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Biomedical subjects

J A Knottnerus

Publications and source records attributed to J A Knottnerus.

At least 109 records · Page 6Linked to original sources
PubMed1996

Is depression in elderly people followed by dementia? A retrospective cohort study based in general practice.

We used a retrospective cohort study design to test the hypothesis of a relation between old-age depression and subsequent dementia. The study sample comprised 19103 patients aged 50 or more and born after 1910, included in a family-practice-based registration network. We estimated odds ratio (OR) and 95% confidence interval (95% CI) for a diagnosis of dementia in patients with or without previous late-onset depression and survival analysis, including hazard ratios resulting from Cox regression analysis. The OR for a diagnosis of dementia subsequent or not to late-onset depression was found at survival analysis: p = 0.26 (log rank test). Hazard ratio for patients with and without previous old age depression and subsequent dementia in patients aged 50 or more and born after 1910. This supports the hypothesis of old-age depression being a predictor, and possibly a causal factor, of subsequent dementia.

Aged↗
PubMed1996

A troubled youth: relations with somatization, depression and anxiety in adulthood.

BACKGROUND: Childhood experiences profoundly affect later functioning as an adult. Family practitioners are well-placed to discover the links between childhood troubles and later somatization, depression or anxiety. OBJECTIVES: We aimed to study the interrelation of somatization, depressive and anxiety disorders in frequently attending patients in general practice; to investigate whether these problems are related to a childhood history of illness experiences, deprivation, life events and abuse; and to determine the independent contributions of these childhood factors to the prediction of adult somatization, depressive and anxiety disorders. METHODS: One hundred and six adult general practice patients with high consultation frequency were studied. Somatization was operationalized as a more comprehensive version of DSM-III-R somatization disorder (5 complaints; SSI 5/5). For depression (ever depressive and/or dysthymic) and anxiety (panic, phobias and/or generalized anxiety) DSM-III-R criteria were used. Using a structured questionnaire we assessed illness experiences, deprivation of parental care, abuse (sexual/physical) and other life events before age 19. RESULTS: The overlap between somatization, depression and anxiety was largely accounted for by 16 patients with a triple problem: somatization and depression and anxiety. Somatization was specifically related to deprivation, depression to other life events. Abuse (prevalence 16%) independently predicted psychiatric problems in general. Youth experiences before age 12 were most important. CONCLUSIONS: The high prevalence of triple problems suggests a need to reconsider concepts like somatic anxiety and anxious depression. The specificity of the relation between deprivation and somatization and of the relation between other life events and depression indicates that distinct causal mechanisms (in youth) contribute to these problems.

Abdominal Pain↗
PubMed1996

Factors predicting differences among general practitioners in test ordering behaviour and in the response to feedback on test requests.

BACKGROUND: In a population of 85 general practitioners diagnostic test ordering behaviour has been changed by means of repeated individual feedback provided since 1985. OBJECTIVES: We studied practitioner and practice characteristics which may explain differences in test ordering behaviour and in the extent to which general practitioners tend to change their behaviour according to the feedback. METHOD: In order to trace such variables, 75 general practitioners were interviewed. In our study request data from individual general practitioners were related to data from several questionnaires. RESULTS: We found no practice characteristics which were of influence on the number of test requests by the general practitioner. Explanatory practitioner characteristics for this were found to be years of experience and working hours per week in practice. CONCLUSIONS: More years of experience as a general practitioner and a shorter duration of consultations correlated with a better response to advice given in the feedback.

Adult↗
PubMed1996

The prevalence of asymptomatic and unrecognized peripheral arterial occlusive disease.

BACKGROUND: The prevalence of peripheral arterial occlusive disease (PAOD), including asymptomatic cases and cases unknown to the general practitioner (GP) was estimated in 18,884 men and women, aged 45-74 years, on the list of 18 general practice centres (GPC). METHODS: The study population (n = 3171) consisted of a stratified sample of the total population. In the GPC data were collected on intermittent claudication (IC), peripheral pulses, vascular risk factors, cardio- and cerebrovascular disease (CCVD) and the ankle brachial systolic pressure ratio (AB ratio) and PAOD was defined as an AB ratio < 0.95 on two consecutive occasions. Results were recalculated for the total population. RESULTS: The prevalence of PAOD was 6.9 percent (95 percent Cl:5.2-7.9 percent), a quarter of which (1.6 percent) met the classic WHO criteria. Peripheral arterial occlusive disease did not occur significantly more often among men than among women but men suffered more often from an advanced stage of PAOD. Of all PAOD cases, 22 percent were symptomatic. The proportion of symptomatic cases correlated positively with higher age, male gender and lower AB ratio. Among asymptomatic PAOD cases the prevelance of concomitant CCVD was three to four times as high as in the group of subjects without PAOD. Of all PAOD cases 68 percent were unknown to the GP and this group mainly represented less advanced cases of atherosclerosis. However, among PAOD cases with an AB ratio <0.75, 42 percent were unknown to the GP. CONCLUSIONS: Our data on asymptomatic and unknown PAOD cases show that GPs can still enhance their efforts towards (secondary) prevention of atherosclerosis.

Adult↗
PubMed1996

Predictors for hidden problem drinkers in general practice.

In The Netherlands general practice attenders are not usually questioned about their drinking habits. The objective of this study was to determine to what extent easily available data (e.g. age, gender) can be used to identify categories of patients who are at risk of problem drinking as a preliminary to more intensive screening. Sixteen practices with a total population of 32,000 patients were involved in the study. All problem drinkers known by their GPs and a random sample of one in ten patients not thought to be problem drinkers were admitted to the study at their first surgery visit during a 1-year period. A screening questionnaire was used to find hidden problem drinkers amongst the individuals thought to be non-problem drinkers. The overall response rate was 91% (n = 1405). Problem drinking was detected in 6% (n = 82) of the group regarded by the GPs as non-problem drinkers (n = 1283). Male gender, smoking, life events and chronic social problems were the strongest non-alcohol-related predictors of hidden problem drinking. We conclude that a pre-selection of patients with a greater risk of problem drinking can be made without information related directly to alcohol. Case-finding in this category is much more effective and probably much more acceptable both to the GP and the patients, than the screening of all patients.

Adolescent↗
PubMed1996

Comparison of appropriateness of cholesterol testing in general practice with the recommendations of national guidelines: an audit of patient records in 20 general practices.

OBJECTIVE: To compare the profiles of those patients selected by general practitioners for measurement of serum cholesterol with the recommended profiles for opportunistic cholesterol testing described in the national practice guidelines published by the Dutch College of General Practitioners. DESIGN: Retrospective audit of general practitioners' records. MATERIALS: Practice records of 3577 adult patients systematically sampled from 20 general practices. MAIN MEASURES: With criteria set by the national guidelines, the proportion of patients per practice (a) for whom cholesterol testing would be considered justified, and (b) for whom cholesterol testing would be considered unjustified, and the proportion of patients within each of these groups who had had a cholesterol measurement recorded. RESULTS: Cholesterol tests were performed on 415 (11.7%) of the 3577 patients. National guidelines on the management of hypercholesterolaemia state that a positive cardiovascular risk profile is an indication for cholesterol measurement. Just under one fifth (668) of the patients in this study were recorded as having a positive cardiovascular risk profile, but only 31% of these had had their cholesterol measured. Of the patients without recorded evidence of a positive cardiovascular risk profile cholesterol had been measured in 8%. Restricting the analyses to the age group 18-65 (n = 3060) of whom 12.5% had a positive risk profile, did not improve the results. In practices with a computerised information system 37% of patients with recorded evidence of a positive cardiovascular risk profile had had their cholesterol measured. CONCLUSIONS: Cholesterol testing was not targeted as selectively as recommended by the national guidelines. The major problem was failure to test those likely to benefit. Improving the targeting of cholesterol measurements would undoubtedly increase the workload of general practitioners. If the national guidelines are to have an effect on health promotion the first step must be to increase the proportion of patients with positive cardiovascular risk profiles who get their cholesterol tested. A major factor in successfully selecting cases seems to be that practices are equipped with a computerised medical information system.

Adolescent↗
PubMed1996

Influenza in The Netherlands.

This paper reports on the occurrence of influenza and the associated burden of illness in The Netherlands. In addition, attention is paid to the effectiveness of vaccination vaccination status and the national strategy to raise the vaccination rate among risk groups. The incidence of influenza in the community appears to be 3 to 6 times higher than the incidence observed in general practice, since most cases do not present to the general practitioner (GP). Annually, 15,000 to 30,000 hospital admissions (1 to 2 per 1000 inhabitants) and 2000 to 2200 deaths (1.3 to 1.5 per 10,000), mostly among the elderly, are related to influenza. Vaccination has been shown to prevent about 50% of the influenza cases. Between 1991 and 1994 the vaccination rate among risk groups increased from 28 to 43%. In this period, a very active campaign was mounted. Much energy is being invested in further raising the vaccination rate among risk groups, with GPs holding a key position. In addition, the Dutch Health Council advises vaccination for persons > or = 65 years of age.

Aged↗
PubMed1996

One-year prognosis of abdominal complaints in general practice: a prospective study of patients in whom no organic cause is found.

BACKGROUND: Data on the one-year prognosis of patients with non-organic, non-acute abdominal complaints in primary care are lacking. Knowledge of prognostic determinants could be helpful in management and health education. AIM: To describe the prognosis after one year of non-organic abdominal complaints in general practice, and to show how this relates to socio-demographic factors, medical history and psychological problems. METHODS: The one-year prognosis of patients with non-organic abdominal complaints in a primary care setting was analysed in a prospective study (n = 756). Clinical and psychological factors were measured and their relative risks regarding unfavourable prognosis were calculated one year after the first consultation. RESULTS: In 68% of the patients examined, the abdominal complaints had either improved or disappeared by the end of the first year. Female sex and depressive mental state were associated with an unfavourable prognosis. Clinical symptoms that were significantly associated with persisting complaints were a combination of abdominal pain, flatulence and bowel irregularities; a specific description of the character of the pain by the patient; looser stools at the onset of the pain; long duration or recurrence, pyrosis; absence of visible distension; and epigastric localization of the pain or tenderness. CONCLUSIONS: The prognosis after one year of non-acute abdominal pain in general practice is better than that reported from studies of outpatient populations. Female sex, depressive mood and some clinical parameters are associated with persistent complaints one year after presentation.

Abdominal Pain↗
PubMed1995

[Glucose intolerance in elderly persons in The Netherlands; the Twello Study].

OBJECTIVE: To determine the prevalence of grades of glucose intolerance in subjects over 64 years of age. DESIGN: Point prevalence study. SETTING: Twello, a rural village in the Netherlands. METHODS: Of a total of 696 persons aged over 64 years recruited from a general practice, 460 subjects had an oral glucose tolerance test (OGTT) in 1985, 56 were known with non-insulin-dependent diabetes mellitus. Glucose estimations were done in capillary whole blood with a Glucometer. OGTT results were classified according to WHO 1985 recommended cut-off points and combination rules. RESULTS: The prevalence of normal glucose tolerance was 42%, of impaired glucose tolerance 27% and of diabetes mellitus 31%. The estimated prevalence in the source population were 45% (44.4-44.6), 28% (28.3-28.5) and 27% (95% CI: 27.1-27.2) respectively, adjusted for age and gender by standardization to the Dutch population of 1985. Re-evaluation of the earlier diagnoses of 'diabetes mellitus' according to the new WHO guidelines revealed that 55% of earlier diabetic with diet as the only therapy were no longer classified as diabetics. The prevalence of diabetes mellitus in persons over 64 was 10% before the investigation took place, and 30% afterwards. CONCLUSIONS: Te prevalence of diabetes mellitus as well as of impaired glucose tolerance from the Twello study rank among the higher rates reported in Caucasian populations. Case finding of glucose intolerance in those at risk over 64 years of age is recommended.

Aged↗
PubMed1995

Effectiveness of joint consultation sessions of general practitioners and orthopaedic surgeons for locomotor-system disorders.

Joint consultation sessions between general practitioners (GPs) and specialists to examine patients for whom decisions about referral are difficult are thought to be helpful, but their effects have not been evaluated. In a randomised, controlled trial we studied the effects of joint sessions of GPs and orthopaedic surgeons on referral and intervention rates. During 1.5 years, 12 GPs (in groups of three) held monthly joint consultation sessions with four participating orthopaedic surgeons: patients were seen by one orthopaedic surgeon in the presence of three GPs. Patients were included in the trial if the GP was uncertain about the diagnostic or therapeutic management and if referral was considered; and excluded if referral was urgently necessary or if there was some other clear indication for referral. By a randomised consent design, patients were assigned to joint consultation sessions (n = 144) or a usual-care control group (n = 128). A year later the patients were examined by an independent orthopaedic surgeon. There were significantly fewer referrals (51/144 [35%] vs 87/128 [68%], p < 0.01) and diagnostic actions in the intervention group than in the control group, without negative effects on health or functional status. More patients in the intervention group were symptom-free at 1 year (35% vs 24%, p < 0.05). Joint consultation sessions of GPs and orthopaedic surgeons within the framework of general practice resulted in more efficient care, with better targeted examination, treatment, and referrals.

Family Practice↗
PubMed1995

Randomised controlled trial of routine individual feedback to improve rationality and reduce numbers of test requests.

Feedback can be described as a way to provide information on doctors' performance to enable changes in future behaviour. Feedback is used with the aim of changing test-ordering behaviour. It can lead to reductions in test usage and cost savings. It is not sufficiently clear, however, whether feedback leads to more appropriate test use. Since 1985, the Diagnostic Coordinating Center Maastricht has been giving feedback on diagnostic tests as a routine health care activity to all family doctors in its region. Both quantity and quality of requests are discussed. In a randomised, controlled trial over 2.5 years, discussion of tests not included previously was added to the existing routine feedback. One group of family doctors (n = 39) received feedback on test-group A (electrocardiography, endoscopy, cervical smears, and allergy tests), the other (n = 40) on test-group B (radiographic and ultrasonographic tests). Thus, each group of doctors acted as a control group for the other. Changes in volume and rationality of requests were analysed. The number of requests decreased during the trial (p = 0.036). Request numbers decreased particularly for test-group A (p = 0.04). The proportion of requests that were non-rational decreased more in the intervention than in the control groups (p = 0.009). Rationality improved predominantly for test-group B (p = 0.043). Thus, routine feedback can change the quantity and quality of requests.

Diagnostic Services↗
PubMed1995

Predictive value of signs and symptoms for colorectal cancer in patients with rectal bleeding in general practice.

The aim of the study is to determine the diagnostic value of (combinations of) signs, symptoms and simple laboratory test results for colorectal cancer in patients with rectal bleeding presenting in general practice. Initial complaints and findings were compared with the final diagnoses based on clinical follow-up after at least 1 year. Patients studied were those presenting overt rectal bleeding to the general practitioner (83 GPs in the South of the Netherlands). Outcome measures are sensitivity, specificity, predictive values, odds ratios and a prediction model derived from multiple logistic regression analysis. Age, change in bowel habit and blood mixed with or on stool show a statistically significant independent value in the discrimination between patients with a low and those with a high probability of colorectal cancer. Many other variables did not show predictive value. The prediction model has a sensitivitiy of 100% and a specificity of 90%. Although the number of patients with colorectal cancer is small (n = 9) it was possible to identify three characteristics which can be helpful in the prediction of presence or absence of colorectal cancer in general practice. Application of the model presented might prevent 90% of 'unnecessary' invasive diagnostic procedures for patients with rectal bleeding who do not have colorectal cancer (true negative). Testing the performance of the model in other general practice populations is recommended.

Adolescent↗
PubMed1995

Long-term effect of feedback and peer comparison on the sampling quality of cervical smears--a randomized controlled trial.

In a randomized controlled trial the effect of feedback and peer review directed at the sample-taking doctor (n = 179) on the sampling quality of cervical smears (n = 21,240) was studied. This paper reports the impact 6 and 12 months after the end of the intervention. Monthly feedback with peer comparison was related to a net improvement in the proportion of cervical smears without endocervical cells during the intervention period, as well as during a follow-up period lasting until 15 months after the end of the intervention. This improvement seemed to be related to a minimum of 50 or even 100 smears performed each year and was therefore not confirmed on clustered data analysis. There is a strong suggestion that the intervention also related to an increase of the number of smears showing cytological pathology, although this study lacked sufficient power to test this hypothesis.

Cluster Analysis↗
PubMed1995

Composition of cervical smears in patients with and without a cervical ectropion.

AIMS: To test the hypothesis that absence of squamous cells in cervical smears obtained by an endocervical sampling technique is more prominent in patients with a cervical ectropion. METHODS: Prospective study exploring the relation between the composition of cervical smears obtained using an endocervical cotton swab in patients with (n = 188) and without (n = 341) a cervical ectropion. Subjects were 529 consecutive patients from whom a cervical smear was prepared at a university gynaecological clinic. RESULTS: In 7% of the endocervical samples no squamous cells were found. There was no correlation, however, between the presence or the size of an ectropion and the absence of squamous cells in those samples. CONCLUSIONS: It was confirmed that endocervical sampling alone is insufficient to obtain good quality cervical smears. The presence of an ectropion proved to be an unreliable predictor of the absence of squamous cells.

Cervix Uteri↗
PubMed1995

Diagnosis and management of cases of suspected dermatomycosis in The Netherlands: influence of general practice based potassium hydroxide testing.

BACKGROUND: Microscopy of a potassium hydroxide preparation of skin scrapings or nail clippings, although widely advocated as a test for dermatomycosis, is used in only a small proportion of cases. AIM: This study set out to investigate the effect of potassium hydroxide testing on the subjectively assessed probability that a dermatomycosis was present. METHOD: The study was undertaken in 1992 in Limburg, a province in the south of the Netherlands. Ten general practitioners and eight trainees completed a questionnaire and performed a potassium hydroxide preparation for each patient presenting with a skin condition that they thought might be caused by dermatomycosis. Skin or nail material was also sent to a microbiology laboratory where another potassium hydroxide preparation as well as a culture were performed, these two tests serving as a gold standard against which to judge the potassium hydroxide preparation by the general practitioners. Data from a total of 164 cases were analysed. RESULTS: The results of the potassium hydroxide test carried out in the practice had a considerable influence on the subjectively assessed probability that a dermatomycosis was present, especially if the outcome was positive. The indication for antifungal treatment was altered as a result of the test in a quarter of all cases, mostly from negative to positive. Use of the practice potassium hydroxide test could increase the proportion of correct therapeutic decisions from 54% to 69%, with 20% of cases being undertreated. Of cases that gave a positive test result in the practice 83% also had a positive laboratory test result, while of cases that gave a negative practice result 43% were positive in the laboratory. CONCLUSION: The potassium hydroxide test improves the diagnostic process in cases of possible dermatomycosis and may result in a change in management. The test can provide a confirmation of the diagnosis of dermatomycosis but is not useful in the exclusion of this diagnosis.

Clinical Laboratory Techniques↗