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Biomedical subjects

J A Knottnerus

Publications and source records attributed to J A Knottnerus.

At least 73 records · Page 4Linked to original sources
PubMed2000

Conservative treatment of sciatica: a systematic review.

Most patients with sciatica (often caused by disc herniations) are managed conservatively at first. The natural course seems to be favorable. The additional value of many conservative therapies remains controversial. Because a systematic review of the conservative treatment of sciatica is lacking, such a review was carried out. After a standardized literature search and selection procedure, methodology and outcome of randomized controlled trials (RCTs) were assessed by three observers. If possible, trial results were statistically pooled (= metaanalysis). The 19 RCTs that were selected showed greatly varying methodologic quality. Pooled odds ratios were calculated for several treatment types. Neither traction, exercise therapy, nor drug therapy was unequivocally effective. Epidural steroids may be beneficial for subgroups of nerve root compression. The literature suggests possible effectiveness of epidural steroids for sciatica. The authors recommend trials to investigate this treatment option further, especially with regard to patient subgroups (e.g., acute sciatica). The effects of clinical heterogeneity and methodology on review results are illustrated.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Consistency of history taking and physical examination in patients with suspected lumbar nerve root involvement.

STUDY DESIGN: A cross-sectional study of interobserver variability in primary care patients. OBJECTIVE: To investigate the consistency of signs and symptoms of nerve root compression in primary care patients with pain irradiating pain into the leg (sciatica). SUMMARY OF BACKGROUND DATA: The literature does not report on all the clinical tests for nerve root compression. In previous studies, most patients had low back pain with no irradiation. Often, little information on examination technique, proportion of positive test results, or clinical patient characteristics was provided. METHODS: A random selection of 91 patients was investigated by a neurologist-resident couple. Agreement percentages, proportions of positive test results, and kappas were calculated. RESULTS: The kappa of the overall conclusion after the history taking was 0.40, increasing to 0.66 after physical examination. Kappas were good for decreased muscle strength and sensory loss (0.57-0.82), intermediate for reflex changes (0.42-0.53), and poor for the examination of the lumbar spine (0.16-0.33). The straight leg raising, crossed straight leg raising, Bragard's sign, and Naffziger's sign were the most consistent nerve root tension signs (> 0.66). CONCLUSIONS: Two clinicians disagreed on the presence of nerve root involvement in one of four patients after history taking, and in one of five patients after physical examination. For a more consistent overall diagnosis, the physician probably should put more emphasis on the history of pain on coughing-straining-sneezing, a feeling of coldness in the legs, and urinary incontinence. The investigation of paresis, sensory loss, reflex changes, straight leg raising, and Bragard's sign provide the most consistent results.

Adolescent↗
PubMed2000

When does the patient with a disc herniation undergo lumbosacral discectomy?

OBJECTIVES: To design a model that could accurately predict eventual lumbar disc surgery in the patient initially presenting with clinical findings of nerve root compression. METHODS: Prospective study in 183 patients with nerve root compression sampled from a primary care population. All patients underwent a standardised history, physical examination, and MRI. Surgery carried out in the next 6 months was recorded. Models were constructed to predict whether patients eventually received surgery. RESULTS: Two models were constructed. Reduced model A was based on baseline findings, only, and contained six variables. Model B incorporated change over time as well and contained 10 variables. The area under the curve (in a receiver operating characteristic) for these models was 0.86 and 0.92, respectively. It was shown that at a probability cut off of 0.60, model B predicted eventual surgery with a sensitivity of 57% and a specificity of 100%. CONCLUSIONS: Given the requirement of a high specificity, eventual operation could be adequately predicted in a sample of 183 patients with clinical nerve root compression. The application of the model in patients with nerve root compression might lead to earlier operation in a subset of patients resulting in a reduction of duration of illness and associated indirect costs. An important prerequisite for future application would be the validation of the prediction rule in another population.

Diskectomy↗
PubMed2000

Health status and management of chronic non-specific abdominal complaints in general practice.

BACKGROUND: While chronic non-specific abdominal complaints are common in general practice, data on patients' perspective and management of these complaints are lacking. Knowledge of these data is important for the development of guidelines for management and assessment of the burden of chronic non-specific abdominal complaints on society. AIM: To draw a comprehensive picture of chronic non-specific abdominal complaints in general practice, including volume, patients' perspective, and health care involvement. METHOD: In a retrospective study, 644 patients were selected in 16 general practices. Patients and general practitioners (GPs) received a questionnaire regarding the nature of complaints and health care management during the previous 12 months. RESULTS: Overall, 619 questionnaires were returned and 291 patients participated. Of the study population, 15% of patients were diagnosed as suffering from non-ulcer dyspepsia, 39% from irritable bowel syndrome, and 45% from other abdominal complaints. Over 50% of patients suffered from chronic non-specific abdominal complaints on a daily or weekly basis. In these patients, general health perception is impaired and above norm scores on SCL-anxiety and SCL-depression scales were recorded. Only 4% of patients showed complete resolution of complaints during the previous 12 months. Fifty-two per cent of patients consulted their GP for abdominal complaints. Diagnostic modalities were used frequently. Medication was prescribed in 83% of patients with abdominal complaints. Twenty per cent of patients were referred to secondary or tertiary care. There was a considerable inter-doctor variation in the management of chronic non-specific abdominal complaints. CONCLUSION: Once non-specific abdominal complaints have become chronic they are mainly managed by the GP. The impact on patients' physiological and psychological well being is large. Diagnostic and therapeutic modalities are frequently used. Given the considerable inter-doctor variation, research into the evidence base of management strategies is recommended.

Adolescent↗
PubMed1999

Primary prevention of arterial thromboembolism in non-rheumatic atrial fibrillation in primary care: randomised controlled trial comparing two intensities of coumarin with aspirin.

OBJECTIVE: To investigate the effectiveness of aspirin and coumarin in preventing thromboembolism in patients with non-rheumatic atrial fibrillation in general practice. DESIGN: Randomised controlled trial. PARTICIPANTS: 729 patients aged >/=60 years with atrial fibrillation, recruited in general practice, who had no established indication for coumarin. Mean age was 75 years and mean follow up 2. 7 years. SETTING: Primary care in the Netherlands. INTERVENTIONS: Patients eligible for standard intensity coumarin (international normalised ratio 2.5-3.5) were randomly assigned to standard anticoagulation, very low intensity coumarin (international normalised ratio 1.1-1.6), or aspirin (150 mg/day) (stratum 1). Patients ineligible for standard anticoagulation were randomly assigned to low anticoagulation or aspirin (stratum 2). MAIN OUTCOME MEASURES: Stroke, systemic embolism, major haemorrhage, and vascular death. RESULTS: 108 primary events occurred (annual event rate 5.5%), including 13 major haemorrhages (0.7% a year). The hazard ratio was 0.91 (0.61 to 1.36) for low anticoagulation versus aspirin and 0.78 (0.34 to 1.81) for standard anticoagulation versus aspirin. Non-vascular death was less common in the low anticoagulation group than in the aspirin group (0.41, 0.20 to 0.82). There was no significant difference between the treatment groups in bleeding incidence. High systolic and low diastolic blood pressure and age were independent prognostic factors. CONCLUSION: In a general practice population (without established indications for coumarin) neither low nor standard intensity anticoagulation is better than aspirin in preventing primary outcome events. Aspirin may therefore be the first choice in patients with atrial fibrillation in general practice.

Aged↗
PubMed1999

[Differences in incidence of (violent) traumatic events in the national registration systems, population surveys and studies from family practice; a review of literature].

OBJECT: Comparison of (cumulative) incidences of traumatic events from population surveys and registration systems as well as from studies in general practice. DESIGN: Literature study. METHOD: Literature searches were done about the frequencies of accidents, sudden death, physical and sexual abuse listed in electronic databases and relevant catalogs covering 1986-1998, after which more references were searched via the references found, going back to 1984. RESULTS: There were large discrepancies between frequencies found in the several studies, such as national registration systems (n = 4), surveys in the open population (n = 10) and studies in general practice (n = 4). The incidence (per 1000 persons per year) of physical abuse were 66, 2.7 and 1-3 for surveys in the open population, police and general practitioners' registration systems respectively. For sexual abuse the figures were 21, 0.025 and 0.2-2.9 respectively. Different definitions and methods were used in the studies. CONCLUSION: General practitioners are aware of only a fraction of what their patients experience.

Accidents↗
PubMed1999

Lack of effectiveness of bed rest for sciatica.

BACKGROUND AND METHODS: Bed rest is widely advocated for sciatica, but its effectiveness has not been established. To study the effectiveness of bed rest in patients with a lumbosacral radicular syndrome of sufficient severity to justify treatment with bed rest for two weeks, we randomly assigned 183 subjects to either bed rest or watchful waiting for this period. The primary outcome measures were the investigator's and patient's global assessments of improvement after 2 and 12 weeks, and the secondary outcome measures were changes in functional status and in pain scores (after 2, 3, and 12 weeks), absenteeism from work, and the need for surgical intervention. Neither the investigators who assessed the outcomes nor those involved in data entry and analysis were aware of the patients' treatment assignments. RESULTS: After two weeks, 64 of the 92 patients in the bed-rest group (70 percent) reported improvement, as compared with 59 of the 91 patients in the control (watchful-waiting) group (65 percent) (adjusted odds ratio for improvement in the bed-rest group, 1.2; 95 percent confidence interval, 0.6 to 2.3). After 12 weeks, 87 percent of the patients in both groups reported improvement. The results of assessments of the intensity of pain, the bothersomeness of symptoms, and functional status revealed no significant differences between the two groups. The extent of absenteeism from work and rates of surgical intervention were similar in the two groups. CONCLUSIONS: Among patients with symptoms and signs of a lumbosacral radicular syndrome, bed rest is not a more effective therapy than watchful waiting.

Absenteeism↗
PubMed1999

Diagnostic value of history and physical examination in patients suspected of sciatica due to disc herniation: a systematic review.

We conducted a systematic review of the literature from 1965-1994 to assess the value of history and physical examination in the diagnosis of sciatica due to disc herniation; we also included population characteristics and features of the study design affecting diagnostic value. Studies on the diagnostic value of history and physical examination in the diagnosis of sciatica due to disc herniation are subject to important biases, and information on numerous signs and symptoms is scarce or absent. Our search revealed 37 studies meeting the selection criteria; these were systematically and independently read by three readers to determine diagnostic test properties using a standard scoring list to determine the methodological quality of the diagnostic information. A meta-analysis was performed when study results allowed statistical pooling. Few studies investigated the value of the history. Pain distribution seemed to be the only useful history item. Of the physical examination signs the straight leg raising test was the only sign consistently reported to be sensitive for sciatica due to disc herniation. However, the sensitivity values varied greatly, the pooled sensitivity and specificity values being 0.85 and 0.52, respectively. The crossed straight leg raising test was the only sign shown to be specific; the pooled sensitivity and specificity values were 0.30 and 0.84, respectively. There was considerable disagreement on the specificity of the other neurological signs (paresis, sensory loss, reflex loss). Several types of bias and other methodological drawbacks were encountered in the studies limiting the validity of the study results. As a result of these drawbacks it is probable that test sensitivity was overestimated and test specificity underestimated.

Evaluation Studies as Topic↗
PubMed1999

Primary prevention of arterial thromboembolism in nonrheumatic atrial fibrillation: the PATAF trial study design.

Patients with nonrheumatic atrial fibrillation (NRAF) have a higher risk of thromboembolism than patients in sinus rhythm. Several trials have been conducted to establish the best preventive regimen in patients with NRAF, but not in the primary-care setting. The Primary Prevention of Arterial Thromboembolism in Nonrheumatic Atrial Fibrillation (PATAF) study, a primary-care-based trial, was set up to compare the preventive efficacy of low-intensity anticoagulation (AC), target range International Normalized Ratio (INR) 1.1 < INR < 1.6 and regular-intensity AC (2.5 < INR < 3.5) therapies with that of aspirin 150 mg/d for the occurrence of thromboembolism in NRAF patients. Patients eligible for regular-intensity AC were randomly assigned to aspirin at 150 mg/d, low-intensity AC, or regular AC in group I. In cases of noneligibility for regular AC, the trial randomized patients between aspirin and low-intensity AC (assigned to group II). Primary outcome events were stroke (including intracranial hemorrhage), systemic embolism, major hemorrhage, or vascular death. Analysis of the data was based on Cox regression to compute the hazard ratio (HR) with a 95% confidence interval, using the likelihood ratio test. The trial randomized 729 patients. Patient enrollment and follow-up has been stopped, and the final analysis is now complete. We shall publish the main results as soon as possible.

Aged↗
PubMed1999

The influence of experience on the reproducibility of the ankle-brachial systolic pressure ratio in peripheral arterial occlusive disease.

OBJECTIVES: to estimate the intra-observer variability of the measurement of the ankle-brachial systolic pressure index (ABPI) and to compare the reproducibility of the measurements by experienced vascular laboratory assistants and by less-experienced general practice personnel. DESIGN: repeated measurement of ABPI by general practitioners (GPs), GP-assistants and vascular laboratory assistants using a pocket Doppler device and a random-zero sphygmomanometer. METHODS AND MATERIALS: ABPI was measured in six patients with various degrees of PAOD by two experienced observers (vascular laboratory assistants) and by 24 less-experienced observers (18 practice assistants, six GPs). RESULTS: the total number of measurements was 354. The overall intra-observer variability estimate was 11.8% ABPI. The intra-observer variability was 7.3% in the experienced observers and 12.0% in the less-experienced observers. The difference of variability between experienced and less-experienced observers was significant. CONCLUSIONS: the ABPI is suitable in follow-up studies where repeated measurements are needed. Differences between measurements can be minimised by performing repeated measurements or by using more experienced observers.

Aged↗
PubMed1999

Feasibility of a national cholesterol guideline in daily practice. A randomized controlled trial in 20 general practices.

OBJECTIVE: To evaluate the feasibility and implementation needs of a cholesterol guideline by assessing the effectiveness of simple dissemination as well as extensive implementation of this guideline on actual performance of general practitioners (GPs). DESIGN: Randomized controlled trial. SETTING AND SUBJECTS: Thirty-two Dutch GPs in 20 general practices, 3950 patient records. INTERVENTIONS: Guideline dissemination to all 32 GPs, and a 5-month programme for improvement in the intervention group. This programme was developed after barriers to working according to the guideline had been investigated, and consisted of group education, desktop supportive materials, feedback on performance, and face-to-face instruction on location. MAIN OUTCOME MEASURES: The outcome parameters were defined as quality of selective case finding and quality of diagnostic procedures, and were measured by chart audit. RESULTS: The quality of selective case finding, especially the targeting of cholesterol testing to those with positive cardiovascular risk profiles, did not improve following intervention. Performance of the procedure necessary to diagnose hypercholesterolaemia even deteriorated. The quantity of cholesterol testing increased in both groups, but this was probably explained by the increased availability of desktop cholesterol analysers. CONCLUSIONS: Neither simple dissemination nor an intensive programme for improvement had measurable impact on actual performance on working according to the cholesterol guideline. Both the validity and the opinion about feasibility of the guideline in daily practice deserve more attention during guideline development.

Family Practice↗
PubMed1999

The prognosis of non-critical limb ischaemia: a systematic review of population-based evidence.

BACKGROUND: Peripheral arterial occlusive disease (PAOD) is the most common peripheral vascular disorder in the elderly. A clear picture of the disease's course, especially in patients with non-critical limb ischaemia (Fontaine stages I and II), is essential for the general practitioner, who plays a key role in the diagnosis and management of PAOD. AIM: To evaluate the population-based evidence on the course and prognosis of PAOD. METHODS: An exhaustive literature search yielded 16 population-based studies on the prognosis of PAOD. The methodological qualities of the studies were assessed according to eight criteria. RESULTS: Thirteen studies of high methodological quality show that data on the course, cardiovascular morbidity, and mortality of asymptomatic PAOD are scarce. Only a small group of asymptomatic patients seem to develop intermittent claudication symptoms. However, asymptomatic patients appear to have the same increased risk for cardiovascular morbidity and mortality when compared with claudicants. No data were available on prognostic factors for intermittent claudication and cardiovascular morbidity in asymptomatic patients. The course, cardiovascular morbidity, and mortality of symptomatic PAOD are better documented. A small group of claudicants experience symptom progression. Smoking, hypertension, increasing age, and diabetes are the most relevant risk factors for intermittent claudication. Claudicants are at a higher risk for developing other cardiovascular diseases, resulting in a significantly increased mortality mainly owing to coronary heart disease. Intermittent claudication and a low ankle-brachial pressure index are significant predictors of mortality. Men had intermittent claudication and symptom progression more often than women. Cardiovascular (co-)morbidity was common in both male and female PAOD patients, but male PAOD patients had a higher mortality compared with female PAOD patients. CONCLUSION: Given the current knowledge on the prognosis of PAOD in the general population, an important task for (secondary) prevention is reserved for the general practitioner. Further research is required to document the course and prognosis of asymptomatic PAOD patients.

Adult↗
PubMed1999

Role of the electronic patient record in the development of general practice in The Netherlands.

From the end of the seventies practice computer systems have been introduced in Dutch general practice. In 1998 90% of the GPs had a practice computer and 60% used it for medical purposes, with good patient acceptance. Collaboration between pioneer GPs, professional organizations, academic institutions and software manufacturers has been of decisive importance. While the practice computer is early recognized as a powerful tool for administrative purposes, it is increasingly supporting clinical and preventive care, quality of care improvement, clinical training of students and vocational training of general practice trainees. Also for scientific research and practice supporting research, automatization has proven to be innovating. Much attention is paid to designing valid databases and database-related research. In addition, practice automatization has opened new perspectives for health policy and management. Further development of technical and methodological issues is needed, and, very importantly, of patients' and consumers' involvement. EPR technology in general practice does not optimally work without good numerator and denominator data, and a good quality patient-doctor relationship over time. While the EPR is a useful tool to facilitate a better performance, it may enable the doctor to focus more on the health care essentials.

Family Practice↗
PubMed1998

The prevalence of low bone mineral density in Dutch perimenopausal women: the Eindhoven perimenopausal osteoporosis study.

The aim of this study was to estimate the prevalence of osteopenia and osteoporosis in perimenopausal women, and to assess determinants of low bone mineral density (BMD). All women born between 1941 and 1947 (aged between 46 and 54 years) living in the city of Eindhoven were invited to participate in the study: 5896 white Dutch women, representing 73% of the total number of Dutch women in this age group, were studied. Of these, 24% were using estrogen preparations and 19% had undergone hysterectomy, with or without oophorectomy. All women were interviewed and bone mineral density (BMD) of the lumbar spine was measured by dual-energy X-ray absorptiometry (DXA). Osteopenia and osteoporosis were defined according to the criteria proposed by a WHO working group. In the population studied the prevalence of osteopenia and osteoporosis was 27.3% and 4.1%, respectively. With progression from premenopause to menopause, the prevalence of osteoporosis increased from 0.4% to 12.7%, and that of osteopenia from 14.5% to 42.8%. An increased risk for low BMD (osteopenia and osteoporosis) was associated with age, menopausal status and smoking, while alcohol consumption, high body mass index (BMI) and use of estrogens had a protective effect. This study of a large population-based cohort of perimenopausal women revealed a high prevalence of low bone mass and, therefore, a higher risk for osteoporotic fractures. The data further suggest that, when issues on the long-term efficacy and safety of preventive treatments are resolved, it may be possible to identify women at higher risk who are most likely to benefit from screening strategies.

Absorptiometry, Photon↗
PubMed1998

Multimorbidity in general practice: prevalence, incidence, and determinants of co-occurring chronic and recurrent diseases.

Increasing numbers of people are found to have two or more diseases at the same time, which is termed multimorbidity. We studied the prevalence, incidence, and determinants of multimorbidity and the statistical clustering of chronic and recurrent diseases in a general practice setting. Prevalence of multimorbidity increased with all age groups from 10% in the 0-19-year-old age group up to 78% in subjects aged 80 and over. Increasing age, lower level of education, and public health insurance were related to the occurrence of morbidity, but even more strongly to the occurrence and degree of multimorbidity. The one-year incidence of multimorbidity (the new occurrence of two or more diseases in one year) was related to increasing age, public health insurance, and the presence of prevalent diseases at baseline. Statistical clustering of diseases was stronger than expected, especially among the younger subjects.

Adolescent↗
PubMed1998

Risk factors and cardiovascular diseases associated with asymptomatic peripheral arterial occlusive disease. The Limburg PAOD Study. Peripheral Arterial Occlusive Disease.

OBJECTIVES: To describe the risk-factor profile and cardiovascular comorbidity of asymptomatic peripheral arterial occlusive disease (PAOD). DESIGN: A cross-sectional survey. Asymptomatic PAOD was defined as an ankle-brachial pressure index < 0.95, measured on two consecutive occasions, without intermittent claudication. Logistic regression analyses were performed to investigate independent associations between age, gender, smoking status, hypertension, obesity, diabetes, hypercholesterolaemia, physical activity, a family history of cardiovascular disease, the occurrence of ischaemic heart disease and cerebrovascular disease (CeVD) and asymptomatic PAOD. SETTING: 18 general practices in the province of Limburg, the Netherlands. SUBJECTS: A total of 3650 subjects, aged 40-78 years. MAIN RESULTS: Asymptomatic PAOD was present in 8.6% (n = 314) and symptomatic disease in 3.8% (n = 138) of the participants. Age, smoking status, hypertension, and diabetes were significantly associated with asymptomatic PAOD. The ratio of asymptomatic to symptomatic PAOD was higher among the younger age groups. Male gender, hypertension and smoking status were stronger associated with symptomatic PAOD compared with asymptomatic PAOD. Asymptomatic subjects had more IHD and CeVD comorbidity compared with the healthy population. CONCLUSION: Our findings suggest that the risk-factor profile and cardiovascular comorbidity of asymptomatic subjects is comparable to claudicants. Preventive efforts could be made to diminish the influence of especially smoking, diabetes and hypertension in asymptomatic subjects.

Adult↗