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Biomedical subjects

Daniel Schuermans

Publications and source records attributed to Daniel Schuermans.

4 recordsLinked to original sources

Early detection of COPD: a case finding study in general practice.

OBJECTIVES: To estimate the prevalence of undiagnosed chronic obstructive pulmonary disease (COPD) in a population of general practice patients at risk for developing COPD. A further aim was to evaluate the presence of respiratory symptoms as a predictor for the diagnosis of COPD. METHODS: This study was conducted by eight general practitioners (GP) in six semi-rural general practices. During two consecutive months all patients attending their GP were included if they met the following criteria: current smokers between 40 and 70 yr of age, and a smoking history of at least 15 pack-years. A questionnaire regarding smoking history, respiratory symptoms, exposure to dust or chemical fumes, and history of respiratory diseases was completed for all patients. Subjects without known COPD were invited for spirometric testing. RESULTS: Off the 146 general practice patients included, 17.1% already had an established COPD diagnosis. Screening by spirometry revealed a 46.6% prevalence of COPD. Underdiagnosis of COPD was more frequent in the younger age categories (40-49 Yr; 50-59 Yr). Objective wheezing was the only sign that was significantly more frequent in COPD patients than in non-COPD patients (P<0.001). Patients with previously known COPD were significantly older, and complained more of chronic cough and fatigue than newly detected patients. CONCLUSION: Almost half of a general practice population of current smokers between 40 and 70 years of age, with a smoking history of at least 15 pack-years, was diagnosed with COPD, and roughly two thirds of these were newly detected as a result of the case finding programme.

Adult↗

FEV1/FEV6 and FEV6 as an alternative for FEV1/FVC and FVC in the spirometric detection of airway obstruction and restriction.

STUDY OBJECTIVES: To evaluate the use of the FEV(1)/forced expiratory volume at 6 s of exhalation (FEV(6)) ratio and FEV(6) as an alternative for FEV(1)/FVC and FVC in the detection of airway obstruction and lung restriction, respectively. SETTING: Pulmonary function laboratory of the Academic Hospital of the Free University of Brussels. PARTICIPANTS: A total of 11,676 spirometric examinations were analyzed on subjects with the following characteristics: white race; 20 to 80 years of age; 7,010 men and 4,666 women; and able to exhale for at least 6 s. METHODS: Published reference equations were used to determine lower limits of normal (LLN) for FEV(6), FVC, FEV(1)/FEV(6), and FEV(1)/FVC. We considered a subject to have obstruction if FEV(1)/FVC was below its LLN. A restrictive spirometric pattern was defined as FVC below its LLN, in the absence of obstruction. From these data, sensitivity and specificity of FEV(1)/FEV(6) and FEV(6) were calculated. RESULTS: For the spirometric diagnosis of airway obstruction, FEV(1)/FEV(6) sensitivity was 94.0% and specificity was 93.1%; the positive predictive value (PPV) and negative predictive value (NPV) were 89.8% and 96.0%, respectively. The prevalence of obstruction in the entire study population was 39.5%. For the spirometric detection of a restrictive pattern, FEV(6) sensitivity was 83.2% and specificity was 99.6%; the PPVs and NPVs were 97.4% and 96.9%, respectively. The prevalence of a restrictive pattern was 15.7%. Similar results were obtained for male and female subjects. When diagnostic interpretation differed between the two indexes, measured values were close to the LLN. CONCLUSIONS: The FEV(1)/FEV(6) ratio can be used as a valid alternative for FEV(1)/FVC in the diagnosis of airway obstruction, especially for screening purposes in high-risk populations for COPD in primary care. In addition, FEV(6) is an acceptable surrogate for FVC in the detection of a spirometric restrictive pattern. Using FEV(6) instead of FVC has the advantage that the end of a spirometric examination is more explicitly defined and is easier to achieve.

Adult↗

Associations between bronchial hyperresponsiveness and immune cell parameters in patients with chronic fatigue syndrome.

STUDY OBJECTIVE: To examine whether bronchial hyperresponsiveness (BHR) in patients with chronic fatigue syndrome (CFS) is caused by immune system abnormalities. DESIGN: Prospective comparative study. SETTING: A university-based outpatient clinic (Vrije Universiteit; Brussels, Belgium). PARTICIPANTS: One hundred thirty-seven CFS patients and 27 healthy volunteers. MEASUREMENTS: Pulmonary function testing, histamine bronchoprovocation test, immunophenotyping, and ribonuclease (RNase) latent determination. RESULTS: Seventy-three of 137 patients presented with BHR, of whom 64 had normal results of the histamine bronchoprovocation test. No significant differences were found in age or sex characteristics between the groups. There were no differences in the RNase L ratio, total lung capacity, or FEV(1)/FVC ratio between CFS patients with or without BHR. The group of patients in whom BHR was present (BHR+) differs most significantly from the control group with eight differences in the immunophenotype profile in the cell count analysis and seven differences in the percentage distribution profile. The group of patients in whom no BHR was detected (BHR-) only differed from the control subjects in CD25+ count and in the percentage of CD25+ cells. We observed a significant increase in cytotoxic T-cell count and in the percentage of BHR+ patients compared to BHR- patients, which is consistent with the significant reduction in percentage naïve T cells. CONCLUSIONS: These results refute any association between the cleaving of 80 kd RNase L and BHR. Immunophenotyping of our sample confirmed earlier reports on (chronic) immune activation in patients with CFS, compared to healthy control subjects. BHR+ CFS patients have more evidence of immune activation compared to BHR- patients. Inflammation and the consequent IgE-mediated activation of mast cells and eosinophils, as seen in asthma patients, is unlikely to be responsible for the presence of BHR in patients with CFS.

Adult↗