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Biomedical subjects

J F Lassen

Publications and source records attributed to J F Lassen.

At least 19 recordsLinked to original sources
PubMed1999

From science to everyday clinical practice. Need for systematic evaluation of research findings.

This paper focuses on problems attached to using scientific results in everyday clinical practice. Based on examples we raise the question: Are research results obtained under ideal scientific conditions, presented to health professionals and the public in a way that creates unrealistic expectations of the health services? We suggest that the clinical researcher, when reporting scientific results, should be obliged to consider technological aspects, i.e. the human and monetary cost, effectiveness, compliance, the expected consequence for the patient, professionals and society, and resources needed to accomplish it. Presented with these considerations, actors of the health care scene in terms of professionals, administrators, politicians and patients should be better suited to decide if implementation of a new treatment should take place. Such procedures will give the population and the politicians more realistic expectations of the contributions of medical science and the health services in general.

Adult↗
PubMed1999

Near-patient test for C-reactive protein in general practice: assessment of clinical, organizational, and economic outcomes.

BACKGROUND: The benefits of near-patient, point-of-care tests have not been fully examined. We have assessed the clinical, organizational, and economic outcomes of implementing a near-patient test for C-reactive protein (CRP) in general practice. METHODS: In a randomized crossover trial during intervention periods, general practitioners (GPs) were allowed to measure CRP within 3 min, using NycoCard(R) CRP. During control periods, they had to mail blood samples for CRP measurements to the hospital laboratory and received test results 24-48 h later. Twenty-nine general practice clinics participated (64 GPs), and 1853 patients were included in the study. Results were evaluated at both the level of participating GPs and the level of included patients. RESULTS: For participating GPs, the overall use of erythrocyte sedimentation rates (ESRs) decreased by 8% (95% confidence interval, 1-14%) during intervention periods, and the number of blood samples mailed to the hospital laboratory decreased by 6% (1-10%). No reduction in the prescription of antibiotics was seen. The proportion of study patients having a follow-up telephone consultation was reduced from 63% to 53% (P = 0. 0001), and patients with CRP concentrations >50 mg/L had their antibiotic treatments started earlier when CRP was measured in general practices (P = 0.0161). CONCLUSION: The implementation of the near-patient CRP test was cost-effective mainly on the basis of a reduction in the use of services from the hospital laboratory by GPs. If the implementation is followed by education and clinical guidelines, opportunities exist for additional reduction in the use of ESR and for a more appropriate use of antibiotics.

Anti-Bacterial Agents↗
PubMed1998

[Is the randomized controlled trial overvalued as a basis for clinical decision-making? A review with comments].

The randomized controlled trial (RCT) may have considerable limitations in clinical research. Lacking the possibility of blinding impairs the internal validity of the trials. The external validity is often impaired, as results of RCTs obtained in an ideal situation, may be difficult to generalize to a clinical routine situation. Pragmatic randomized trials move from ideal situations towards routine situations, and by modifying the design it is possible to reduce selection bias due to patient and physician preferences. Quasi-experimental studies have varying degrees of problems with internal validity but are necessary contributions to our knowledge of the effect of treatment in clinical routine situations. Limitations of the usefulness of RCTs as well as pragmatic and quasi-experimental studies in clinical research make it necessary to recognise that different methods complement one another. Research in development of RCTs and new methods in clinical research should be encouraged.

Decision Making↗
PubMed1998

Effect of anticoagulant therapy on the hypercoagulable state in patients carrying the factor V Arg506Gln mutation.

Resistance to activated protein C, caused by a single point mutation in the factor V gene (Arg506Gln or FV Leiden), is the most prevalent single risk factor associated with venous thromboembolic disease. The aim of this study was to investigate the effectiveness of standard oral anticoagulant therapy (OAT) in patients with the Arg506Gln mutation compared with a matched control group. The study compared selected variables in 27 patients carrying the Arg506Gln mutation with 27 sex- and age-matched controls in steady state oral anticoagulant treatment (OAT). The study showed that similar doses of vitamin K antagonists in carriers and noncarriers suppress and generate a uniform distribution of coagulation markers in steady state OAT. Thus, it seems that OAT with standard treatment doses is just as effective in patients with the Arg506Gln mutation as in comparable controls without the mutation.

Activated Protein C Resistance↗
PubMed1998

[Cross-sectional therapeutic programs--an example of a cooperative health care system. A review with comments].

There is no tradition for sharing the responsibility for episodes of care between the primary and secondary sectors in the Danish health care system. Concurrently with increased international experience with shared care programmes, there is also a growing interest in Denmark in cooperation between the sectors. Based on literature research, shared care programmes are presented as a method of ensuring continuity and quality in treatment of chronic diseases. Experiences in the areas of diabetes, asthma, rheumatoid arthritis, and cancer are described. It is concluded that the Danish health care system is well prepared for the implementation of shared care programmes; there are only few sources of payment in the system, and an extensive continuing medical education system ensures that general practitioners can participate in relevant education. The implementation of shared care programmes in Denmark should be followed by scientific evaluation and documentation of the quality of the treatment programmes.

Delivery of Health Care↗
PubMed1998

[Diagnostic value of C-reactive protein in bacterial infections. Review of the literature].

Conflicting data for predictive values for C-reactive protein (CRP) in its ability to distinguish between viral and bacterial diseases are reviewed. Study designs regarding setting, patient-mix, severity of disease and prevalence seem to determine the magnitude of predictive values. We have calculated predictive values for patients suspected of septicaemia, meningitis, appendicitis, cholecystitis, upper- and lower respiratory disease, acute sinusitis and acute otitis media, and revealed the highest predictive values among patients suspected for severe and generalized infections. More localized diseases have lower predictive values. We emphasize the importance of a study design where the circumstances resemble the real situations in which the test is supposed to be used. This will ensure the clinical applicability of predictive values for a diagnostic test.

Adult↗
PubMed1998

[Differences in the use of C-reactive protein analysis and erythrocyte sedimentation in general practice and hospitals. Development from 1986 to 1995].

Analysis for C-reactive protein (CRP) was introduced in the Vejle Hospital catchment area in 1987. During the next ten year period the use of CRP has increased to reach a stable level both on hospital wards, out-patient clinics and in general practice. While the use of erythrocyte sedimentation rate on wards has decreased correspondingly, this is not seen in out-patient clinics or in general practice. There are medical as well as practical reasons for this discrepancy. It is believed that the possibility of performing a CRP as a point-of-care test in the GPs office in the future will lead to a reduction in the number of analyses of erythrocyte sedimentation rate performed in general practice as well.

Blood Sedimentation↗
PubMed1998

The Arg506Gln mutation (FV Leiden) among a cohort of 4188 unselected Danish newborns.

Resistance to activated protein C (APC) is the most prevalent single phenomenon associated with thromboembolic disease. It is caused by a single point mutation in the factor V gene (Arg506Gln or FV Leiden), replacing an Arg506 with a Gln at the APC-cleavage site in factor V. In this study we present a prevalence study of the Arg506Gln mutation in a large Danish cohort. By screening 4188 newborns (8376 alleles) we identified 3.4% alleles (95% CI: 3.0-3.8) of the Arg506Gln mutation, corresponding to a heterozygous prevalence of 6.6% (95% CI: 5.9-7.4) in Denmark. This is significantly lower than what has been reported from southern Sweden. The birth cohort has been selected from the entire country, providing representative and accurate estimates of the gene frequencies. Equal gender distribution was found, and the Arg506Gln mutation is probably not a considerable risk factor in fetal life in the general population.

Cohort Studies↗
PubMed1998

Markers of coagulation and fibrinolysis as measures of disease activity in inflammatory bowel disease.

BACKGROUND: Activation of coagulation and fibrinolysis occurs in patients with inflammatory bowel disease. Our aim was to study the course of a marker for activation of the coagulation cascade, prothrombin fragment 1 + 2 (F1+2), and fibrinolysis, fibrin degradation products (FbDP), in patients with ulcerative colitis and Crohn's disease before and during therapy with glucocorticoids. METHODS: Twenty-seven patients with active ulcerative colitis and 42 with active Crohn's disease treated with glucocorticoids were studied. Plasma samples were drawn before, during, and at end of therapy or at time of treatment failure. F1+2 and FbDP were measured with commercially available enzyme immunoassays. RESULTS: Mean base-line concentrations of F1+2 were significantly increased in patients with ulcerative colitis (4.77 +/- 0.50 nmol/l; P < 0.0001) and in Crohn's disease (4.66 +/- 0.59 nmol/l; P < 0.0001) compared with healthy controls (1.57 +/- 0.09 nmol/l). Mean base-line concentrations of FbDP were significantly increased in patients with ulcerative colitis (1264 +/- 161 microg FE/l; P < 0.0001) and in Crohn's disease (491 +/- 51 microg FE/l; P < 0.0001) compared with healthy controls (194 +/- 21 microg FE/l). During treatment with glucocorticoids the plasma concentrations of FbDP decreased in patients with Crohn's disease achieving remission and in patients with ulcerative colitis avoiding surgery but remained unchanged in patients not responding to therapy. In contrast, F1+2 remained increased in patients with Crohn's disease and ulcerative colitis irrespective of outcome. CONCLUSION: The present data support the concept that coagulation cascade and fibrinolysis is activated in patients with active inflammatory bowel disease. F1+2 and FbDP correlate poorly with the clinical disease activity and acute-phase reactants. The clinical response to treatment with glucocorticoids is accompanied by a decrease in plasma concentrations of FbDP but not in F1+2. FbDP may emerge as a new marker in the assessment of disease activity in patients with inflammatory bowel disease.

Adult↗
PubMed1997

C-reactive protein in general practice--how commonly is it used and why?

OBJECTIVE: C-reactive protein (CRP) is a well-known diagnostic tool in general practice. The scope of this study was to assess how frequently CRP is used by general practitioners and to evaluate the reasons for using it. DESIGN: A retrospective part based on data from a laboratory database system, and a prospective part with a questionnaire-based registration. SETTING: 30 general practice clinics in the catchment area of Vejle County Central Hospital. SUBJECTS: Retrospectively, all patients from general practice serviced by the laboratory for one year. Prospectively, 1190 patients from whom a blood sample was taken for CRP-measurement during a 2 month study period. MAIN OUTCOME MEASURES: The frequency of using CRP and the reason requesting it; A) diagnosing a new disease, B) monitoring a well-known disease, or C) "screening". Furthermore; 1) infections, 2) chronic inflammatory disease, 3) malignant disease, or 4) others. RESULTS: CRP-measurements were ordered in 3.7% of all consultations in general practice and for 34.1% of all patients whose blood sample was analysed at the central laboratory. The use of CRP was as follows: A-1: 28.6%, A-2: 6.7%, A-3,4: 9.3%, B-1: 8.2%, B-2: 12.4%, B-3,4: 6.5%, C-1: 5.7%, C-2: 3.2%, C-3: 3.5% and C-4: 15.2%. Diagnosing a new (infectious) disease was the most frequent single reason for CRP-measurement. There was major interpractice variation. CONCLUSIONS: CRP is frequently used in general practice, mostly (65.4%) in the field of infections and chronic inflammatory diseases. Because of major interpractice variation, the most correct way of using CRP should be evaluated and guidelines should be provided.

Adolescent↗
PubMed1997

Graphical interpretation of analytical data from comparison of a field method with reference method by use of difference plots.

Various viewpoints have been offered regarding the appropriate use of scatter plots or difference plots (bias plots or residual plots) in comparing analytical methods. In many of these discussions it seems the basic concepts of identity (within inherent imprecision) and acceptability based on analytical goals (analytical quality specifications) have been forgotten. With the increasing number of Reference Methods in laboratory medicine, these basic concepts are becoming more important in validation of field methods. Here we describe a simple and effective graphical test of these hypotheses (identity and acceptability) by use of difference plots. These plots display the underlying hypothesis before the measured differences are plotted and allow interpretation of the results according to specific criteria. We further describe simple but effective interpretations of the data, when the hypothesis is not fulfilled, by using two data sets drawn from comparisons of field methods for S-creatinine with a Reference Method for this analyte. The difference plot is a graphical tool with related simple statistics for comparison of a field method with a Reference Method, focusing on (a) identity within the inherent analytical imprecision or (b) acceptability within analytical quality specifications. Calculation of the standard deviation of the differences is an indispensable tool for evaluation of aberrant-sample bias (matrix effects).

Chemistry, Clinical↗
PubMed1997

Evaluation of a near-patient test for C-reactive protein used in daily routine in primary healthcare by use of difference plots.

We have assessed the technical performance and robustness of NycoCard CRP Whole Blood, a near-patient test for C-reactive protein (CRP), when used in realistic daily routine situations in general practice clinics (GPC). Thirteen GPCs participated, five of them with technician staff. From 898 patients, split-sample measurements for CRP were made. Results from GPCs were compared with results from a turbidimetric laboratory method, traceable to international reference preparations (IFCC CRM 470). Results were evaluated in difference plots where the expected distribution, due to an estimated analytical variation, was compared with measured differences. Of all difference points, 91.5% (n = 819) were within a 95% prediction interval based on the imprecision of both methods. Mean bias (95% confidence interval) was -0.3 mg/L (-0.9 to 0.3). No differences in analytic quality were found between GPCs with technician staffs and GPCs without, and between test results obtained within the first and second week, compared with the rest of the study period. We find the test as good when used in GPCs as could be expected from laboratory testing, and consequently robust, which is a necessity for use in routine situations in general practice. General application of difference plots in test evaluations are discussed in detail.

Adolescent↗
PubMed1997

Biological variation of International Normalized Ratio for prothrombin times, and consequences in monitoring oral anticoagulant therapy: computer simulation of serial measurements with goal-setting for analytical quality.

Oral anticoagulant therapy (OAT) has a well-established efficacy in prophylaxis and treatment of thromboembolic disorders. Because complications are related to intensity of OAT, optimal control of treatment is mandatory. In studies of OAT, as many as 30% of International Normalized Ratio (INR) measurements for prothrombin times fall outside the therapeutic interval. Preanalytical, analytical, and biological variation all contribute to this. Computer simulations of serial INR measurements were performed for various assumed in-treatment setpoints within the therapeutic interval INR 2.0-3.0 and for an "in-treatment within-subject variation" (CV) of 10.1%. Results are presented in difference plots with therapeutic intervals and critical differences. If the in-treatment setpoint is mid-interval (INR = 2.5), only 5% of simulated INR values fall outside the therapeutic interval. Setpoints deviating from the mid-interval and increases in the in-treatment within-subject variation considerably increase the number of observations outside the therapeutic interval and the critical differences. In conclusion, random variation, biological or analytical, and setpoints (targets) deviating from mid-interval explain a substantial number of the INR values outside therapeutic intervals observed in clinical studies. Analytical imprecision should be kept < 5% and analytical bias < +/- 0.2 INR.

Administration, Oral↗
PubMed1996

[Resistance to activated protein C. The most common cause of familial thrombophilia].

Resistance to activated protein C (APC) is caused by the most prevalent single gene defect associated with thromboembolic disease so far described. The majority of cases are caused by a single point mutation in the Factor V gene, which predicts replacement of Arg506 in the APC-cleavage site with a Gln. APC resistance is found in 20-60% of patients with venous thrombosis and in 3-10% of the normal population among Caucasians. In its heterozygous state, the mutation is associated with a 5-10-fold increased risk of thrombosis. Homozygosity is associated with more severe APC resistance, and a higher risk of developing thrombosis. By the age of 33 years, 8% of normals, 20% of heterozygotes, and 40% of homozygotes have had manifestations of venous thrombosis. APC resistance has been described in 60% of women with thromboembolic complications during pregnancy and in approximately 30% of women with thromboembolic complications using oral contraceptives. Development of clinical episodes of thrombosis in patients with APC resistance is likely to occur on a multifactorial basis. Hypercoagulable states may result from multigene interactions, and prothrombotic insults in patients with an inherited predisposition may precipitate thrombotic complications. In this review we present and discuss results from the recent medical literature.

Anticoagulants↗
PubMed1996

[Insect stings. A prospective study of complications and injury mechanisms].

The aim of the study was to evaluate complications to insect stings, and to describe the circumstances in which the patients were stung. During a one year period (1.1.-31.12.1991) a total of 178 hospital and emergency room contacts due to insect stings were registered. All patients afterwards received a mailed questionnaire concerning insect stings. Nearly 3/4 of the patients were able to identify the stinging insect by use of an identification chart. One hundred and forty-five patients had mild symptoms, 33 patients had moderate symptoms and three presented severe symptoms with anaphylactic shock. Eleven percent of the patients required admission and another 21% were seen in out-patient clinics. More children than adults could after a physical examination be discharged from the hospital without treatment. More than 3/4 of the stings occurred in July, August and September and more than 3/4 were during the day and evening. We found that most of the insect stings were due to either wasps or bees and that no one stung by insects other than wasps or bees needed admission to hospital. We conclude that a major part of insect stings could be avoided by following ordinary precautions.

Adolescent↗
PubMed1995

[Anticoagulant and thrombolytic therapy in deep venous thrombosis and pulmonary embolism].

During the last 10 years anticoagulant (AC) therapy and thrombolytic treatment of venous thromboembolism (VT) have been evaluated in randomized studies. Adjusted subcutaneous (s.c.) heparin and low molecular weight heparin (LMWH) are found at least as effective as intravenous (i.v.) infusion of heparin in deep venous thrombosis (DVT) without an increased bleeding risk. In pulmonary embolism (PE) randomized trials assessing the efficacy of s.c. heparin and LMWH are missing. Oral AC-treatment can be initiated from the first or second day in VT. The recommended duration is three months for medical patients, and 4 weeks seem appropriate for surgical patients that are completely mobilized and without persisting predisposing factors. Long-term efficacy of thrombolytic treatment of DVT has only been assessed in small trials showing a trend towards reduced risk of developing chronic venous insufficiency. Short-term thrombolytic treatment of DVT is evaluated in ongoing trials. In the treatment of PE short-term thrombolysis with either t-PA or urokinase is found to be as effective as long-term thrombolytic treatment with a reduced bleeding risk. Thrombolytic therapy rapidly reduces embolic mass and stabilizes haemodynamics, but mortality and long-term efficacy of thrombolysis and AC-treatment versus AC-treatment alone in PE are being assessed in ongoing studies.

Anticoagulants↗