Health technology assessment : HTA
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Health Technol Assess · Jan 2000
ReviewCoronary artery stents in the treatment of ischaemic heart disease: a rapid and systematic review.
Coronary artery stents are prosthetic linings inserted into coronary arteries via a catheter to widen the artery and increase blood flow to ischaemic heart muscle. They are used in the treatment of ischaemic heart disease (IHD). IHD is a major cause of morbidity and mortality (123,000 deaths per annum) in the UK and a major cost to the NHS. Clinical effects of IHD include subacute manifestations (stable and unstable angina) and acute manifestations (particularly myocardial infarction [MI]). Treatment includes attention to risk factors, drug therapy, percutaneous invasive interventions (PCIs) (including percutaneous transluminal coronary angioplasty [PTCA] and stents) and coronary artery bypass graft surgery (CABG). In the last decade there has been a steady and significant increase in the rate of PCIs for IHD. In the UK, rates per million population increased from 174 in 1991 to 437 in 1998. Stents are now used in about 70% of PCIs. Data from the rest of Europe suggest there is potential for PCI and stent rates to increase considerably. In the UK there is evidence of under-provision and inequity of access to revascularisation procedures. ⋯ For the review of clinical effectiveness, inclusion criteria were: (i) RCT design; (ii) study population comprising adults with IHD in native or graft vessels (including patients with subacute IHD or AMI); (iii) procedure involving elective insertion of coronary artery stents; (iv) elective PTCA (including PTCA with provisional stenting) or CABG as comparator; (v) outcomes defined as one or more of: combined event rate (or event-free survival), death, MI, angina, target vessel revascularisation, CABG, repeat PTCA, angiographic outcomes; (vi) trials that had closed and reported results for all or almost all recruited patients. For the economic evaluation, studies of adults with IHD were included if they were of the following types: studies reporting UK costs; comparative economic evaluation combining both costs and outcomes; economic evaluations reporting costs and outcomes separately for the years 1998 and 1999 (to ensure current practice was included).(ABSTRACT TRUNCATED)
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Health Technol Assess · Jan 2000
Review Comparative StudyA systematic review of comparisons of effect sizes derived from randomised and non-randomised studies.
There is controversy about the value of evidence about the effectiveness of healthcare interventions from non-randomised study designs. Advocates for quasi-experimental and observational (QEO) studies argue that evidence from randomised controlled trials (RCTs) is often difficult or impossible to obtain, or is inadequate to answer the question of interest. Advocates for RCTs point out that QEO studies are more susceptible to bias and refer to published comparisons that suggest QEO estimates tend to find a greater benefit than RCT estimates. However, comparisons from the literature are often cited selectively, may be unsystematic and may have failed to distinguish between different explanations for any discrepancies observed. ⋯ Relevant literature was identified from: The Cochrane Library, MEDLINE, EMBASE, DARE, and the Science Citation Index. References of relevant papers already identified experts. Electronic searches were very difficult to design and yielded few papers for the first strategy and when identifying study designs. CHOICE OF INTERVENTIONS TO REVIEW FOR STRATEGIES 1 AND 2: For strategy 1, any intervention was eligible. For strategy 2, interventions for which the population, intervention and outcome investigated were anticipated to be homogeneous across studies were selected for review: Mammographic screening (MSBC) of women to reduce mortality from breast cancer. Folic acid supplementation (FAS) to prevent neural tube defects in women trying to conceive. DATA EXTRACTION AND QUALITY ASSESSMENT: Data were extracted by the first author and checked by the second author. Disagreements were negotiated with reference to the paper concerned. For strategy 1, study quality was scored using a checklist to assess whether the RCT and QEO study estimates were derived from the same populations, whether the assessment of outcomes was 'blinded', and the extent to which the QEO study estimate took account of possible confounding. For strategy 2, a more detailed instrument was used to assess study quality on four dimensions: the quality of reporting, the generalisability of the results, and the extent to which estimates of effectiveness may have been subject to bias or confounding. All quality assessments were carried out by three people. DATA SYNTHESIS AND ANALYSIS: For strategy 1, pairs of comparisons between RCT and QEO study estimates were classified as high or low quality. Seven indices of the size of discrepancies between estimates of effect size and outcome frequency were calculated, where possible, for each comparison. Distributions of the size and direction of discrepancies were compared for high- and low-quality comparisons. FOR STRATEGY 2, THREE ANALYSES WERE CARRIED OUT: Attributes of the instrument were described by k statistics, percentage agreement, and Cronbach's a values. Regression analyses were used to investigate -variations in study quality. (ABSTRACT TRUNCATED)
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Health Technol Assess · Jan 2000
ReviewOutcome measures for adult critical care: a systematic review.
1. To identify generic and disease specific measures of impairment, functional status and health-related quality of life that have been used in adult critical care (intensive and high-dependency care) survivors. 2. To review the validity, reliability and responsiveness of the measures in adult critical care survivors. 3. To consider the implications for future policy and to make recommendations for further methodological research. 4. To review what is currently known of the outcome of adult critical care. ⋯ MEASURES USED IN CRITICAL CARE: Measures of impairment were largely confined to the respiratory system so are almost certainly not appropriate for many critical care survivors. They can be categorised as respiratory volumes (e.g. vital capacity), gas flow within the respiratory system (e.g. forced expiratory volume in 1 second (FEV1)), pulmonary diffusing capacity (e.g. carbon monoxide diffusing capacity) and visualisation of the upper airway (e.g. bronchoscopy). Multiple tests are often performed. Eight measures of physical functional status were used, five generic and three disease-specific. The most frequently used generic measures were multi-item scales. Two single-item global measures attempted to capture a person's overall activity level or functional status. Five multi-item measures of mental functional status were used, four generic and one specific to trauma patients. The generic measures were either confined to assessing depressive symptoms or also encompassed a measure of anxiety. Measures of neuropsychological functioning relate to a person's cognition, attention, ability to process information and memory. Apart from one single-item measure, which focused on communication level, six multi-item measures were used with critical care survivors. Such measures are particularly appropriate for use with survivors of head injury or other neurological insult and, in that sense, they are disease-specific rather than generic measures. Single item measures of recovery were frequently used but researchers often invented their own, so there was little consistency in the wording. These measures had five principal foci - return to work, return to own home, degree of recovery, productivity and chronic health status. One multi-item scale was also used. (ABSTRACT TRUNCATED)
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Health Technol Assess · Jan 2000
Randomized Controlled Trial Comparative Study Clinical TrialRandomised controlled trial of non-directive counselling, cognitive-behaviour therapy and usual general practitioner care in the management of depression as well as mixed anxiety and depression in primary care.
The aim of this study was to determine both the clinical and cost-effectiveness of usual general practitioner (GP) care compared with two types of brief psychological therapy (non-directive counselling and cognitive-behaviour therapy) in the management of depression as well as mixed anxiety and depression in the primary care setting. ⋯ At 4 months, both psychological therapies had reduced depressive symptoms to a significantly greater extent than usual GP care. Patients in the psychological therapy groups exhibited mean scores on the Beck Depression Inventory that were 4-5 points lower than the mean score of patients in the usual GP care group, a difference that was also clinically significant. These differences did not generalize to other measures of outcome. There was no significant difference in outcome between the two psychological therapies when they were compared directly using all 260 patients randomised to a psychological therapy by either randomised allocation method. At 12 months, the patients in all three groups had improved to the same extent. The lack of a significant difference between the treatment groups at this point resulted from greater improvement of the patients in the GP care group between the 4- and 12-month follow-ups. At 4 months, patients in both psychological therapy groups were more satisfied with their treatment than those in the usual GP care group. However, by 12 months, patients who had received non-directive counselling were more satisfied than those in either of the other two groups. There were few differences in the baseline characteristics of patients who were randomised or expressed a treatment preference, and no differences in outcome between these patients. Similar outcomes were found for patients who chose either psychological therapy. Again, there were no significant differences between the two groups at 4 or 12 months. Patients who chose counselling were more satisfied with treatment than those who chose c
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Health Technol Assess · Jan 2000
ReviewFalse-negative results in screening programmes: systematic review of impact and implications.
When assessing whether a screening programme is appropriate, there is a particular obligation to ensure that the harms as well as the benefits are considered. Among these harms is the likelihood that false-negative results will occur. In some cases, the consequences of these can be difficult to assess, although false reassurance leading to diagnostic delay and subsequent treatment has been suggested. However, no test is totally accurate (with 100% sensitivity and specificity), and false-negative results are inherent in any screening programme that does not have 100% sensitivity. This review was carried out to assess the medical, psychological, economic and legal consequences of false-negative results that occur in national screening programmes. ⋯ False-negatives are evident in all screening programmes, even when the quality of the service provided is high. They may have the potential to delay the detection of breast and cervical cancer, but there is little evidence to help assess their psychological consequences in these or other screening programmes. False-negatives are likely to lead to legal action being taken by those individuals affected, and potentially may reduce public confidence in screening. (ABSTRACT TRUNCATED)