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Biomedical subjects

D L Hahn

Publications and source records attributed to D L Hahn.

At least 19 recordsLinked to original sources
PubMed2006

Knee arthrodesis with the Wichita Fusion Nail: an outcome comparison.

UNLABELLED: The Wichita Fusion Nail (WFN) is a knee arthrodesis stabilization system that employs compression via an intramedullary rod. It was designed for use in the salvage of the irretrievably failed total knee arthroplasty and other severe knee pathologies. Questionnaires covering the fusion success rate, fusion time, and complication rate were obtained from 33 surgeons who were among the first to use the device. Data from these questionnaires were analyzed to determine if the rate of successful fusion was close to 100%, which was the primary hypothesis of this study. The average time required to achieve fusion and the rate of complications were also calculated and compared to similar results available in the literature. The results for 44 selected patients were included and it was determined that all achieved fusion for a success rate of 100%. This compared favorably with reported success rates in the range of 54% to 96%. The average fusion time was 15.5 weeks. Complications included: six delayed unions, three deep infections, and two periimplant fractures for a major complications rate of 20.4%. Both the fusion times and complication rate compared favorably with other reported results. Surgeons using the device for the first time had outcomes equal to those of more experienced users. Our results demonstrated that a rate of successful arthrodesis close to 100% could be consistently achieved with the WFN. Overall, the WFN facilitated an improved outcome for a previously difficult procedure. LEVEL OF EVIDENCE: Therapeutic study, level IV (case series). See the Guidelines for Authors for a complete description of level of evidence.

Adult↗
PubMed2000

Serologic markers for Chlamydia pneumoniae in asthma.

BACKGROUND: Chlamydia pneumoniae infection has been reported as a possible etiologic agent in asthma, which in primary care settings often appears to be initiated by acute respiratory infections. OBJECTIVE: To determine if serologic markers for C. pneumoniae are associated with adult asthma that first became symptomatic after an acute respiratory illness (asthma associated with infection: AAWI). METHODS: Serum samples from 164 primary care outpatients, mean age 44 years, (68 with AAWI; 36 with atopic, occupational or exercise-induced asthma (non-AAWI); 16 nonasthmatic patients with acute bronchitis; and 44 asymptomatic nonasthmatic controls) were tested for the presence of C. pneumoniae-specific IgG and IgA antibodies. Levels of chlamydial heat shock protein 60 (CHSP60) antibody were also measured. Those positive for CHSP60 were tested for C. pneumoniae-specific IgE antibodies by immunoblotting. RESULTS: Statistically significant differences in IgG and IgA seroreactivity were noted between groups: acute bronchitis and AAWI had the highest levels (93% to 94% IgG seroreactivity, 69% to 75% IgA seroreactivity) whereas non-AAWI and asymptomatic controls had the lowest levels (61% to 84% IgG seroreactivity, 31% to 43% IgA seroreactivity, P < .02 after adjustment for age, sex and smoking). CHSP60 antibodies were significantly more prevalent in AAWI than in non-AAWI (19% versus 3%, P = .02). IgE antibodies against C. pneumoniae 60, 62, and/or 70 kD antigens were detected in 5 of 13 CHSP60 positive AAWI patients. Persistent IgG, IgA, and CHSP60 seroreactivities were noted in all seropositive asthma patients with serial serum samples. CONCLUSIONS: Serologic markers of C. pneumoniae infection were associated with acute bronchitis and with asthma that first became symptomatic following respiratory illness. Serologic responses to C. pneumoniae may be useful in the classification and diagnosis of asthma.

Adult↗
PubMed2000

Physician opportunity costs for performing practice-based research.

An inverse association has been documented between the magnitude of patient care responsibilities (health maintenance organization penetration) and the amount of clinical research produced by academic medical centers. The output of academic family practice research is affected by this calculus. This article presents evidence that current market-place demands to increase patient care services may have an even greater impact on nonacademic family practice clinician researchers involved in practice-based research (PBR).

Academic Medical Centers↗
PubMed2000

The cost of primary care research.

A significant portion of research project costs is incurred before the receipt of grant funds. This poses a problem for the initiation of primary care research, especially in community practice settings. Potential investigators need financial support for staff time, training, pilot work, and grant proposal writing if primary care researchers are to compete successfully for grant funds. To find this support, we need to understand and eventually quantify the actual costs of research with attention to those that are incurred before the receipt of grant funds. We outline 10 phases of the research process and provide a model for understanding where costs are incurred and by whom. Costs include those associated with maintaining practice interest in research, supporting practice participation, and disseminating research findings. They may be incurred by either an academic center or a research network, by the practices and physicians themselves, or by an extramural funding source. The needed investment for initiating primary care research can be itemized and, with further research, quantified. This will enhance the arguments for capital investments in the primary care research enterprise.

Costs and Cost Analysis↗
PubMed1999

Chlamydia pneumoniae, asthma, and COPD: what is the evidence?

LEARNING OBJECTIVES: Reading this article will familiarize the reader with (1) the unique chlamydial intracellular life cycle and the propensity for human chlamydial infections to become persistent and to result in immunopathologic (inflammatory) damage in target organs and (2) current evidence linking Chlamydia pneumoniae (Cpn) infection to obstructive lung diseases (asthma and chronic obstructive pulmonary disease, COPD). Potential therapeutic implications of the Cpn-asthma association are also discussed. DATA SOURCES: All Medline articles (January 1985 to March 1999) that cross-referenced the exploded MESH headings "lung diseases, obstructive" and "Chlamydia pneumoniae" (N = 76). Additional referenced articles, published abstracts, book chapters, and conference proceedings were also utilized. STUDY SELECTION: (1) Case reports and case series that identified Cpn infection in asthma and/or COPD and (2) epidemiologic studies of markers for Cpn infection in asthma and/or COPD that included one or more control groups. RESULTS: Of 18 controlled epidemiologic studies (over 4000 cases/controls), 15 found significant associations between Cpn infection and asthma using organism detection (polymerase chain reaction (PCR) testing (n = 2 studies) or fluorescent antigen testing (n = 1)), Cpn-specific secretory IgA (sIgA) antibody testing (n = 1), and/or specific serum IgE (n = 2), IgA (n = 4), IgG (n = 3) or other antibody criteria (n = 7). Eight case reports and 13 case series of Cpn infection in asthma (over 100 patients) also include descriptions of improvement or complete disappearance of asthma symptoms after prolonged antibiotic therapy directed against Cpn. Significant associations with COPD (over 1000 cases/controls) were reported in 5 of 6 studies. Results of treating chronic chlamydial infections in COPD patients have not been reported. CONCLUSIONS: Although the full clinical significance of these Cpn-obstructive lung disease associations remains to be established, reports of asthma improvement after treatment of Cpn infection deserve further investigation. Clinicians who manage asthma should be aware of this information since it may help to manage difficult cases. The hypothesis that Cpn infection in COPD can amplify smoking-associated inflammation and worsen fixed obstruction also deserves further study.

Acute Disease↗
PubMed1999

The delivery of clinical preventive services: acute care intervention.

BACKGROUND: . Evidence-based clinical preventive services are underutilized. We explored the major factors associated with delivery of these services in a large physician-owned community-based group practice that provided care for both fee-for-service (FFS) and health maintenance organization (HMO) patient populations. METHODS: We performed a cross-sectional audit of the computerized billing data of all adult outpatients seen at least once by any primary care provider in 1995 (N = 75,621). Delivery of preventive services was stratified by age, sex, visit frequency, insurance status (FFS or HMO), and visit type (acute care only or scheduled preventive visit). RESULTS: Insurance status and visit type were the strongest predictors of clinical preventive service delivery. Patients with FFS coverage received 6% to 13% (absolute difference) fewer of these services than HMO patients. Acute-care-only patients received 9% to 45% fewer services than patients who scheduled preventive visits. The combination of these factors was associated with profound differences. CONCLUSIONS: Having insurance to pay for preventive services is an important factor in the delivery of such care. Encouraging all patients to schedule preventive visits has been suggested as a strategy for increasing delivery, but that is not practical in this setting. Assessing the need for preventive services and offering them during acute care visits has equal potential for increasing delivery.

Adult↗
PubMed1998

Evidence for Chlamydia pneumoniae infection in steroid-dependent asthma.

BACKGROUND: Chlamydia pneumoniae is an obligate intracellular respiratory pathogen capable of persistent infection. Seroepidemiologic studies and the results of open-label antimicrobial treatment of patients with non-steroid-dependent asthma have suggested a potential role for C. pneumoniae in asthma. OBJECTIVE: To evaluate the results of antimicrobial treatment in patients with uncontrolled steroid-dependent asthma and serologic evidence suggesting C. pneumoniae infection. METHODS: Three nonsmoking asthmatic patients (aged 13 to 65 years) whose symptoms remained poorly controlled despite daily administration of inhaled and oral steroid (10 to 40 mg/d). All met serologic criteria for current or recent C. pneumoniae infection. RESULTS: After prolonged treatment (6 to 16 weeks) with clarithromycin or azithromycin all three patients were able to discontinue oral steroids. All three patients have remained well controlled with inhaled antiasthma therapy only during 3 to 24 months of postantibiotic therapy observation. CONCLUSIONS: In adolescent and adult asthmatic patients, Chlamydia pneumoniae infection may contribute to symptoms of asthma that are poorly controlled by steroids. Serologic evidence for C. pneumoniae infection should be sought in such patients. A trial of appropriate antibiotic therapy may be helpful in those patients with high titers of anti-C. pneumoniae IgG antibodies.

Administration, Inhalation↗
PubMed1998

Can acute Chlamydia pneumoniae respiratory tract infection initiate chronic asthma?

BACKGROUND: Chlamydia pneumoniae infection can cause acute respiratory illnesses (including sinusitis, bronchitis, and pneumonia) that are sometimes associated with wheezing. Little is known about whether acute infection in a previously unexposed, nonasthmatic individual can produce persistent wheezing leading to a diagnosis of chronic asthma. OBJECTIVE: We sought to determine whether patients with acute C. pneumoniae respiratory tract infections would develop chronic asthma. METHODS: A consecutive series of 163 primary care outpatient adolescents and adults (average age 43, 45% male) who had acute wheezing illnesses or chronic asthma were evaluated for C. pneumoniae infection by serologic testing. A subgroup of these patients also had nasopharyngeal cultures for C. pneumoniae. RESULTS: Twenty patients (12%) were diagnosed with C. pneumoniae infection defined by serology (15), culture isolation (3), or both (2). Of these 20, 10 patients wheezed for the first time and 6 of them subsequently developed chronic asthma (5) or chronic bronchitis (1) along with a serologic profile suggesting chronic infection. The other 10 patients diagnosed with C. pneumoniae infection already had a diagnosis of chronic asthma. In these patients initial serologic findings suggested chronic rather than acute infection. CONCLUSIONS: Acute C. pneumoniae respiratory tract infections in previously unexposed, nonasthmatic individuals can result in chronic asthma. Patients previously diagnosed with chronic asthma should be evaluated for possible chronic C. pneumoniae infection.

Acute Disease↗