Case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review

OBJECTIVE

To identify case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), and explore how the validity of case definitions can be evaluated in the absence of a reference standard.

DESIGN

Systematic review.

SETTING

International.

PARTICIPANTS

A literature search, updated as of November 2013, led to the identification of 20 case definitions and inclusion of 38 validation studies.

PRIMARY AND SECONDARY OUTCOME MEASURE

Validation studies were assessed for risk of bias and categorised according to three validation models: (1) independent application of several case definitions on the same population, (2) sequential application of different case definitions on patients diagnosed with CFS/ME with one set of diagnostic criteria or (3) comparison of prevalence estimates from different case definitions applied on different populations.

RESULTS

A total of 38 studies contributed data of sufficient quality and consistency for evaluation of validity, with CDC-1994/Fukuda as the most frequently applied case definition. No study rigorously assessed the reproducibility or feasibility of case definitions. Validation studies were small with methodological weaknesses and inconsistent results. No empirical data indicated that any case definition specifically identified patients with a neuroimmunological condition.

CONCLUSIONS

Classification of patients according to severity and symptom patterns, aiming to predict prognosis or effectiveness of therapy, seems useful. Development of further case definitions of CFS/ME should be given a low priority. Consistency in research can be achieved by applying diagnostic criteria that have been subjected to systematic evaluation.

The Scleroderma Patient-centered Intervention Network (SPIN) Cohort: protocol for a cohort multiple randomised controlled trial (cmRCT) design to support trials of psychosocial and rehabilitation interventions in a rare disease context

INTRODUCTION

Psychosocial and rehabilitation interventions are increasingly used to attenuate disability and improve health-related quality of life (HRQL) in chronic diseases, but are typically not available for patients with rare diseases. Conducting rigorous, adequately powered trials of these interventions for patients with rare diseases is difficult. The Scleroderma Patient-centered Intervention Network (SPIN) is an international collaboration of patient organisations, clinicians and researchers. The aim of SPIN is to develop a research infrastructure to test accessible, low-cost self-guided online interventions to reduce disability and improve HRQL for people living with the rare disease systemic sclerosis (SSc or scleroderma). Once tested, effective interventions will be made accessible through patient organisations partnering with SPIN.

METHODS AND ANALYSIS

SPIN will employ the cohort multiple randomised controlled trial (cmRCT) design, in which patients consent to participate in a cohort for ongoing data collection. The aim is to recruit 1500-2000 patients from centres across the world within a period of 5 years (2013-2018). Eligible participants are persons ≥18 years of age with a diagnosis of SSc. In addition to baseline medical data, participants will complete patient-reported outcome measures every 3 months. Upon enrolment in the cohort, patients will consent to be contacted in the future to participate in intervention research and to allow their data to be used for comparison purposes for interventions tested with other cohort participants. Once interventions are developed, patients from the cohort will be randomly selected and offered interventions as part of pragmatic RCTs. Outcomes from patients offered interventions will be compared with outcomes from trial-eligible patients who are not offered the interventions.

ETHICS AND DISSEMINATION

The use of the cmRCT design, the development of self-guided online interventions and partnerships with patient organisations will allow SPIN to develop, rigourously test and effectively disseminate psychosocial and rehabilitation interventions for people with SSc.

Representativeness and optimal use of body mass index (BMI) in the UK Clinical Practice Research Datalink (CPRD)

OBJECTIVES

To assess the completeness and representativeness of body mass index (BMI) data in the Clinical Practice Research Datalink (CPRD), and determine an optimal strategy for their use.

DESIGN

Descriptive study.

SETTING

Electronic healthcare records from primary care.

PARTICIPANTS

A million patient random sample from the UK CPRD primary care database, aged ≥16 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

BMI completeness in CPRD was evaluated by age, sex and calendar period. CPRD-based summary BMI statistics for each calendar year (2003-2010) were age-standardised and sex-standardised and compared with equivalent statistics from the Health Survey for England (HSE).

RESULTS

BMI completeness increased over calendar time from 37% in 1990-1994 to 77% in 2005-2011, was higher among females and increased with age. When BMI at specific time points was assigned based on the most recent record, calendar-year-specific mean BMI statistics underestimated equivalent HSE statistics by 0.75-1.1 kg/m(2). Restriction to those with a recent (≤3 years) BMI resulted in mean BMI estimates closer to HSE (≤0.28 kg/m(2) underestimation), but excluded up to 47% of patients. An alternative strategy of imputing up-to-date BMI based on modelled changes in BMI over time since the last available record also led to mean BMI estimates that were close to HSE (≤0.37 kg/m(2) underestimation).

CONCLUSIONS

Completeness of BMI in CPRD increased over time and varied by age and sex. At a given point in time, a large proportion of the most recent BMIs are unlikely to reflect current BMI; consequent BMI misclassification might be reduced by employing model-based imputation of current BMI.

Identification of acute myocardial infarction from electronic healthcare records using different disease coding systems: a validation study in three European countries

OBJECTIVE

To evaluate positive predictive value (PPV) of different disease codes and free text in identifying acute myocardial infarction (AMI) from electronic healthcare records (EHRs).

DESIGN

Validation study of cases of AMI identified from general practitioner records and hospital discharge diagnoses using free text and codes from the International Classification of Primary Care (ICPC), International Classification of Diseases 9th revision-clinical modification (ICD9-CM) and ICD-10th revision (ICD-10).

SETTING

Population-based databases comprising routinely collected data from primary care in Italy and the Netherlands and from secondary care in Denmark from 1996 to 2009.

PARTICIPANTS

A total of 4 034 232 individuals with 22 428 883 person-years of follow-up contributed to the data, from which 42 774 potential AMI cases were identified. A random sample of 800 cases was subsequently obtained for validation.

MAIN OUTCOME MEASURES

PPVs were calculated overall and for each code/free text. 'Best-case scenario' and 'worst-case scenario' PPVs were calculated, the latter taking into account non-retrievable/non-assessable cases. We further assessed the effects of AMI misclassification on estimates of risk during drug exposure.

RESULTS

Records of 748 cases (93.5% of sample) were retrieved. ICD-10 codes had a 'best-case scenario' PPV of 100% while ICD9-CM codes had a PPV of 96.6% (95% CI 93.2% to 99.9%). ICPC codes had a 'best-case scenario' PPV of 75% (95% CI 67.4% to 82.6%) and free text had PPV ranging from 20% to 60%. Corresponding PPVs in the 'worst-case scenario' all decreased. Use of codes with lower PPV generally resulted in small changes in AMI risk during drug exposure, but codes with higher PPV resulted in attenuation of risk for positive associations.

CONCLUSIONS

ICD9-CM and ICD-10 codes have good PPV in identifying AMI from EHRs; strategies are necessary to further optimise utility of ICPC codes and free-text search. Use of specific AMI disease codes in estimation of risk during drug exposure may lead to small but significant changes and at the expense of decreased precision.

Colorectal cancer survival in the USA and Europe: a CONCORD high-resolution study

OBJECTIVES

To assess the extent to which stage at diagnosis and adherence to treatment guidelines may explain the persistent differences in colorectal cancer survival between the USA and Europe.

DESIGN

A high-resolution study using detailed clinical data on Dukes' stage, diagnostic procedures, treatment and follow-up, collected directly from medical records by trained abstractors under a single protocol, with standardised quality control and central statistical analysis.

SETTING AND PARTICIPANTS

21 population-based registries in seven US states and nine European countries provided data for random samples comprising 12 523 adults (15-99 years) diagnosed with colorectal cancer during 1996-1998.

OUTCOME MEASURES

Logistic regression models were used to compare adherence to 'standard care' in the USA and Europe. Net survival and excess risk of death were estimated with flexible parametric models.

RESULTS

The proportion of Dukes' A and B tumours was similar in the USA and Europe, while that of Dukes' C was more frequent in the USA (38% vs 21%) and of Dukes' D more frequent in Europe (22% vs 10%). Resection with curative intent was more frequent in the USA (85% vs 75%). Elderly patients (75-99 years) were 70-90% less likely to receive radiotherapy and chemotherapy. Age-standardised 5-year net survival was similar in the USA (58%) and Northern and Western Europe (54-56%) and lowest in Eastern Europe (42%). The mean excess hazard up to 5 years after diagnosis was highest in Eastern Europe, especially among elderly patients and those with Dukes' D tumours.

CONCLUSIONS

The wide differences in colorectal cancer survival between Europe and the USA in the late 1990s are probably attributable to earlier stage and more extensive use of surgery and adjuvant treatment in the USA. Elderly patients with colorectal cancer received surgery, chemotherapy or radiotherapy less often than younger patients, despite evidence that they could also have benefited.

Extending the use of PROMs in the NHS--using the Oxford Knee Score in patients undergoing non-operative management for knee osteoarthritis: a validation study

OBJECTIVES

To assess the validity of the Oxford Knee Score (OKS) for use in patients undergoing non-operative management for their knee osteoarthritis (OA) within the National Health Service (NHS).

DESIGN

Observational cohort study.

SETTING

Single orthopaedic centre in England.

PARTICIPANTS

134 patients undergoing non-operative management for knee OA.

MAIN OUTCOME MEASURES

OKS, the Intermittent and Constant Osteoarthritis Pain (ICOAP), the Knee Injury and Osteoarthritis Score-Physical Function Short Form (KOOS-PS), at baseline and 3-month follow-up, transition item of change at 3 months.

RESULTS

The OKS summary scale and its pain and functional component subscales demonstrated good test-retest reliability (intraclass correlation coefficient 0.93, 0.91 and 0.92, respectively) and measurement precision which, allows its use with groups of patients with knee OA (research/audit) and with individuals (clinical practice). The results in this study were consistent with a priori set hypotheses about the relationship of OKS with other validated measures (KOOS-PS, ICOAP and short form 12 (SF-12)), which provided evidence of its construct validity and responsiveness. Confirmatory factor analysis confirmed the structural validity of OKS. However, there was a lack of satisfactory evidence of structural validity for ICOAP and KOOS. The minimum detectable change (MDC90) was ±6 for OKS (±16 for the Pain Component Score (OKS-PCS) and ±15 for the Functional Component Score (OKS-FCS)). Minimal important changes were ≈7 for OKS (≈17 for OKS-PCS and ≈11 for OKS-FCS) and minimal important differences were ≈6 for OKS (≈14 for OKS-PCS and ≈10 for OKS-FCS). These values were also calculated for ICOAP and KOOS-PS.

CONCLUSIONS

The OKS summary scale, together with its pain and functional component subscales, has excellent measurement properties when used with patients with knee OA undergoing non-operative treatment and is superior to ICOAP and KOOS-PS for this purpose. This evidence provides support for the validity of the use of OKS when used across the spectrum of knee OA disease severity, both in research and clinical practice.

Positive and negative reasons for sickness presenteeism in Norway and Sweden: a cross-sectional survey

OBJECTIVES

This article investigates various reasons for sickness presenteeism (SP), that is, going to work despite illness. The research questions asked is: What are the main reported reasons for SP in Norway and Sweden?

DESIGN

Cross-sectional survey in Norway and Sweden. Use of binomial logistic regression analysis.

PARTICIPANTS

A random sample of people aged between 20 and 60 years was obtained from complete and updated databases of the Norwegian and Swedish populations. A postal questionnaire was sent to the selected individuals, with response rate 33% (n=2843). 2533 workers responded to questions about SP during the last 12 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

The article informs about the distribution of reasons for SP in Norway and Sweden, selected by the respondents from a closed list. The article also examines which factors influence the most often reported reasons for SP.

RESULTS

56% of the Norwegian and Swedish respondents experienced SP in the previous year. The most frequently reported reasons for SP include not burden colleagues (43%), enjoy work (37%) and feeling indispensable (35%). A lower proportion of Norwegians state that they cannot afford taking sick leave adjusted OR (aOR 0.16 (95% CI 0.10 to 0.22)), while a higher proportion of Norwegians refer to that they enjoy their work (aOR=1.64 (95% CI 1.28 to 2.09)). Women and young workers more often report that they do not want to burden their colleagues. Managers (aOR=2.19 (95% CI 1.67 to 2.86)), highly educated persons and the self-employed more often report that they are indispensable.

CONCLUSIONS

Positive and negative reasons for SP are reported, and there are significant differences between respondents from the two countries. The response rate is low and results must be interpreted with caution.

STUDY DESIGN

Cross-sectional study.

Assessing communication quality of consultations in primary care: initial reliability of the Global Consultation Rating Scale, based on the Calgary-Cambridge Guide to the Medical Interview

OBJECTIVES

To investigate initial reliability of the Global Consultation Rating Scale (GCRS: an instrument to assess the effectiveness of communication across an entire doctor-patient consultation, based on the Calgary-Cambridge guide to the medical interview), in simulated patient consultations.

DESIGN

Multiple ratings of simulated general practitioner (GP)-patient consultations by trained GP evaluators.

SETTING

UK primary care.

PARTICIPANTS

21 GPs and six trained GP evaluators.

OUTCOME MEASURES

GCRS score.

METHODS

6 GP raters used GCRS to rate randomly assigned video recordings of GP consultations with simulated patients. Each of the 42 consultations was rated separately by four raters. We considered whether a fixed difference between scores had the same meaning at all levels of performance. We then examined the reliability of GCRS using mixed linear regression models. We augmented our regression model to also examine whether there were systematic biases between the scores given by different raters and to look for possible order effects.

RESULTS

Assessing the communication quality of individual consultations, GCRS achieved a reliability of 0.73 (95% CI 0.44 to 0.79) for two raters, 0.80 (0.54 to 0.85) for three and 0.85 (0.61 to 0.88) for four. We found an average difference of 1.65 (on a 0-10 scale) in the scores given by the least and most generous raters: adjusting for this evaluator bias increased reliability to 0.78 (0.53 to 0.83) for two raters; 0.85 (0.63 to 0.88) for three and 0.88 (0.69 to 0.91) for four. There were considerable order effects, with later consultations (after 15-20 ratings) receiving, on average, scores more than one point higher on a 0-10 scale.

CONCLUSIONS

GCRS shows good reliability with three raters assessing each consultation. We are currently developing the scale further by assessing a large sample of real-world consultations.

Intention-to-treat analyses and missing data approaches in pharmacotherapy trials for alcohol use disorders

OBJECTIVES

Intention to treat (ITT) is an analytic strategy for reducing potential bias in treatment effects arising from missing data in randomised controlled trials (RCTs). Currently, no universally accepted definition of ITT exists, although many researchers consider it to require either no attrition or a strategy to handle missing data. Using the reports of a large pool of RCTs, we examined discrepancies between the types of analyses that alcohol pharmacotherapy researchers stated they used versus those they actually used. We also examined the linkage between analytic strategy (ie, ITT or not) and how missing data on outcomes were handled (if at all), and whether data analytic and missing data strategies have changed over time.

DESIGN

Descriptive statistics were generated for reported and actual data analytic strategy and for missing data strategy. In addition, generalised linear models determined changes over time in the use of ITT analyses and missing data strategies.

PARTICIPANTS

165 RCTs of pharmacotherapy for alcohol use disorders.

RESULTS

Of the 165 studies, 74 reported using an ITT strategy. However, less than 40% of the studies actually conducted ITT according to the rigorous definition above. Whereas no change in the use of ITT analyses over time was found, censored (last follow-up completed) and imputed missing data strategies have increased over time, while analyses of data only for the sample actually followed have decreased.

CONCLUSIONS

Discrepancies in reporting versus actually conducting ITT analyses were found in this body of RCTs. Lack of clarity regarding the missing data strategy used was common. Consensus on a definition of ITT is important for an adequate understanding of research findings. Clearer reporting standards for analyses and the handling of missing data in pharmacotherapy trials and other intervention studies are needed.

Differences in research funding for women scientists: a systematic comparison of UK investments in global infectious disease research during 1997-2010

OBJECTIVES

There has not previously been a systematic comparison of awards for research funding in infectious diseases by sex. We investigated funding awards to UK institutions for all infectious disease research from 1997 to 2010, across disease categories and along the research and development continuum.

DESIGN

Systematic comparison.

METHODS

Data were obtained from several sources for awards from the period 1997 to 2010 and each study assigned to-disease categories; type of science (preclinical, phases I-III trials, product development, implementation research); categories of funding organisation. Fold differences and statistical analysis were used to compare total investment, study numbers, mean grant and median grant between men and women.

RESULTS

6052 studies were included in the final analysis, comprising 4357 grants (72%) awarded to men and 1695 grants (28%) awarded to women, totalling £2.274 billion. Of this, men received £1.786 billion (78.5%) and women £488 million (21.5%). The median value of award was greater for men (£179 389; IQR £59 146-£371 977) than women (£125 556; IQR £30 982-£261 834). Awards were greater for male principal investigators (PIs) across all infectious disease systems, excepting neurological infections and sexually transmitted infections. The proportion of total funding awarded to women ranged from 14.3% in 1998 to 26.8% in 2009 (mean 21.4%), and was lowest for preclinical research at 18.2% (£285.5 million of £1.573 billion) and highest for operational research at 30.9% (£151.4 million of £489.7 million).

CONCLUSIONS

There are consistent differences in funding received by men and women PIs: women have fewer funded studies and receive less funding in absolute and in relative terms; the median funding awarded to women is lower across most infectious disease areas, by funder, and type of science. These differences remain broadly unchanged over the 14-year study period.

Incorporation of assessments of risk of bias of primary studies in systematic reviews of randomised trials: a cross-sectional study

OBJECTIVE

We examined how assessments of risk of bias of primary studies are carried out and incorporated into the statistical analysis and overall findings of a systematic review.

DESIGN

A cross-sectional review.

SAMPLE

We assessed 200 systematic reviews of randomised trials published between January and March 2012; Cochrane (n=100), non-Cochrane (Database of Reviews of Effects) (n=100).

MAIN OUTCOMES

Our primary outcome was a descriptive analysis of how assessments of risk of bias are carried out, the methods used, and the extent to which such assessments were incorporated into the statistical analysis and overall review findings.

RESULTS

While Cochrane reviews routinely reported the method of risk of bias assessment and presented their results either in text or table format, 20% of non-Cochrane reviews failed to report the method used and 39% did not present the assessment results. Where it was possible to evaluate the individual results of the risk of bias assessment (n=154), 75% (n=116/154) of reviews had ≥1 trial at high risk of bias; the median proportion of trials per review at high risk of bias was 50% (IQR 31% to 89%). Despite this, only 56% (n=65/116) incorporated the risk of bias assessment into the interpretation of the results in the abstract and 41% (n=47/116) (49%; n=40/81 Cochrane and 20%; n=7/35 non-Cochrane) incorporated the risk of bias assessment into the interpretation of the conclusions. Of the 83% (n=166/200) systematic reviews which included a meta-analysis, only 11% (n=19/166) incorporated the risk of bias assessment into the statistical analysis.

CONCLUSIONS

Cochrane reviews were more likely than non-Cochrane reviews to report how risk of bias assessments of primary studies were carried out; however, both frequently failed to take such assessments into account in the statistical analysis and conclusions of the systematic review.

Implementing GRADE: calculating the risk difference from the baseline risk and the relative risk

A key step in implementing the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system is the estimation of a risk difference based on estimates of the baseline risk and the relative risk estimated from different sources. In this paper we describe a simple and effective method to calculate confidence intervals (CIs) for the risk difference for this situation. Whenever an independent source is available to estimate the baseline risk for the population to which the effect estimates should be applied, this source should be used and CIs for the absolute risk difference should be calculated taking all sources of uncertainty into account.

Psychometric properties of the WHO Violence Against Women instrument in a female population-based sample in Sweden: a cross-sectional survey

OBJECTIVE

To explore psychometric properties of the Violence Against Women instrument in a randomly selected national sample of women (N=573) aged 18-65 years and residing in Sweden.

DESIGN

Cross-sectional survey study.

SETTING

Sweden.

PARTICIPANTS

A postal survey was sent to 1006 women between January and March 2009, during which 624 women (62%) returned the questionnaire. 51 women who did not answer any of the violence items were excluded from the analyses, resulting in a final sample of 573 women.

PRIMARY AND SECONDARY OUTCOME MEASURES

Self-reported exposure to psychological, physical and sexual intimate partner violence.

RESULTS

Cronbach's α coefficients were 0.79 (psychological scale), 0.80 (physical scale), 0.72 (sexual scale) and 0.88 (total scale). A predetermined three-component solution largely replicated the explored three component conceptual model of the Violence Against Women instrument. The instrument was able to discriminate between groups known from previous studies to differ in exposure to physical and/or sexual violence, that is, respondents with poor versus good self-rated health and witnessed versus not witnessed physical violence at home when growing up. Past-year prevalence of physical (8.1%; 95% CI 5.9 to 10.3) and sexual (3%; 1.6 to 4.4) violence was similar to that reported in other Nordic studies; however, earlier-in-life prevalence was lower in the current study (14.3%; 95% CI 11.4 to 17.2 and 9.2%; 95% CI 6.8 to 11.6, respectively). Reported exposure rates were higher than those obtained from a concurrently administered instrument (NorVold Abuse Questionnaire).

CONCLUSIONS

The Violence Against Women instrument demonstrated good construct validity and internal reliability in an adult female population in Sweden. However, further studies examining these and other psychometric properties need to be conducted in other countries.

Selective reporting of outcomes in randomised controlled trials in systematic reviews of cystic fibrosis

BACKGROUND

Outcome reporting bias (ORB) in randomised trials has been identified as a threat to the validity of systematic reviews. Previous work highlighting this problem is limited to considering a single primary review outcome. The aim of this study was to assess ORB across all efficacy outcomes in the Cochrane systematic reviews of cystic fibrosis.

METHODS

Systematic reviews of interventions for cystic fibrosis published on the Cochrane Library by the Cochrane Cystic Fibrosis and Genetic Disorders Group before 2010 were assessed for discrepancies in outcomes between review protocol and full review. ORB in eligible trials was also assessed for all efficacy review outcomes. Two authors independently classified each outcome using a nine-point classification system developed by the Outcome Reporting Bias In Trials study. These classifications were used to inform the assessment of the risk of bias for selective outcome reporting for each trial.

RESULTS

-46 Cochrane cystic fibrosis systematic reviews were included. The median number of primary outcomes, number of trials and participants per trial in the reviews were 3 (IQR 2, 3), 4 (IQR 2, 8) and 21 (IQR 14, 41), respectively. 18 reviews (39%, 18/46) had a discrepancy in outcomes between protocol and full review. 37 reviews were eligible to be included in the ORB assessment. When considering review primary outcomes and all review outcomes, ORB was suspected in at least one trial in 86% and 100%, respectively.

CONCLUSIONS

Assessment of ORB within a systematic review of a single primary outcome underestimates the risk of ORB in comparison to the assessment of multiple primary and secondary outcomes. ORB in trials is highly prevalent within systematic reviews of cystic fibrosis when assessed across all outcomes. This could be reduced by the development of a core outcome set for trials and systematic reviews in cystic fibrosis.

Trends in the incidence and mortality of multiple births by socioeconomic deprivation and maternal age in England: population-based cohort study

OBJECTIVE

To investigate temporal trends in multiple birth rates and associated stillbirth and neonatal mortality by socioeconomic deprivation and maternal age in England.

DESIGN

Population cohort study.

SETTING

England.

PARTICIPANTS

All live births and stillbirths (1 January 1997 to 31 December 2008).

MAIN OUTCOME MEASURES

Multiple maternity rate, stillbirth and neonatal death rate by year of birth, decile of socioeconomic deprivation and maternal age.

RESULTS

The overall rate of multiple maternities increased over time (+0.64% per annum 95% CI (0.47% to 0.81%)) with an increase in twin maternities (+0.85% per annum 95% CI (0.67% to 1.0%)) but a large decrease in triplet and higher order maternities (-8.32% per annum 95% CI (-9.39% to -7.25%)). Multiple maternities were significantly lower in the most deprived areas, and this was most evident in the older age groups. Women over 40 years of age from the most deprived areas had a 34% lower rate of multiple births compared with similar aged women from the most deprived areas (rate ratio (RR) 0.66 95% CI (0.61 to 0.73)). Multiple births remain at substantially higher risk of neonatal mortality (RR 6.30 95% CI (6.07 to 6.53)). However, for stillbirths, while twins remain at higher risk, this has decreased over time (1997-2000: RR 2.89 (2.69 to 3.10); 2005-2008: RR 2.22 95% CI (2.06 to 2.40)). Socioeconomic inequalities existed in mortality for singletons and multiple births.

CONCLUSIONS

This period has seen increasing rates of twin pregnancies and decreasing rates of higher order births which have coincided with changes in recommendations regarding assisted reproductive techniques. Socioeconomic differences in multiple births may reflect differential access to these treatments. Improved monitoring of multiple pregnancies is likely to have led to the reductions in stillbirths over this time.

Mobile phone text messages for improving adherence to antiretroviral therapy (ART): a protocol for an individual patient data meta-analysis of randomised trials

INTRODUCTION

Mobile phone text messaging is emerging as an important tool in the care of people living with HIV; however, reports diverge on its efficacy in improving adherence to antiretroviral therapy (ART), and little is known about which patient groups may benefit most from phone-based adherence interventions. We will conduct an individual patient data meta-analysis to investigate the overall and subgroup effects of text messaging in three recently published text-messaging randomised controlled trials.

METHODS AND ANALYSIS

Data from two Kenyan and one Cameroonian trial will be verified, reformatted and merged. We will determine pooled effect sizes for text messaging versus standard care for improving adherence to ART using individual patient random-effects meta-analysis. We will test for the interaction effects of age, gender, level of education and duration on ART. Sensitivity analyses will be conducted with regard to thresholds for adherence, methods of handling missing data and fixed-effects meta-analysis. Only anonymised data will be collected from the individual studies.

ETHICS AND DISSEMINATION

Ethical approval was obtained for the individual studies. The results of this paper will be disseminated as peer-reviewed publications, at conferences and as part of a doctoral thesis. This individual patient data meta-analysis may provide important insights into the effects of text messaging on ART adherence in different subpopulations, with important implications for programme implementation involving such interventions and future research.

Are there sleep-specific phenotypes in patients with chronic fatigue syndrome? A cross-sectional polysomnography analysis

OBJECTIVES

Despite sleep disturbances being a central complaint in patients with chronic fatigue syndrome (CFS), evidence of objective sleep abnormalities from over 30 studies is inconsistent. The present study aimed to identify whether sleep-specific phenotypes exist in CFS and explore objective characteristics that could differentiate phenotypes, while also being relevant to routine clinical practice.

DESIGN

A cross-sectional, single-site study.

SETTING

A fatigue clinic in the Netherlands.

PARTICIPANTS

A consecutive series of 343 patients meeting the criteria for CFS, according to the Fukuda definition.

MEASURES

Patients underwent a single night of polysomnography (all-night recording of EEG, electromyography, electrooculography, ECG and respiration) that was hand-scored by a researcher blind to diagnosis and patient history.

RESULTS

Of the 343 patients, 104 (30.3%) were identified with a Primary Sleep Disorder explaining their diagnosis. A hierarchical cluster analysis on the remaining 239 patients resulted in four sleep phenotypes being identified at saturation. Of the 239 patients, 89.1% met quantitative criteria for at least one objective sleep problem. A one-way analysis of variance confirmed distinct sleep profiles for each sleep phenotype. Relatively longer sleep onset latencies, longer Rapid Eye Movement (REM) latencies and smaller percentages of both stage 2 and REM characterised the first phenotype. The second phenotype was characterised by more frequent arousals per hour. The third phenotype was characterised by a longer Total Sleep Time, shorter REM Latencies, and a higher percentage of REM and lower percentage of wake time. The final phenotype had the shortest Total Sleep Time and the highest percentage of wake time and wake after sleep onset.

CONCLUSIONS

The results highlight the need to routinely screen for Primary Sleep Disorders in clinical practice and tailor sleep interventions, based on phenotype, to patients presenting with CFS. The results are discussed in terms of matching patients' self-reported sleep to these phenotypes in clinical practice.

Methods used to conduct and report Bayesian mixed treatment comparisons published in the medical literature: a systematic review

OBJECTIVES

To identify published closed-loop Bayesian mixed treatment comparisons (MTCs) and to summarise characteristics regarding their conduct and reporting.

DESIGN

Systematic review.

METHODS

We searched multiple bibliographic databases (January 2006-31 July 2011) for full-text, English language publications of Bayesian MTCs comparing the effectiveness or safety of ≥3 interventions based on randomised controlled trials and having at least one closed loop. Methodological and reporting characteristics of MTCs were extracted in duplicate and summarised descriptively.

RESULTS

We identified 34 Bayesian MTCs spanning 13 clinical areas. Publication of MTCs increased over the 5-year period; with 76.5% published during or after 2009. MTCs included a mean (±SD) of 35.9±30.1 trials (n=33 459±71 233 participants) and 8.5±4.3 interventions (85.7% pharmacological). Non-informative and informative prior distributions were reported to be used in 44.1% and 8.8% of MTCs, respectively, with the remainder failing to specify the prior used. A random-effects model was used to analyse the networks of trials in 58.5% of MTCs, all using WinBUGS; however, code was infrequently provided (20.6%). More than two-thirds of MTCs (76.5%) also conducted traditional meta-analysis. Methods used to evaluate convergence, heterogeneity and inconsistency were infrequently reported, but from those providing detail, methods appeared varied. MTCs most often used a binary effect measure (85.3%) and ranking of interventions based on probability was common (61.8%), although rarely displayed in a figure (8.8% of MTCs). MTCs were published in 24 different journals with a mean impact factor of 9.20±8.71. While 70.8% of journals imposed limits on word counts and 45.8% limits on the number of tables/figures, online supplements/appendices were allowed in 79.2% of journals. Publication of closed-loop Bayesian MTCs is increasing in frequency, but details regarding their methodology are often poorly described. Efforts in clarifying the appropriate methods and reporting of Bayesian MTCs should be of priority.

Can analyses of electronic patient records be independently and externally validated? The effect of statins on the mortality of patients with ischaemic heart disease: a cohort study with nested case-control analysis

OBJECTIVE

To conduct a fully independent and external validation of a research study based on one electronic health record database, using a different electronic database sampling the same population.

DESIGN

Using the Clinical Practice Research Datalink (CPRD), we replicated a published investigation into the effects of statins in patients with ischaemic heart disease (IHD) by a different research team using QResearch. We replicated the original methods and analysed all-cause mortality using: (1) a cohort analysis and (2) a case-control analysis nested within the full cohort.

SETTING

Electronic health record databases containing longitudinal patient consultation data from large numbers of general practices distributed throughout the UK.

PARTICIPANTS

CPRD data for 34 925 patients with IHD from 224 general practices, compared to previously published results from QResearch for 13 029 patients from 89 general practices. The study period was from January 1996 to December 2003.

RESULTS

We successfully replicated the methods of the original study very closely. In a cohort analysis, risk of death was lower by 55% for patients on statins, compared with 53% for QResearch (adjusted HR 0.45, 95% CI 0.40 to 0.50; vs 0.47, 95% CI 0.41 to 0.53). In case-control analyses, patients on statins had a 31% lower odds of death, compared with 39% for QResearch (adjusted OR 0.69, 95% CI 0.63 to 0.75; vs OR 0.61, 95% CI 0.52 to 0.72). Results were also close for individual statins.

CONCLUSIONS

Database differences in population characteristics and in data definitions, recording, quality and completeness had a minimal impact on key statistical outputs. The results uphold the validity of research using CPRD and QResearch by providing independent evidence that both datasets produce very similar estimates of treatment effect, leading to the same clinical and policy decisions. Together with other non-independent replication studies, there is a nascent body of evidence for wider validity.

Virtual colleagues, virtually colleagues--physicians' use of Twitter: a population-based observational study

OBJECTIVE

To investigate potential violations of patient confidentiality or other breaches of medical ethics committed by physicians and medical students active on the social networking site Twitter.

DESIGN

Population-based cross-sectional observational study.

SETTING

The social networking site Twitter (Swedish-speaking users, n=298819).

POPULATION

Physicians and medical students (Swedish-speaking users, n=237) active on the social networking site Twitter between July 2007 and March 2012.

MAIN OUTCOME MEASURE

Postings that reflect unprofessional behaviour and ethical breaches among physicians and medical students.

RESULTS

In all, 237 Twitter accounts were established as held by physicians and medical students and a total of 13 780 tweets were analysed by content. In all, 276 (1.9%) tweets were labelled as 'unprofessional'. Among these, 26 (0.2%) tweets written by 15 (6.3%) physicians and medical students included information that could violate patient privacy. No information on the personal ID number or names was disclosed, but parts of the patient documentation or otherwise specific indicatory information on patients were found. Unprofessional tweets were more common among users writing under a pseudonym and among medical students.

CONCLUSIONS

In this study of physicians and medical students on Twitter, we observed potential violations of patient privacy and other breaches of medical ethics. Our findings underline that every physician and medical student has to consider his or her presence on social networking sites. It remains to be investigated if the introduction of social networking site guidelines for medical professionals will improve awareness.

Development of a Croatian version of the US Hospital Survey on Patient Safety Culture questionnaire: dimensionality and psychometric properties

BACKGROUND

The Hospital Survey on Patient Safety Culture (HSOPSC), originally developed in the USA, is used worldwide to assess patient safety culture in hospitals. A limited number of studies have provided data on psychometric properties outside of the US healthcare system. Our aim was to determine if all 12 dimensions of the US HSOPSC were applicable, valid and reliable to Croatian healthcare workers.

METHODS

The study was conducted from September 2010 to April 2011. Questions were translated into Croatian and then translated back into English. The questionnaires (ie, the Croatian translation of the US HSOPSC) were distributed in unmarked envelopes along with a consent form to all the doctors and nurses in four Croatian hospitals. The responses were analysed using explorative factor analyses, reliability testing, and confirmatory factor analyses.

RESULTS

The study included 561 healthcare workers in four Croatian hospitals--a response rate of 32.69%. Our results are similar to the original US sample, but with some differences: 11 dimensions with acceptable reliability scores were identified by exploratory factor analysis compared with the original 12 in the US sample; five of 12 dimensions had a Cronbach's α higher than 0.7, suggesting a reasonable fit to the original US HSOPSC; the dimensions 'Staffing' and 'Organisational learning--continuous improvement' were found to have a Cronbach's α <0.6. The use of confirmatory factor analysis confirmed a good fit to the original US model.

CONCLUSIONS

Results show that the Croatian translation of the US HSOPSC is compatible in 11 of the original 12 dimensions. Results suggest that for the purposes of research in Croatia, the dimensions 'Staffing', 'Communication openness', and 'Organisational learning-continuous improvement' should be revised. For example, the use of question A7 ('We use more agency/temporary staff than is best for patient care') in the context of European healthcare systems should be adapted or removed for the Croatian version of the US HSOPSC questionnaire.

Adapting data collection methods in the Australian Life Histories and Health Survey: a retrospective life course study

OBJECTIVE

Ideally, life course data are collected prospectively through an ongoing longitudinal study. We report adaptive multimethod fieldwork procedures that gathered life history data by mail survey and telephone interview, comparable with the face-to-face methods employed in the English Longitudinal Study on Ageing (ELSA).

DESIGN

The Australian Life Histories and Health (LHH) Survey was a substudy of the Australian 45 and Up Study, with data collection methods modified from the ELSA Study. A self-complete questionnaire and life history calendar were completed by the participants, followed by a computer-assisted telephone interview recording key life events.

RESULTS

The LHH survey developed and tested procedures and instruments that gathered rich life history data within an ongoing Australian longitudinal survey on ageing. Data collection proved to be economical. The use of a self-complete questionnaire in conjunction with a life history calendar and coordinated computer-assisted telephone interview was successful in collecting retrospective life course information, in terms of being thorough, practical and efficient. This study has a diverse collection of data covering the life course, starting with early life experiences and continuing with socioeconomic and health exposures and outcomes during adult life.

CONCLUSIONS

Mail and telephone methodology can accurately and economically add a life history dimension to an ongoing longitudinal survey. The method is particularly valuable for surveying widely dispersed populations. The results will facilitate understanding of the social determinants of health by gathering data on earlier life exposures as well as comparative data across geographical and societal contexts.

Protocol for a randomised controlled trial of VAsopressin versus Noradrenaline as Initial therapy in Septic sHock (VANISH)

INTRODUCTION

Vasopressin is an alternative vasopressor in the management of septic shock. It spares catecholamine use but whether it improves outcome remains uncertain. Current evidence suggests that it may be most effective if used early and possibly in conjunction with corticosteroids. This trial will compare vasopressin to noradrenaline as initial vasopressor in the management of adult septic shock and investigate whether there is an interaction of vasopressin with corticosteroids.

METHODS AND ANALYSIS

This is a multicentre, factorial (2×2), randomised, double-blind, placebo-controlled trial. 412 patients will be recruited from multiple UK intensive care units and randomised to receive vasopressin (0-0.06 U/min) or noradrenaline (0-12 µg/min) as a continuous intravenous infusion as initial vasopressor therapy. If maximum infusion rates of this first study drug are reached, the patient will be treated with either hydrocortisone (initially 50 mg intravenous bolus six-hourly) or placebo, before additional open-label catecholamine vasopressors are prescribed. The primary outcome of the trial will be the difference in renal failure-free days between treatment groups. Secondary outcomes include need for renal replacement therapy, survival rates, other organ failures and resource utilisation.

ETHICS AND DISSEMINATION

The trial protocol and information sheets have received a favourable opinion from the Oxford A Research Ethics Committee (12/SC/0014). There is an independent Data Monitoring and Ethics Committee and independent membership of the Trial Steering Committee including patient and public involvement. The trial results will be published in peer-reviewed journals and presented at national and international scientific meetings.

TRIAL REGISTRATION NUMBER

ISRCTN 20769191 and EudraCT 2011-005363-24.

A GIS-based spatiotemporal analysis of violent trauma hotspots in Vancouver, Canada: identification, contextualisation and intervention

BACKGROUND

In 2002, the WHO declared interpersonal violence to be a leading public health problem. Previous research demonstrates that urban spaces with a high incidence of violent trauma (hotspots) correlate with features of built environment and social determinants. However, there are few studies that analyse injury data across the axes of both space and time to characterise injury-environment relationships. This paper describes a spatiotemporal analysis of violent injuries in Vancouver, Canada, from 2001 to 2008.

METHODS

Using geographic information systems, 575 violent trauma incidents were mapped and analysed using kernel density estimation to identify hotspot locations. Patterns between space, time, victim age and sex and mechanism of injury were investigated with an exploratory approach.

RESULTS

Several patterns in space and time were identified and described, corresponding to distinct neighbourhood characteristics. Violent trauma hotspots were most prevalent in Vancouver's nightclub district on Friday and Saturday nights, with higher rates in the most socioeconomically deprived neighbourhoods. Victim sex, age and mechanism of injury also formed strong patterns. Three neighbourhood profiles are presented using the dual axis of space/time to describe the hotspot environments.

CONCLUSIONS

This work posits the value of exploratory spatial data analysis using geographic information systems in trauma epidemiology studies and further suggests that using both space and time concurrently to understand urban environmental correlates of injury provides a more granular or higher resolution picture of risk. We discuss implications for injury prevention and control, focusing on education, regulation, the built environment and injury surveillance.

Validity of the International Classification of Diseases, 10th revision discharge diagnosis codes for hyponatraemia in the Danish National Registry of Patients

OBJECTIVE

To examine the validity of the International Classification of Diseases, 10th revision (ICD-10) codes for hyponatraemia in the nationwide population-based Danish National Registry of Patients (DNRP) among inpatients of all ages.

DESIGN

Population-based validation study.

SETTING

All somatic hospitals in the North and Central Denmark Regions from 2006 through 2011.

PARTICIPANTS

Patients of all ages admitted to hospital (n=819 701 individual patients) during the study period. The patient could be included in the study more than once, and our study did not restrict to patients with serum sodium measurements (total of n=2 186 642 hospitalisations).

MAIN OUTCOME MEASURE

We validated ICD-10 discharge diagnoses of hyponatraemia recorded in the DNRP, using serum sodium measurements obtained from the laboratory information systems (LABKA) research database as the gold standard. One sodium value <135 mmol/L measured at any time during hospitalisation confirmed the diagnosis. We estimated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for ICD-10 codes for hyponatraemia overall and for cut-off points for increasing hyponatraemia severity.

RESULT

An ICD-10 code for hyponatraemia was recorded in the DNRP in 5850 of the 2 186 642 hospitalisations identified. According to laboratory measurements, however, hyponatraemia was present in 306 418 (14%) hospitalisations. Sensitivity of hyponatraemia diagnoses was 1.8% (95% CI 1.7% to 1.8%). For sodium values <115 mmol/L, sensitivity was 34.3% (95% CI 32.6% to 35.9%). The overall PPV was 92.5% (95% CI 91.8% to 93.1%) and decreased with increasing hyponatraemia severity. Specificity and NPV were high for all cut-off points (≥99.8% and ≥86.2%, respectively). Patients with hyponatraemia without a corresponding ICD-10 discharge diagnosis were younger and had higher Charlson Comorbidity Index scores than patients with hyponatraemia with a hyponatraemia code in the DNRP.

CONCLUSIONS

ICD-10 codes for hyponatraemia in the DNRP have high specificity but very low sensitivity. Laboratory test results, not discharge diagnoses, should be used to ascertain hyponatraemia.