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J A Knottnerus

Publications and source records attributed to J A Knottnerus.

At least 37 records · Page 2Linked to original sources
PubMed2004

Influence of the presence of doctors-in-training on the blood pressure of patients: a randomised controlled trial in 22 teaching practices.

Until now, no information is available about the effect of the presence of a doctor-in-training on a patient's blood pressure. We tested the hypothesis that the presence of a last year medical student might increase the blood pressure of the patient, in addition to the possible pressor response to the doctor-trainer. Normotensive and hypertensive patients with a minimum age of 25 years, visiting for any reason, were recruited at 22 teaching general practices. Patients were randomised into a 'trainee' group (n=133) and a 'no trainee' (n=129) group. The blood pressure was measured at two subsequent contacts. In the 'trainee' group, a student was present at the first visit only. In the 'no trainee' group, both visits were without student. Both groups had similar anthropometric characteristics at entry. At the first visit, systolic pressure was higher in the 'trainee' group than in the control group (139.5 vs 133.1 mmHg, P=0.004), with a similar trend for diastolic pressure (80.2 vs 77.8 mmHg, P=0.07). From the first contact to the follow-up visit, blood pressure decreased in the trainee group by 4.8 mmHg systolic (P<0.001) and 1.7 mmHg diastolic (P=0.03), whereas the corresponding changes in the control group were -0.1 mmHg (P=0.90) and +1.5 mmHg (P=0.03). Thus, the between group differences in these trends averaging 4.7 mmHg (CI 1.5-7.9, P=0.005) systolic and 3.2 mmHg (CI 1.1-5.3, P=0.003) diastolic were statistically significant. We conclude that in teaching-practices, the presence of a doctor-in-training has a significant pressor effect when an experienced general practitioner measures a patient's blood pressure. If confirmed, our findings imply that doctors should be cautious to initiate or adjust antihypertensive treatment when blood pressure readings are obtained in the presence of a student.

Adult↗
PubMed2004

Compliance of asthmatic families with a primary prevention programme of asthma and effectiveness of measures to reduce inhalant allergens--a randomized trial.

BACKGROUND: Compliance to and the effect of pre- and post-natal exposure reduction measures to prevent asthma in high-risk children from asthmatic families were studied. METHOD: Families were randomized to a special care group (n=222) and a control group (n=221). Educational advice on measures to reduce their newborn's exposure to allergens and smoke was provided to the special care group during three visits (two pre-natal and one post-natal). The control group (n=221) received usual care. RESULT: After the intervention, the special care group differed significantly (P<0.01) from the usual care group in: use of anti-mite encasings (parental: 88% vs. 14%; baby: 98% vs. 10%); keeping pets outside (51% vs. 19%); combined breast- and hypoallergenic formula feeding (55% vs. 22%); first solids postponement until after the sixth month (71% vs. 28%); maternal post-natal smoking (52% vs. 28%). Little or no compliance was found for other sanitary measures (cleaning habits, providing a smooth floor covering, ventilation/airing, pet removal), exclusive breastfeeding, pre-natal smoking and partner smoking. In spite of pre-existent low allergen levels in both groups, there was a significant reduction of mite, cat, and dog allergens on the mattresses and mite and cat allergens in the living room in the special care group and were significantly lower compared with the usual care group after 1 year. CONCLUSION: High compliance was found for the use of anti-mite encasings; substantial compliance for using hypoallergenic formula, solid food postponement, keeping pets outside and reported post-natal maternal smoking. There was no compliance for sanitary measures and the reduction of maternal pre-natal passive smoking. Mite and pet allergens on mattresses were strongly reduced by anti-mite encasings.

Air Pollutants↗
PubMed2004

Psychological characteristics of patients with newly developed psychogenic seizures.

OBJECTIVES: To assess psychopathological symptoms and history of childhood trauma in patients with newly developed psychogenic seizures. METHODS: Using validated scales, 178 patients from the general population diagnosed with newly developed seizures were assessed, at a point in time when the nature of their seizures was yet unknown to either doctors or patients. After standardised neurological examination, 138 patients were diagnosed with non-psychogenic seizures (NPS), while 40 patients were found to have psychogenic seizures (PS). To evaluate possible differences between the genders and the diagnostic groups, univariate analyses of variance were done. RESULTS: PS patients reported significantly more comorbid psychopathological complaints, dissociative experiences, anxiety, and self-reported childhood trauma than NPS patients. In addition, PS patients had lower quality of life ratings than NPS patients. These effects were not modulated by gender. CONCLUSIONS: The results of the present study indicate that patients with newly developed PS constitute a group with complex psychopathological features that warrant early detection and treatment.

Adolescent↗
PubMed2003

Assessment of the accuracy of diagnostic tests: the cross-sectional study.

In diagnostic accuracy studies, the contrast of interest can be one of the following: one single test contrast; comparing two or more single tests; further testing in addition to previous diagnostics; and comparing alternative diagnostic strategies. The clinical diagnostic problem under study must be specified. Studies of "extreme contrasts" (as early phase evaluations) and studies in "clinical practice" settings (assessing clinical value) should be distinguished. Design options are (1) survey of the total study population, (2) case-referent approach, or (3) test-based enrollment. Data collection should generally be prospective, but ambispective and retrospective approaches are sometimes appropriate. In addition to determinants of primary interest [the test(s) under study] possible modifiers of test accuracy and confounding variables must be specified. The reference standard procedure should be independent from the test results. Applying a reference standard can be difficult in case of classification errors, lack of a clear pathophysiologic concept, incorporation bias, or invasive or complex investigations. Possible solutions are: an independent expert panel, and the delayed type cross-sectional study (clinical follow-up). Also, a prognostic criterion can be chosen. For studies to be relevant for practice, inclusion criteria must be based on "intention to diagnose" or "intention to screen." The recruitment procedure is preferably a consecutive series of presenting patients or a target population screening, respectively. Sample size estimation should be routine. Analysis has to be focused on the contrast of interest. Estimating test accuracy and prediction of outcome need different approaches. External (clinical) validation requires repeated studies in other, similar populations. Also, systematic reviews and meta-analysis have a role. To enable readers of diagnostic research reports to evaluate whether methodological key issues were addressed, authors are advised to follow the STARD guidelines.

Cross-Sectional Studies↗
PubMed2003

Community genetics and community medicine.

In the decades to come, molecular genetic insights and techniques will have great influence on prevention and health care. Health care providers should anticipate important new developments rather than just wait and see. For community doctors, who can impossibly oversee all relevant developments in sufficient detail, close communication with the community and clinical genetic specialists is necessary to keep pace with progress. With regard to genetic counselling and reproductive medicine, working agreements between primary care and specialist centres are important. General communication about hereditary issues can be dealt with by well informed GPs, with appropriate computerized decision support, but in order to address specific risks and disorders consultation at a clinical genetic centre is preferred. In clinical medicine, much work is being done on DNA-based 'dia-prognosis' and more targeted interventions. Estimations of when such innovations will really have an impact range from 2005 to beyond 2020, and there are still many uncertainties, especially regarding common multifactorial disorders. Community-based genetic epidemiology has become a basic science in understanding the human genome. Clinical epidemiological methodology can contribute a lot to the quality of molecular clinico-genetic studies. Long-term follow-up to evaluate predictions and interventions needs more attention, and can easily be integrated into primary care medicine. In view of the ambition to develop more tailormade interventions, research methodology will be challenged regarding n = 1 studies. With respect to counselling and clinical practice, many ethical issues, relevant for community medicine, have to be considered in the domains of both reproductive medicine and clinical practice. Doctors, patients and society, traditionally battling to reduce diagnostic and prognostic uncertainties, must now learn to cope with approaching certainties. As for all new technologies, cost-effectiveness is an important topic for genetics. Increased cost-effectiveness because of better targeted interventions may be counterbalanced by the price of the new technologies and an expanding indicated population. In view of current developments, community practitioners must integrate community genetics into their daily routine, and critically anticipate possibly relevant innovations. More efforts in genetic risk assessment and communication are necessary in undergraduate and postgraduate training. A multidisciplinary approach is needed, in collaboration with primary care-oriented genetic specialists. Efforts to educate the public and (potential) patients should start at an early age, and must focus on what (future) health care users need for a balanced appraisal of genetic information and for optimal decision making in health promotion and health care.

Cost-Benefit Analysis↗
PubMed2003

Outcome measures in irritable bowel syndrome: comparison of psychometric and methodological characteristics.

OBJECTIVES: Although there is growing interest in irritable bowel syndrome (IBS) research, there is as yet no consensus regarding the preferred outcome measure. We aimed to evaluate and to compare the validity and appropriateness of available IBS outcome measures. METHODS: IBS symptom and IBS health-related quality of life (HRQOL) scales were identified through a literature search. In a panel evaluation, six reviewers independently rated the scales according to predetermined psychometric and methodological validation criteria. RESULTS: Five IBS symptom scales and five IBS HRQOL instruments were identified. Two of the symptom scales were rated as good. The Adequate Relief question scored best. This scale demonstrates responsiveness as well as face and construct validity, and its score was considered easy to interpret and appropriate for use. According to the reviewers, the IBS Severity Scoring System performed well with regard to psychometric capacities, but its practical utility was considered debatable. The properties of the other three symptom scales were suboptimal. The practical utility of the five IBS-specific HRQOL scales was considered poor. However, the reviewers agreed that, at present, the IBS Quality of Life measurement (Patrick et al.) is the best choice, because it has been the most extensively validated and shows appropriate psychometric quality. CONCLUSIONS: The Adequate Relief question is the measure of first choice when assessing global symptomatology as an outcome in IBS studies. For a more detailed IBS symptom assessment, the IBS Severity Scoring System is preferable. Finally, the IBS Quality of Life measurement scale can be used to establish changes in health-related quality of life.

Colonic Diseases, Functional↗
PubMed2003

Fatigue, burnout, and chronic fatigue syndrome among employees on sick leave: do attributions make the difference?

BACKGROUND: Persistent fatigue among employees, burnout, and chronic fatigue syndrome (CFS) are three fatigue conditions that share some characteristics in theory. However, these conditions have not been compared in empirical research, despite conceptual similarities. METHODS: This cross sectional study aimed to investigate relations between persistent fatigue, burnout, and CFS by describing the clinical features of a sample of 151 fatigued employees on sick leave. Using validated instruments, subgroups based on research criteria for CFS and burnout within the sample of fatigued employees and a reference group of 97 diagnosed CFS patients were compared. Analyses of covariance were performed. RESULTS: A total of 66 (43.7%) fatigued employees met research criteria for CFS (except symptom criteria) and 76 (50.3%) met research criteria for burnout. "CFS-like employees" (fatigued employees who met CFS criteria) reported stronger somatic attributions than "non-CFS-like employees". Burnt out CFS-like employees were more depressed and distressed than CFS-like employees who were not burnt out. Burnout cases among the non-CFS-like employees had stronger psychological attributions than fatigued employees who were not burnt out. Compared to diagnosed CFS patients, CFS-like employees merely had a shorter duration of fatigue complaints. Burnt out CFS-like employees had stronger psychological attributions and were more distressed than CFS patients. CONCLUSIONS: Fatigued employees shared many important characteristics with CFS patients, regardless of burnout status, and many fatigued employees met CFS criteria and/or burnout criteria. Differences however concerned the causal attributions that were made. This raises questions about the role of causal attributions: are they modified by fatigue complaints or do they determine illness outcome?

Adult↗
PubMed2003

A randomised controlled trial of joint consultations with general practitioners and cardiologists in primary care.

BACKGROUND: Joint consultation sessions of a small group of general practitioners (GPs) and a specialist in orthopaedics proved to be an effective way of decreasing the referral rate of orthopaedic patients. Cardiac complaints comprise an important category of health problems with high referral rates. AIMS: To study the effects of joint consultation on the quality of care and referrals for patients with cardiac complaints. DESIGN OF STUDY: Randomised controlled trial. SETTING: Forty-nine GPs participated in 16 consultation groups, each with one of 13 cardiologists, in monthly joint consultations over a period of about 18 months. METHOD: The GPs selected patients about whom they were uncertain, and those needing urgent referral were excluded. Patients were randomly assigned to joint consultation or to usual care. After a follow-up period all patients had a joint consultation for outcome assessment. Referral data were provided by two regional health insurance companies and questionnaires were given to the patients, GPs, and cardiologists to gauge their opinion of the trial. RESULTS: One hundred and forty-eight patients in the intervention group and 158 patients in the control group fulfilled the whole protocol. The quality of care was similar in both groups. In the intervention group, 34% of the patients were referred, compared with 55% in the control group (P = 0.001), and fewer patients underwent further diagnostic procedures (7% compared with 16%, P = 0.013). Referrals to cardiology as a proportion of all referrals decreased in the practices of the participating GPs, compared with their reference districts (P = 0.024). CONCLUSION: Joint consultation is an effective method that provides a quality of care that at least equals usual care and that contributes to a better selection of patients who need specialist care.

Adult↗
PubMed2003

Contributions of symptoms, signs, erythrocyte sedimentation rate, and C-reactive protein to a diagnosis of pneumonia in acute lower respiratory tract infection.

BACKGROUND: Diagnostic tests enabling general practitioners (GPs) to differentiate rapidly between pneumonia and other lower respiratory tract infections (LRTIs) are needed to prevent increase of bacterial resistance by unjustified antibiotic prescribing. AIMS: To assess the diagnostic value of symptoms, signs, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) for pneumonia; to derive a prediction rule for the presence of pneumonia; and to identify a low-risk group of patients who do not require antibiotic treatment. DESIGN OF STUDY: Cross-sectional. SETTING: Fifteen GP surgeries in the southern part of The Netherlands. METHOD: Twenty-five GPs recorded clinical information and diagnosis in 246 adult patients presenting with LRTI. Venous blood samples for CRP and ESR were taken and chest radiographs (reference standard) were made. Odds ratios, describing the relationships between discrete diagnostic variables and reference standard (pneumonia or no pneumonia) were calculated. Receiver operating characteristic analysis of ESR, CRP, and final models for pneumonia was performed. Prediction rules for pneumonia were derived from multiple logistic regression analysis. RESULTS: Dry cough, diarrhoea, and a recorded temperature of > or = 38 degrees C were independent and statistically significant predictors of pneumonia, whereas abnormal pulmonary auscultation and clinical diagnosis of pneumonia by the GPs were not. ESR and CRP had higher diagnostic odds ratios than any of the symptoms and signs. Adding CRP to the final 'symptoms and signs' model significantly increased the probability of correct diagnosis. Applying a prediction rule for low-risk patients, including a CRP of < 20, 80 of the 193 antibiotic prescriptions could have been prevented with a maximum risk of 2.5% of missing a pneumonia case. CONCLUSION: Most symptoms and signs traditionally associated with pneumonia are not predictive of pneumonia in general practice. The prediction rule for low-risk patients presented here, including a CRP of < 20, can considerably reduce unjustified antibiotic prescribing.

Adolescent↗
PubMed2002

[Centenary of the Health Council of the Netherlands. I. Introduction].

The Health Council of the Netherlands [Dutch name: Gezondheidsraad] is an independent, statutory advisory body whose task is to inform the Dutch government on the current level of knowledge with respect to public health issues. Its work covers the entire terrain of curative and preventive healthcare, environmental protection, nutrition, occupational hygiene and environmental hygiene. The Health Council has existed in one form or another since 1 August 1902. Its present form was established by the 1956 Health Act, which was amended in 1997. To perform its task, the Health Council brings together multidisciplinary committees of leading experts--nominated in a personal capacity--on specific topics both at the government's request and on its own initiative. About thirty committees are operative at any one time. The Health Council has published more than 2000 advisory reports during its 100 years of existence.

Financing, Government↗
PubMed2002

Menopausal transition and increased depressive symptomatology: a community based prospective study.

OBJECTIVE: Prevalence of depression is suggested to be substantially higher in women around menopause. Declining estrogen levels might be an explanation. This study attempts to determine whether depressive symptomatology in healthy women is independently related to menopausal transition. METHOD: All caucasian women born between 1941 and 1947, living in the city of Eindhoven the Netherlands were invited to take part in a screening program (n=8098) of whom 78% participated (n=6648). About 92% returned the questionnaires of which 81% (n=4975) was fully completed. Women using estrogens and/or having undergone hysterectomy and/or ovariectomy were excluded (43.6%). Of the remaining 2820 women, after 3.5 years, 2748 returned another postal questionnaire, of which 76% was fully completed (n=2103). Depressive symptomatology was assessed using the Edinburgh Depression Scale (EDS). Independent relationship between an intra-individual change in EDS score during the follow-up period and menopausal transition was analysed by multiple logistic regression (enter as well as stepwise method). RESULTS: Beside the classical determinants of depression (unemployment OR 3.1, CI 1.6-5.8, inability to work OR 1.7, CI 1.0-2.8, financial problems OR 2.9, CI 1.1-7.3 death of a partner OR 2.6, CI 1.1-6.1, death of a child OR 5.9, CI 1.1-32.1 and a previous episode of depression OR 2.0, CI 1.5-2.7) transition from pre to perimenopause and peri to postmenopause was significantly related to a high increase (>5.4) of the EDS score (OR 1.8, CI 1.1-3.3 and OR 1.8, CI 1.5-2.7, respectively). CONCLUSION: The transition from pre to perimenopause as well as from peri to postmenopause seems to be independently related to a high increase of depressive symptomatology. This suggests that the decrease of ovarian estrogen production is a risk factor for depressive symptomatology.

Climacteric↗
PubMed2002

[The benefit of population screening for breast cancer; an advisory report from the Health Council of the Netherlands].

A recent Cochrane review does not nullify the evidence supporting the practice of mammographic population screening for breast cancer for women aged 50 years and over. Thus concludes the Health Council of the Netherlands in an advisory report to the Dutch Government. A central feature of the Cochrane review is the conclusion that breast-cancer mortality is an unreliable outcome that is biased in favour of screening. The Health Council finds this conclusion too extreme and does not support the view that breast-cancer mortality must be replaced by overall mortality as an outcome. The Health Council does agree with the view that the use of disease-specific mortality as the only endpoint renders cancer-screening trials subject to bias. Therefore, careful attention should be paid to total cancer mortality, other important causes of death, and overall mortality.

Breast Neoplasms↗
PubMed2002

Increased risk of Parkinson's disease after depression: a retrospective cohort study.

BACKGROUND: Depression has been linked to the occurrence of a number of somatic diseases. There are no data for PD. OBJECTIVE: To determine if depression is associated with a subsequent risk for PD. METHODS: A retrospective cohort study design based in general practice was applied. All subjects diagnosed with depression between 1975 and 1990 were included and matched with subjects with the same birth year who were never diagnosed with depression. Follow-up ended at April 30, 2000. Hazard ratios (HR) and 95% CI were calculated using Cox proportional hazards models adjusted for age, sex, and socioeconomic status. Subgroups based on sex and age at diagnosis of depression were evaluated separately. RESULTS: Among the 1,358 depressed subjects, 19 developed PD, and among the 67,570 nondepressed subjects, 259 developed PD. The HR (95% CI) for depressed vs nondepressed subjects was 3.13 (1.95 to 5.01) in multivariable analysis. Associations in subgroups were comparable with the overall association. CONCLUSION: A strong positive association was found between depression and subsequent incidence of D.

Adult↗
PubMed2002

A risk model for the prediction of recurrent falls in community-dwelling elderly: a prospective cohort study.

The object of this article was to determine the predictive value of risk factors for recurrent falls and the construction of a fall risk model as a contribution to a mobility assessment for the identification of community-dwelling elderly at risk for recurrent falling in general practice. The design was a prospective cohort study (n = 311). There were four primary health care centers. A sample stratified on previous falls, age, and gender of community-dwelling elderly persons aged 70 years or over (n = 311) was taken from the respondents to a mail questionnaire (n = 1660). They were visited at home to assess physical and mental health, balance and gait, mobility and strength. A 36-week follow-up with telephone calls every 6 weeks was conducted. Falls and fall injuries were measured. During follow-up 197 falls were reported by 33% of the participants: one fall by 17% and two or more falls by 16%. Injury due to a fall was reported by 45% of the fallers: 2% hip fractures, 4% other fractures, and 39% minor injuries. A fall risk model for the prediction of recurrent falls with an area under the curve (AUC) of 0.79, based on logistic regression analysis, showed that the main determinants for recurrent falls were: an abnormal postural sway (OR 3.9; 95% Cl 1.3-12.1), two or more falls in the previous year (OR 3.1; 95% Cl 1.5-6.7), low scores for hand grip strength (OR 3.1; 95% Cl 1.5-6.6), and a depressive state of mind (OR 2.2; 95% CI 1.1-4.5). To facilitate the use of the model for clinical practice, the model was converted to a "desk model" with three risk categories: low risk (0-1 predictor), moderate risk (two predictors), and high risk (> or =3 predictors). A fall risk model converted to a "desk model," consisting of the predictors postural sway, fall history, hand dynamometry, and depression, provides added value in the identification of community-dwelling elderly at risk for recurrent falling and facilitates the prediction of recurrent falls.

Accidental Falls↗
PubMed2002

Diagnostic value of history and physical examination in patients suspected of lumbosacral nerve root compression.

OBJECTIVE: To evaluate patient characteristics, symptoms, and examination findings in the clinical diagnosis of lumbosacral nerve root compression causing sciatica. METHODS: The study involved 274 patients with pain radiating into the leg. All had a standardised clinical assessment and magnetic resonance (MR) imaging. The associations between patient characteristics, clinical findings, and lumbosacral nerve root compression on MR imaging were analysed. RESULTS: Nerve root compression was associated with three patient characteristics, three symptoms, and four physical examination findings (paresis, absence of tendon reflexes, a positive straight leg raising test, and increased finger-floor distance). Multivariate analysis, analysing the independent diagnostic value of the tests, showed that nerve root compression was predicted by two patient characteristics, four symptoms, and two signs (increased finger-floor distance and paresis). The straight leg raise test was not predictive. The area under the curve of the receiver-operating characteristic was 0.80 for the history items. It increased to 0.83 when the physical examination items were added. CONCLUSIONS: Various clinical findings were found to be associated with nerve root compression on MR imaging. While this set of findings agrees well with those commonly used in daily practice, the tests tended to have lower sensitivity and specificity than previously reported. Stepwise multivariate analysis showed that most of the diagnostic information revealed by physical examination findings had already been revealed by the history items.

Adolescent↗
PubMed2002

Predicting the outcome of sciatica at short-term follow-up.

BACKGROUND: The prognostic value of the clinical findings elicited in the patient presenting with sciatica is unknown. AIM: To investigate whether history and physical examination findings can predict outcome. DESIGN OF STUDY: Prospective study of prognostic factors. SETTING: A sample of primary care patients with sciatica. METHOD: Short-term favourable outcome was registered as improvement perceived by the patient after two weeks. Long-term failure was defined as eventual surgery or lack of improvement after three months. RESULTS: The signs and symptoms that most consistently predicted an unfavourable outcome were: a disease duration of more than 30 days; increased pain on sitting; and more pain on coughing, sneezing or straining. The straight leg raising test and, to a lesser degree the reversed straight leg raising test, were the most consistent examination findings associated with poor outcome. Chances of short-term improvement were also related to the body weight relative to the length. CONCLUSION: The predictors in this study can indicate the prognosis of patients with sciatica at an early stage. Knowledge of these prognostic factors may help to fine tune treatment decisions and improve patient selection in trials of conservative therapy strategies.

Adult↗
PubMed2002

The evidence to support mammography screening.

A recent Cochrane review claimed that mammography screening did not save lives and could actually be harmful. In an advisory report to the Dutch government, a committee of the Health Council of The Netherlands concludes that the Cochrane review does not nullify the evidence supporting breast cancer screening programmes for women aged 50 or over. Except for one flawed trial, the committee found no convincing arguments to exclude four out of the six other eligible trials entirely or partially from the analysis. The committee considers the reviewers' conclusions that breast cancer mortality as an outcome is unreliable (biased in favour of screening) and must be replaced by overall mortality to be too extreme. In the committee's view, breast cancer mortality is an important outcome. However, this outcome should be considered in conjunction with all-cancer mortality and all-cause mortality when interpreting the results of screening trials (or observational studies).

Breast Neoplasms↗