Presenting risk information--a review of the effects of "framing" and other manipulations on patient outcomes

Discussing risks and benefits of treatments or care options is becoming an increasingly important part of modern health care. This paper reviews the literature about manipulations of risk and benefit information in the clinical setting. There is a paucity of evidence in this field, particularly when examining specific manipulations. Only three categories of manipulation had three or more studies. The available evidence shows that the way information is presented can have significant effects on decisions made. The largest effects are evident when relative risk information is presented, as compared with absolute risk data. In addition, "loss framing" is more effective in influencing screening uptake behaviors than "gain framing" (odds ratio 1.18 [95% confidence interval 1.01-1.38]). There is also a pattern of evidence from studies comparing simpler with more complex information, more data with less, and those comparing numerical with verbal descriptions of risks. These studies suggest that providing more information, and which is more understandable to the patient, is associated with improved patient knowledge and a greater wariness to take treatments or participate in trials. These findings can contribute to efforts to improve communication between professionals and patients.

The mechanical behavior of vascular grafts: a review

The development of intimal hyperplasia (IH) near the anastomosis of a vascular graft to artery is directly related to changes in the wall shear rate distribution. Mismatch in compliance and diameter at the end-to-end anastomosis of a compliant artery and rigid graft cause shear rate disturbances that may induce intimal hyperplasia and ultimately graft failure. The principal strategy being developed to prevent IH is based on the design and fabrication of compliant synthetic or innovative tissue-engineered grafts with viscoelastic properties that mirror those of the human artery. The goal of this review is to discuss how mechanical properties including compliance mismatch, diameter mismatch, Young's modulus and impedance phase angle affect graft failure due to intimal hyperplasia.

Ultrasonographic evaluation of the postpartum uterus

OBJECTIVES

To define the ultrasonographic appearance of the uterus and the uterine cavity, including its contents, in normal women making an uncomplicated postpartum recovery.

METHODS

Forty women were scanned on days 7, 14, and 21 postpartum. At each scan the uterine and cavity volumes were estimated, and the appearance of the uterine cavity contents was documented. The amount and duration of postpartum vaginal bleeding, and method of infant feeding were also recorded.

RESULTS

The mean duration of postpartum bleeding was 24.5 (range 14-45) days. Fifty-one percent (95% confidence interval 34-68) of the subjects scanned at 7 days postpartum, 21%(8-36) at 14 days, and 6%(0.8-20) at 21 days, had an echogenic mass within the uterine cavity. Statistical analysis revealed no difference, in terms of bleeding duration, between women with a uterine cavity echogenic mass noted at 7, 14, or 21 days postpartum, and those without (unpaired t-test, P = 0.42, 0.39, and 0.06). The presence of an echogenic mass was not associated with heavier bleeding at the time of any of the scans (chi-squared test, P = 0.58, 0.56, and 0.28). Statistical analysis revealed no correlation between the duration or amount of bleeding, and the uterine or cavity volume, at any of the three scans.

CONCLUSION

In this study, ultrasound evaluation of the uterine cavity revealed an echogenic mass in 51% of women with normal postpartum bleeding at 7 days, 21% at 14 days, and 6% at 21 days postpartum. This questions the significance of echogenic material within the uterine cavity in the postpartum period.

Shared decision making and the concept of equipoise: the competences of involving patients in healthcare choices

BACKGROUND

Involving patients in healthcare decisions makes a potentially significant and enduring difference to healthcare outcomes. One difficulty (among many) is that the 'involvement' of patients in decisions has been left undefined. It is usually conceptualised as 'patient centredness', which is a broad and variably interpreted concept that is difficult to assess using current tools. This paper attempts to gauge general practitioners' (GPs') attitudes to patient involvement in decision making and their views about the contextual factors, competences, and stages required to achieve shared decisions within consultations.

AIM

To explore and understand what constitutes the appropriate involvement of patients in decision making within consultations, to consider previous theory in this field, and to propose a set of competences (skills) and steps that would enable clinical practitioners (generalists) to undertake 'shared decision making' in their clinical environment.

METHOD

Qualitative study using focus group interviews of key informants.

RESULTS

Experienced GPs with educational roles have positive attitudes to the involvement of patients in decisions, provided the process matches the role individuals wish to play. They perceive some clinical problems as being more suited to a cooperative approach to decision making and conceptualised the existence of professional equipoise towards the existence of legitimate treatment options as an important facilitative factor. A sequence of skills was proposed as follows: 1) implicit or explicit involvement of patients in the decision-making process; 2) explore ideas, fears, and expectations of the problem and possible treatments; 3) portrayal of equipoise and options; 4) identify preferred data format and provide tailor-made information; 5) checking process: understanding of information and reactions (e.g. ideas, fears, and expectations of possible options); 6) acceptance of process and decision making role preference; 7) make, discuss or defer decisions; 8) arrange follow-up.

CONCLUSIONS

These clinicians viewed involvement as an implicit ethos that should permeate medical practice, provided that clinicians respect and remain alert to patients' individual preferred roles in decision making. The interpersonal skills and the information requirements needed to successfully share decisions are major challenges to the clinical consultation process in medical practice. The benefits of patient involvement and the skills required to achieve this approach need to be given much higher priority at all levels: at policy, education, and within further professional development strategies.

Compliance properties of conduits used in vascular reconstruction

BACKGROUND

Compliance mismatch between native artery and prosthetic graft used for infrainguinal bypass is implicated in the aetiology of graft failure. The aim was to quantify the elastic properties of a new compliant poly(carbonate)polyurethane (CPU) vascular graft, and to compare the compliance properties of grafts made from CPU, expanded polytetrafluoroethylene (ePTFE), Dacron and human saphenous vein with that of human muscular artery.

METHODS

A pulsatile flow phantom was used to perfuse vessel and prosthetic graft segments at physiological pulse pressure and flow. Intraluminal pressure was measured using a Millar Mikro-tip catheter transducer and vessel wall motion was determined with duplex ultrasonography using an echo-locked wall-tracking system. Diametrical compliance and a stiffness index were then calculated for each type of conduit over mean pressures ranging from 30 to 100 mmHg by 10-mmHg increments.

RESULTS

The compliance values of CPU and artery (mean over the pressure range) were similar (mean(s.d.) 8.1(0.4) and 8.0(5.9) per cent per mmHg x 10(-2) respectively), although the elastic behaviour of artery was anisotropic unlike CPU, which was isotropic. Dacron and ePTFE grafts had lower compliance values (1.8(1.2) and 1.2(0.3)per cent per mmHg x 10(-2) respectively, averaged over the pressure range). In both these cases, compliance and stiffness differed significantly from that of artery over a mean pressure range of 30-90 mmHg. Human saphenous vein exhibited anisotropic behaviour and, although compliant at low pressure (30 mmHg), was markedly incompliant at higher pressures.

CONCLUSION

Compliant polyurethane grafts offer a greater degree of compliance match than either ePTFE or Dacron.

Changes in the incidence of childhood autism and other autistic spectrum disorders in preschool children from two areas of the West Midlands, UK

The incidence of childhood autism and other autistic spectrum disorders (ASDs) in preschool children was determined for two areas of the West Midlands between 1991 and 1996. Children diagnosed before the age of 5 years and residing within the study areas at diagnosis were detected from the records of four child development centres. The incidence rate per 10,000 children per year for the combined areas was 8.3 for all children with ASDs, 3.5 for classical childhood autism (CA), and 4.8 for other ASDs. Rates were similar in both areas, despite differences in social deprivation and proportions of ethnic minorities. While rates for classical CA increased by 18% per year, a much larger increase (55% per year) was seen for 'other ASDs', suggesting that clinicians are becoming increasingly able and/or willing to diagnose ASDs in preschool children.

Clinical features of lichen sclerosus in men attending a department of genitourinary medicine

OBJECTIVES

To characterise the clinical presentation and response to treatment of lichen sclerosus (LS) in men attending a department of genitourinary medicine.

METHODS

A case note review of all men attending a GUM department over a 32 month period, who had been diagnosed as having LS.

RESULTS

66 men were seen with genital LS. The mean age at diagnosis was 36.5 years but symptoms had been present for up to 10 years before the diagnosis was made. 55 men underwent biopsy and the diagnosis was made histologically in 47 of these men. At the time of presentation 30% of men had no symptoms relating to their LS. All were treated with potent topical steroids and surgery was avoided in nearly all of them.

CONCLUSIONS

LS is not uncommon in men presenting to a GUM department, and is often asymptomatic. The disease responds well to potent topical steroids allowing the normal anatomy to be preserved in most individuals.

The effectiveness of one-to-one risk communication interventions in health care: a systematic review

OBJECTIVES

To assess whether risk-communication interventions are associated with changes in patient knowledge, attitudes, and behaviors, and to identify aspects of these interventions that modify these effects.

DESIGN

Systematic review.

DATA SOURCES

96 studies from the period 1985-1996 retrieved by electronic searching of eight databases, hand searching of four journals, contacting key authors, and reference list searching.

MAIN OUTCOME MEASURES

The effect size of the principal outcome was identified from each study. Outcomes measuring behavioral change were preferred; if these were not available, knowledge, anxiety, or risk perceptions were used, according to the focus of the study. Data were available to calculate the principal effect sizes for 82 of the studies.

ANALYSIS

Meta-regression.

RESULTS

The methodologic qualities of the studies varied. Nevertheless, risk-communication interventions generally had positive (beneficial) effects. Interventions addressing treatment choices were associated with larger effects than were those in other contexts, such as prevention or screening. Interventions using individual risk estimates were associated with larger effects than were those using more general risk information. Two design variables were identified as effect modifiers: randomized controlled trials were associated with smaller effects than other designs, and dichotomous outcomes were associated with larger effects than continuous outcomes.

CONCLUSIONS

Risk communication interventions may be most productive if they include individual risk estimates in the discussion between professional and patient. Patient decisions about treatment appear more amenable to change by these interventions than attendance for screening or modification of risky behavior.

The renal medullary microcirculation

Blood flow to the renal medulla is supplied through descending vasa recta (DVR), which are derived from the efferent arterioles of juxtamedullary glomeruli. In addition to their role as conduits for blood flow, it is accepted that the vasa recta are countercurrent exchangers. That process, however, involves events which are more complicated than paracellular diffusive exchange of NaCl and urea. Urea transport in DVR is accommodated through the combined expression of endothelial and erythrocyte facilitated carriers while transport of water involves solute driven efflux across water channels. Unlike DVR, which have a continuous endothelium, ascending vasa recta (AVR) are fenestrated with a very high hydraulic conductivity. Transport of water in AVR is probably governed by transmural hydraulic and oncotic pressure gradients. The parallel arrangement of DVR in outer medullary vascular bundles coupled with their capacity for vasomotion implies a role for regulation of the regional distribution of blood flow within the medulla The importance of the latter process in the urinary concentrating mechanism and the exchange of nutrients and O2 is poorly defined. The large number of hormones and autacoids that influence DVR vasomotion, however, suggests that DVR have evolved to optimize the functions of the renal medulla.

Diaries of evidence-based tutors: beyond 'numbers needed to teach'

Interprofessional evidence-based health care courses have been held throughout the UK over the last few years, modelled on the approach used in McMaster University of using problem-based facilitated small-group formats to achieve the stated goals. Both delegates and tutors have been aware of the tensions which are inherent within these courses between: (a) the variation in learning cultures which is exhibited by the delegates and the effect this has on processes (i.e. the tension between the reductionist approach of bioscience and the more qualitative leanings of the applied and 'caring' disciplines); and (b) the conflict which arises between the goal of 'learning' applied healthcare biostatistics and the ability to leave the course with the skills to teach others. This qualitative study uses tutor-kept diaries to understand some of the tensions apparent to the teaching faculty during a week-long course in Wales, UK.

Judging the 'weight of evidence' in systematic reviews: introducing rigour into the qualitative overview stage by assessing Signal and Noise

The 'weight of evidence' in a topic area can be judged by assessing the 'Signal' from available research publications and tempering the importance attached by the level of 'Noise' (the inverse of methodological quality). This assessment process has validity and reliability and can be applied to the 'qualitative overview' stage of systematic reviews. This enables the important themes and areas of relevance to the research question to be identified. Important findings from individual papers may also be identified providing further information which may not be evident from quantitative analysis. The findings from these more qualitative stages of analysis complement, but do not replace, quantitative analysis.

Prognosis following a second whiplash injury

Five percent of the population have suffered a whiplash injury. Of these, 43% suffer long-term symptoms. We undertook a retrospective study of 79 patients who had suffered two whiplash injuries. The severity of each patient's symptoms was assessed after the first and second injuries using the Gargan and Bannister classification. Overall, 84% of patients reported increased symptoms following the second injury. Ninety-seven percent of patients who had been symptom free before the second injury reported persisting discomfort.

Diffusion of high molecular weight compounds through sclera

PURPOSE

To determine the in vitro permeability of the sclera to high molecular weight compounds and the relationship between scleral permeability and molecular size.

METHODS

Fresh rabbit sclera was mounted in a two-chamber diffusion apparatus, and its permeability to sodium fluorescein, fluorescein isothiocyanate (FITC)-conjugated bovine serum albumin, FITC-IgG, and FITC dextrans ranging in molecular weight from 4 to 150 kDa was determined by fluorescence spectrophotometry. Electron microscopy was used to assess the impact of the experimental design on scleral ultrastructural integrity. The effect of the diffusion apparatus on scleral hydration was examined. Rabbit scleral permeability was compared with previously reported data for human and bovine sclera.

RESULTS

Scleral permeability decreased with increasing molecular weight and molecular radius, consistent with previous human and bovine data. Molecular radius was a better predictor of scleral permeability than molecular weight. The sclera was more permeable to globular proteins than to linear dextrans of similar molecular weight. The experimental apparatus did not alter scleral ultrastructure. Permeability of rabbit sclera was similar to human sclera but greater than bovine sclera.

CONCLUSIONS

Large molecules, such as IgG, diffuse across sclera in a manner consistent with porous diffusion through a fiber matrix. Transscleral delivery of immunoglobulins and other large compounds to the choroid and retina may be feasible.

Computer users' postures and associations with workstation characteristics

This investigation tested the hypotheses that (1) physical workstation dimensions are important determinants of operator posture, (2) specific workstation characteristics systematically affect worker posture, and (3) computer operators assume "neutral" upper limb postures while keying. Operator head, neck, and upper extremity posture and selected workstation dimensions and characteristics were measured among 379 computer users. Operator postures were measured with manual goniometers, workstation characteristics were evaluated by observation, and workstation dimensions by direct measurement. Considerably greater variability in all postures was observed than was expected from application of basic geometric principles to measured workstation dimensions. Few strong correlations were observed between worker posture and workstation physical dimensions; findings suggest that preference is given to keyboard placement with respect to the eyes (r = 0.60 for association between keyboard height and seated elbow height) compared with monitor placement with respect to the eyes (r = 0.18 for association between monitor height and seated eye height). Wrist extension was weakly correlated with keyboard height (r = -0.24) and virtually not at all with keyboard thickness (r = 0.07). Use of a wrist rest was associated with decreased wrist flexion (21.9 versus 25.1 degrees, p < 0.01). Participants who had easily adjustable chairs had essentially the same neck and upper limb postures as did those with nonadjustable chairs. Sixty-one percent of computer operators were observed in nonneutral shoulder postures and 41% in nonneutral wrist postures. Findings suggest that (1) workstation dimensions are not strong determinants of at least several neck and upper extremity postures among computer operators, (2) only some workstation characteristics affect posture, and (3) contrary to common recommendations, a large proportion of computer users do not work in so-called neutral postures.

Interstitial water and solute recovery by inner medullary vasa recta

A recent model of volume and solute microvascular exchange in the renal medulla was extended by simulating the deposition of NaCl, urea, and water into the medullary interstitium from the loops of Henle and collecting ducts with generation rates that undergo spatial variation within the inner medullary interstitium. To build an exponential osmolality gradient in the inner medulla, as suggested by Koepsell et al. (H. Koepsell, W. E. A. P. Nicholson, W. Kriz, and H. J. Höhling. Pflügers Arch. 350: 167-184, 1974), the ratio of the interstitial area-weighted generation rate of small solutes to that of water must increase along the corticomedullary axis. We satisfied this condition either by holding the area-weighted generation rate of water constant while increasing that of NaCl and urea or by reducing the input rate of water with medullary depth. The latter case, in particular, yielded higher solute concentrations at the papillary tip. Assuming that the fraction of the filtered load recovered by inner medullary vasa recta for water, NaCl, and urea is 1%, 1%, and 40%, respectively, papillary tip osmolality is 1,470 mosmol/kgH(2)O when urea generation and NaCl generation per unit volume of interstitium increase exponentially and linearly, respectively. The inner medullary osmolar gradient also increases further when 1) medullary blood flow is reduced, 2) hydraulic conductivity of descending vasa recta (DVR) is lowered, and 3) vasa recta permeability to NaCl and urea is maximized. The coupling between water and small solute transport, resulting from aquaporin-1-mediated transcellular flux in DVR, also enhances tip osmolality.

Requirement of aquaporin-1 for NaCl-driven water transport across descending vasa recta

Deletion of AQP1 in mice results in diminished urinary concentrating ability, possibly related to reduced NaCl- and urea gradient-driven water transport across the outer medullary descending vasa recta (OMDVR). To quantify the role of AQP1 in OMDVR water transport, we measured osmotically driven water permeability in vitro in microperfused OMDVR from wild-type, AQP1 heterozygous, and AQP1 knockout mice. OMDVR diameters in AQP1(-/-) mice were 1.9-fold greater than in AQP1(+/+) mice. Osmotic water permeability (P(f)) in response to a 200 mM NaCl gradient (bath > lumen) was reduced about 2-fold in AQP1(+/-) mice and by more than 50-fold in AQP1(-/-) mice. P(f) increased from 1015 to 2527 microm/s in AQP1(+/+) mice and from 22 to 1104 microm/s in AQP1(-/-) mice when a raffinose rather than an NaCl gradient was used. This information, together with p-chloromercuribenzenesulfonate inhibition measurements, suggests that nearly all NaCl-driven water transport occurs by a transcellular route through AQP1, whereas raffinose-driven water transport also involves a parallel, AQP1-independent, mercurial-insensitive pathway. Interestingly, urea was also able to drive water movement across the AQP1-independent pathway. Diffusional permeabilities to small hydrophilic solutes were comparable in AQP1(+/+) and AQP1(-/-) mice but higher than those previously measured in rats. In a mathematical model of the medullary microcirculation, deletion of AQP1 resulted in diminished concentrating ability due to enhancement of medullary blood flow, partially accounting for the observed urine-concentrating defect.

Sexual origins of placental dysfunction

Severe placental dysfunction is much more common in pregnancies with a male than with a female fetus. Furthermore, the birthweight/placental weight ratio is increased in these pregnancies, consistent with fetal growth restriction, and is higher with a male fetus than with a female fetus. These observations of placental insufficiency may underlie the increased in-utero loss rate of male fetuses.

Criteria for evaluating alternative MEDLINE search engines

With so many options available for searching MEDLINE on the World Wide Web or as a component of an online service, evaluation criteria are suggested as a means of assisting librarians in determining the positive and negative aspects of alternative MEDLINE sites. A set of searches was utilized to systematically compare MEDLINE sites. Sites evaluated included Avicenna, America Online, HealthGate, PubMed, Medscape, and Physicians' Online. Some features used to evaluate these sites were: default fields; operators (default); access to MeSH; subheadings; stop words protected in MeSH; truncation; and stemming. This article will describe the group process used to arrive at the evaluation criteria, as well as some general conclusions which will help librarians in directing their users to a particular MEDLINE site.