Objectives In this monograph we examine the added value of new psychometric methods (Rasch measurement and Item Response Theory) over traditional psychometric approaches by comparing and contrasting their psychometric evaluations of existing sets of rating scale data. We have concentrated on Rasch measurement rather than Item Response Theory because we believe that it is the more advantageous method for health measurement from a conceptual, theoretical and practical perspective. Our intention is to provide an authoritative document that describes the principles of Rasch measurement and the practice of Rasch analysis in a clear, detailed, non-technical form that is accurate and accessible to clinicians and researchers in health measurement. Review methods A comparison was undertaken of traditional and new psychometric methods in five large sets of rating scale data: (1) evaluation of the Rivermead Mobility Index (RMI) in data from 666 participants in the Cannabis in Multiple Sclerosis (CAMS) study; (2) evaluation of the Multiple Sclerosis Impact Scale (MSIS-29) in data from 1725 people with multiple sclerosis; (3) evaluation of test-retest reliability of MSIS-29 in data from 150 people with multiple sclerosis; (4) examination of the use of Rasch analysis to equate scales purporting to measure the same health construct in 585 people with multiple sclerosis; and (5) comparison of relative responsiveness of the Barthel Index and Functional Independence Measure in data from 1400 people undergoing neurorehabilitation. Results Both Rasch measurement and Item Response Theory are conceptually and theoretically superior to traditional psychometric methods. Findings from each of the five studies show that Rasch analysis is empirically superior to traditional psychometric methods for evaluating rating scales, developing rating scales, analysing rating scale data, understanding and measuring stability and change, and understanding the health constructs we seek to quantify. Conclusions There is considerable added value in using Rasch analysis rather than traditional psychometric methods in health measurement. Future research directions include the need to reproduce our findings in a range of clinical populations, detailed head-to-head comparisons of Rasch analysis and Item Response Theory, and the application of Rasch analysis to clinical practice.

https://njl-admin.nihr.ac.uk/document/download/2001725

Improving the evaluation of therapeutic interventions in multiple sclerosis: the role of new psychometric methods.

Objective To generate a classification of methods to evaluate medical tests when there is no gold standard. Methods Multiple search strategies were employed to obtain an overview of the different methods described in the literature, including searches of electronic databases, contacting experts for papers in personal archives, exploring databases from previous methodological projects and cross-checking of reference lists of useful papers already identified. Results All methods available were classified into four main groups. The first method group, impute or adjust for missing data on reference standard, needs careful attention to the pattern and fraction of missing values. The second group, correct imperfect reference standard, can be useful if there is reliable information about the degree of imperfection of the reference standard and about the correlation of the errors between the index test and the reference standard. The third group of methods, construct reference standard, have in common that they combine multiple test results to construct a reference standard outcome including deterministic predefined rules, consensus procedures and statistical modelling (latent class analysis). In the final group, validate index test results, the diagnostic test accuracy paradigm is abandoned and research examines, using a number of different methods, whether the results of an index test are meaningful in practice, for example by relating index test results to relevant other clinical characteristics and future clinical events. Conclusions The majority of methods try to impute, adjust or construct a reference standard in an effort to obtain the familiar diagnostic accuracy statistics, such as sensitivity and specificity. In situations that deviate only marginally from the classical diagnostic accuracy paradigm, these are valuable methods. However, in situations where an acceptable reference standard does not exist, applying the concept of clinical test validation can provide a significant methodological advance. All methods summarised in this report need further development. Some methods, such as the construction of a reference standard using panel consensus methods and validation of tests outwith the accuracy paradigm, are particularly promising but are lacking in methodological research. These methods deserve particular attention in future research.

pdf/evaluation-of-diagnostic-tests-when-there-is-no-gold-32ak9pyd20.pdf

Evaluation of diagnostic tests when there is no gold standard. A review of methods.

The evidence suggested that SMBG is of limited clinical effectiveness in improving glycaemic control in people with T2DM on oral agents, or diet alone, and is therefore unlikely to be cost-effective. SMBG may lead to improved glycaemic control only in the context of appropriate education - both for patients and health-care professionals - on how to respond to the data, in terms of lifestyle and treatment adjustment. Also, SMBG may be more effective if patients are able to self-adjust drug treatment. Further research is required on the type of education and feedback that are most helpful, characteristics of patients benefiting most from SMBG, optimal timing and frequency of SMBG, and the circumstances under which SMBG causes anxiety and/or depression.

/pdf/self-monitoring-of-blood-glucose-in-type-2-diabetes-45kw710uqp.pdf

Self-monitoring of blood glucose in type 2 diabetes: systematic review.

BACKGROUND Despite increasing contraceptive availability, unintended pregnancy remains a global problem, representing as many as 30% of all known pregnancies. Various strategies have been proposed to reverse this disturbing trend, especially increased use of long-acting reversible contraceptive (LARC) methods. In this review we aim to discuss the role of LARC methods and importance of contraceptive counseling in reducing unintended pregnancy rates. METHODS References/resources cited were identified based on searches of medical literature (MEDLINE, 1990-2009), bibliographies of relevant publications and the Internet. RESULTS AND CONCLUSIONS LARC methods-copper intrauterine devices (IUDs), progestogen-releasing intrauterine system and injectable and implantable contraceptives-are safe and effective contraceptive options (unintended pregnancy rates with typical versus perfect use: 0.05-3.0 versus 0.05-0.6%) that are appropriate for a wide range of women seeking to limit or space childbearing. Despite their safety and efficacy records, these methods remain underutilized; injectable and implantable methods are used by an estimated 3.4% and intrauterine methods by 15.5% of women worldwide. LARC methods require no daily or coital adherence and avoid the adverse events and health risks of estrogen-containing contraceptives. The copper IUD and progestin-only injections and implants have been shown to be more cost-effective than more commonly used methods, such as condoms and the pill (5-year savings: $13,373-$14,122, LARC; $12,239, condoms; $12,879, pill). Women who are considering use of LARC methods should receive comprehensive contraceptive counseling, as women who receive counseling before use demonstrate higher rates of after-use method satisfaction, continuation and acceptance than those who do not.

Strategies to prevent unintended pregnancy: increasing use of long-acting reversible contraception

Objectives To determine the clinical effectiveness and cost utility of procedures alternative to TURP (transurethral resection of the prostate) for benign prostatic enlargement (BPE) unresponsive to expectant, non-surgical treatments. Data sources Electronic searches of 13 databases to identify relevant randomised controlled trials (RCTs). Review methods Two reviewers independently assessed study quality and extracted data. The International Prostate Symptom Score/American Urological Association (IPSS/AUA) symptom score was the primary outcome; others included quality of life, peak urine flow rate and adverse effects. Cost-effectiveness was assessed using a Markov model reflecting likely care pathways. Results 156 reports describing 88 RCTs were included. Most had fewer than 100 participants (range 12–234). TURP provided consistent, high-level, long-term symptomatic improvement. Minimally invasive procedures resulted in less marked improvement. Ablative procedures gave improvements equivalent to TURP. Holmium laser enucleation of the prostate (HoLEP) additionally resulted in greater improvement in flow rate. HoLEP is unique amongst the newer technologies in offering an advantage in urodynamic outcomes over TURP, although long-term follow-up data are lacking. Severe blood loss was more common following TURP. Rates of incontinence were similar across all interventions other than transurethral needle ablation (TUNA) and laser coagulation, for which lower rates were reported. Acute retention and reoperation were commoner with newer technologies, especially minimally invasive interventions. The economic model suggested that minimally invasive procedures were unlikely to be cost-effective compared with TURP. Transurethral vaporisation of the prostate (TUVP) was both less costly and less effective than TURP. HoLEP was estimated to be more cost-effective than a single TURP but less effective than a strategy involving repeat TURP if necessary. The base-case analysis suggested an 80% chance that TUVP, followed by HoLEP if required, would be cost-effective at a threshold of £20,000 per quality-adjusted life-year. At a £50,000 threshold, TUVP, followed by TURP as required, would be cost-effective, although considerable uncertainty surrounds this finding. The main limitations are the quantity and quality of the data available, in the context of multiple comparisons. Conclusions In the absence of strong evidence in favour of newer methods, the standard – TURP – remains both clinically effective and cost-effective. There is a need for further research to establish (i) how many years of medical treatment are necessary to offset the cost of treatment with a minimally invasive or ablative intervention; (ii) more cost-effective alternatives to TURP; and (iii) strategies to improve outcomes after TURP.

/pdf/systematic-review-and-economic-modelling-of-effectiveness-t9z6ifq698.pdf

Systematic review and economic modelling of effectiveness and cost utility of surgical treatments for men with benign prostatic enlargement

OBJECTIVES: To assess the contraceptive efficacy, tolerability and acceptability of hormonally impregnated intrauterine systems (IUSs) in comparison to other reversible contraceptive methods. SEARCH STRATEGY: Literature was identified through database searches, reference lists and individuals/organisations working in the field. SELECTION CRITERIA: All randomised controlled trials comparing IUSs with other forms of reversible contraceptives and reporting on pre-determined outcomes in women of reproductive years. The primary outcomes were pregnancy due to method/user failure and continuation rate. DATA COLLECTION AND ANALYSIS: The quality assessment of studies and data extraction were completed independently by two blinded reviewers. A quality checklist was designed to identify general methodological and contraceptive specific factors which could bias results. Events per women months and single decrement life table rates were extracted where possible for pregnancy, continuation, adverse events and reasons for discontinuation. Events per total number of women at follow up were collected for hormonal side effects and menstrual disturbance. When appropriate, data were pooled at the same points of follow up to calculate rate ratios in order to determine the relative effectiveness of one method compared to another. For the single decrement life table rates, the rate differences were pooled to determine the absolute difference in effectiveness of one method compared to another. Interventions were only combined if the contraceptive methods were similar. Non-hormonal IUDs were divided into three categories for the purpose of comparison with IUSs: IUDs >250mm2 (i.e. CuT 380A IUD and CuT 380 Ag IUD), IUDs 250mm2 users. However, women using the LNG-20 IUS were significantly less likely to become pregnant than those using the IUD 250mm2. LNG-20 users were significantly more likely than all the IUD users to discontinue because of hormonal side effects and menstrual disturbance, which on further breakdown of the data was due to amenorrhoea. When the LNG-20 IUS was compared to Norplant-2, the LNG-20 users were significantly more likely to experience amenorrhoea and oligomenorrhoea, but significantly less likely to experience prolonged bleeding and spotting. No other significant differences were observed. Progestasert users were significantly less likely to become pregnant and less likely to continue on the method than non-medicated IUD users after one year, but no significant differences was noted for these two outcomes when Progestasert users were compared to IUD 250mm2 and Norplant-2 users. The LNG-20 IUS was more effective in preventing either intrauterine or extrauterine pregnancies than IUDs <=250mm2. The contraceptive effectiveness of Progestasert was significantly better than non-medicated IUDs, but no difference was observed when compared to IUDs<=250mm2. Continuation of LNG-20 IUS use was similar to continuation of the non-hormonal IUDs and Norplant-2. Amenorrhoea was the main reason for the discontinuation for the LNG-20 IUS and women should be informed of this prior to starting this method.

/pdf/hormonally-impregnated-intrauterine-systems-iuss-versus-2ahcgbtktl.pdf

Hormonally impregnated intrauterine systems (IUSs), versus other forms of reversible contraceptives as effective methods of preventing pregnancy.

Levonorgestrel-releasing (20 μg/day) intrauterine systems (Mirena) compared with other methods of reversible contraceptives

Subdermal implantable contraceptives versus other forms of reversible contraceptives as effective methods of preventing pregnancy.

Obestetrics/ Gynecology/ Urinary tract Title Implantable Contraceptives (subdermal implants and hormonally impregnated intrauterine systems) Vs Other Forms of Reversible Contraceptives: Two Systematic Reviews to Assess Relative Effectiveness, Acceptability, Tolerability and Cost Effectiveness Agency NCCHTA, National Coordinating Centre for Health Technology Assessment Mailpoint 728, Boldrewood, University of Southampton, Southampton SO16 7PX, United Kingdom Reference Health Technol Assess 2000;4(07). June 2000. www.ncchta.org/execsumm/summ407.htm

/pdf/implantable-contraceptives-subdermal-implants-and-hormonally-2g48i3mfa1.pdf

Implantable contraceptives (subdermal implants and hormonally impregnated intrauterine systems) versus other forms of reversible contraceptives: two systematic reviews to assess relative effectiveness, acceptability, tolerability and cost-effectiveness.

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Hormonally impregnated intrauterine systems (IUSs), versus other forms of reversible contraceptives as effective methods of preventing pregnancy.

Levonorgestrel-releasing (20 μg/day) intrauterine systems (Mirena) compared with other methods of reversible contraceptives

Subdermal implantable contraceptives versus other forms of reversible contraceptives as effective methods of preventing pregnancy.

Implantable contraceptives (subdermal implants and hormonally impregnated intrauterine systems) versus other forms of reversible contraceptives: two systematic reviews to assess relative effectiveness, acceptability, tolerability and cost-effectiveness.