients who had a mean age of 37.7 years (standard deviation 15.4 years), a clinical diagnosis of chronic asthma, and baseline pulmonary function test results available for analysis. RESULTS: There was sufficient history available to classify asthma as infectious in 41 (45%) of 92 patients. Patients with infectious asthma reported a much shorter duration of asthma symptoms than did patients with atopic, occupational, and exercise-induced asthma (5.6 vs 13.3 years, P = .001). Nevertheless, patients with infectious asthma had significantly worse percentages of predicted FEV1 and FEF25%-75%, both before and after bronchodilator therapy. CONCLUSIONS: Infectious asthma was common in this primary care setting. Compared with patients with other asthma syndromes, those with infectious asthma had worse pulmonary function despite a shorter duration of symptomatic disease. Further studies of the cause and prognosis of this clinical entity are warranted.

Adult↗
PubMed1994

PSA screening.

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Aged↗
PubMed1994

Diagnosed and possible undiagnosed asthma: a Wisconsin Research Network (WReN) Study. Wisconsin Research Network (WReN) Asthma Prevalence Study Group.

BACKGROUND: Adult-onset asthma is frequently encountered in primary care and is responsible for a large proportion of asthma morbidity and mortality. The primary goal of this survey was to describe the epidemiology of diagnosed and possible undiagnosed asthma in Wisconsin Research Network (WReN) practices. METHODS: Physicians from 59 practices interviewed a systematic sample of their clinical population, which included all patients encountered during office visits one day each week for 3 or 12 months, to obtain a history of physician-diagnosed asthma or symptoms suggesting undiagnosed asthma (wheezing and shortness of breath). Age at diagnosis or at onset of symptoms and current disease activity were also recorded. RESULTS: The 14,127 patients surveyed closely resembled the age-sex composition of the 1990 general and family practice component of the National Ambulatory Medical Care Survey. Physician-diagnosed asthma that was active within the previous year was reported by 6.1% of WReN patients (5.8% of patients younger than 20 years of age and 6.2% of adults). Undiagnosed asthma that was active within the previous year was reported by 3.3% (2.9% of patients younger than 20 years of age and 3.4% of adults). Adult-onset asthma was reported by 46.3% of all patients with diagnosed asthma; and 56.7% of patients with undiagnosed asthma reported that their symptoms began in adulthood. CONCLUSIONS: Adult-onset asthma accounts for approximately one half of all asthma cases. Since most patients with adult-onset asthma are managed by primary care physicians, practice-based research is necessary for the understanding, treatment, and possible prevention of this important disease.

Adolescent↗
PubMed1994

Asthma and chlamydial infection: a case series.

BACKGROUND: Adult-onset asthma is frequently associated with antecedent respiratory symptoms that could represent either previously undiagnosed asthma or previous lung infections that result in subsequent asthma. To further investigate a reported association of Chlamydia pneumoniae infection and adult reactive airway disease, we looked for evidence of atypical infections in patients with acute wheezing and nonwheezing respiratory illnesses. METHODS: Pharyngeal cultures and acute and convalescent serology for C pneumoniae and Mycoplasma pneumoniae were obtained from 131 primary care outpatients (mean age, 36 years) with acute wheezing or nonwheezing respiratory illnesses. Peak flow measurements were obtained in patients with cough or wheeze. Spirometry before and after bronchodilator use was obtained to substantiate the diagnosis of chronic asthma in patients who had persistent wheezing and dyspnea after enrollment. RESULTS: Twelve (9.2%) of 131 patients were classified as having chronic asthma, 5/12 developed chronic asthma for the first time during the study period. Thirty (22.9%) patients were classified with acute asthmatic bronchitis, and 89 (67.9%) had nonwheezing illness. Two of the newly diagnosed asthmatics met serologic criteria for acute C pneumoniae infection, and one had serologic evidence for acute M pneumoniae infection. Compared with patients with nonwheezing respiratory illnesses, C pneumoniae seroreactivity was significantly (P < .001) associated with both chronic asthma and with acute asthmatic bronchitis. CONCLUSIONS: Acute wheezing illness was encountered frequently in this primary care setting. Although most acute wheezing respiratory illness resolved without obvious chronic sequelae, some patients had persistent symptoms and were diagnosed with chronic asthma. C pneumoniae seroreactivity was associated with both acute and chronic wheezing, suggesting that pulmonary infection with this intracellular pathogen plays a role in the natural history of reactive airway disease.

Acute Disease↗