http://repub.eur.nl/res/aut/4885/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/30970/ 2011-09-16T00:00:00Z Purpose: In about 5% of all cases LBP is associated with serious underlying pathology requiring diagnostic confirmation and directed treatment. Magnetic resonance imaging (MRI) is often used for this diagnostic purpose yet its role remains controversial. Consequently, this review aimed to summarize the available evidence on the diagnostic accuracy of MRI for identifying lumbar spinal pathology in adult low back pain (LPB) or sciatica patients. Methods: MEDLINE, EMBASE and CINAHL were searched (until December 2009) for observational studies assessing the diagnostic accuracy of MRI compared to a reference test for the identification of lumbar spinal pathology. Two reviewers independently selected studies for inclusion, extracted data and assessed methodological quality. Pooled summary estimates of sensitivity and specificity with 95% confidence intervals were calculated for homogenous subsets of studies. Results: Eight studies were included in this review. Strata were defined for separate pathologies i.e. lumbar disc herniation (HNP) and spinal stenosis. Five studies comparing MRI to findings at the surgery for identifying HNP were included in a meta-analysis. Pooled analysis resulted in a summary estimate of sensitivity of 75% (95% CI 65-83%) and specificity of 77% (95% CI 61-88%). For spinal stenosis pooling was not possible. Conclusions: The results suggest that a considerable proportion of patients may be classified incorrectly by MRI for HNP and spinal stenosis. However, the evidence for the diagnostic accuracy of MRI found by this review is not conclusive, since the results could be distorted due to the limited number of studies and large heterogeneity. http://repub.eur.nl/res/pub/14387/ 2008-11-05T00:00:00Z http://repub.eur.nl/res/pub/36260/ 2007-08-01T00:00:00Z Objective: Research in general practice has grown considerably over the past decades, but many projects face problems when recruiting patients. Lasagna's Law states that medical investigators overestimate the number of patients available for a research study. We aimed to assess factors related to success or failure of recruitment in general practice research. Study Design and Setting: Survey among investigators involved in primary care research in The Netherlands. Face-to-face interviews were held with investigators of 78 projects, assessing study design and fieldwork characteristics as well as success of patient recruitment. Results: Studies that focused on prevalent cases were more successful than studies that required incident cases. Studies in which the general practitioner (GP) had to be alert during consultations were less successful. When the GP or practice assistant was the first to inform the patient about the study, patient recruitment was less successful than when the patient received a letter by mail. There was a strong association among these three factors. Conclusion: Lasagna's Law also holds in Dutch primary care research: many studies face recruitment problems. Awareness of study characteristics affecting participation of GPs and patients may help investigators to improve their study design. http://repub.eur.nl/res/pub/9422/ 2000-01-01T00:00:00Z BACKGROUND: Conducting a pragmatic randomised trial in primary care is often accompanied by practical problems. Such problems are seldom reported and may constitute useful lessons for researchers planning future trials. AIM: To address the difficulties involved in patient recruitment and to present measures to minimise bias during outcome assessment. METHOD: A recently conducted trial comparing the effects of corticosteroid injections and physiotherapy for painful stiff shoulder was used to illustrate problems related to patient recruitment and outcome assessment. RESULTS: Recruitment of patients was not without difficulties despite careful preparation. Recruitment was discontinued after 20 months, when 109 of the intended 120 patients had been admitted to the trial. The shoulder trial mainly included patient-oriented subjective outcome measures. Subgroup analyses demonstrated that patient preferences might have had some influence on outcome. CONCLUSIONS: General practitioners might be willing or unwilling to participate in research for many reasons. The researcher should take these motivations into account when inviting physicians to take part in research. Strategies to enhance enrolment should be prepared before the start of the trial. When blinding of patients is problematic, patient preferences should be assessed before randomisation and their influence on the outcome studied. Although involving a blinded independent observer enables a more objective assessment of outcome, the success of blinding should be clearly evaluated.