New methods can extend the use of minimal important difference units in meta-analyses of continuous outcome measures

For continuous outcomes measured using instruments with an established minimally important difference (MID), pooled estimates can be usefully reported in MID units. Approaches suggested thus far omit studies that used instruments without an established MID. We describe an approach that addresses this limitation.

Minimum important difference between patients with rheumatoid arthritis : the patient's perspective

OBJECTIVE: To determine the point at which differences in clinical assessment scores on physical ability, pain and overall condition are sufficiently large to correspond to a subjective perception of a meaningful difference from the perspective of the patient. METHODS: Forty patients with a diagnosis of rheumatoid arthritis participated in an evening of clinical assessment and one-on-one conversations with each other regarding their arthritic condition. The assessments included tender and swollen joint counts, clinician and patient global assessments, participant assessment of pain and the Health Assessment Questionnaire (HAQ) on physical ability. After each conversation, participants rated themselves relative to their conversational partner on physical ability, pain and overall condition. These subjective comparative ratings were compared to the differences of the individual clinical assessments. RESULTS: In total there were 120 conversations. Generally participants judged themselves as less disabled than others. They rated themselves as "somewhat better" than their conversation partner when they had a (mean) 7% better score on the HAQ, 6% less pain, and 9% better global assessment. In contrast, they rated themselves as "somewhat worse" when they had a (mean) 16% worse score on the HAQ, 16% more pain, and 29% worse global assessment. CONCLUSIONS: Patients view clinically important differences in an asymmetric manner. These results can provide guidance in interpreting results and planning clinical trials.

An individual-based versus group-based exercise and counselling intervention for improving quality of life in breast cancer survivors. A feasibility and efficacy study

Background Cancer and its treatments produce lingering side-effects that undermine the quality of life (QOL) of survivors. Exercise and psycho-therapies increase QOL among survivors, however, research is needed to identify intervention characteristics most associated with such improvements. Objective This research aimed to assess the feasibility of a 9 week individual or group based exercise and counselling program, and to examine if a group based intervention is as effective at improving the QOL of breast cancer survivors as an individual-based intervention. Methods A three group design was implemented to compare the efficacy of a 9 week individual (IEC n = 12) and group based exercise and counselling (GEC n = 14) intervention to a usual care (UsC n = 10) group on QOL of thirty-six breast cancer survivors. Results Across all groups, 90% of participants completed the interventions, with no adverse effects documented. At the completion of the intervention, there was a significant difference between groups for change in global QOL across time (p < 0.023), with IEC improving significantly more (15.0 points) than the UsC group (1.8 points). The effect size was moderate (0.70). Although the GEC improved QOL by almost 10.0 points, this increase did not reach significance. Both increases were above the minimally important difference of 7–8 points. Conclusion These preliminary results suggest a combined exercise and psychological counseling program is both a feasible and acceptable intervention for breast cancer survivors. Whilst both the individual and group interventions improved QOL above the clinically important difference, only the individual based intervention was significant when compared to UsC.

Tooth replacement for partially dentate elders: a randomised controlled trial

Objective: This study aimed to compare two different tooth replacement strategies for partially dentate older patients namely; removable partial dentures (RPDs) and functionally orientated treatment based on the shortened dental arch (SDA) concept. Method: 88 partially dentate older patients (mean age 69.4 years) completed a randomised controlled clinical trial. 43 patients received RPDs and 45 received functionally orientated treatment where resin bonded bridgework was used to provide 10 pairs of occluding contacts. Patients were followed for 1 year after treatment intervention. The impact of treatment on oral health-related quality of life (OHrQOL) and cost effectiveness were used as outcome measures. Each patient completed the short form of the Oral Health Impact Profile (OHIP-14) at baseline, 6 months and 1 year after treatment intervention. All costs involved in providing and maintaining each intervention were recorded including dental laboratory bills, materials and professional time. Result: Both the RPD (p=0.004) and the functionally orientated (p<0.001) treatment groups demonstrated statistically significant improvements in OHrQOL 1 year after treatment intervention. On average 9.4 visits were required to complete and maintain the RPDs over the 1 year period as compared to 5.3 visits for the functionally orientated group. The average laboratory cost for the RPDs was $537.45 per patient versus $367.89 for functionally orientated treatment. The cost of achieving the Minimally Important Difference of 5 scale points in OHIP-14 score with RPDs was $732.17. For the functionally orientated group the cost was $356.88. Therefore, functionally orientated treatment was more than twice as cost effective (1:2.05). Conclusion: For partially dentate older patients, functionally orientated treatment based on the SDA concept resulted in sustained, significant improvements in OHrQOL. Provision of functionally orientated treatment was also more than twice as cost effective compared to conventional treatment using RPDs.

Evidence-based guidelines for interpreting change scores for the European Organisation for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30

Aim: To use published literature and experts' opinion to investigate the clinical meaning and magnitude of changes in the Quality of Life (QOL) of groups of patients measured with the European Organisation for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). Methods: An innovative method combining systematic review of published studies, expert opinions and meta-analysis was used to estimate large, medium, and small mean changes over time for QLQ-C30 scores. Results: Nine hundred and eleven papers were identified, leading to 118 relevant papers. One thousand two hundred and thirty two mean changes in QOL over time were combined in the meta-analysis, with timescales ranging from four days to five years. Guidelines were produced for trivial, small, and medium size classes, for each subscale and for improving and declining scores separately. Estimates for improvements were smaller than respective estimates for declines. Conclusions: These guidelines can be used to aid sample size calculations and interpretation of mean changes over time from groups of patients. Observed mean changes in the QLQ-C30 scores are generally small in most clinical situations, possibly due to response shift. Careful consideration is needed when planning studies where QOL changes over time are of primary interest; the timing of follow up, sample attrition, direction of QOL changes, and subscales of primary interest are key considerations. (C) 2012 Elsevier Ltd. All rights reserved.

Determining the minimum clinically important differences for outcomes in the DOMINO trial

Although less likely to be reported in clinical trials than expressions of the statistical significance of differences in outcomes, whether or not a treatment has delivered a specified minimum clinically important difference (MCID) is also relevant to patients and their caregivers and doctors. Many dementia treatment randomised controlled trials (RCTs) have not reported MCIDs and, where they have been done, observed differences have not reached these.

Cost-effectiveness of tooth replacement strategies for partially dentate elderly: a randomized controlled clinical trial

OBJECTIVE: To conduct a cost-effectiveness analysis comparing two different tooth replacement strategies for partially dentate older patients, namely partial removable dental prostheses (RDP) and functionally orientated treatment based on the shortened dental arch concept (SDA).

METHODS: Ninety-two partially dentate older patients completed a randomized controlled clinical trial. Patients were randomly allocated to two treatment groups: the RDP group and the SDA group. Treatment effect was measured using impact on oral health-related quality of life (OHrQOL), and the costs involved in providing and maintaining care were recorded for all patients. Patients were followed for 12 months after treatment intervention. All treatment was provided by a single operator.

RESULTS: The total cost of achieving the minimally important clinical difference (MID) in OHrQOL for an average patient in the RDP group was €464.64. For the SDA group, the cost of achieving the MID for an average patient was €252.00. The cost-effectiveness ratio was therefore 1:1.84 in favour of SDA treatment.

CONCLUSION: With an increasingly ageing population, many patients will continue to benefit from removable prostheses to replace their missing natural teeth. From a purely economic standpoint, the results from this analysis suggest that the treatment of partially dentate older adults should be focused on functionally orientated treatment because it is simply more cost-effective.

Adolescent-parent disagreement on health-related quality of life of food-allergic adolescents:who makes the difference?

Background: Food-allergic adolescents are at highest risk for food allergy fatalities, which may be partly due to compromised self-management behavior. Such behavior may be negatively influenced by conflictual situations caused by adolescent–parent disagreement on the adolescent’s health-related quality of life (HRQL). Comparisons of adolescent-self-reported and parent-proxy-reported HRQL of food-allergic adolescents have never extensively been studied. The aims of this study were to investigate disagreement in adolescent-self-reports and parent-proxy-reports on the HRQL of food-allergic adolescents and to investigate the factors influencing adolescent–parent disagreement. Methods: Teenager Form (TF) and Parent Form (PFA) of the Food Allergy Quality of Life Questionnaire (FAQLQ), Food Allergy Independent Measure (FAIM), and Brief-Illness Perception Questionnaire (Brief-IPQ) were sent to food-allergic Dutch adolescents (13–17 years) and their parents. ICCs, t-tests, and Bland–Altman plots were used to investigate adolescent–parent disagreement. Participant characteristics, illness expectations, and illness perceptions influencing adolescent–parent disagreement were studied using regression analysis. Results: Seventy adolescent–parent pairs were included. There were a moderate correlation (ICC = 0.61, P < 0.001) and no significant difference (3.78 vs 3.56, P = 0.103) between adolescent-self-reported and parent-proxy-reported HRQL at group level. However, Bland–Altman plots showed relevant differences (exceeding the minimal important difference) for 63% of all adolescent–parent pairs. Adolescent’s age (>15 years), poorer adolescent-reported illness comprehension (Brief-IPQ-TF, coherence), and higher adolescent-reported perceived disease severity (Food Allergy Independent Measure-Teenager Form & -Parent Form) were associated with adolescent–parent disagreement. Conclusions: Adolescent–parent disagreement on the adolescent’s HRQL was mainly associated with adolescents’ rather than parents’ perceptions and characteristics. Illness comprehension of the adolescent may be an important target for intervention aimed at reducing adolescent–parent disagreement.

A comparison of two business cycle dating methods

We study the suggestion that Markov switching (MS) models should be used to determine cyclical turning points. A Kalman filter approximation is used to derive the dating rules implicit in such models. We compare these with dating rules in an algorithm that provides a good approximation to the chronology determined by the NBER. We find that there is very little that is attractive in the MS approach when compared with this algorithm. The most important difference relates to robustness. The MS approach depends on the validity of that statistical model. Our approach is valid in a wider range of circumstances.

Comparative analysis of panicum streak virus and maize streak virus diversity, recombination patterns and phylogeography

Background: Panicum streak virus (PanSV; Family Geminiviridae; Genus Mastrevirus) is a close relative of Maize streak virus (MSV), the most serious viral threat to maize production in Africa. PanSV and MSV have the same leafhopper vector species, largely overlapping natural host ranges and similar geographical distributions across Africa and its associated Indian Ocean Islands. Unlike MSV, however, PanSV has no known economic relevance. Results: Here we report on 16 new PanSV full genome sequences sampled throughout Africa and use these together with others in public databases to reveal that PanSV and MSV populations in general share very similar patterns of genetic exchange and geographically structured diversity. A potentially important difference between the species, however, is that the movement of MSV strains throughout Africa is apparently less constrained than that of PanSV strains. Interestingly the MSV-A strain which causes maize streak disease is apparently the most mobile of all the PanSV and MSV strains investigated. Conclusion: We therefore hypothesize that the generally increased mobility of MSV relative to other closely related species such as PanSV, may have been an important evolutionary step in the eventual emergence of MSV-A as a serious agricultural pathogen. The GenBank accession numbers for the sequences reported in this paper are GQ415386-GQ415401. © 2009 Varsani et al; licensee BioMed Central Ltd.

Wind speed measurements of land-falling tropical cyclones using SWIRLnet, a portable anemometer network

Wind speed measurement systems are sparse in the tropical regions of Australia. Given this, tropical cyclone wind speeds impacting communities are seldom measured and often only ‘guestimated’ by analysing the extent of damage to structures. In an attempt to overcome this dearth of data, a re-locatable network of anemometers to be deployed prior to tropical cyclone landfall is currently being developed. This paper discusses design criteria of the network’s tripods and tie down system, proposed deployment of the anemometers, instrumentation and data logging. Preliminary assessment of the anemometer response indicates a reliable system for measuring the spectral component of wind with frequencies of approximately 1 Hz. This system limitation highlights an important difference between the capabilities of modern instrumentation and that of the Dines anemometer (around 0.2 seconds) that was used to develop much of the design criteria within the Australian building code and wind loading standard.

8-13 Hz fluctuations in rectal pressure are an objective marker of clitorally-induced orgasm in women

Orgasm is a subjective experience accompanied by involuntary muscle contractions. We hypothesized that orgasm in women would be distinguishable by frequency analysis of a perineal muscle-derived signal. Rectal pressure, an index of perineal muscle activity, was measured continuously in 23 healthy women during different sexual tasks: receiving clitoral stimulation, imitation of orgasm, and attempt to reach orgasm, in which case the women were asked to report whether orgasm had been reached ("orgasm") or not ("failed orgasm attempt"). We performed spectral analysis on the rectal pressure data and calculated the spectral power in the frequency bands delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-25 Hz). The most significant and most important difference in spectral power between orgasm and both control motor tasks (imitation of orgasm and failed orgasm attempt) was found in the alpha band. An objective rule based on spectral power in the alpha band recognized 94% (29/31) of orgasms and correctly labeled 69% (44/64) of all orgasm attempts as either successful or failed. Because outbursts of alpha fluctuations in rectal pressure only occurred during orgasm and not during voluntary imitation of orgasm or failed attempts, we propose that they represent involuntary contractions of muscles in the rectal vicinity. This is the first objective and quantitative measure that has a strong correspondence with the subjective experience of orgasm.

The Effects of Reduction Mammaplasty

Symptomatic hypertrophic breasts cause a health burden with physical and psychosocial morbidity. The value of reduction mammaplasty in the treatment of symptomatic breast hypertrophy has been consistently reported by patients and has been well recognised by plastic surgeons for a long time. However, the scientific evidence of the effects of reduction mammaplasty has been weak or lacking. During the design of this study most of the previous studies were retrospective and the few prospective studies had methodological limitations. Therefore, an obvious need for prospective randomised studies was present. Nevertheless, practical and ethical considerations seemed to make this study design impossible, because the waiting time for the operation was several years. The legislation and subsequent introduction of the uniform criteria for access to non-emergency treatment in Finland removed these obstacles, as all patients received their treatment within a reasonable time. As a result, a randomised controlled trial with a six-month follow-up time was designed and conducted. In addition, a follow-up study with two to five years follow-up was also carried out later. The effects of reduction mammaplasty on the patients breast-related symptoms, psychological symptoms, pain and quality of life was assessed. In addition, factors affecting the outcome were investigated. This study was carried out in the Hospital District of Helsinki and Uusimaa, Finland. Eighty-two out of the approximately 300 patients on the waiting list in 2004 agreed to participate in the study. Patients were randomised either to be operated (40 patients) on or to be followed up (42 patients). The follow-up time for both groups was six months. The patients were operated on by plastic surgeons or trainees at the Department of Plastic Surgery at Helsinki University Central Hospital or at the Department of Surgery at Hyvinkää Hospital. The patients completed five questionnaires: the SF-36 and the 15D quality of life questionnaires, the Finnish Breast-Associated Symptoms questionnaire (FBAS), a mood questionnaire (Raitasalo s modification of the short form of the Beck Depression Inventory, RBDI), and a pain questionnaire (The Finnish Pain Questionnaire, FPQ). Sixty-two out of the original 82 patients agreed to participate in the prospective follow-up study. In this study, patients completed the 15D quality of life questionnaire, the Finnish Breast-Associated Symptoms questionnaire, and the RBDI mood questionnaire. After six months follow-up, patients who had undergone reduction mammaplasty had a significantly better quality of life, fewer breast-associated symptoms and less pain, and they were less depressed or anxious when compared to patients who had not undergone surgery. The change in quality of life was more than two times the minimal clinically important difference. The patients preoperative quality of life was significantly inferior when compared to the age-standardised general population. This health burden was removed with reduction mammaplasty. The health loss related to symptomatic breast hypertrophy was comparable to that of patients with major joint arthrosis. In terms of change in quality of life, the intervention effect of reduction mammaplasty was comparable to that of hip joint replacement and more pronounced than that of knee joint replacement surgery. The outcome of reduction mammaplasty was affected more by preoperative psychosocial factors than by changes in breast dimensions. The effects of reduction mammaplasty remained stable at two to five years follow-up. In terms of quality of life, symptomatic breast hypertrophy causes a considerable health loss comparable to that of major joint arthrosis. Patients who undergo surgery have fewer breast-associated symptoms and less pain, and they are less depressed or anxious and have an improved quality of life. The intervention effect is comparable to that of major joint replacement surgery, and it remains stable at two to five years follow-up. The outcome of reduction mammaplasty is affected by preoperative psychosocial factors.

Impacts of climate change and management responses in tropical forests depend on complex frugivore-mediated seed dispersal

AimBiodiversity outcomes under global change will be influenced by a range of ecological processes, and these processes are increasingly being considered in models of biodiversity change. However, the level of model complexity required to adequately account for important ecological processes often remains unclear. Here we assess how considering realistically complex frugivore-mediated seed dispersal influences the projected climate change outcomes for plant diversity in the Australian Wet Tropics (all 4313 species). LocationThe Australian Wet Tropics, Queensland, Australia. MethodsWe applied a metacommunity model (M-SET) to project biodiversity outcomes using seed dispersal models that varied in complexity, combined with alternative climate change scenarios and habitat restoration scenarios. ResultsWe found that the complexity of the dispersal model had a larger effect on projected biodiversity outcomes than did dramatically different climate change scenarios. Applying a simple dispersal model that ignored spatial, temporal and taxonomic variation due to frugivore-mediated seed dispersal underestimated the reduction in the area of occurrence of plant species under climate change and overestimated the loss of diversity in fragmented tropical forest remnants. The complexity of the dispersal model also changed the habitat restoration approach identified as the best for promoting persistence of biodiversity under climate change. Main conclusionsThe consideration of complex processes such as frugivore-mediated seed dispersal can make an important difference in how we understand and respond to the influence of climate change on biodiversity.

Is there chaotic synchronization in space extend systems

Based on coupled map lattice (CML), the chaotic synchronous pattern in space extend systems is discussed. Making use of the criterion for the existence and the conditions of stability, we find an important difference between chaotic and nonchaotic movements in synchronization. A few numerical results are presented.