[Evidence-based medicine: a discussion of the most frequently occurring criticisms]

Since the introduction of evidence-based medicine (EBM) into the field of health care in the early nineties some major criticisms have appeared in scientific literature. One of the most commonly heard objections to EBM is loss of therapeutic freedom. However even with the advent of EBM the physician continues to look for solutions that are tailored to the patient. The available evidence is often inadequate, there are many inconsistencies and contradictions in the research material and the published outcomes are distorted by publication bias. There is resistance to the opinion that randomized clinical trials (RCTs) provide the best foundations on which to build clinical policies. There must always be room for views expressed in other types of study. EBM is primarily for academics and does not take clinical expertise into account. However as the results of scientific research are becoming increasingly available to a wider public, patients are able to challenge the decisions made by their health-care practitioners and push them to provide the motivation for their decisions. Many health-care practitioners have commented that they always have to take the results of scientific research into account. One strength of EBM in this is the transparent manner in which the overview of the literature develops and the systematic approach to results from scientific study. After all, there is insufficient evidence that the EBM process works effectively and that it therefore improves patient care. It is true to say that patients who receive treatment of which the efficacy has been proven experience better treatment results than other patients. Setting up a definitive randomized study to answer this question would be difficult if not impossible. EBM is an aid to support clinical decision making. The development of principles on which to base this way of thinking and acting and the quest for suitable research designs and the most objective research results in order to be able to answer all the questions posed by caregivers, is not yet complete. EBM is just one of the weapons in the armoury of the caregiver in the battle for the optimal provision.

[Pharmacological treatment of hypercholesterolaemia in primary prevention. The use of the different sources of information]

In the first two articles of this series devoted to Evidence-Based Medicine, we have shown how to translate a clinical problem in a well formulated question and how to derive search terms from the PICO. In this article, we describe in more detail the different sources of information and how to use them. The strategy will be illustrated by answering the question whether it should be recommended to treat hypercholesterolaemia in a young woman without cardiovascular risk factors. In a following article, we will show how to adapt a search strategy to a specific question or PICO.

[The investigation of gene-environment interaction using case-control comparisons]

Many chronic diseases are caused by the interaction of genes and environmental factors. Genetic epidemiologic research seeks to elucidate the role of genetic factors and their interaction with environmental factors in the occurrence of disease. Gene-environment interaction can be assessed using different types of case-control comparisons. The classic case-control design is suitable to investigate the association between multiple genes and environmental factors. Results can be presented in a two-by-four table. In a case-parents design, the genotype of each case is compared with the genotype of a fictitious control formed by the non-transmitted alleles from each parent. In a case-only design, the relationship between a genotype and an environmental factor is examined in a population of affected cases only. Both the case-parents and the case-only designs assume independence between genotype and environmental factors in the control group.

A combination of tests for the diagnosis of dementia had a significant diagnostic value

OBJECTIVE

To study the diagnostic parameters of a number of instruments for a diagnosis of dementia in general practice and the added diagnostic value of these tests.

STUDY DESIGN AND SETTING

Cross-sectional diagnostic research in general practice.

PARTICIPANTS

152 persons aged 65 plus. The Mini-Mental State Examination (MMSE), the Clock Drawing Test, the ADMP scale, the Timed Up and Go Test, the Extrapyramidal Sign Scale, the Behavior Observation Scale, the Poon-Baro-Wens computer battery, and the Cognitive Drug Research Computerized Assessment System were evaluated against the Dutch version of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX-N). Diagnostic characteristics were calculated with their 95% CI. Using forward stepwise logistic regression analysis, a model was built with CAMDEX-N as the dependent variable and the tests under study as independent variables. Area under the curve was the main parameter for the comparisons.

RESULTS

The main diagnostic gain results from age and ADMP, followed by the Clock Drawing Test. Subsequent addition of the MMSE and computer tests results in modest additional gain only. The final model including five tests has an area under the curve of 0.95.

CONCLUSION

Sophisticated neuropsychological computerized tests have little added value in the diagnostic work-up of dementia in general practice. Basic clinical tests used in an appropriate sequence can be very valuable in establishing the diagnosis of dementia.

Prevalence of hepatitis C in drug users in Flanders: determinants and geographic differences

The prevalence of hepatitis C and related risk factors in drug users were compared in two geographic regions in Belgium, the city of Antwerp and the mixed urban-rural area of Limburg. All 310 participants were surveyed and screened for hepatitis B, hepatitis C and HIV. Prevalence rates of anti-HCV, anti-HBc and anti-HIV were 71, 62 and 4% in Antwerp and 46, 21 and 0% in Limburg respectively. Injecting drug use, duration of injecting drug use, work as a commercial sex-worker, originating from Turkey or Northern Africa, marginalization and anti-HBc positivity were identified as independent predictors for hepatitis C infection. In this study an important difference in HCV seroprevalence among drug users in a methadone maintenance programme across two geographic regions in Belgium was demonstrated. This was explained not only by variations in drug-related risk behaviour, but also by differences in sexual risk behaviour and socio-economic status.

The epidemiology of hepatitis C among injecting drug users in Belgium

In industrialised countries, injecting drug use is currently the most important risk factor for infection with hepatitis C, resulting in high prevalence rates of hepatitis C among injecting drug users. To contain the hepatitis C epidemic major efforts should be done to prevent new infection among injecting drug users. Monitoring infection rates are crucial as it may provide feedback on the effectiveness of interventions. In this article the epidemiology of hepatitis C among injecting drug users in Belgium is briefly reviewed. More specifically the prevalence of anti-HCV antibodies, the prevalence of co-infections, the proportion of chronic HCV carriers, the distribution of genotypes and preventive measures among injecting drug users in Belgium are discussed and compared to the situation elsewhere in Western Europe.

Measuring the body temperature: how accurate is the Tempa Dot?

INTRODUCTION

We evaluated the accuracy of a disposable, sterile thermometer that is practical in use and holds no risk of cross-infections.

METHODS

a cross-sectional study was set up in which we compared the Tempa Dot with the mercury thermometer in adults and children. Subjects were recruited from general practice and a paediatric ward. The mercury thermometer was used orally in subjects over 2 years of age and rectally in children up to 2 years old. The Tempa Dot was used either orally or axillary.

RESULTS

The total population consisted of 212 patients, of which 131 children were younger than 16 years old. Their mean age was 17.3 years old, ranging from 1 month to 76 years. The mean difference between the mercury thermometer and the Tempa Dot, used orally or axillary, was 0.04 degrees C. For children between 0 and 16 years old, the mean difference was 0.08 degrees C. Agreement between the two methods as assessed with regression analysis and Bland and Altman plots was very good. ROC curve analysis suggests cut-off points of 37.2 and 37.6 degrees C to detect fever for the Tempa Dot at the oral and the axillary site respectively. Sensitivity and specificity were 100.0% and 79.0% for the total population, measuring orally and 100.0% and 95.9% axillary. In children, sensitivity and specificity were 100.0% and 83.1% orally, and 100.0% and 95.4% axillary. Using a single cut-off point for both measuring sites, namely 37.5 degrees C, sensitivity dropped and specificity increased for the oral site. For the axillary site, sensitivity remained unchanged and specificity was somewhat less.

CONCLUSION

the Tempa Dot is a reliable alternative for the mercury thermometer. In clinical use, a cut-off point of 37.5 degrees C for both the oral and axillary site is most appropriate.

Methadone and buprenorphine maintenance therapies for patients with hepatitis C virus infected after intravenous drug use

Heroin addiction is a chronic relapsing disease that is difficult to cure, but stabilisation and harm reduction can importantly increase the life time expectancy and the quality of life of the patient, his immediate vicinity and society in general. Currently, no proven effective pharmacological interventions are available for cocaine addiction, and treatment has to rely on existing cognitive behaviour therapies combined with contingency management strategies. Substitution therapy, however, is effective in caring for heroin addicts. Methadone is a synthetic opioid that counteracts withdrawal symptoms of heroin. Buprenorphine is a derivative of the morphine alkaloid, thebaine, and is a partial opioid agonist at the micro opioid receptor in the nervous system. A substitution treatment program effectively reduces and often eliminates heroin injection behaviour, rendering patients more socially stabilised. Reduction in the number of viral co-infections can be observed. Methadone undergoes oxidative biotransformation in the liver, but is also stored in the liver and released into the blood in unchanged form. The usual dose can be continued in patients with stable chronic liver disease, including advanced cirrhosis. In acute liver disease or acute decompensation of chronic liver disease, close clinical observation for signs of narcotic overdose or withdrawal is necessary. A modest alteration in methadone dose may be appropriate for some patients. Buprenorphine can cause liver dysfunction after sublingual and even more after intravenous administration. It is advised to follow the liver function during buprenorphine treatment and to warn the clients for intravenous use of buprenorphine. Neither methadone nor buprenorphine do influence the effect of interferon and ribavirin during the treatment of chronic hepatitis C patients. It may be necessary to increase the dosage of methadone during interferon treatment.

Substance use in Belgium : prevalence and management

Substance use is emerging in Belgium. The 'typical user' starts at a young age. Polydrug use has become very common. Cannabis and alcohol are the most frequently used substances among the school population. Heroin and cocaine are the most frequently injected drugs. Sharing of injecting material and paraphernalia is reported to happen in half of the subjects injecting drugs. Substance use causes a lot of adverse organic, social and psychiatric events. Management of substance use consists of information, drug-free treatment and harm reduction, including substitution and maintenance programs. The management of care in Belgium differs between the regions.

Treatment of hepatitis C viral infections in substance abusers

AIMS

To examine the evidence for excluding chronic hepatitis C (CHC) patients with substance abuse from treatment with interferon (IFN) and ribavirin.

METHODS

We reviewed clinical trials focussing on the treatment of chronic hepatitis C of patients with substance abuse between 2001 and 2004. Ten clinical trials concerning antiviral treatment in substance abusers were described of which six were controlled ones. There were no randomised trials. There was one controlled multi-centre trial. One trial used pegylated IFN.

RESULTS

In the total group of substance abusers the sustained viral response (SVR) and the adherence was not different from control groups. In former drug users, active drug users and patients taking substitution therapy for opioid dependence the sustained viral response and adherence was not different from control populations. However, non-substituted active drug users seemed more likely to be lost to follow-up. Discontinuation of treatment occurred most frequently during the first 8 weeks of therapy. Neurobehavioural changes leading to depression started in the first 8 weeks of treatment. Although follow-up periods after SVR were short, the currently described re-infection rate occurring in active intravenous drug users remains low.

CONCLUSIONS

There is no evidence to withhold antiviral treatment against HCV in active substance abusers. It seems important to advise to start substitution therapy in non-substituted active drug users, increase substitution therapy dose in substituted patients and treat depression as early as possible. More prospective controlled trials on HCV treatment in active and difficult-to-reach substance users are needed.

[From PICO to search terms on the Internet: how to find relevant information? New coxibs: do they have a better gastrointestinal safety?]

In the first article of this series, we have shown how to translate a clinical problem into a well built question, by creating a PICO (Patient--Intervention--Comparison--Outcome). In this second article, we will explain how to transform the PICO in English search terms for use on the internet. We use these terms in the different databases to find the answer to the following clinical problem: "In patients aged 65 or over with hip osteoarthritis, and a history of peptic ulcer, is the risk of a new peptic ulcer less using a cox-2 inhibitor than with a classic nonsteroidal anti-inflammatory drug?"

Hepatitis C, interferon alpha and psychiatric co-morbidity in intravenous drug users (IVDU) : guidelines for clinical practice

The evidence regarding the co-morbidity of chronic hepatitis C, psychiatric illness and intravenous drug abuse is reviewed from the literature. Also the occurrence and the treatment of psychiatric side effects during treatment with interferon in patients with a history of drug abuse are reviewed. There is insufficient evidence for a specific hepatitis C induced depression or fatigue, but a direct link between hepatitis C and cerebral dysfunction is not excluded. Immune system activation rather than drug use may explain cerebral symptoms. In HCV positive substance users anxiety and depression are more prevalent than in HCV negative substance users. During treatment with regular or pegylated (PEG) interferon depression is a frequent side effect (ca 30%) and occurs independently from pre-existing psychiatric disorders or drug abuse. A history of drug abuse per se does not increase the risk of depression as a side effect of interferon treatment. It is extremely important to monitor symptoms of depression in the early weeks of treatment and to start antidepressant treatment as early as possible. Antidepressants should be continued throughout the interferon treatment period. There are insufficient data to assess these situations in which preventive antidepressant treatment should be started before interferon treatment. Clinical judgement can, however, lead to preventive antidepressant treatment, even at subclinical levels of depression. A cut off score of > 10 on the Beck Depression Inventory before interferon treatment is associated with a higher risk of depression during treatment. Both selective serotonin reuptake inhibitors and other classes of antidepressants can be used.

Disclosing the diagnosis of dementia: the performance of Flemish general practitioners

BACKGROUND

This issue of whether or not, how and when patients should be told of the diagnosis of dementia remains a matter for discussion. Recent data confirm that the patient is told of the diagnosis in only 40 to 55% of cases. We therefore studied the performance of Flemish general practitioners (GPs) in this area.

METHOD

A postal questionnaire, based on that prepared by Johnson et al., was sent to a random sample of 1000 Flemish GPs, out of a total of 7000.

RESULTS

A total of 647 answers were returned, of which 521 were eligible for analysis (response rate 60%). Thirty-six percent of these 521 GPs always or usually disclose the diagnosis, while 37% provide information about the prognosis. Most doctors (75%) see benefits in disclosure, particularly as regards planning care, providing treatment and encouraging a good doctor-patient relationship. Only 61% of respondents present an appropriate differential diagnosis.

DISCUSSION

The results obtained from the Flemish GPs are similar to those of other known studies. A detailed analysis of the reasons for and the benefits of disclosing the diagnosis reveal a less reluctant attitude than could be inferred from the rough data. GPs pay a great deal of attention to the patient's feelings, experiences and ability to cope and to the proper timing of their information. However, intensive educational projects have to be set up in order to stimulate a more etiologically-oriented diagnosis and to improve the quality of the process of disclosing the diagnosis of dementia.

[EBM: otitis media in children: how to formulate a PICO question]

This series of articles begins with a problem frequently encountered in children: acute otitis media. Under the insistence of parents, antibiotics are frequently prescribed. The physician knows that the value of that therapy is debatable, but what for a child of 6 years of age? The physician whishes to compare his/her opinion with what is published in the litterature or available on the web. How to start his/her research? In this first article the physician will find out how to translate his/her practical question into a question which leads to a practical answer, and then to a PICO question. This will allow the physician to find sources of directly usable and relevant data which will offer a rational and wellfounded answer to his/her clinical question.

Is depression related to subsequent diabetes mellitus?

OBJECTIVE

To compare the risk of developing diabetes mellitus (DM) in the general population between subjects who had a depression and subjects who never had a depression.

METHOD

Retrospective cohort design. People with depression were diagnosed with a depression between 1975 and 1990; controls never had a depression. Both groups were followed for a diagnosis of type II diabetes until 2000. Data on 1334 depressed and 66 670 non-depressed subjects were available from a large general practice-based database.

RESULTS

No overall relation was found, but among males below age 50 there was a 78% increase in the rate of development of DM compared with non-depressed patients (hazard ratio 1.78, 95% CI: 1.21-2.62).

CONCLUSION

Depression in males between the age of 20 and 50 years is related to an increased risk of developing DM.

CUGE: A SCREENING INSTRUMENT FOR ALCOHOL ABUSE AND DEPENDENCE IN STUDENTS

OBJECTIVES

The prevalence of alcohol abuse on college campuses ranges from 7 to 17%. Frequent heavy drinkers place themselves and others at risk for a variety of adverse consequences and frequently remain undetected. Brief individual interventions result in a significant reduction on the number of drinks. Therefore, detection of students at risk is useful and desirable. The CUGE has been elsewhere described as a promising screening device for problem drinking in students. In order to determine the diagnostic value of this new questionnaire, we set up a validation study in a new and independent population of freshmen.

METHODS

A cross-sectional diagnostic study. Participants were college freshmen of the Katholieke Universiteit Leuven. All students received a questionnaire, containing the CUGE, being the test of interest, and the CIDI as the reference test.

RESULTS

The CUGE combines a very high sensitivity of 91% with a reasonable specificity of 76.3% in this validation group.

CONCLUSIONS

The CUGE is an excellent screening device in this population of students. In addition, it is a short questionnaire with only yes or no questions. This makes the CUGE easily applicable as a part of broad routine questionnaires.

The value of the CAGE in screening for alcohol abuse and alcohol dependence in general clinical populations: a diagnostic meta-analysis

OBJECTIVE

To perform a meta-analysis to assess diagnostic characteristics of the CAGE in screening for alcohol abuse or dependence in a general clinical population and to test a new method for pooling of ROC curves.

METHODS

Medline search performed over the period 1/1/1974 to 31/12/2001.

MEASUREMENT

Calculation of diagnostic values.

RESULTS

We identified 35 articles using the DSM criteria as the gold standard to test the diagnostic value of the CAGE. Only 10 studies could be included for the meta-analysis. With a cutoff point > or =2, the pooled sensitivity is far better in inpatients (0.87) than in primary care patients (0.71) or ambulatory patients (0.60). The pooled specificity also differs for each group. The likelihood ratios seem to be relatively constant over the populations (overall LR+:3.44;LR-:0.18). We calculated a pooled AUC of 0.87 (95% CI 0.85-0.89). At low specificity values, the sensitivity was homogeneous over the studies, and at a low sensitivity, the specificity was heterogeneous.

CONCLUSION

The diagnostic value of the CAGE is of limited value using this test for screening purposes at his recommended cutpoint of > or =2.

Geographical differences in cancer incidence in the Belgian province of Limburg

Correctly addressing the questions of worried citizens with respect to possible clusters of cancer occurrence requires a risk communication strategy that is informed by a previously established analytical procedure. The aim of this study was to analyse cancer registration data in order to identify municipalities or clusters of municipalities with an increased incidence of one or more cancer types, adjusted for background characteristics at the same level. Ideally, the approach is proactive, straightforward, and easy for untrained citizens to follow and imprecision effects are taken into account. For all municipalities and most cancers, all relevant calculations were performed proactively and all methods and decision thresholds were defined beforehand. For each municipality, standardised incidence ratios (SIRs) were calculated and smoothed using a Poisson-gamma (PG) and a conditional autoregressive (CAR) model. Clusters were confirmed using the Spatial scan statistic of Kulldorff. Identified clusters were tested for possible confounders using all information that was available for each municipality. The Limburg Cancer Registry, serving the population of the Belgian province of Limburg (n=781 759) was used. We identified a possible cluster of increased prostate cancer incidence (smoothed SIRs around 1.2) and a cluster of increased bladder cancer incidence in males that included seven municipalities with CAR-smoothed SIRs between 1.5 and 2.1. SIRs followed a more or less circular decrease around the centre that was situated in Alken and Hasselt, the provincial capital. Bladder cancer incidence was positively related to an index of socio-economic status (SES) per municipality. No relationship was found with the other indexes that were available. 82% of all bladder cancers were transitional cell carcinomas (TCC). A repeated analysis based on TCCs only resulted in similar results with CAR-smoothed relative risks that tended to be even higher in the cluster zone. A pre-emptive analysis of possible cancer incidence clustering on the municipality level proved to be feasible.

Higher attack rates for left motor deficit among men with cerebrovascular events

The authors report the findings of a prospectively collected database of stroke and TIA recorded from 1998 through 1999 by the 178 family physicians of the Belgian sentinel network. The yearly age-adjusted attack rate per 100,000 men was estimated as 109 (95% CI = 86 to 137) for left motor deficit and 75 (95% CI = 56 to 99) for right motor deficit (p = 0.011). This difference was not observed among women nor in the entire sample population. The authors suggest that handedness should be systematically recorded and compared to both sex and the side of the event.

Prostate-specific antigen screening coverage and prostate cancer incidence rates in the Belgian province of Limburg in 1996-1998

According to the 1996-1998 cancer incidence report of the cancer registry of the Belgian province of Limburg (LIKAR), prostate cancer is the most common cancer in men with a crude invasive cancer incidence rate of 123.7 per 100000 person-years (125.4 and 81.8 after standardization for the European and the world standard population). In a study on geographical differences between the occurrence of cancers in municipalities, prostate cancer standardized incidence rates (SIRs) were significantly higher in a number of municipalities, with mean relative risks of 1.2 and 1.3 after full Bayesian smoothing. We hypothesized that prostate cancer incidence rates are largely influenced by the prostate-specific antigen (PSA) screening policy of local physicians and that differences between municipalities are more informative about local screening habits then about real differences in cancer occurrence. The aim of this study was to test this hypothesis by relating local prostate cancer SIRs to the PSA screening coverage of the population of men in each municipality. The SIRs of prostate cancer in 1996-1998 for each municipality were provided by LIKAR. They related to all histologically or cytologically proven new invasive prostate cancers during these years. For each municipality, PSA coverage data were provided by the largest sick fund of the region. Coverage was defined as the proportion of men above the age of 40 that was tested at least once within the registration period. The SIR of each municipality (dependent variable) was related to the age-standardized corresponding coverage (independent variable) by linear regression and was adjusted for the number of inhabitants per municipality: log (standardized incidence rate) = 164 + 602 * (standardized PSA coverage), = 0.12. The model explained 6% of the variance in incidence. In conclusion, in this study no statistically significant relationship was identified between PSA coverage and prostate cancer incidence rate per municipality. This could result from no such relationship existing or from low statistical power.