Chest pain, depression and anxiety in coronary heart disease: Consequence or cause? A prospective clinical study in primary care.

OBJECTIVE: To examine if chest pain increases the risk of depression and anxiety, or, on the other hand, depression and anxiety increase the risk of chest pain onset in patients with coronary heart disease (CHD). DESIGN: Prospective clinical study. SETTING: 16 general practices in the Greater London Primary Care Research Network. PARTICIPANTS: 803 participants with a confirmed diagnosis of CHD at baseline on the Quality and Outcomes Framework (QOF) CHD registers. MAIN OUTCOME MEASURES: Rose Angina Questionnaire, HADS depression and anxiety subscales and PHQ-9 were assessed at seven time points, each 6 months apart. Multi-Level Analysis (MLA) and Structural Equation Modelling (SEM) were applied. RESULTS: Chest pain predicts both more severe anxiety and depression symptoms at all time points until 30 months after baseline. However, although anxiety predicted chest pain in the short term with a strong association, this association did not last after 18 months. Depression had only a small, negative association with chest pain. CONCLUSIONS: In persons with CHD, chest pain increases the risk of both anxiety and depression to a great extent. However, anxiety and depression have only limited effects on the risk for chest pain. This evidence suggests that anxiety and depression tend to be consequences rather than causes of cardiac chest pain. Intervention studies that support persons with CHD by providing this information should be devised and evaluated, thus deconstructing potentially catastrophic cognitions and strengthening emotional coping.

Screening high-risk patients and assisting in diagnosing anxiety in primary care: the Patient Health Questionnaire evaluated.

BACKGROUND: Questionnaires may help in detecting and diagnosing anxiety disorders in primary care. However, since utility of these questionnaires in target populations is rarely studied, the Patient Health Questionnaire anxiety modules (PHQ) were evaluated for use as: a) a screener in high-risk patients, and/or b) a case finder for general practitioners (GPs) to assist in diagnosing anxiety disorders. METHODS: A cross-sectional analysis was performed in 43 primary care practices in the Netherlands. The added value of the PHQ was assessed in two samples: 1) 170 patients at risk of anxiety disorders (or developing them) according to their electronic medical records (high-risk sample); 2) 141 patients identified as a possible 'anxiety case' by a GP (GP-identified sample). All patients completed the PHQ and were interviewed using the Mini International Neuropsychiatric interview to classify DSM-IV anxiety disorders. Psychometric properties were calculated, and a logistic regression analysis was performed to assess the diagnostic value of the PHQ. RESULTS: Using only the screening questions of the PHQ, the area under the curve was 83% in the high-risk sample. In GP-identified patients the official algorithm showed the best characteristics with an area under the curve of 77%. Positive screening questions significantly increased the odds of an anxiety disorder diagnosis in high-risk patients (odds ratio = 23.4; 95% confidence interval 6.9 to 78.8) as did a positive algorithm in GP-identified patients (odds ratio = 13.9; 95% confidence interval 3.8 to 50.6). CONCLUSIONS: The PHQ screening questions can be used to screen for anxiety disorders in high-risk primary care patients. In GP-identified patients, the benefit of the PHQ is less evident.

A high physical symptom count reduces the effectiveness of treatment for depression, independently of chronic medical conditions.

AIM: To assess to what extent a high physical symptom count influences the effect of treatment for major depressive disorder (MDD), and whether or not actual comorbid medical conditions explain this relationship. METHOD: Secondary data-analysis on a cluster-randomized trial in primary care, comparing the effectiveness of collaborative care with care as usual (CAU). MDD was measured using the PHQ-9. The Physical Symptoms Questionnaire (PSQ) was filled out at baseline by 115 patients (77.2% of those who entered the trial). Multilevel logistic regression models were used to test whether a high physical symptom count predicted lack of response to treatment, adding interaction terms to test differential effects on collaborative care versus CAU. RESULTS: A high physical symptom count negatively influenced the effect of both collaborative care and care as usual (no interaction). Specifically, a high physical symptom count predicted lack of response in both conditions at 3 (odds ratio=6.8), 6 (OR=4.1), and 9 months follow-up (OR=6.4). This was not explained by chronic physical illness. CONCLUSION: In this RCT, patients with MDD accompanied by a high physical symptom count benefited less from treatment for MDD in primary care, regardless of the type of treatment (either collaborative care or CAU). This was not explained by the presence of comorbid medical conditions. Further research is needed to improve treatment for MDD accompanied by a high physical symptom count, although collaborative care for depression is still more effective than CAU for this group of patients. TRIAL REGISTRATION: Dutch trial register ISRCTN15266438.

A target-driven collaborative care model for Major Depressive Disorder is effective in primary care in the Netherlands. A randomized clinical trial from the depression initiative.

BACKGROUND: Practice variation in the primary care treatment of depression may be considerable in the Netherlands, due to relatively small and unregulated practices. We adapted the collaborative care model for the treatment of Major Depressive Disorder (MDD) to accommodate existing practice variation and tested whether this had added value over Care as Usual (CAU). METHODS: A cluster randomized controlled trial was conducted to compare an adapted target driven collaborative care model with Care as Usual (CAU). Randomization was at the level of 18 (sub)urban primary care centers. The care manager and GP were supported by a web-based tracking and decision aid system that advised targeted treatment actions to achieve rapid response and if possible remission, and that warned the consultant psychiatrist if such treatment advice was not followed up. Eligible patients had a score of 10 or higher on the PHQ9, and met diagnostic criteria for major depression at the subsequent MINI Neuropsychiatric interview. A total of 93 patients were identified by screening. They received either collaborative care (CC) or CAU. Another 56 patients received collaborative care after identification by the GP. The outcome measures were response to treatment (50% or greater reduction of the PHQ9-total score from baseline) at three, six, nine and twelve months, and remission (a score of 0-4 on the PHQ9 at follow-up). RESULTS: Treatment response and remission in CAU were low. Collaborative care was more effective on achieving treatment response than CAU at three months for the total group of patients who received collaborative care [OR 5.2 ((1.41-16.09), NNT 2] and at nine months [OR 5.6 ((1.40-22.58)), NNT 3]. The effect was not statistically significant at 6 and 12 months. LIMITATIONS: A relatively high percentage of patients (36.5%) did not return one or more follow-up questionnaires. There was no evidence for selective non response. CONCLUSIONS: Our adapted target driven CC was considerably more effective than CAU for MDD in primary care in the Netherlands. The Numbers Needed To Treat (NNT) to achieve response in one additional patient were low (2-3), which suggest that introducing CC at a larger scale may be beneficial. The relatively large effects may be due to our focus on reducing practice variation through the introduction of easy to use web based tracking and decision aids. The findings are highly relevant for the application of the model in areas where practices tend to be small and for mixed healthcare systems such as in many countries in Europe. TRIAL REGISTRATION: Dutch trial register ISRCTN15266438 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=820).

Collaborative care for sick-listed workers with major depressive disorder: a randomised controlled trial from the Netherlands Depression Initiative aimed at return to work and depressive symptoms.

OBJECTIVES: Major depressive disorder (MDD) is associated with absenteeism. In this study, the effectiveness of collaborative care, with a focus on return to work (RTW), was evaluated in its effect on depressive symptoms and the duration until RTW in sick-listed workers with MDD in the occupational health setting. METHODS: In this randomised controlled trial, 126 sick-listed workers with MDD were randomised to usual care (N=61) or collaborative care (N=65). Collaborative care was applied by the occupational physician care manager, supported by a web-based tracking system and a consultant psychiatrist. Primary outcome measure was time to response. Secondary outcome measures were time to remission, depressive symptoms as continuous measure and the duration until full RTW. RESULTS: Collaborative care participants had a shorter time to response, with a difference of 2.8 months. However, no difference was found on time to remission or depressive symptoms as continuous measure. With a mean of 190 days in the collaborative care group, and 210 days in the usual care group, the groups did not differ significantly from each other in the duration until full RTW. Adherence to the collaborative care intervention was low. CONCLUSIONS: These results do not justify a widespread implementation of collaborative care in occupational healthcare, as it was operationalised in this study. However, since the study might have been underpowered for RTW and because treatment integrity was low, further research, with larger sample sizes, is needed to develop the best fitting (collaborative care) model for addressing RTW in depressed sick-listed workers. TRIAL REGISTRATION: : ISRCTN78462860.

Faster return to work after psychiatric consultation for sicklisted employees with common mental disorders compared to care as usual. A randomized clinical trial.

INTRODUCTION: Return to work (RTW) of employees on sick leave for common mental disorders may require a multidisciplinary approach. This article aims to assess time to RTW after a psychiatric consultation providing treatment advice to the occupational physician (OP) for employees on sick leave for common mental disorders in the occupational health (OH) setting, compared to care as usual (CAU). METHODS: Cluster randomized clinical trial evaluating patients of 12 OPs receiving consultation by a psychiatrist, compared to CAU delivered by 12 OPs in the control group. 60 patients suffering from common mental disorders and ≥ six weeks sicklisted were included. Follow up three and six months after inclusion. Primary outcome measure was time to RTW. Intention- to-treat multilevel analysis and a survival analysis were performed to evaluate time to RTW in both groups. RESULTS: In CAU, referral was the main intervention. Both groups improved in terms of symptom severity and quality of life, but time to RTW was significantly shorter in the psychiatric consultation group. At three months follow up, 58% of the psychiatric consultation group had full RTW versus 44% of the control group, a significant finding (P = 0.0093). Survival analysis showed 68 days earlier RTW after intervention in the psychiatric consultation group (P = 0.078) compared to CAU. CONCLUSION: Psychiatric consultation for employees on sick leave in the OH setting improves time to RTW in patients with common mental disorders as compared to CAU. In further research, focus should be on early intervention in patients with common mental disorders on short sick leave duration. Psychiatric consultation might be particularly promising for improvement of RTW in those patients. TRIAL REGISTRATION NUMBER: ISRCTN: 86722376.

A new graph and scoring system simplified analysis of changing states: disease remissions in a rheumatoid arthritis clinical trial.

BACKGROUND: In the setting of multiple remission and relapse periods of a chronic disease, simple endpoint analysis does not fully capture all relevant information, and we need methods to additionally describe both the duration of remission as well as the interruptions in this desired state. Probably the two-state continuous Markov process model comprises the best mathematical approach to data analysis. However, this approach is complex and not intuitive to clinicians. In this paper we propose a simple scoring system and a graph that can enhance the information about the remission experience in a trial or cohort study. METHODS: The continuity rewarded ('ConRew') score sums up periods in remission, and rewards extended periods by placing more value on uninterrupted periods than on interrupted periods. The 'patient vector graph' attempts to plot each patient's remission experience over time as a horizontal line (the 'vector') that is visible when the patient is in remission, but interrupted whenever relapse occurs. In this way a pattern is formed that conveys the number of patients experiencing remission, their individual total duration and interruptions, and time when these occur. RESULTS: In a dataset of a randomized trial in early rheumatoid arthritis, the graph clearly showed both early and late benefit of one group over the other. The scoring system demonstrated the main benefit was in the number of remission periods, not in their 'uninterruptedness'. CONCLUSION: Both approaches proved feasible and added extra information.

Collaborative stepped care for anxiety disorders in primary care: aims and design of a randomized controlled trial.

BACKGROUND: Panic disorder (PD) and generalized anxiety disorder (GAD) are two of the most disabling and costly anxiety disorders seen in primary care. However, treatment quality of these disorders in primary care generally falls beneath the standard of international guidelines. Collaborative stepped care is recommended for improving treatment of anxiety disorders, but cost-effectiveness of such an intervention has not yet been assessed in primary care. This article describes the aims and design of a study that is currently underway. The aim of this study is to evaluate effects and costs of a collaborative stepped care approach in the primary care setting for patients with PD and GAD compared with care as usual. METHODS/DESIGN: The study is a two armed, cluster randomized controlled trial. Care managers and their primary care practices will be randomized to deliver either collaborative stepped care (CSC) or care as usual (CAU). In the CSC group a general practitioner, care manager and psychiatrist work together in a collaborative care framework. Stepped care is provided in three steps: 1) guided self-help, 2) cognitive behavioral therapy and 3) antidepressant medication. Primary care patients with a DSM-IV diagnosis of PD and/or GAD will be included. 134 completers are needed to attain sufficient power to show a clinically significant effect of 1/2 SD on the primary outcome measure, the Beck Anxiety Inventory (BAI). Data on anxiety symptoms, mental and physical health, quality of life, health resource use and productivity will be collected at baseline and after three, six, nine and twelve months. DISCUSSION: It is hypothesized that the collaborative stepped care intervention will be more cost-effective than care as usual. The pragmatic design of this study will enable the researchers to evaluate what is possible in real clinical practice, rather than under ideal circumstances. Many requirements for a high quality trial are being met. Results of this study will contribute to treatment options for GAD and PD in the primary care setting. Results will become available in 2011. TRIAL REGISTRATION: NTR1071.

Practical guidelines for economic evaluations alongside equivalence trials.

An effective treatment already exists for many diseases. In these cases the effectiveness of a new treatment may be established by showing that the new treatment is as effective as (i.e., equivalent to) or at least as effective as (i.e., noninferior to) the old treatment. For an economic evaluation accompanying a clinical equivalence or noninferiority trial it is important to decide before the start of the study on the appropriate research question. In many cases the objective of the economic evaluation will be to show equivalence or noninferiority of the cost-effectiveness of the treatments. This has major implications for the design and analysis of the economic evaluation. In this article we propose methods for the analysis of economic equivalence and noninferiority studies that are similar to the methods applied to clinical equivalence and noninferiority trials. Furthermore, cost-effectiveness planes prove to be a valuable tool in the interpretation of the results in an economic equivalence or noninferiority trial. The concepts described in the article are illustrated using the results from an economic noninferiority trial.

Clinical effectiveness of usual care with or without antidepressant medication for primary care patients with minor or mild-major depression: a randomized equivalence trial.

BACKGROUND: Minor and mild-major depression are highly prevalent in primary care. There is insufficient evidence for the effectiveness of antidepressants in the treatment of minor and mild-major depression. We compared the effectiveness of usual primary care treatment, with or without antidepressants, in minor and mild-major depression. METHODS: A pragmatic patient-randomized equivalence trial with 52 weeks follow-up was conducted in The Netherlands. In total, 59 primary care physicians (PCPs) recruited and treated 181 adult patients with minor or mild-major depression. Patients were randomized to four consultations within 3 months of usual care plus antidepressants (UCandAD) or usual care alone (UCnoAD). The Montgomery Asberg Depression Rating Scale (MADRS) was used to assess changes in severity of depressive symptoms. The predefined equivalence margin was set at five points. Multilevel analysis was used to analyze the data. Secondary outcome measures were the Short-Form 36 (SF-36), and the Client Satisfaction Questionnaire (CSQ-8). RESULTS: Patients received on average 3.0 (SD 1.4) 15-min consultations within 3 months with (n = 85) or without paroxetine (n = 96). Equivalence of UCandAD and UCnoAD was demonstrated in the intention-to-treat analyses as well as the per-protocol analysis after 6 weeks, but not at 13, 26 and 52 weeks follow-up. No statistical differences in effectiveness between treatment groups were found in the intention-to-treat analysis. No differences in the physical and mental functioning (SF-36) were found between the treatment groups. Patients allocated to UCandAD were slightly more satisfied with their treatment at 13 weeks follow-up (but not at 52 weeks follow-up) than patients allocated to UCnoAD. Preliminary analyses suggested that subgroups such as patients with mild-major (instead of a minor) depression might benefit from antidepressant treatment. Patients who were assigned to their preferred treatment (in particular to UCnoAD) were more often compliant and had better clinical outcomes. CONCLUSION: UCandAD was as effective as UCnoAD over the first 6 weeks, but not at 13, 26, and 52 weeks. However, superiority of either treatment could not be demonstrated either. The question whether antidepressants add any clinical effect to usual care remains unresolved. We recommend future studies to look for subgroups of patients who may benefit from antidepressants. TRIAL REGISTRATION: Dutch Trial Registry ISRCN03007807.

Surgery is more cost-effective than splinting for carpal tunnel syndrome in the Netherlands: results of an economic evaluation alongside a randomized controlled trial.

BACKGROUND: Carpal tunnel syndrome (CTS) is a common disorder, often treated with surgery or wrist splinting. The objective of this economic evaluation alongside a randomized trial was to evaluate the cost-effectiveness of splinting and surgery for patients with CTS. METHODS: Patients at 13 neurological outpatient clinics with clinically and electrophysiologically confirmed idiopathic CTS were randomly allocated to splinting (n = 89) or surgery (n = 87). Clinical outcome measures included number of nights waking up due to symptoms, general improvement, severity of the main complaint, paraesthesia at night and during the day, and utility. The economic evaluation was performed from a societal perspective and involved all relevant costs. RESULTS: There were no differences in costs. The mean total costs per patient were in the surgery group EURO 2,126 compared to EURO 2,111 in the splint group. After 12 months, the success rate in the surgery group (92%) was significantly higher than in the splint group (72%). The acceptability curve showed that at a relatively low ceiling ratio of EURO 2,500 per patient there is a 90% probability that surgery is cost-effective. CONCLUSION: In the Netherlands, surgery is more cost-effective compared with splinting, and recommended as the preferred method of treatment for patients with CTS.

Randomised controlled trial of a collaborative care model with psychiatric consultation for persistent medically unexplained symptoms in general practice.

BACKGROUND: Patients with persistent medically unexplained symptoms often exhibit general dysfunction and psychiatric comorbidity and frequently resist psychiatric referral. The aim of this study was to evaluate the efficacy of a collaborative care model including training for general practitioners (GPs) and a psychiatric consultation model for patients with persistent medically unexplained symptoms in general practice. METHOD: Randomised controlled trial. Cluster randomisation at GP practices and multilevel analysis were performed. A total of 81 patients from 36 general practices completed the study. A collaborative care model of training and psychiatric consultation in general practice in the presence of the GP was compared with training plus care as usual by the GP. Outcome assessment on the patients' well-being, functioning and utilisation of health care services was performed 6 weeks and 6 months later. RESULTS: All the patients had somatoform disorders (Whitely Index 7.46), and 86% had comorbid psychiatric disorders. In the intervention group, the severity of the main medically unexplained symptoms decreased by 58%. The patients' social functioning improved. The utilization of health care was lower than in the care as usual group. CONCLUSIONS: A collaborative care model combining training with psychiatric consultation in the general practice setting is an effective intervention in the treatment of persistent medically unexplained symptoms. Anxiety and depressive disorders are highly comorbid in this group. The findings warrant a larger study.

The Four-Dimensional Symptom Questionnaire (4DSQ): a validation study of a multidimensional self-report questionnaire to assess distress, depression, anxiety and somatization.

BACKGROUND: The Four-Dimensional Symptom Questionnaire (4DSQ) is a self-report questionnaire that has been developed in primary care to distinguish non-specific general distress from depression, anxiety and somatization. The purpose of this paper is to evaluate its criterion and construct validity. METHODS: Data from 10 different primary care studies have been used. Criterion validity was assessed by comparing the 4DSQ scores with clinical diagnoses, the GPs' diagnosis of any psychosocial problem for Distress, standardised psychiatric diagnoses for Depression and Anxiety, and GPs' suspicion of somatization for Somatization. ROC analyses and logistic regression analyses were used to examine the associations. Construct validity was evaluated by investigating the inter-correlations between the scales, the factorial structure, the associations with other symptom questionnaires, and the associations with stress, personality and social functioning. The factorial structure of the 4DSQ was assessed through confirmatory factor analysis (CFA). The associations with other questionnaires were assessed with Pearson correlations and regression analyses. RESULTS: Regarding criterion validity, the Distress scale was associated with any psychosocial diagnosis (area under the ROC curve [AUC] 0.79), the Depression scale was associated with major depression (AUC = 0.83), the Anxiety scale was associated with anxiety disorder (AUC = 0.66), and the Somatization scale was associated with the GPs' suspicion of somatization (AUC = 0.65). Regarding the construct validity, the 4DSQ scales appeared to have considerable inter-correlations (r = 0.35-0.71). However, 30-40% of the variance of each scale was unique for that scale. CFA confirmed the 4-factor structure with a comparative fit index (CFI) of 0.92. The 4DSQ scales correlated with most other questionnaires measuring corresponding constructs. However, the 4DSQ Distress scale appeared to correlate with some other depression scales more than the 4DSQ Depression scale. Measures of stress (i.e. life events, psychosocial problems, and work stress) were mainly associated with Distress, while Distress, in turn, was mainly associated with psychosocial dysfunctioning, including sick leave. CONCLUSION: The 4DSQ seems to be a valid self-report questionnaire to measure distress, depression, anxiety and somatization in primary care patients. The 4DSQ Distress scale appears to measure the most general, most common, expression of psychological problems.

Does prenatal screening influence anxiety levels of pregnant women? A longitudinal randomised controlled trial.

OBJECTIVES: Questions addressed are: (1) Does offering prenatal screening increase anxiety? (2) Does receiving a negative screening result make women less anxious and does a positive screening result make women more anxious? (3) What are the long-term consequences on anxiety of offering screening and receiving a screening result? METHODS: Women were offered prenatal screening or no screening in a randomised controlled trial. State anxiety (STAI) and child-related anxiety (PRAQ-R) were measured. Questionnaires were filled in before prenatal screening was offered (T1), after the offer (T2), after the test result (T3), and in the third trimester of pregnancy (T4). RESULTS: Child-related anxiety levels were higher in women who chose to be screened compared to women who declined screening. Offering prenatal screening did not lead to increased anxiety levels. General anxiety increased in positively screened women, but decreased later in pregnancy. Women who were negatively screened or declined screening scored lower than the control group. CONCLUSION: For most women, offering prenatal screening and receiving the test result do not adversely affect anxiety. Giving pregnant women a choice to have prenatal screening done seems to have a small favourable effect on general feelings of anxiety.

Administering the MADRS by telephone or face-to-face: a validity study.

BACKGROUND: The Montgomery Asberg Depression Rating Scale (MADRS) is a frequently used observer-rated depression scale. In the present study, a telephonic rating was compared with a face-to-face rating in 66 primary care patients with minor or mild-major depression. The aim of the present study was to assess the validity of the administration by telephone. Additional objective was to study the validity of the first item, 'apparent sadness', the only item purely based on observation. METHODS: The present study was a validity study. During an in-person interview at the patient's home a trained interviewer administered the MADRS. A few days later the MADRS was administered again, but now by telephone and by a : Mean total score on the in-person administration was 24.0 (SD = 11.1), and on the telephone administration 23.5 (SD = 10.4). The ICC for the full scale was 0.65. Homogeneity analysis showed that the observation item 'apparent sadness' fitted well into the scale. CONCLUSION: The full MADRS, including the observation item 'apparent sadness', can be administered reliably by telephone.

Effectiveness and cost-effectiveness of early screening and treatment of malnourished patients.

BACKGROUND: About 25-40% of hospital patients are malnourished. With current clinical practices, only 50% of malnourished patients are identified by the medical and nursing staff. OBJECTIVE: The objective of this study was to report the cost and effectiveness of early recognition and treatment of malnourished hospital patients with the use of the Short Nutritional Assessment Questionnaire (SNAQ). DESIGN: The intervention group consisted of 297 patients who were admitted to 2 mixed medical and surgical wards and who received both malnutrition screening at admission and standardized nutritional care. The control group consisted of a comparable group of 291 patients who received the usual hospital clinical care. Outcome measures were weight change, use of supplemental drinks, use of tube feeding, use of parenteral nutrition and in-between meals, number of consultations by the hospital dietitian, and length of hospital stay. RESULTS: The recognition of malnutrition improved from 50% to 80% with the use of the SNAQ malnutrition screening tool during admission to the hospital. The standardized nutritional care protocol added approximately 600 kcal and 12 g protein to the daily intake of malnourished patients. Early screening and treatment of malnourished patients reduced the length of hospital stay in malnourished patients with low handgrip strength (ie, frail patients). To shorten the mean length of hospital stay by 1 d for all malnourished patients, a mean investment of 76 euros (91 US dollars) in nutritional screening and treatment was needed. The incremental costs were comparably low in the whole group and in the subgroup of malnourished patients with low handgrip strength. CONCLUSIONS: Screening with the SNAQ and early standardized nutritional care improves the recognition of malnourished patients and provides the opportunity to start treatment at an early stage of hospitalization. The additional costs of early nutritional care are low, especially in frail malnourished patients.

Are factor analytical techniques used appropriately in the validation of health status questionnaires? A systematic review on the quality of factor analysis of the SF-36.

Factor analysis is widely used to evaluate whether questionnaire items can be grouped into clusters representing different dimensions of the construct under study. This review focuses on the appropriate use of factor analysis. The Medical Outcomes Study Short Form-36 (SF-36) is used as an example. Articles were systematically searched and assessed according to a number of criteria for appropriate use and reporting. Twenty-eight studies were identified: exploratory factor analysis was performed in 22 studies, confirmatory factor analysis was performed in five studies and in one study both were performed. Substantial shortcomings were found in the reporting and justification of the methods applied. In 15 of the 23 studies in which exploratory factor analysis was performed, confirmatory factor analysis would have been more appropriate. Cross-validation was rarely performed. Presentation of the results and conclusions was often incomplete. Some of our results are specific for the SF-36, but the finding that both the application and the reporting of factor analysis leaves much room for improvement probably applies to other health status questionnaires as well. Optimal reporting and justification of methods is crucial for correct interpretation of the results and verification of the conclusions. Our list of criteria may be useful for journal editors, reviewers and researchers who have to assess publications in which factor analysis is applied.

The spinal cord in multiple sclerosis: relationship of high-spatial-resolution quantitative MR imaging findings to histopathologic results.

PURPOSE: To correlate quantitative magnetic resonance (MR) imaging data (ie, relaxation times and magnetization transfer ratios [MTRs]) with histopathologic findings of demyelination and axonal disease in cervical spinal cord specimens from patients with multiple sclerosis (MS) and control subjects. MATERIALS AND METHODS: Formaldehyde-fixed cervical spinal cord specimens from 11 patients with MS-three men and eight women (mean age at death, 66 years +/- 11.3 [standard deviation])-and two female control subjects without neurologic disease (83 and 41 years of age at death) were examined at 4.7 T. Relaxation time measurements and MTR mapping were performed. Analyses included the whole cord area and region-of-interest measurements. Histopathologic analyses included semiquantitative myelin and quantitative axonal analysis. RESULTS: Compared with control specimens (P < .001, analysis of variance), specimens from patients with MS had smaller cord areas (mean area, 59.0 mm(2) +/- 12.5 vs 72.7 mm(2) +/- 10.0), significant prolongation of T1 (mean prolongation, 30%) and T2 (mean prolongation, 13%), and decreased MTRs (mean, 10.5%). Within MS specimens, 58% of the white matter area displayed signal intensity abnormalities on intermediate-weighted MR images. The number of axons in normal-appearing white matter in MS specimens was, on average, 46% lower than the number of axons in white matter in control specimens. All quantitative MR parameters correlated well with demyelination; the correlation with T2 relaxation time was the strongest (r = 0.77, Spearman and Kendall nonparametric correlations). By contrast, quantitative MR parameters correlated less well with axonal density; the correlation with T2 relaxation time was the strongest (r = -0.44, Spearman and Kendall nonparametric correlations). Multilevel analysis, corrected for age and MS phenotype, could not result in a model explaining axonal density on the basis of quantitative MR parameters when myelin density was included as a predictor. CONCLUSION: Changes in quantitative MR imaging parameters in the cervical spinal cord in MS are mainly determined by demyelination and do not reflect axonal disease well.