Biomedical subjects

J J den Otter

Publications and source records attributed to J J den Otter.

8 recordsLinked to original sources

PubMed2000

Lung function measurement in general practice. General practice measurements compared with laboratory measurements during the DIMCA trial.

BACKGROUND: Lung function measurement in the general practice setting (GPS) is of growing importance. OBJECTIVE.:The aim of this study was to compare results from a lung function laboratory (LFL) with those in a GPS. METHODS: Comparisons were made for decline calculated from GPS and LFL measurements and intra-individual paired measurements. Test characteristics of the spirometer used in the GPS were also assessed. RESULTS: The mean decline in lung function was: -0.037 l/year [95% confidence interval (CI) -0.202 to 0.129] from LFL data and -0.027 l/year (95% CI -0.242 to 0.188) from GPS data. The mean intra-individual difference was -0.0025 l (95% CI -0.493 to 0.488 l). The test characteristics of the spirometer used in GPS did not meet all of the American Thoracic Society guidelines; in particular, the random error was too large. The difference in assessments between measurement in LFL and GPS were such that misclassification might occur if slopes were calculated. CONCLUSIONS. :Repeated measurement in this study showed that GPS measurements are not interchangeable with LFL measurements. Therefore, one has to be cautious when interchanging lung function data from an LFL and a GPS.

Clinical Trials as Topic↗

PubMed1998

Active detection of chronic obstructive pulmonary disease and asthma in the general population. Results and economic consequences of the DIMCA program.

The aim of this prospective study was to detect subjects in the general population with objective signs of chronic obstructive pulmonary disease (COPD) or asthma at an early stage. This was done by means of a two-stage protocol involving screening and a subsequent 2-yr monitoring of all subjects with positive results of screening. The study was done in 10 general practices located in the eastern part of the Netherlands. A random sample was taken from the general population aged 25 to 70 yr. All known COPD and asthma patients were excluded. A total of 1,749 subjects met the inclusion criteria: 1,155 subjects (66%) agreed to participate in the screening stage of the study. A total of 604 subjects (52.3%) showed symptoms or objective signs of COPD or asthma during the screening and were considered "positive." Of those with positive screening results, 384 subjects (64%) agreed to participate in the second, 2-yr monitoring stage of the study. The costs involved in detection were calculated for three different scenarios, as follows: (1) The detection of subjects with persistently decreased lung function or an increased level of bronchial hyperresponsiveness (BHR) during 6 mo of monitoring; (2) Scenario 1 plus the detection of subjects with a rapid decline in lung function with signs of BHR during 12 mo of monitoring; (3) Scenario 2 plus the detection of subjects with a moderate increase in the decline in lung function or signs of BHR during 24 mo of monitoring. The costs of lung function assessments, organization, transportation, and patient time were included. The costs were converted to United States dollars on the basis of purchasing power (1 United States dollar = 2.08 Netherlands guilders). During the second stage, 252 subjects were detected with objective signs of COPD or asthma at an early stage. Smoking status as a screening criterion was neither sensitive nor specific. Because there was no evidence of biased recruitment or selection during the program, the proportions of subjects found to have objective signs of COPD or asthma at an early stage could be extrapolated to the general population. Of the general population, 7.7% showed persistently reduced lung function or increased BHR. Another 12.5 % of the general population showed a rapid decline in lung function (> 80 ml/yr) in combination with signs of BHR, and a further 19.4% of the general population showed mild objective signs of COPD or asthma. The average costs per detected case varied from US$953 (Scenario 1) to US$469 (Scenario 3). In conclusion, detection of COPD or asthma at an early stage by means of a two-stage protocol was feasible at relatively little expense in comparison with other mass screening programs. Persistently decreased lung function or a rapid decline in lung function (Scenario 2) was observed in approximately 20% of the general adult population.

Adult↗

PubMed1998

How to avoid underdiagnosed asthma/chronic obstructive pulmonary disease?

The prevalence of asthma and chronic obstructive pulmonary disease (COPD) is rising in most countries, including The Netherlands. It has been suggested that a majority of these cases of (self-reported) symptoms related to asthma/COPD are not diagnosed in general practice. We compared a population screening for underdiagnosed asthma/COPD with a high-risk approach by a questionnaire form with specified questions about asthma/COPD-related symptoms. A case-controlled study including a record review was performed of cases and controls. The results of a population screening were used to classify patients as (a) asthma/COPD, (b) at risk for asthma/COPD, or (c) no asthma/COPD. Eleven hundred fifty-five patients were screened. One hundred fifty-five patients reported previous asthma/COPD-related care (cases). The difference between number of cases and controls in asthma/COPD diagnosis was chosen as main outcome measure. The population screening revealed 85 subjects with a diagnosis of asthma/COPD and 154 subjects with an increased risk. Nineteen diagnoses could be made in cases, and eight diagnoses in controls. The chart review showed that only seven cases and two controls were known to the general practitioner. From this study it can be concluded that in order to reduce the number of un- and underdiagnosed patients, all listed patients in general practice should be screened. However, if screening of all patients is not feasible, active case finding by asking a few questions about shortness of breath or wheezing to all patients in the group of listed individuals is recommended.

Adult↗

PubMed1997

Spirometry in general practice: the performance of practice assistants scored by lung function technicians.

Recently, spirometers have become available for use within general practice as an alternative to peak flow meters. This study investigates whether practice assistants, after comprehensive training, can effectively carry out spirometry with patients suffering from asthma and other chronic obstructive pulmonary diseases. A scoring system, consisting of 20 items, was devised to determine the effectiveness of the assistants' instructions and to assess the patient's subsequent use of the spirometer. About half the instructions and half the patient performance items were considered to be carried out satisfactorily.

Asthma↗

PubMed1997

Testing bronchial hyper-responsiveness: provocation or peak expiratory flow variability?

BACKGROUND: Assessing bronchial hyper-responsiveness (BHR) is a main diagnostic criterion of asthma. Provocation testing is not readily available in general practice, but peak expiratory flow (PEF) is. Several guidelines promote the use of PEF variability as a diagnostic tool for BHR. This study tested the agreement between histamine challenge testing and PEF variability, and the consequences for diagnosing asthma. AIM: To investigate the possibility of assessing BHR by PEF variability, using a histamine provocation test as a reference. METHOD: Subjects with signs of symptoms indicating asthma (persistent or recurrent respiratory symptoms or signs of reversible bronchial obstruction) (n = 323) were studied. They had been identified in a population screening for asthma. A histamine provocation test and PEF variability were assessed over a three-week period. Asthma was defined as signs or symptoms together with a reversible airflow obstruction or BHR to the histamine challenge test. BHR was defined as a PC20 histamine of < or = 8 mg/ml or a PEF variability of > or = 15%. Overall correlation between PC20 and PEF variability was calculated using Spearman's rho. Furthermore, a decision tree was constructed to clarify the role of BHR in diagnosing asthma. RESULTS: Thirty-two patients had a reversibility in forced expiratory volume in 1 second (FEV1) of > or = 9% predicted, 131 patients showed a PC20 of < or = 8 and 11 patients had a PEF variability of > or = 15%. Overall correlation was poor at only -0.27 (P < 0.0001). One hundred and fourteen of the 131 patients diagnosed as having asthma when the histamine challenge test was used were not diagnosed by PEF variability. CONCLUSION: PEF variability cannot replace bronchial provocation testing in assessing BHR. This indicates that PEF variability and bronchial provocation do not measure the same aspects of BHR. If BHR testing is required in diagnosing asthma, a bronchial provocation test has to be used in general practice as well.

Adult↗

PubMed1996

Prevalence of asthma and COPD in general practice in 1992: has it changed since 1977?

BACKGROUND: Asthma and COPD are common diseases of the airways which are mainly diagnosed and treated in general practice. AIM: Various studies have reported an increase in the morbidity of asthma and COPD. There are two possible reasons for such an increase. The first is an apparent increase caused by using different criteria in defining asthma/COPD, and by increased awareness of the disease by doctors and patients. The second is a real increase caused by an increase in the prevalence of airway pathology. The aim of this study was to determine the cause of the observed increase in morbidity. METHOD: In 1977, a sample of 2328 adults from the general population were screened for asthma and COPD. Those screened were then divided into five sub-groups (grades 1-5), according to severity of: (1) respiratory symptoms; and (2) loss in FEV1. The number of patients who were not known to the general practitioner prior to the screening as having asthma or COPD grades 1-5 were also assessed. In 1992, we studied a different sample of 1184 adults of the general population in the same area. We used the same criteria as in 1977 to analyse our results. The number of patients not known to the general practitioner prior to the screening was also studied. RESULTS: The overall prevalence (grades 1-5) of asthma and COPD has increased from +/- 19% in 1977 to +/- 31% in 1992 (range 21-42). The main reason for this is an increase in prevalence of very mild to moderate asthma and COPD (grades 1-3) from 17% in 1977 to 27% in 1992. The prevalence of severe cases (grades 4-5) increased from 2% in 1977 to 4% in 1992. In 1992, around 65% of the patients were not known to the general practitioner as having any grade of asthma or COPD. This was only slightly lower than the 72% in 1977. All patients with a severe disease (grade 5) were known to the general practitioner. CONCLUSIONS: There is a real increase in the prevalence of asthma and COPD, caused predominantly by an increase in the number of mild cases. The percentage of patients not known to the GP were predominantly mild cases.

Adult↗

PubMed1995

Periodic treatment regimens with inhaled steroids in asthma or chronic obstructive pulmonary disease. Is it possible?

OBJECTIVE: To determine whether inhaled corticosteroids can be discontinued in the stable phase of asthma or chronic obstructive pulmonary disease (COPD) or if this therapy should be continued. DESIGN: Nonrandomized open uncontrolled 5-year trial. SETTING: Prospective study in general practice. PATIENTS: Forty-eight patients with steroid-dependent asthma or COPD who had shown a decline in forced expiratory volume in 1 second (FEV1) of at least 80 mL per year and at least one exacerbation per year during the first 2 years of bronchodilator treatment. Subjects were treated additionally with inhaled steroids for another 2 years and were finally given the option to stop using steroids. Sixteen patients were willing to stop using beclomethasone and were studied for another year. No recruitment bias took place in this consecutive sample in the fifth year of follow-up. Two of 16 patients developed carcinomas and dropped out. INTERVENTIONS: Two years of bronchodilator treatment alone (400 micrograms of salbutamol or 40 micrograms of ipratropium bromide four times daily), followed by 2 years of additional inhaled corticosteroid treatment (400 micrograms of beclomethasone two times daily), and finally 1 year of bronchodilator treatment alone. MAIN OUTCOME MEASURES: Decline in lung function (FEV1), change in bronchial hyperresponsiveness, indicated by a provocative concentration of histamine causing a 20% fall in FEV1 (PC20), morning peak expiratory flow rate (PEFR), diurnal PEFR, week-to-week variation of PEFR, bronchial symptoms, and exacerbations. RESULTS: The course of FEV1 during the year in which beclomethasone was discontinued was not significantly different when compared with the 2-year period of beclomethasone treatment. Neither did the course of PC20, morning PEFR, diurnal PEFR, symptom score, and exacerbation rate change. Only the week-to-week variation of the PEFR increased after discontinuing steroids. CONCLUSIONS: Discontinuing inhaled steroids is possible in some patients with asthma or COPD after 2 years of regular treatment. This might indicate that for certain groups of patients with mild asthma or COPD, periodic treatment schedules with inhaled steroids is the treatment policy for the future.

Administration, Inhalation↗

PubMed1992

Does the continuous use of bronchodilators mask the progression of asthma or chronic bronchitis?

Recently, we published data of a 2 year randomized controlled study in which the effects of continuous versus symptomatic bronchodilator treatment in patients with moderate asthma or chronic bronchitis were investigated. The results showed that FEV1 decline in the continuously treated group was significantly larger than in the symptomatically treated group (72 versus 20 ml/year, P < 0.05). We reanalysed these data in order to investigate the hypothesis that the continuous use of bronchodilators may mask a rapid decline in lung function. Lung function decline was assessed by regression analysis of seven FEV1 measurements. Respiratory symptoms were assessed by means of the MRC questionnaire every 12 months, and they were also recorded by the patients in a weekly report. Of the participating patients 144 completed the study. Increased lung function decline in the continuously treated group was not reflected in a significant deterioration of the symptoms. Moreover, the decline in FEV1 showed no correlation at all with changes in respiratory symptoms in continuously treated patients (r = -0.03, P = 0.80), whereas in the symptomatically treated group, there was a better relation (r = -0.32, P = 0.003) to changes in respiratory symptoms. These results show that continuous bronchodilation may indeed mask the worsening of the disease. This lack of awareness of deterioration of the disease is probably caused by the continuous symptom relief of bronchodilators. It may be misleading to both patients and physicians.

Adult↗