Patient satisfaction and survey response in 717 hospital surveys in Switzerland: a cross-sectional study.

BACKGROUND: The association between patient satisfaction and survey response is only partly understood. In this study, we describe the association between average satisfaction and survey response rate across hospital surveys, and model the association between satisfaction and propensity to respond for individual patients. METHODS: Secondary analysis of patient responses (166'014 respondents) and of average satisfaction scores and response rates obtained in 717 annual patient satisfaction surveys conducted between 2011 and 2015 at 164 Swiss hospitals. The satisfaction score was the average of 5 items scored between 0 and 10. The association between satisfaction and response propensity in individuals was modeled as the function that predicted best the observed response rates across surveys. RESULTS: Among the 717 surveys, response rates ranged from 16.1 to 80.0% (pooled average 49.8%), and average satisfaction scores ranged from 8.36 to 9.79 (pooled mean 9.15). At the survey level, the mean satisfaction score and response rate were correlated (r = 0.61). This correlation held for all subgroups of surveys, except for the 5 large university hospitals. The estimated individual response propensity function was "J-shaped": the probability of responding was lowest (around 20%) for satisfaction scores between 3 and 7, increased sharply to about 70% for those maximally satisfied, and increased slightly for the least satisfied. Average satisfaction scores projected for 100% participation were lower than observed average scores. CONCLUSIONS: The most satisfied patients were the most likely to participate in a post-hospitalization satisfaction survey. This tendency produces an upward bias in observed satisfaction scores, and a positive correlation between average satisfaction and response rate across surveys.

Internists' and intensivists' roles in intensive care admission decisions: a qualitative study.

BACKGROUND: Intensive care Unit (ICU) admission decisions involve collaboration between internists and intensivists. Clear perception of each other's roles is a prerequisite for good collaboration. The objective was to explore how internists and intensivists perceive their roles during admission decisions. METHODS: Individual in-depth interviews with 12 intensivists and 12 internists working at a Swiss teaching hospital. Interviews were analyzed using a thematic approach. RESULTS: Roles could be divided into practical roles and identity roles. Internist and intensivists had the same perception of each other's practical roles. Internists' practical roles were: recognizing signs of severity when the patient becomes acutely ill, calling the intensivist at the right moment, having the relevant information about the patient and having determined the goals of care. Intensivists' practical roles were: assessing the patient on the ward, giving expert advice, making quick decisions, managing access to the ICU, having the final decision power and, sometimes, deciding whether or not to limit treatment. In complex situations, perceived flaws in performing practical roles could create tensions between the doctors. Intensivists' identity roles included those of leader, gatekeeper, life-death decision maker, and supporting colleague doctors (consultant, senior and helper). These roles could be perceived as emotionally burdensome. Internists' identity roles were those of leader and partner. CONCLUSIONS: Despite a common perception of each other's practical roles, tensions can arise between internists and intensivists in complex situations of ICU admission decisions. Training in communication skills and interprofessional education interventions aimed at a better understanding of each other roles would improve collaboration.

Kappa statistic to measure agreement beyond chance in free-response assessments.

BACKGROUND: The usual kappa statistic requires that all observations be enumerated. However, in free-response assessments, only positive (or abnormal) findings are notified, but negative (or normal) findings are not. This situation occurs frequently in imaging or other diagnostic studies. We propose here a kappa statistic that is suitable for free-response assessments. METHOD: We derived the equivalent of Cohen's kappa statistic for two raters under the assumption that the number of possible findings for any given patient is very large, as well as a formula for sampling variance that is applicable to independent observations (for clustered observations, a bootstrap procedure is proposed). The proposed statistic was applied to a real-life dataset, and compared with the common practice of collapsing observations within a finite number of regions of interest. RESULTS: The free-response kappa is computed from the total numbers of discordant (b and c) and concordant positive (d) observations made in all patients, as 2d/(b + c + 2d). In 84 full-body magnetic resonance imaging procedures in children that were evaluated by 2 independent raters, the free-response kappa statistic was 0.820. Aggregation of results within regions of interest resulted in overestimation of agreement beyond chance. CONCLUSIONS: The free-response kappa provides an estimate of agreement beyond chance in situations where only positive findings are reported by raters.

Determinants of the calibration of SAPS II and SAPS 3 mortality scores in intensive care: a European multicenter study.

BACKGROUND: The aim of the Simplified Acute Physiology Score (SAPS) II and SAPS 3 is to predict the mortality of patients admitted to intensive care units (ICUs). Previous studies have suggested that the calibration of these scores may vary across countries, centers, and/or characteristics of patients. In the present study, we aimed to assess determinants of the calibration of these scores. METHODS: We assessed the calibration of the SAPS II and SAPS 3 scores among 5266 patients admitted to ICUs during a 4-week period at 120 centers in 17 European countries. We obtained calibration curves, Brier scores, and standardized mortality ratios. Points attributed to SAPS items were reevaluated and compared with those of the original scores. Finally, we tested associations between the calibration and center characteristics. RESULTS: The mortality was overestimated by both scores: The standardized mortality ratios were 0.75 (95% CI 0.71-0.79) for the SAPS II score and 0.91 (95% CI 0.86-0.96) for the SAPS 3 score. This overestimation was partially explained by changes in associations between some items of the scores and mortality, especially the heart rate, Glasgow Coma Scale score, and diagnosis of AIDS for SAPS II. The calibration of both scores was better in countries with low health expenditures. The between-center variability in calibration curves was much greater than expected by chance. CONCLUSIONS: Both scores overestimate current mortality among European ICU patients. The magnitude of the miscalibration of SAPS II and SAPS 3 scores depends not only on patient characteristics but also on center characteristics. Furthermore, much between-center variability in calibration remains unexplained by these factors. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01422070 . Registered 19 August 2011.

Clinical and radiographic predictors of acute compartment syndrome in the treatment of tibial plateau fractures: a retrospective cohort study.

BACKGROUND: The aim of the study was to evaluate the relation between demographic, injury-related, clinical and radiological factors of patients with tibial plateau fractures and the development of acute compartment syndrome. METHODS: All consecutive adult patients with intra-articular tibial plateau fractures admitted in our urban academic medical centre between January 2005 and December 2009 were included in this retrospective cohort study. The main outcome measurement was the development of acute compartment syndrome. RESULTS: The charts of 265 patients (mean age 48.6 years) sustaining 269 intra-articular tibial plateau fractures were retrospectively reviewed. Acute compartment syndrome occurred in 28 fractures (10.4%). Four patients presented bilateral tibial plateau fractures; of them, 2 had unilateral, but none had bilateral acute compartment syndrome. Non-contiguous tibia fracture or knee dislocation and higher AO/OTA classification (type 41-C) were statistically significantly associated with the development of acute compartment syndrome in multivariable regression analysis, while younger age (<45 years), male sex, higher Schatzker grade (IV-V-VI), higher tibial widening ratio (≥1.05) and higher femoral displacement ratio (≥0.08) were significantly associated in the analysis adjusted for age and sex. CONCLUSIONS: Two parameters related to the occurrence of ACS in tibial plateau fractures were highlighted in this study: the presence of a non-contiguous tibia fracture or knee dislocation, and higher AO/OTA classification. They may be especially useful when clinical findings are difficult to assess (doubtful clinical signs, obtunded, sedated or intubated patients), and should rise the suspicion level of the treating surgeon. In these cases, regular clinical examinations and/or intra-compartmental pressure measurements should be performed before and after surgery, even if acute compartment syndrome seemed unlikely during initial assessment. However, larger studies are mandatory to confirm and refine both factors in predicting the occurrence of acute compartment syndrome.

Patient enrollment and logistical problems top the list of difficulties in clinical research: a cross-sectional survey.

BACKGROUND: Many medical research projects encounter difficulties. The objective of this study was to assess the self-reported frequency of difficulties encountered by medical researchers while conducting research and to identify factors associated with their occurrence. METHODS: The authors conducted a cross-sectional survey in 2010 among principal investigators of 996 study protocols approved by the Research Ethics Committee in Geneva, Switzerland, between 2001 and 2005. The authors asked principal investigators to rate the level of difficulty (1: none, to 5: very great) encountered across the research process. RESULTS: 588 questionnaires were sent back (participation rate 59.0 %). 391 (66.5 %) studies were completed at the time of the survey. Investigators reported that the most frequent difficulties were related to patient enrollment (44.3 %), data collection (26.7 %), data analysis and interpretation (21.5 %), collaboration with caregivers (21.0 %), study design (20.4 %), publication in peer-reviewed journal (20.2 %), hiring of competent study personnel (20.2 %), and getting funding (19.2 %). On average, investigators reported 2.8 difficulties per project (SD 2.8, range 0 to 12). In multivariable analysis, the number of difficulties was higher for studies initiated by public sponsors (vs. private), single center studies (vs. multicenter), and studies about treatment, diagnosis or prognosis (i.e., clinical vs. other studies). CONCLUSIONS: Medical researchers reported substantial logistical difficulties in conducting clinical research.

Comparison of Diagnostic Accuracy of PCR Targeting the 47-Kilodalton Protein Membrane Gene of Treponema pallidum and PCR Targeting the DNA Polymerase I Gene: Systematic Review and Meta-analysis.

Treponema pallidum PCR (Tp-PCR) testing now is recommended as a valid tool for the diagnosis of primary or secondary syphilis. The objectives were to systematically review and determine the optimal specific target gene to be used for Tp-PCR. Comparisons of the performance of the two main targets are tpp47 and polA genes were done using meta-analysis. Three electronic bibliographic databases, representing abstract books from five conferences specialized in infectious diseases from January 1990 to March 2015, were searched. Search keywords included ("syphilis" OR "Treponema pallidum" OR "neurosyphilis") AND ("PCR" OR "PCR" OR "molecular amplification"). We included diagnostic studies assessing the performance of Tp-PCR targeting tpp47 (tpp47-Tp-PCR) or the polA gene (polA-Tp-PCR) in ulcers from early syphilis. All studies were assessed against quality criteria using the QUADAS-2 tool. Of 37 studies identified, 62.2% were judged at low risk of bias or applicability. Most used the U.S. Centers for Disease Control and Prevention (CDC) case definitions for primary or secondary (early) syphilis (89.2%; n = 33); 15 (40.5%) used darkfield microscopy (DFM). We did not find differences in sensitivity and specificity between the two Tp-PCR methods in the subgroup of studies using adequate reference tests. Among studies using DFM as the reference test, sensitivities were 79.8% (95% confidence intervals [CI], 72.7 to 85.4%) and 71.4% (46.0 to 88.0%) for tpp47-Tp-PCR and polA-Tp-PCR (P = 0.217), respectively; respective specificities were 95.3% (93.5 to 96.6%) and 93.7% (91.8 to 95.2%) (P = 0.304). Our findings suggest that the two Tp-PCR methods have similar accuracy and could be used interchangeably.

Sample size for pre-tests of questionnaires.

PURPOSE: To provide guidance regarding the desirable size of pre-tests of psychometric questionnaires, when the purpose of the pre-test is to detect misunderstandings, ambiguities, or other difficulties participants may encounter with instrument items (called «problems¼). METHODS: We computed (a) the power to detect a problem for various levels of prevalence and various sample sizes, (b) the required sample size to detect problems for various levels of prevalence, and (c) upper confidence limits for problem prevalence in situations where no problems were detected. RESULTS: As expected, power increased with problem prevalence and with sample size. If problem prevalence was 0.05, a sample of 10 participants had only a power of 40 % to detect the problem, and a sample of 20 achieved a power of 64 %. To achieve a power of 80 %, 32 participants were necessary if the prevalence of the problem was 0.05, 16 participants if prevalence was 0.10, and 8 if prevalence was 0.20. If no problems were observed in a given sample, the upper limit of a two-sided 90 % confidence interval reached 0.26 for a sample size of 10, 0.14 for a sample size of 20, and 0.10 for a sample of 30 participants. CONCLUSIONS: Small samples (5-15 participants) that are common in pre-tests of questionaires may fail to uncover even common problems. A default sample size of 30 participants is recommended.

Prognostic ROC curves: a method for representing the overall discriminative capacity of binary markers with right-censored time-to-event endpoints.

Survival curves are a popular tool for representing the association between a binary marker and the risk of an event. The separation between the survival curves in patients with a positive marker (high-risk group) and a negative marker (low-risk group) reflects the prognostic ability of the marker. In this article, we propose an alternative graphical approach to represent the discriminative capacity of the marker-a receiver operating characteristic (ROC) curve, tentatively named prognostic ROC curve-obtained by plotting 1 minus the survival in the high-risk group against 1 minus the survival in the low-risk group. The area under the curve corresponds to the probability that a patient in the low-risk group has a longer lifetime than a patient in the high-risk group. The prognostic ROC curve provides complementary information compared with survival curves. However, when the survival functions do not reach 0, the prognostic ROC curve is incomplete. We show how a range of possible values for the area under the curve can be derived in this situation. A simulation study is performed to analyze the accuracy of this methodology, which is also illustrated by applications to the survival of patients with brain metastases and survival of kidney transplant recipients.

Effect of numbering of return envelopes on participation, explicit refusals, and bias: experiment and meta-analysis.

BACKGROUND: Tracing mail survey responses is useful for the management of reminders but may cause concerns about anonymity among prospective participants. We examined the impact of numbering return envelopes on the participation and the results of a survey on a sensitive topic among hospital staff. METHODS: In a survey about regrets associated with providing healthcare conducted among hospital-based doctors and nurses, two randomly drawn subsamples were provided numbered (N = 1100) and non-numbered (N = 500) envelopes for the return of completed questionnaires. Participation, explicit refusals, and item responses were compared. We also conducted a meta-analysis of the effect of questionnaire/envelope numbering on participation in health surveys. RESULTS: The participation rate was lower in the "numbered" group than in the "non-numbered" group (30.3% vs. 35.0%, p = 0.073), the proportion of explicit refusals was higher in the "numbered" group (23.1% vs 17.5%, p = 0.016), and the proportion of those who never returned the questionnaire was similar (46.6% vs 47.5%, p = 0.78). The means of responses differed significantly for 12 of 105 items (11.4%), which did not differ significantly from the expected frequency of type 1 errors, i.e., 5% (permutation test, p = 0.078). The meta-analysis of 7 experimental surveys (including this one) indicated that numbering is associated with a 2.4% decrease in the survey response rate (95% confidence interval 0.3% to 4.4%). CONCLUSIONS: Numbered return envelopes may reduce the response rate and increase explicit refusals to participate in a sensitive survey. Reduced participation was confirmed by a meta-analysis of randomized health surveys. There was no strong evidence of bias.

Validation of a 10-item care-related regret intensity scale (RIS-10) for health care professionals.

BACKGROUND: Regret after one of the many decisions and interventions that health care professionals make every day can have an impact on their own health and quality of life, and on their patient care practices. OBJECTIVES: To validate a new care-related regret intensity scale (RIS) for health care professionals. RESEARCH DESIGN: Retrospective cross-sectional cohort study with a 1-month follow-up (test-retest) in a French-speaking University Hospital. SAMPLE: A total of 469 nurses and physicians responded to the survey, and 175 answered the retest. MEASURES: RIS, self-report questions on the context of the regret-inducing event, its consequences for the patient, involvement of the health care professionals, and changes in patient care practices after the event. We measured the impact of regret intensity on health care professionals with the satisfaction with life scale, the SF-36 first question (self-reported health), and a question on self-esteem. RESULTS: On the basis of factor analysis and item response analysis, the initial 19-item scale was shortened to 10 items. The resulting scale (RIS-10) was unidimensional and had high internal consistency (α=0.87) and acceptable test-retest reliability (0.70). Higher regret intensity was associated with (a) more consequences for the patient; (b) lower life satisfaction and poorer self-reported health in health care professionals; and (c) changes in patient care practices. Nurses reported analyzing the event and apologizing, whereas physicians reported talking preferentially to colleagues, rather than to their supervisor, about changing practices. CONCLUSIONS: The RIS is a valid and reliable measure of care-related regret intensity for hospital-based physicians and nurses.

Sensitivity, specificity and likelihood ratios of PCR in the diagnosis of syphilis: a systematic review and meta-analysis.

OBJECTIVE: To systematically review and estimate pooled sensitivity and specificity of the polymerase chain reaction (PCR) technique compared to recommended reference tests in the diagnosis of suspected syphilis at various stages and in various biological materials. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Search of three electronic bibliographic databases from January 1990 to January 2012 and the abstract books of five congresses specialized in the infectious diseases' field (1999-2011). Search key terms included syphilis, Treponema pallidum or neurosyphilis and molecular amplification, polymerase chain reaction or PCR. REVIEW METHODS: We included studies that used both reference tests to diagnose syphilis plus PCR and we presented pooled estimates of PCR sensitivity, specificity, and positive and negative likelihood ratios (LR) per syphilis stages and biological materials. RESULTS: Of 1160 identified abstracts, 69 were selected and 46 studies used adequate reference tests to diagnose syphilis. Sensitivity was highest in the swabs from primary genital or anal chancres (78.4%; 95% CI: 68.2-86.0) and in blood from neonates with congenital syphilis (83.0%; 55.0-95.2). Most pooled specificities were ∼95%, except those in blood. A positive PCR is highly informative with a positive LR around 20 in ulcers or skin lesions. In the blood, the positive LR was <10. CONCLUSIONS: The pooled values of LR showed that T. pallidum PCR was more efficient to confirm than to exclude syphilis diagnosis in lesions. PCR is a useful diagnostic tool in ulcers, especially when serology is still negative and in medical settings with a high prevalence of syphilis.

Self-rated health: analysis of distances and transitions between response options.

PURPOSE: We explored health differences between population groups who describe their health as excellent, very good, good, fair, or poor. METHODS: We used data from a population-based survey which included self-rated health (SRH) and three global measures of health: the SF36 general health score (computed from the 4 items other than SRH), the EQ-5D health utility, and a visual analogue health thermometer. We compared health characteristics of respondents across the five health ratings. RESULTS: Survey respondents (N = 1.844, 49.2 % response) rated their health as excellent (12.2 %), very good (39.1 %), good (41.9 %), fair (6.0 %), or poor (0.9 %). The means of global health assessments were not equidistant across these five groups, for example, means of the health thermometer were 95.8 (SRH excellent), 88.8 (SRH very good), 76.6 (SRH good), 49.7 (SRH fair), and 33.5 (SRH poor, p < 0.001). Recoding the SRH to reflect these mean values substantially improved the variance explained by the SRH, for example, the linear r (2) increased from 0.50 to 0.56 for the health thermometer if the SRH was coded as poor = 1, fair = 2, good = 3.7, very good = 4.5, and excellent = 5. Furthermore, transitions between response options were not explained by the same health-related characteristics of the respondents. CONCLUSIONS: The adjectival SRH is not an evenly spaced interval scale. However, it can be turned into an interval variable if the ratings are recoded in proportion to the underlying construct of health. Possible improvements include the addition of a rating option between good and fair or the use of a numerical scale instead of the classic adjectival scale.

Growing discontent of Swiss doctors, 1998-2007.

BACKGROUND: Work satisfaction of doctors is a useful indicator of the functioning of the health-care system. We documented the work satisfaction of doctors nine years apart, before and after the implementation of several health-care reforms (limitation of working hours for medical trainees, restrictions on new doctors' offices, new reimbursement fee schedule, greater administrative controls). METHODS: Two surveys of all doctors working in the Canton of Geneva, Switzerland (1998: 1146 respondents, 2007: 1546 respondents). The doctors filled in a 17-item questionnaire rating their satisfaction with different aspects of their professional life, each on a scale between 1 and 7. For each item, proportions of highly satisfied (scores 6-7) and highly dissatisfied (scores 1-2) doctors were compared over time. RESULTS: The proportion of doctors who were highly satisfied decreased significantly for 15 out of 17 items between 1998 and 2007. Meanwhile, 'time available for family, friends, or leisure' improved, and 'opportunity for continuing education' remained stable. Proportions of highly satisfied respondents decreased the most for 'enjoyment of work' (-17.2%), 'autonomy in treating your patients' (-15.8%), 'autonomy in referring patients to a specialist' (-14.0%), 'relations with patients' (-13.9%) and 'global satisfaction with current work situation' (-13.3%). The proportion of respondents who were highly dissatisfied (score 1-2) increased the most for 'administrative burden' (+8.9%) and 'social status and respect' (+5.0%). CONCLUSIONS: Doctors' satisfaction with most aspects of their professional lives has decreased sharply during the past decade. This trend may be linked, tentatively, with specific policy changes.

Sensitivity and predictive value of 15 PubMed search strategies to answer clinical questions rated against full systematic reviews.

BACKGROUND: Clinicians perform searches in PubMed daily, but retrieving relevant studies is challenging due to the rapid expansion of medical knowledge. Little is known about the performance of search strategies when they are applied to answer specific clinical questions. OBJECTIVE: To compare the performance of 15 PubMed search strategies in retrieving relevant clinical trials on therapeutic interventions. METHODS: We used Cochrane systematic reviews to identify relevant trials for 30 clinical questions. Search terms were extracted from the abstract using a predefined procedure based on the population, interventions, comparison, outcomes (PICO) framework and combined into queries. We tested 15 search strategies that varied in their query (PIC or PICO), use of PubMed's Clinical Queries therapeutic filters (broad or narrow), search limits, and PubMed links to related articles. We assessed sensitivity (recall) and positive predictive value (precision) of each strategy on the first 2 PubMed pages (40 articles) and on the complete search output. RESULTS: The performance of the search strategies varied widely according to the clinical question. Unfiltered searches and those using the broad filter of Clinical Queries produced large outputs and retrieved few relevant articles within the first 2 pages, resulting in a median sensitivity of only 10%-25%. In contrast, all searches using the narrow filter performed significantly better, with a median sensitivity of about 50% (all P < .001 compared with unfiltered queries) and positive predictive values of 20%-30% (P < .001 compared with unfiltered queries). This benefit was consistent for most clinical questions. Searches based on related articles retrieved about a third of the relevant studies. CONCLUSIONS: The Clinical Queries narrow filter, along with well-formulated queries based on the PICO framework, provided the greatest aid in retrieving relevant clinical trials within the 2 first PubMed pages. These results can help clinicians apply effective strategies to answer their questions at the point of care.

Doctors and patients' susceptibility to framing bias: a randomized trial.

BACKGROUND: Framing of risk influences the perceptions of treatment benefit. OBJECTIVE: To determine which risk framing format corresponds best to comprehensive multi-faceted information, and to compare framing bias in doctors and in patients. DESIGN: Randomized mail surveys. PARTICIPANTS: One thousand four hundred and thirty-one doctors (56% response rate) and 1121 recently hospitalized patients (65% response rate). INTERVENTION: Respondents were asked to interpret the results of a hypothetical clinical trial comparing an old and a new drug. They were randomly assigned to the following framing formats: absolute survival (new drug: 96% versus old drug: 94%), absolute mortality (4% versus 6%), relative mortality reduction (reduction by a third) or all three (fully informed condition). The new drug was reported to cause more side-effects. MAIN MEASURE: Rating of the new drug as more effective than the old drug. RESULTS: The proportions of doctors who rated the new drug as more effective varied by risk presentation format (abolute survival 51.8%, absolute mortality 68.3%, relative mortality reduction 93.8%, and fully informed condition 69.8%, p < 0.001). In patients these proportions were similar (abolute survival 51.7%, absolute mortality 66.8%, relative mortality reduction 89.3%, and fully informed condition 71.2%, p < 0.001). In both doctors (p = 0.72) and patients (p = 0.23) the fully informed condition was similar to the absolute risk format, but it differed significantly from the other conditions (all p < 0.01). None of the differences between doctors and patients were significant (all p > 0.1). In comparison to the fully informed condition, the odds ratio of greater perceived effectiveness was 0.45 for absolute survival (p < 0.001), 0.89 for absolute mortality (p = 0.29), and 4.40 for relative mortality reduction (p < 0.001). CONCLUSIONS: Framing bias affects doctors and patients similarly. Describing clinical trial results as absolute risks is the least biased format, for both doctors and patients. Presenting several risk formats (on both absolute and relative scales) should be encouraged.

Does prevalence matter to physicians in estimating post-test probability of disease? A randomized trial.

BACKGROUND: The probability of a disease following a diagnostic test depends on the sensitivity and specificity of the test, but also on the prevalence of the disease in the population of interest (or pre-test probability). How physicians use this information is not well known. OBJECTIVE: To assess whether physicians correctly estimate post-test probability according to various levels of prevalence and explore this skill across respondent groups. DESIGN: Randomized trial. PARTICIPANTS: Population-based sample of 1,361 physicians of all clinical specialties. INTERVENTION: We described a scenario of a highly accurate screening test (sensitivity 99% and specificity 99%) in which we randomly manipulated the prevalence of the disease (1%, 2%, 10%, 25%, 95%, or no information). MAIN MEASURES: We asked physicians to estimate the probability of disease following a positive test (categorized as <60%, 60-79%, 80-94%, 95-99.9%, and >99.9%). Each answer was correct for a different version of the scenario, and no answer was possible in the "no information" scenario. We estimated the proportion of physicians proficient in assessing post-test probability as the proportion of correct answers beyond the distribution of answers attributable to guessing. KEY RESULTS: Most respondents in each of the six groups (67%-82%) selected a post-test probability of 95-99.9%, regardless of the prevalence of disease and even when no information on prevalence was provided. This answer was correct only for a prevalence of 25%. We estimated that 9.1% (95% CI 6.0-14.0) of respondents knew how to assess correctly the post-test probability. This proportion did not vary with clinical experience or practice setting. CONCLUSIONS: Most physicians do not take into account the prevalence of disease when interpreting a positive test result. This may cause unnecessary testing and diagnostic errors.

Exploration of health dimensions to be included in multi-attribute health-utility assessment.

OBJECTIVE: Measurement of health utility is important for quality improvement, but instruments vary in their content. Multi-attribute health utility measures typically assess a small number of health problems, e.g. the EuroQoL EQ-5D questionnaire explores five dimensions of health. We aimed to examine whether a small number of dimensions explains a sufficient amount of variance in self-perceived health, and what can be gained from adding additional dimensions. DESIGN: Cross-sectional mail survey that explored health utility and self-perceived health. SETTING: General resident population of French-speaking Switzerland. PARTICIPANTS: Non-institutionalized adults. MAIN OUTCOME MEASURES: EQ-5D (which measures mobility, self-care, usual activities, pain/discomfort, anxiety/depression and a visual analogue health scale between 0 and 100 (VAS)). A subsample rated five additional health dimensions (sleep, memory/concentration, energy/fatigue, sight/hearing, contacts with others). RESULTS: In total, 349 adults returned the extended 10-item questionnaire. All added items were strongly and significantly associated with the VAS for perceived health. The proportion of variance explained (R(2)) in the VAS was 0.47 for the original EQ-5D items (adjusted for attenuation: 0.65), 0.47 for the new items (adjusted for attenuation: 0.65) and 0.56 for the 10 items together (adjusted for attenuation: 0.78). Forty-four percent of the respondents who had a perfect health utility on the EQ-5D reported at least one problem in the new health dimensions. CONCLUSION: Self-perceived health among the general public is influenced by more health dimensions than are typically measured in a multi-attribute health-utility instrument.

How to use likelihood ratios to interpret evidence from randomized trials.

OBJECTIVE: The likelihood ratio is a method for assessing evidence regarding two simple statistical hypotheses. Its interpretation is simple - for example, a value of 10 means that the first hypothesis is 10 times as strongly supported by the data as the second. A method is shown for deriving likelihood ratios from published trial reports. STUDY DESIGN: The likelihood ratio compares two hypotheses in light of data: that a new treatment is effective, at a specified level (alternate hypothesis: for instance, the hazard ratio equals 0.7), and that it is not (null hypothesis: the hazard ratio equals 1). The result of the trial is summarised by the test statistic z (ie, the estimated treatment effect divided by its standard error). The expected value of z is 0 under the null hypothesis, and A under the alternate hypothesis. The logarithm of the likelihood ratio is given by z·A - A2/2. The values of A and z can be derived from the alternate hypothesis used for sample size computation, and from the observed treatment effect and its standard error or confidence interval. RESULTS: Examples are given of trials that yielded strong or moderate evidence in favor of the alternate hypothesis, and of a trial that favored the null hypothesis. The resulting likelihood ratios are applied to initial beliefs about the hypotheses to obtain posterior beliefs. CONCLUSIONS: The likelihood ratio is a simple and easily understandable method for assessing evidence in data about two competing a priori hypotheses.

Physicians' Views and Agreement about Patient- and Context-Related Factors Influencing ICU Admission Decisions: A Prospective Study.

BACKGROUND: Single patient- and context-related factors have been associated with admission decisions to intensive care. How physicians weigh various factors and integrate them into the decision-making process is not well known. OBJECTIVES: First, to determine which patient- and context-related factors influence admission decisions according to physicians, and their agreement about these determinants; and second, to examine whether there are differences for patients with and without advanced disease. METHOD: This study was conducted in one tertiary hospital. Consecutive ICU consultations for medical inpatients were prospectively included. Involved physicians, i.e., internists and intensivists, rated the importance of 13 factors for each decision on a Likert scale (1 = negligible to 5 = predominant). We cross-tabulated these factors by presence or absence of advanced disease and examined the degree of agreement between internists and intensivists using the kappa statistic. RESULTS: Of 201 evaluated patients, 105 (52.2%) had an advanced disease, and 140 (69.7%) were admitted to intensive care. The mean number of important factors per decision was 3.5 (SD 2.4) for intensivists and 4.4 (SD 2.1) for internists. Patient's comorbidities, quality of life, preferences, and code status were most often mentioned. Inter-rater agreement was low for the whole population and after stratifying for patients with and without advanced disease. Kappa values ranged from 0.02 to 0.34 for all the patients, from -0.05 to 0.42 for patients with advanced disease, and from -0.08 to 0.32 for patients without advanced disease. The best agreement was found for family preferences. CONCLUSION: Poor agreement between physicians about patient- and context-related determinants of ICU admission suggests a lack of explicitness during the decision-making process. The potential consequences are increased variability and inequity regarding which patients are admitted. Timely advance care planning involving families could help physicians make the decision most concordant with patient preferences.