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Biomedical subjects

G J Dinant

Publications and source records attributed to G J Dinant.

At least 37 records · Page 2Linked to original sources
PubMed1999

The effect of smoking on influenza, influenza vaccination efficacy and on the antibody response to influenza vaccination.

We examined the relation between cigarette smoking and (1) the occurrence of influenza, (2) the efficacy of influenza vaccination and (3) the antibody response to influenza vaccination in fifteen family practices in South-Limburg, the Netherlands, during the influenza season 1991 1992. Data were used from a randomized double-blind placebo-controlled trial into the efficacy of influenza vaccination in which smoking status was measured 10 weeks after the start of the trial. A total of 1838 subjects aged 60 years or older, of whom 1531 subjects (321 smokers, 1152 non-smokers and 58 cigar/pipe smokers) who returned the smoking questionnaire and were not previously vaccinated, were used in the analyses. The main outcome measures were serological influenza (fourfold increase of antibody titre between 3 weeks and 5 months after vaccination); clinical influenza as determined by criteria of the Dutch Sentinel Stations from self reported symptoms in postal questionnaires 10 weeks and 5 months after vaccination; increases after vaccination and decreases after 5 months in logarithmic titres of antibody against the vaccine strains. No relation between smoking and either serological or clinical influenza was found, although the risk for serological influenza was slightly (not significantly) elevated in smokers compared to non-smokers. A statistical interaction was found between smoking and vaccination when serological influenza was the outcome measure indicating that the efficacy of vaccination was greater in smokers than in non-smokers (comparison of model with and without interaction; likelihood ratio test, p < 0.0001). This finding is supported by a greater titre rise 3 weeks after vaccination for two out of four strains, but not by the antibody response after vaccination in previous studies on influenza and other infectious diseases. Also, this possible difference of immunogenicity is not reflected in a better protection for clinical influenza. The rise in antibody titre 3 weeks after vaccination was higher in smokers for A/Singapore/6/86 and B/Beijing/11/87, but not for the other two strains. Decline in titres after 5 months was similar for smokers and non-smokers. We conclude that smoking has no clinical or preventive significance for risk of influenza in the elderly.

Aged↗
PubMed1998

[The Audioscope III in family practice: an instrument suitable for the diagnosis of hearing loss in comparison with the regular audiometer].

OBJECTIVE: To compare the results of hearing tests performed with the Audioscope III and the classical audiometer. DESIGN: Cross-sectional study. SETTING: Two general practices in South Limburg, the Netherlands. METHOD: The hearing of 115 patients aged 55-93 years who visited the practice for any reason was tested with the Audioscope III and subsequently with the screening audiometer, in two silent examination rooms. The tests were performed independently by two general practice trainees. Finally, the subjects were asked which instrument they preferred. An ear was diagnosed as 'hard or hearing' if the Fletcher index measured with the audiometer was > 30 dB or if, with the Audioscope III, 1, 2, 3 or 4 tones were not heard at 40 dB. RESULTS: Depending on the number of tones not heard, the agreement between the measuring results ranged from 65 to 86%. If subjects during the examination with the Audioscope III failed to hear > or = 2 tones at 40 dB, the conclusion 'hardness of hearing', judged by the audiometric results, was correct in all cases. Conversely, the proportion of ears incorrectly diagnosed as 'not abnormal' at this limit was 39%. Hearing tests with the Audioscope III took little time (0.5-4 minutes) and were in general tolerated well. CONCLUSION: The Audioscope III is a useful instrument in situations in which there is a high prevalence of auditory disorders, for instance in general practices with a relatively elderly patient population.

Aged↗
PubMed1998

The predictive value of influenza symptomatology in elderly people.

OBJECTIVE: We aimed to determine the complex of symptoms which has the highest predictive value for the diagnosis of influenza. METHOD: A questionnaire study with questions regarding the symptomatology of influenza among patients aged 60 and older (n = 1838). Thirty-four participating GPs recorded the symptomatology of patients who came to their general practice with influenza-like complaints. The validity of the diagnostic conclusion of the GP, as well as the diagnostic validity of the criteria of the International Classification of Health Problems in Primary Care (ICHPPC-2) and the Sentinel Stations in The Netherlands, was determined with the help of the predictive value and odds ratio, using serologically confirmed influenza as the gold standard. The same method was used to determine which complex of symptoms has the highest predictive value for influenza. The results were verified using logistic regression analysis. RESULTS: The predictive value of the diagnostics of the GP amounted to 35%. The predictive values of the diagnostics according to the criteria of the two classification methods were 24% (Sentinel Stations) and 18% (ICHPPC-2). Of the individual symptoms, the combination of fever, coughing and acute onset had the highest predictive value (30.3%) for the diagnosis of influenza. CONCLUSION: It is recommended that the criteria of the Sentinel Stations in The Netherlands and the ICHPPC-2 be adapted in the following way: influenza is likely if, out of the entire complex of symptoms, at least fever, coughing and an acute onset occur.

Acute Disease↗
PubMed1997

Identifying relevant diagnostic studies in MEDLINE. The diagnostic value of the erythrocyte sedimentation rate (ESR) and dipstick as an example.

OBJECTIVE: We aimed to examine sensitivity and positive predictive value of MEDLINE searching for diagnostic studies, relevant for the primary health care setting. METHOD: Results of MEDLINE searches were compared with a reference standard collection of studies on two subjects, the diagnostic value of ESR in discriminating between 'pathology' and 'no pathology', and the dipstick method in diagnosing urinary tract infections. The main outcome measures were sensitivity (proportion of the total number of reference standard diagnostic studies that could be identified by the search) and positive predictive value (proportion of the total number of publications retrieved by MEDLINE that were incorporated in the reference standard). RESULTS: The combined MeSH and freetext search was more sensitive than MeSH term searching only, for both the ESR and the dipstick search. With this combined search sensitivities of 0.91 and 0.98 and predictive values of 0.10 and 0.68 were found for ESR and dipstick respectively. By restricting the search with keywords describing the primary health care setting the predictive values increased to 0.72 and 1.00 but sensitivity dropped to 0.10 and 0.07 (ESR and dipstick respectively). CONCLUSION: Combining freetext and MeSH term searching, without restriction to the primary health care setting, is a valuable strategy in systematically searching for available evidence on the value of a diagnostic test in the scope of a specific disease. The predictive value seems to depend on the breadth of the disease area. MEDLINE should provide a term such as 'diagnostic evaluation study' to be used in the limit field Publication Type to specify diagnostic studies.

Blood Sedimentation↗
PubMed1995

[The Accutrend glucose-cholesterol meter in family practice compared to laboratory determinations].

OBJECTIVE: To determine the similarity in clinical consequences that follow, according to the guidelines of the Dutch General Practice Standards, from measured glucose and cholesterol concentrations with the Accutrend glucose cholesterol meter in general practice on one hand and the usual measurements in a laboratory on the other. DESIGN: Comparative study. SETTING: Two general practices in the district 'Zuid-Limburg' in the Netherlands. METHOD: 66 patients with non-insulin-dependent diabetes mellitus and 34 control patients had their capillary blood glucose and cholesterol concentrations measured with the Accutrend glucose cholesterol meter. The same measurements were done with simultaneously taken venous blood samples, according to usual laboratory methods, in a laboratory. The clinical consequences of the measurements in the general practice and the laboratory, according to the Standards, were compared and if they contained different recommendations they were regarded as clinically relevant. RESULTS: In 5% of the cases a clinically relevant difference between the glucose measurements done in the general practice and the laboratory was found. For the cholesterol measurements a clinically relevant difference was found in 18%. Besides, 16% of the cholesterol measurements in the general practice were outside the range of the meter. CONCLUSION: The Accutrend glucose cholesterol meter is a qualitatively good instrument for blood glucose measurements in general practice. For blood cholesterol measurements, the quality as well as the range of the meter are still insufficient.

Blood Glucose↗
PubMed1995

[Hypertension diagnosis by the family physician: measurements according to the NHG-standard (Dutch College of General Practitioners) compared with ambulatory blood pressure determination].

OBJECTIVE: To compare the standard procedure (SP) for determining hypertension as described by the DCGP with the results of ambulatory blood pressure measurement (ABM). DESIGN: Prospective study. SETTING: Practices of 17 GPs in central and south Limburg, the Netherlands. METHOD: The SP of the DCGP was executed in 94 of 102 patients with possible hypertension. In each patient a 24-hour ABM was performed simultaneously as reference value. RESULTS: The correlation between the SP and the ABM was low (r = 0.51) and the blood pressure was mostly overestimated by the SP. Sensitivity and specificity of the SP were 0.67 and 0.52 respectively. When the first blood pressure measurement was high in a patient with probable hypertension (diastolic pressure 105-115 mmHg) SP correlated well with ABM. When the first blood pressure measured was relatively low (diastolic pressure 95-105 mmHg) correlation was also low. CONCLUSION: The difference in blood pressure measured by the physician in his office compared with measurement at home ('white coat effect') was observed in this study also. The results support the advice of the DCGP to check the blood pressure more often in hypertensive patients with low than in those with high initial diastolic values.

Blood Pressure Determination↗
PubMed1995

Diagnostic value of C-reactive protein measurement does not justify replacement of the erythrocyte sedimentation rate in daily general practice.

The purpose of this paper was to establish the diagnostic value of the C-reactive protein measurement (CRP) in patients attending their general practitioner (GP) with a new complaint for which the GP considers determination of the erythrocyte sedimentation rate (ESR) to be indicated. During 4 successive months in 1992, 11 GPs in four general practice centres in the Netherlands identified patients indicated for the erythrocyte sedimentation rate. ESR and CRP were determined at the local hospital laboratory. One year later, an independent GP established the follow-up diagnoses. By comparing the test results with the follow-up diagnoses, using logistic regression analysis and Receiver Operating Characteristic curves, sensitivities, specificities, predictive values and odds ratios were established. In 396 patients the prevalence of inflammatory diseases and malignancies ('pathology') was found to be 26% in males and 15% in females. Both ESR and CRP were valuable in discriminating pathology from harmless, often self-limiting diseases. The optimal upper limits of reference values ('cut-off points') for ESR were found to be 31 mm in both males and females. At these cut-off points, the diagnostic gains from positive and negative test results (positive predictive value minus prevalence, and negative predictive value minus 100% minus prevalence) were 45% and 4% for males and 30% and 2% for females. The optimal cut-off point for CRP was found at 15 mg L-1 in males and 34 mg L-1 in females. The diagnostic gain from positive and negative test results were 18% and 9% in males and 25% and 4% in females.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

The efficacy of influenza vaccination in elderly individuals. A randomized double-blind placebo-controlled trial.

OBJECTIVE: To determine the efficacy of influenza vaccination in elderly people. DESIGN: Randomized double-blind placebo-controlled trial. SETTING: Fifteen family practices in the Netherlands during influenza season 1991-1992. PARTICIPANTS: A total of 1838 subjects aged 60 years or older, not known as belonging to those high-risk groups in which vaccination was previously given. INTERVENTION: Purified split-virion vaccine containing A/Singapore/6/86(H1N1), A/Beijing/353/89(H3N2), B/Beijing/1/87, and B/Panama/45/90 (n = 927) or intramuscular placebo containing physiological saline solution (n = 911). MAIN OUTCOME MEASURES: Patients presenting with influenzalike illness up to 5 months after vaccination; self-reported influenza in postal questionnaires 10 weeks and 5 months after vaccination; serological influenza (fourfold increase of antibody titer between 3 weeks and 5 months after vaccination). RESULTS: The incidence of serological influenza was 4% in the vaccine group and 9% in the placebo group (relative risk [RR], 0.50; 95% confidence interval [CI], 0.35 to 0.61). The incidences of clinical influenza were 2% and 3%, respectively (RR, 0.53; 95% CI, 0.39 to 0.73). The effect was strongest for the combination of serological and clinical influenza (RR, 0.42; 95% CI, 0.23 to 0.74). The effect was less pronounced for self-reported influenza. CONCLUSION: In the elderly, influenza vaccination may halve the incidence of serological and clinical influenza (in periods of antigenic drift).

Aged↗
PubMed1994

Immune response to influenza vaccination of elderly people. A randomized double-blind placebo-controlled trial.

The objective of this study was to determine the immune response to influenza vaccination in elderly people, using a randomized, double-blind, placebo-controlled trial. Venous blood was taken from 1838 people aged 60 years and older, prior to injection with the influenza vaccine or a placebo. A second blood sample was taken three weeks later. The antibody reaction was measured by comparing the geometric mean titre and the percentage of participants who had a protective antibody titre before and after vaccination and for all sera of each strain. A protective antibody titre was found in 43-68% of those who had received the vaccine, depending on the strain investigated. Patients potentially at risk showed a response similar to the other participants. We conclude that influenza vaccination in elderly people provides a reasonable to good immune response. Research is needed on whether a good immune response decreases the incidence of influenza.

Aged↗
PubMed1994

Reliability of C-reactive protein measurement in general practice in The Netherlands.

The aim of this study was to compare the reliability of the whole blood NycoCard C-reactive protein measurement (CRP) with the erythrocyte sedimentation rate (ESR) in four general practice centres (GPCs) in The Netherlands with 443 patients indicated for ESR. During 4 successive months in 1992 NycoCard CRP was measured in capillary (whole) blood at the GPC. A venous blood sample was then transported to the local hospital laboratory in order to determine CRP turbidimetrically in plasma. Westergren's ESR was measured at the GPC and at the laboratory. The dichotomized CRP values measured at the GPCs corresponded with the laboratory values in 88% of the cases. Kappa was 65% (p < 0.00001). Using a 20 mm cut-off point, ESR values measured at the GPCs and the laboratory corresponded in 96% of cases (Kappa = 90%, p < 0.00001). Interpractice variabilities and learning effects did not influence the results. 'False normal' rates for CRP and ESR were 8% and 1%; 'false elevated' rates were 28% and 12% respectively. The reliability of the NycoCard CRP measurement in whole blood disappointed. In particular the 'false elevated' rate is unacceptably high for daily general practice. The background of the poor reliability remains unclear.

Blood Sedimentation↗
PubMed1993

Adverse reactions to influenza vaccine in elderly people: randomised double blind placebo controlled trial.

OBJECTIVE: To assess the frequency and type of side effects after influenza vaccination in elderly people. DESIGN: Randomised double blind placebo controlled study. SETTING: 15 general practices in the southern Netherlands. SUBJECTS: 1806 patients aged 60 or older, of whom 904 received influenza vaccine and 902 placebo. MAIN OUTCOME MEASURES: Adverse reactions reported on postal questionnaire completed four weeks after vaccination. RESULTS: 210 (23%) patients given vaccine reported one or more adverse reactions compared with 127 (14%) given placebo. The frequency of local adverse reactions were 17.5% in the vaccine group and 7.3% in the placebo group (p < 0.001). There was no difference in systemic adverse reactions (11% v 9.4%; p = 0.34). In general, men reported fewer side effects than women. CONCLUSION: Only local side effects were more common in vaccinated patients and all side effects were mild.

Age Factors↗
PubMed1992

Plasma viscosity and erythrocyte sedimentation rate in inflammatory and non-inflammatory rheumatic disorders.

Plasma viscosity (PV) and erythrocyte sedimentation rate (ESR) are considered to reflect the complex of acute phase reactants in inflammations. Both tests were studied with regard to their ability to discriminate between inflammatory and non-inflammatory rheumatic diseases. PV and ESR were measured using the Coulter Viscometer II and the Westergren method, respectively. ESR was found to be a better parameter for rheumatoid arthritis and ankylosing spondylitis than PV, independent of the chosen reference values, age, gender and the hemoglobin level. ESR may still be regarded as an acceptable parameter for monitoring inflammatory rheumatic diseases.

Adult↗
PubMed1992

Diagnostic impact of the erythrocyte sedimentation rate in general practice: a before-after analysis.

Despite its frequent use and long history, little is known about the diagnostic impact of the measurement of the erythrocyte sedimentation rate (ESR) in general practice. We prospectively followed 362 patients who were seen by their general practitioner (GP) because of a new complaint, for which the GP wanted to know the ESR. The GPs recorded the most probable diagnosis, as well as their clinical judgements in terms of 'severe' and 'not severe', and the expected ESR values, before and after the determination of the ESR in the local hospital laboratory. Having compared the results before ESR determination with the results after, we conclude that ESR is valuable in reassuring the patient and the doctor when 'no pathology' is suspected rather than in confirming the presence of inflammatory diseases and malignancies.

Adolescent↗
PubMed1992

Discriminating ability of plasma viscosity and erythrocyte sedimentation rate; a prospective study at the rheumatology out-patient department.

Measurements of plasma viscosity (PV) and erythrocyte sedimentation rate (ESR) are supposed to reflect the complex of acute phase reactants in inflammations. Both tests were prospectively studied at the rheumatology out-patient department with regard to their ability to discriminate between inflammatory and non-inflammatory rheumatic diseases in new patients (n = 235). PV and ESR were measured using the Coulter Viscometer II and the Westergren method, respectively. The Receiver Operating Characteristic curve for PV was slightly better than for ESR. However, at the higher cut-off points (PV greater than 1.81 mPa.s, ESR greater than 25 mm/l hr), sensitivities, specificities, predictive values and odds ratios were more favourable for ESR. Furthermore, since the costs of PV measurement are considerably higher, there is no reason for an implementation of PV in the daily routine of the rheumatologist at the outpatient department.

Adolescent↗
PubMed1991

Leucocyte count as an alternative to ESR in general practice?

We investigated the ability of the leucocyte count to discriminate between "inflammatory diseases and malignancies" on the one hand and other, often harmless and self-limiting diseases on the other, and compared this ability with that of the erythrocyte sedimentation rate (ESR) in general practice. In cooperation with nine general practitioners (GP) we prospectively followed 151 patients who were seen by their GP because of a new complaint for which the GP wanted to know their ESR. ESR and one leucocyte count measurement (Technicon H6000) were performed at the local hospital laboratory. The patients were seen again after three months, to determine the follow-up diagnoses. By comparing the test results with the follow-up diagnoses, ESR was found to have a better discriminating ability than the leucocyte count test (ESR: sensitivity = 53%, specificity = 84%, positive predictive value = 29%, negative predictive value = 93%, Odds Ratio = 5.73). Using Receiver Operating Characteristic analysis, this conclusion could be shown to be independent of the chosen reference values. We conclude that the determination of the leucocyte count is not a clinically interesting alternative to ESR.

Adolescent↗
PubMed1991

Discriminating ability of the erythrocyte sedimentation rate: a prospective study in general practice.

Despite its frequent use, little is known about the ability of the erythrocyte sedimentation rate to discriminate between 'pathology' (inflammatory diseases and malignancies) and 'no pathology' in general practice. This has been studied by following 362 patients who presented to their general practitioner with a new complaint, for which the general practitioner considered determination of the erythrocyte sedimentation rate to be indicated. The test was performed at the local hospital laboratory and the patients were seen again after three months, in order to establish the follow-up diagnoses. By comparing the test results with the follow-up diagnoses, combined with receiver operating characteristic curves and regression analysis, the erythrocyte sedimentation rate was found to have a reasonable discriminating ability with respect to malignancies and inflammatory diseases (sensitivity 53%, specificity 94%, positive predictive value 48%, negative predictive value 91%, odds ratio 15.1). The upper limit for the normal erythrocyte sedimentation rate should be set at approximately 12 mm hour-1 for men and 28 mm hour-1 for women, and needs no correction for age. It is concluded that the erythrocyte sedimentation rate still deserves a place in the general practitioner's daily routine.

Adolescent↗
PubMed1989

Reliability of the erythrocyte sedimentation rate in general practice.

Because of the need for an accurate determination of the erythrocyte sedimentation rate (ESR), and because of the fact that many general practitioners frequently determine ESR in their own surgery, we investigated the reliability of the blood test in this setting. For this purpose, blood samples, obtained from the local hospital laboratory, were distributed, and the participating general practice centres were requested to determine ESR in each sample. A clinically important intra- and interpractice variability was found in the ESR values measured. The experiment was then repeated one year later under more standardized conditions, which resulted in a significant decrease in the intra- and interpractice variability (p = 0.04 and 0.003, respectively). Vibrations within the hospital building could not account for the systematically higher ESR values measured in the hospital laboratory. We conclude that a considerable increase in the quality of ESR performance in general practice can be achieved by means of relatively simple interventions.

Blood Sedimentation↗