Sample sizes of studies on diagnostic accuracy: literature survey

OBJECTIVES: To determine sample sizes in studies on diagnostic accuracy and the proportion of studies that report calculations of sample size. DESIGN: Literature survey. DATA SOURCES: All issues of eight leading journals published in 2002. METHODS: Sample sizes, number of subgroup analyses, and how often studies reported calculations of sample size were extracted. RESULTS: 43 of 8999 articles were non-screening studies on diagnostic accuracy. The median sample size was 118 (interquartile range 71-350) and the median prevalence of the target condition was 43% (27-61%). The median number of patients with the target condition--needed to calculate a test's sensitivity--was 49 (28-91). The median number of patients without the target condition--needed to determine a test's specificity--was 76 (27-209). Two of the 43 studies (5%) reported a priori calculations of sample size. Twenty articles (47%) reported results for patient subgroups. The number of subgroups ranged from two to 19 (median four). No studies reported that sample size was calculated on the basis of preplanned analyses of subgroups. CONCLUSION: Few studies on diagnostic accuracy report considerations of sample size. The number of participants in most studies on diagnostic accuracy is probably too small to analyse variability of measures of accuracy across patient subgroups.

Management of phenylketonuria in Europe: survey results from 19 countries

To gain better insight in the most current diagnosis and treatment practices for phenylketonuria (PKU) from a broad group of experts, a European PKU survey was performed. The questionnaire, consisting of 33 questions, was sent to 243 PKU professionals in 165 PKU centers in 23 European countries. The responses were compiled and descriptive analyses were performed. One hundred and one questionnaires were returned by 93/165 centers (56%) from 19/23 European countries (83%). The majority of respondents (77%) managed patients of all age groups and more than 90% of PKU teams included physicians or dieticians/nutritionists. The greatest variability existed especially in the definition of PKU phenotypes, therapeutic blood phenylalanine (Phe) target concentrations, and follow-up practices for PKU patients. The tetrahydrobiopterin (BH4; sapropterin) loading test was performed by 54% of respondents, of which 61% applied a single dose test (20mg/kg over 24h). BH4 was reported as a treatment option by 34%. This survey documents differences in diagnostic and treatment practices for PKU patients in European centers. In particular, recommendations for the treatment decision varied greatly between different European countries. There is an urgent need to pool long-term data in PKU registries in order to generate an evidence-based international guideline.

First countrywide survey of third-generation cephalosporin-resistant Escherichia coli from broilers, swine, and cattle in Switzerland

The herd prevalence of third-generation cephalosporin-resistant Escherichia coli (3GC-R-Ec) was determined for broilers (25.0% [95% confidence interval (CI) 17.6-33.7%]), pigs (3.3% [(95% CI 0.4-11.5%]), and cattle (3.9% [95% CI 0.5-13.5%]), using a sampling strategy that was representative of the livestock population slaughtered in Switzerland between October 2010 and April 2011. The 3GC-R-Ec isolates were characterized by the measurement of the MICs of various antibiotics, microarray analyses, analytical isoelectric focusing, polymerase chain reaction and DNA sequencing for bla genes, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing. CMY-2 (n = 12), CTX-M-1 (n = 11), SHV-12 (n = 5), TEM-52 (n = 3), CTX-M-15 (n = 2), and CTX-M-3 (n = 1) producers were found. The majority of CMY-2 producers fell into 1 PFGE cluster, which predominantly contained ST61, whereas the CTX-M types were carried by heterogeneous clones of E. coli, as shown by the numerous PFGE profiles and STs that were found. This is the first national Swiss study that focuses on the spread of 3GC-R Enterobacteriaceae among slaughtered animals.

Epidemiological, social, diagnostic and economic evaluation of population screening for genital chlamydial infection

OBJECTIVES: To investigate epidemiological, social, diagnostic and economic aspects of chlamydia screening in non-genitourinary medicine settings. METHODS: Linked studies around a cross-sectional population-based survey of adult men and women invited to collect urine and (for women) vulvovaginal swab specimens at home and mail these to a laboratory for testing for Chlamydia trachomatis. Specimens were used in laboratory evaluations of an amplified enzyme immunoassay (PCE EIA) and two nucleic acid amplification tests [Cobas polymerase chain reaction (PCR), Becton Dickinson strand displacement amplification (SDA)]. Chlamydia-positive cases and two negative controls completed a risk factor questionnaire. Chlamydia-positive cases were invited into a randomised controlled trial of partner notification strategies. Samples of individuals testing negative completed psychological questionnaires before and after screening. In-depth interviews were conducted at all stages of screening. Chlamydia transmission and cost-effectiveness of screening were investigated in a transmission dynamic model. SETTING AND PARTICIPANTS: General population in the Bristol and Birmingham areas of England. In total, 19,773 women and men aged 16-39 years were randomly selected from 27 general practice lists. RESULTS: Screening invitations reached 73% (14,382/19,773). Uptake (4731 participants), weighted for sampling, was 39.5% (95% CI 37.7, 40.8%) in women and 29.5% (95% CI 28.0, 31.0%) in men aged 16-39 years. Chlamydia prevalence (219 positive results) in 16-24 year olds was 6.2% (95% CI 4.9, 7.8%) in women and 5.3% (95% CI 4.4, 6.3%) in men. The case-control study did not identify any additional factors that would help target screening. Screening did not adversely affect anxiety, depression or self-esteem. Participants welcomed the convenience and privacy of home-sampling. The relative sensitivity of PCR on male urine specimens was 100% (95% CI 89.1, 100%). The combined relative sensitivities of PCR and SDA using female urine and vulvovaginal swabs were 91.8% (86.1, 95.7, 134/146) and 97.3% (93.1, 99.2%, 142/146). A total of 140 people (74% of eligible) participated in the randomised trial. Compared with referral to a genitourinary medicine clinic, partner notification by practice nurses resulted in 12.4% (95% CI -3.7, 28.6%) more patients with at least one partner treated and 22.0% (95% CI 6.1, 37.8%) more patients with all partners treated. The health service and patients costs (2005 prices) of home-based postal chlamydia screening were 21.47 pounds (95% CI 19.91 pounds, 25.99) per screening invitation and 28.56 pounds (95% CI 22.10 pounds, 30.43) per accepted offer. Preliminary modelling found an incremental cost-effectiveness ratio (2003 prices) comparing screening men and women annually to no screening in the base case of 27,000 pounds/major outcome averted at 8 years. If estimated screening uptake and pelvic inflammatory disease incidence were increased, the cost-effectiveness ratio fell to 3700 pounds/major outcome averted. CONCLUSIONS: Proactive screening for chlamydia in women and men using home-collected specimens was feasible and acceptable. Chlamydia prevalence rates in men and women in the general population are similar. Nucleic acid amplification tests can be used on first-catch urine specimens and vulvovaginal swabs. The administrative costs of proactive screening were similar to those for opportunistic screening. Using empirical estimates of screening uptake and incidence of complications, screening was not cost-effective.

[Radiation protection in diagnostic radiology]

For every diagnostical X-ray radiation exposure the applied dose has to be limited to the smallest possible value. Within the scope of a general Swiss survey it has been found that in the various medical practices and hospitals the applied doses varied quite strongly. The main reasons leading to an overdose were the operating conditions of the X-ray and film processing equipment, the film and foil materials and improper filming techniques. The applied single dose served as a measure for the radiation protection assessment of diagnostical X-ray exposures. To prevent this in the future, individual patients who are exposed to unnecessary radiation loads should be regularly checked in quality-ensuring tests.

Diagnostic workup of patients with acute transverse myelitis: spectrum of clinical presentation, neuroimaging and laboratory findings

STUDY DESIGN: Retrospective 9-year survey. OBJECTIVES: Clinical presentation of acute myelitis syndromes is variable, and neuroimaging and laboratory findings are not specific enough to establish the diagnosis with certainty. We evaluated the spectrum clinical features and paraclinical findings encountered during diagnostic workup and aiding the diagnosis. SETTING: Department of Neurology, Inselspital Bern, Switzerland. MATERIAL: Charts and magnetic resonance imaging (MRI) of 63 patients discharged with the diagnosis of acute transverse myelitis. RESULTS: The diagnosis was supported by abnormal MRI and cerebrospinal fluid (CSF) findings in 52 patients (82.5%) and suspected in the remaining either because of a spinal cord MRI lesion suggestive of myelitis (n=5), or abnormal CSF findings (n=4), or electrophysiological evidence of a spinal cord dysfunction (n=2). Clinical impairment was mild (ASIA D) in the majority. All patients had sensory disturbances, whereas motor deficit and autonomic dysfunction were less frequent. Neurological levels were mainly located in cervical or thoracic dermatomes. Spinal cord lesions were visualized by MRI in 90.4% of the patients and distributed either in the cervical or thoracic cord, or both. Multiple lesions were present in more than half of the patients, and lateral, centromedullary and posterior locations were most common. A high percentage of multiple sclerosis (MS)-typical brain lesions and CSF findings suggested a substantial number of MS-related myelitis in our cohort. CONCLUSION: The diagnostic workup of acute myelitis discloses a broad spectrum of CSF or MRI findings, and may be associated with diagnostic uncertainty due to lack of specific CSF or MRI features, or pathological findings.

CT radiation dose for computer-assisted endoscopic sinus surgery: dose survey and determination of dose-reduction limits

BACKGROUND AND PURPOSE: Computer-assisted navigation is increasingly used in functional endoscopic sinus surgery (FESS) to prevent injury to vital structures, necessitating preparative CT and, thus, radiation exposure. The purpose of our study was to investigate currently used radiation doses for CT in computer-assisted navigation in sinus surgery (CAS-CT) and to assess minimal doses required. MATERIALS AND METHODS: A questionnaire inquiring about dose parameters used for CAS-CT was sent to 30 radiologic institutions. The feasibility of low-dose registration was tested with a phantom. The influence of CAS-CT dose on technical accuracy and on the practical performance of 5 ear, nose, and throat (ENT) surgeons was evaluated with cadaver heads. RESULTS: The questionnaire response rate was 63%. Variation between minimal and maximal dose used for CAS-CT was 18-fold. Phantom registration was possible with doses as low as 1.1 mGy. No dose dependence on technical accuracy was found. ENT surgeons were able to identify anatomic landmarks on scans with a dose as low as 3.1 mGy. CONCLUSIONS: The vast dose difference between institutions mirrors different attitudes toward image quality and radiation-protection issues rather than being technically founded, and many patients undergo CAS-CT at higher doses than necessary. The only limit for dose reduction in CT for computer-assisted endoscopic sinus surgery is the ENT surgeon's ability to cope with impaired image quality, whereas there is no technically justified lower dose limit. We recommend, generally, doses used for the typical diagnostic low-dose sinus CT (120 kV/20-50 mAs). When no diagnostic image quality is needed, even a reduction down to a third is possible.

Management of fragility fractures in Switzerland: results of a nationwide survey

A nationwide survey was conducted in Switzerland to assess the quality level of osteoporosis management in patients aged 50 years or older presenting with a fragility fracture to the emergency ward of the participating hospitals. Eight centres recruited 4966 consecutive patients who presented with one or more fractures between 2004 and 2006. Of these, 3667 (2797 women, 73.8 years old and 870 men, 73.0 years old in average) were considered as having a fragility fracture and included in the survey. Included patients presented with a fracture of the upper limbs (30.7%), lower limbs (26.4%), axial skeleton (19.5%) or another localisation, including malleolar fractures (23.4%). Thirty-two percent reported one or more previous fractures during adulthood. Of the 2941 (80.2%) hospitalised women and men, only half returned home after discharge. During diagnostic workup, dual x-ray absorptiometry (DXA) measurement was performed in 31.4% of the patients only. Of those 46.0% had a T-score < or =-2.5 SD and 81.1% < or =-1.0 SD. Osteoporosis treatment rate increased from 26.3% before fracture to 46.9% after fracture in women and from 13.0% to 30.3% in men. However, only 24.0% of the women and 13.8% of the men were finally adequately treated with a bone active substance, generally an oral bisphosphonate, with or without calcium / vitamin D supplements. A positive history of previous fracture vs none increased the likelihood of getting treatment with a bone active substance (36.6 vs 17.9%, ? 18.7%, 95% CI 15.1 to 22.3, and 22.6 vs 9.9%, ? 12.7%, CI 7.3 to 18.5, in women and men, respectively). In Switzerland, osteoporosis remains underdiagnosed and undertreated in patients aged 50 years and older presenting with a fragility fracture.

Survey of selected tick-borne diseases in dogs in Finland

BACKGROUND: Due to climate changes during the last decades, ticks have progressively spread into higher latitudes in northern Europe. Although some tick borne diseases are known to be endemic in Finland, to date there is limited information with regard to the prevalence of these infections in companion animals. We determined the antibody and DNA prevalence of the following organisms in randomly selected client-owned and clinically healthy hunting dogs living in Finland: Ehrlichia canis (Ec), Anaplasma phagocytophilum (Ap), Borrelia burgdorferi (Bb) and Bartonella. METHODS: Anti-Ap, -Bb and -Ec antibodies were determined in 340 Finnish pet dogs and 50 healthy hunting dogs using the 4DX Snap(R)Test (IDEXX Laboratories). In addition, PCRs for the detection of Ap and Bartonella DNA were performed. Univariate and multivariate logistic regression analyses were used to identify risk factors associated with seropositivity to a vector borne agent. RESULTS: The overall seroprevalence was highest for Ap (5.3%), followed by Bb (2.9%), and Ec (0.3%). Seropositivities to Ap and Bb were significantly higher in the Aland Islands (p <0.001), with prevalence of Ap and Bb antibodies of 45 and 20%, respectively. In healthy hunting dogs, seropositivity rates of 4% (2/50) and 2% (1/50) were recorded for Ap and Bb, respectively. One client-owned dog and one hunting dog, both healthy, were infected with Ap as determined by PCR, while being seronegative. For Bartonella spp., none of the dogs tested was positive by PCR. CONCLUSIONS: This study represents the first data of seroprevalence to tick borne diseases in the Finnish dog population. Our results indicate that dogs in Finland are exposed to vector borne diseases, with Ap being the most seroprevalent of the diseases tested, followed by Bb. Almost 50% of dogs living in Aland Islands were Ap seropositive. This finding suggests the possibility of a high incidence of Ap infection in humans in this region. Knowing the distribution of seroprevalence in dogs may help predict the pattern of a tick borne disease and may aid in diagnostic and prevention efforts.

Leader–member exchange (LMX), job autonomy, and creative work involvement

Researchers have claimed that high quality of supervisor–employee relationships (i.e., leader– member exchange; LMX) fosters creativity at work. Moreover, researchers have acknowledged that this relationship is not clear-cut but rather complex. The present study focused on the moderating role of job autonomy in the LMX-creative work involvement relationship. Longitu-dinal field survey data (N = 144) collected in a high-technology firm revealed a positive asso-ciation between LMX and creative work involvement and confirmed our assumptions on the moderating role of job autonomy. The positive relationship between LMX and creative work involvement was stronger when employees experienced greater job autonomy. Our findings point to the importance of considering the interplay of both, the leader–member relationship and job design issues for increasing employees' creative work involvement.

The impact of medical errors on Swiss anaesthesiologists: a cross-sectional survey.

BACKGROUND Clinicians involved in medical errors can experience significant distress. This study aims to examine (1) how medical errors impact anaesthesiologists in key work and life domains; (2) anaesthesiologists' attitudes regarding support after errors; (3) and which anaesthesiologists are most affected by errors. METHODS This study is a mailed cross-sectional survey completed by 281 of the 542 clinically active anaesthesiologists (52% response rate) working at Switzerland's five university hospitals between July 2012 and April 2013. RESULTS Respondents reported that errors had negatively affected anxiety about future errors (51%), confidence in their ability as a doctor (45%), ability to sleep (36%), job satisfaction (32%), and professional reputation (9%). Respondents' lives were more likely to be affected as error severity increased. Ninety per cent of respondents disagreed that hospitals adequately support them in coping with the stress associated with medical errors. Nearly all of the respondents (92%) reported being interested in psychological counselling after a serious error, but many identified barriers to seeking counselling. However, there were significant differences between departments regarding error-related stress levels and attitudes about error-related support. Respondents were more likely to experience certain distress if they were female, older, had previously been involved in a serious error, and were dissatisfied with their last error disclosure. CONCLUSION Medical errors, even minor errors and near misses, can have a serious effect on clinicians. Health-care organisations need to do more to support clinicians in coping with the stress associated with medical errors.

Development of a diagnostic online tool system for Swiss sport psychology practitioners

Psychological assessment is a central component of applied sport psychology. Despite obvious and well-documented advantages of diagnostic online tools, there is a lack of a system for such tools for sport psychologists so far in Switzerland. Having the most frequently used questionnaires available online in one single tool for all listed Swiss sport psychologists would make the work of practitioners a lot easier and less time consuming. Therefore, the main goal of this project is to develop a diagnostic online tool system with the possibility to make available different questionnaires often used in sport psychology. Furthermore, we intend to survey status and use of this diagnostic online tool system and the questionnaires by Swiss sport psychologists. A specific challenge is to limit the access to qualified sport psychologists and to secure the confidentiality for the client. In particular, approved sport psychologists get an individual code for each of their athletes for the required questionnaire. With the help of this code, athletes can access the test via a secure website at any place of the world. As soon as they complete and submit the online questionnaire, analysed and interpreted data reach the sport psychologist via E-Mail, which is timesaving and easy applicable for the sport psychologist. Furthermore, data are available for interpretation with athletes and documentation of individual development over time is possible. Later on, completed and anonymised questionnaires will be collected and analysed. Bigger number of collected data give more insight in the psychometric properties, thus helping to improve and further develop the questionnaires. In this presentation, we demonstrate the tool and its feasibility using the German version of the Test of Performance Strategies (TOPS, Schmid et al., 2010). To conclude, this diagnostic online tool system offers new possibilities for sport psychologists working as practitioner.

Job satisfaction of Swiss general practitioners with and without proficiency certificate in homeopathy

Introduction: Job satisfaction and therefore wellbeing of physicians is an important issue in high quality and safety of health care provision. The role of additional qualification in complementary medicine (CM) for job satisfaction of general practitioners (GPs), however, has not been explored. This study compared job satisfaction of conventional and homeopathic Swiss GPs. Methods: Participants of the Swiss Family Doctors Conference 2013 and members of the Swiss Association of Homeopathic Physicians participated in the survey. They indicated the extent of job satisfaction on 17 questions covering patient care, work-related burden, income-prestige, personal rewards, and professional relations. Results: Data of n = 125 GPs with homeopathic proficiency certificate and data of n = 143 GPs without any proficiency certificate in CM were analyzed. Overall job satisfaction was high and did not differ between the groups. However, due to lower number of patients per day, homeopathic GPs reported higher satisfaction in relations with patients and with workload, and lower satisfaction with income and in relations with peers compared to conventional GPs. Controlling for further confounding variables (e.g. working hours per week, practice setting), homeopathic GPs reported less satisfaction with their income than their conventional colleagues. Conclusions: Longer consultation time and lower number of patients homeopathic GPs see per day, may allowthem to unfold a deeper and more satisfying relationship with their patients and to lessen the workload. However, this comes along with financial discontent compared to conventional GPs. Certification in homeopathy and increased consultation time, respectively, may represent a way to enhance GPs’ job satisfaction.

Minimally invasive surgery when treating endometriosis has a positive effect on health and on quality of work life of affected women

STUDY QUESTION: What is the effect of the minimally invasive surgical treatment of endometriosis on health and on quality of work life (e.g. working performance) of affected women? SUMMARY ANSWER: Absence from work, performance loss and the general negative impact of endometriosis on the job are reduced significantly by the laparoscopic surgery. WHAT IS KNOWN ALREADY: The benefits of surgery overall and of the laparoscopic method in particular for treating endometriosis have been described before. However, previous studies focus on medical benchmarks without including the patient's perspective in a quantitative manner. STUDY DESIGN, SIZE, DURATION: A retrospective questionnaire-based survey covering 211 women with endometriosis and a history of specific laparoscopic surgery in a Swiss university hospital, tertiary care center. Data were returned anonymously and were collected from the beginning of 2012 until March 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women diagnosed with endometriosis and with at least one specific laparoscopic surgery in the past were enrolled in the study. The study investigated the effect of the minimally invasive surgery on health and on quality of work life of affected women. Questions used were obtained from the World Endometriosis Research Foundation (WERF) Global Study on Women's Health (GSWH) instrument. The questionnaire was shortened and adapted for the purpose of the present study. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 587 women invited to participate in the study, 232 (232/587 = 40%) returned the questionnaires. Twenty-one questionnaires were excluded due to incomplete data and 211 sets (211/587 = 36%) were included in the study. Our data show that 62% (n = 130) of the study population declared endometriosis as influencing the job during the period prior to surgery, compared with 28% after surgery (P < 0.001). The mean (maximal) absence from work due to endometriosis was reduced from 2.0 (4.9) to 0.5 (1.4) hours per week (P < 0.001). The mean (maximal) loss in working performance after the surgery averaged out at 5.7% (12.6%) compared with 17.5% (30.5%) before this treatment (P < 0.001). LIMITATIONS, REASONS FOR CAUTION: The mediocre response rate of the study weakens the representativeness of the investigated population. Considering the anonymous setting a non-responder investigation was not performed. A bias due to selection, information and negativity effects within a retrospective survey cannot be excluded, although study-sensitive questions were provided in multiple ways. The absence of a control group (sham group; e.g. patients undergoing specific diagnostic laparoscopy without treatment) is a further limitation of the study. WIDER IMPLICATIONS OF THE FINDINGS: Our study shows that indicated minimally invasive surgery has a clear positive effect on the wellbeing and working performance of women suffering from moderate to severe endometriosis. Furthermore, national net savings in indirect costs with the present number of surgeries is estimated to be €10.7 million per year. In an idealized setting (i.e. without any diagnosis delay) this figure could be more than doubled. STUDY FUNDING/COMPETING INTERESTS: The study was performed on behalf of the University Hospital of Bern (Inselspital) as one of the leading Swiss tertiary care centers. The authors do not declare any competing interests.

Diagnosis and therapy of retained fetal membranes, puerperal metritis and clinical endometritis in cattle: Results of the Online-survey among Swiss practitioners. II. Puerperal metritis and clinical endometritis

The aim of the study was to obtain the diagnostic and therapeutic approach among Swiss practitioners in cows with puerperal metritis and clinical endometritis (part 2). All members of the Association for ruminant health were contacted per email via the newsletter. The survey was completed by 128 veterinarians, partially responded by 140 veterinarians. The following main symptoms of puerperal metritis were stated by the practitioners: purulent vaginal discharge, fever and reduced appetite. A vaginal and rectal examination was performed to diagnose the disease. Usually, an intrauterine treatment with tetracycline or cefapirin was done. Parenteral administration of tetracycline or penicillin was often combined with PGF(2α), NSAIDS or cortisone. Clinical endometritis was also diagnosed by vaginal and rectal examination and the main symptom indicated was purulent vaginal discharge. The therapy consisted of the administration of PGF(2α), uterine infusions predominantly with cefapirin, and rarely with parenteral administration of antibiotics. Further diagnostic tools were not used and normally cows were not rechecked. The success of the therapy of puerperal metritis and clinical endometritis was judged to be satisfactory to excellent.