Informative observation in health data: Association of past level and trend with time to next measurement

In routine health data, risk factors and biomarkers are typically measured irregularly in time, with the frequency of their measurement depending on a range of factors – for example, sicker patients are measured more often. This is termed informative observation. Failure to account for this in subsequent modelling can lead to bias. Here, we illustrate this issue using body mass index measurements taken on patients with type 2 diabetes in Salford, UK. We modelled the observation process (time to next measurement) as a recurrent event Cox model, and studied whether previous measurements in BMI, and trends in the BMI, were associated with changes in the frequency of measurement. Interestingly, we found that increasing BMI led to a lower propensity for future measurements. More broadly, this illustrates the need and opportunity to develop and apply models that account for, and exploit, informative observation

Experiences and outcomes of maternal Ramadan fasting during pregnancy: results from a sub-cohort of the Born in Bradford birth cohort study

Background: Observing the fast during the holy month of Ramadan is one of the five pillars of Islam. Although pregnant women and those with pre-existing illness are exempted from fasting many still choose to fast during this time. The fasting behaviours of pregnant Muslim women resident in Western countries remain largely unexplored and relationships between fasting behaviour and offspring health outcomes remain contentious. This study was undertaken to assess the prevalence, characteristics of fasting behaviours and offspring health outcomes in Asian and Asian British Muslim women within a UK birth cohort. Methods: Prospective cohort study conducted at the Bradford Royal Infirmary UK from October to December 2010 comprising 310 pregnant Muslim women of Asian or Asian British ethnicity that had a live singleton birth at the Bradford Royal Infirmary. The main outcome of the study was the decision to fast or not during Ramadan. Secondary outcomes were preterm births and mean birthweight. Logistic regression analyses were used to investigate the relationship between covariables of interest and women's decision to fast or not fast. Logistic regression was also used to investigate the relationship between covariables and preterm birth as well as low birth weight. Results: Mutually adjusted analysis showed that the odds of any fasting were higher for women with an obese BMI at booking compared to women with a normal BMI, (OR 2.78 (95% C.I. 1.29-5.97)), for multiparous compared to nulliparous women(OR 3.69 (95% C.I. 1.38-9.86)), and for Bangladeshi origin women compared to Pakistani origin women (OR 3.77 (95% C.I. 1.04-13.65)). Odds of fasting were lower in women with higher levels of education (OR 0.40 (95% C.I. 0.18-0.91)) and with increasing maternal age (OR 0.87 (95% C.I. 0.80-0.94). No associations were observed between fasting and health outcomes in the offspring. Conclusions: Pregnant Muslim women residing in the UK who fasted during Ramadan differed by social, demographic and lifestyle characteristics compared to their non-fasting peers. Fasting was not found to be associated with adverse birth outcomes in this sample although these results require confirmation using reported fasting data in a larger sample before the safety of fasting during pregnancy can be established

Overprescribing antibiotics for asymptomatic bacteriuria in older adults: a case series review of admissions in two UK hospitals

Background: Overdiagnosis and overtreatment of urinary tract infection (UTI) with antibiotics is a concern. In older adults, diagnosis of UTI using near-patient urine tests (reagent strip tests, dipsticks) is advised against because the age-related increase in asymptomatic bacteriuria can cause false-positive results. Instead, UTI diagnosis should be based on a full clinical assessment. Previous research lacks systematic information on urine dipstick use in hospitals. The aim of this study was to examine the use of urine dipstick tests and microbiology among older adult hospital admissions in relation to recommended UTI diagnostic criteria. A further aim was to assess factors associated with the use of dipsticks. Methods: A case series review of patients aged ≥70 years admitted to two NHS Trust hospitals in England. Records from 312 patients admitted in 2015 meeting inclusion criteria were selected at random. Results: Of 298 complete patient records, 54% had at least one urine dipstick test recorded. 13% (21/161) of patients who received a urine dipstick test were diagnosed as having a UTI, only 2 out of these 21 cases had two or more clinical signs and symptoms. 60 patients received a second dipstick test, leading to 13 additional cases of UTI diagnosis. Dipstick tests were more likely to be performed on patients with a history of falls (OR 1.93, 95% CI:1.21, 3.07, p < 0.01), and less likely on those with dementia (OR 0.44, 95% CI: 0.22, 0.87, p < 0.05). The most common reason for testing was routine admissions policy (49.1% of cases), but these cases were predominantly in one hospital. Conclusions: Use of urine dipstick tests was high among older adults admitted to hospitals. Most cases were asymptomatic and therefore received inappropriate antibiotic therapy. This paper highlights the need to implement new Public Health England diagnostic guidelines to hospital admission and emergency departments

Can different primary care databases produce comparable estimates of burden of disease: results of a study exploring venous leg ulceration

Background. Primary care databases from the UK have been widely used to produce evidence on the epidemiology and health service usage of a wide range of conditions. To date there have been few evaluations of the comparability of estimates between different sources of these data. Aim. To estimate the comparability of two widely used primary care databases, the Health Improvement Network Database (THIN) and the General Practice Research Database (GPRD) using venous leg ulceration as an exemplar condition. Design of study. Cross prospective cohort comparison. Setting. GPRD and the THIN databases using data from 1998 to 2006. Method. A data set was extracted from both databases containing all cases of persons aged 20 years or greater with a database diagnosis of venous leg ulceration recorded in the databases for the period 1998–2006. Annual rates of incidence and prevalence of venous leg ulceration were calculated within each database and standardized to the European standard population and compared using standardized rate ratios. Results. Comparable estimates of venous leg ulcer incidence from the GPRD and THIN databases could be obtained using data from 2000 to 2006 and of prevalence using data from 2001 to 2006. Conclusions. Recent data collected by these two databases are more likely to produce comparable results of the burden venous leg ulceration. These results require confirmation in other disease areas to enable researchers to have confidence in the comparability of findings from these two widely used primary care research resources

Methods for identifying surgical wound infection after discharge from hospital: a systematic review

Background: Wound infections are a common complication of surgery that add significantly to the morbidity of patients and costs of treatment. The global trend towards reducing length of hospital stay post-surgery and the increase in day case surgery means that surgical site infections (SSI) will increasingly occur after hospital discharge. Surveillance of SSIs is important because rates of SSI are viewed as a measure of hospital performance, however accurate detection of SSIs post-hospital discharge is not straightforward. Methods: We conducted a systematic review of methods of post discharge surveillance for surgical wound infection and undertook a national audit of methods of post-discharge surveillance for surgical site infection currently used within United Kingdom NHS Trusts. Results: Seven reports of six comparative studies which examined the validity of post-discharge surveillance methods were located; these involved different comparisons and some had methodological limitations, making it difficult to identify an optimal method. Several studies evaluated automated screening of electronic records and found this to be a useful strategy for the identification of SSIs that occurred post discharge. The audit identified a wide range of relevant post-discharge surveillance programmes in England, Scotland and Wales and Northern Ireland; however, these programmes used varying approaches for which there is little supporting evidence of validity and/or reliability. Conclusion: In order to establish robust methods of surveillance for those surgical site infections that occur post discharge, there is a need to develop a method of case ascertainment that is valid and reliable post discharge. Existing research has not identified a valid and reliable method. A standardised definition of wound infection (e.g. that of the Centres for Disease Control) should be used as a basis for developing a feasible, valid and reliable approach to defining post discharge SSI. At a local level, the method used to ascertain post discharge SSI will depend upon the purpose of the surveillance, the nature of available routine data and the resources available. © 2006 Petherick et al; licensee, BioMed Central Ltd

A feasibility study to explore the governance processes required for linkage between dental epidemiological, and birth cohort, data in the UK

Birth cohort initiatives, such as ‘Born in Bradford’, provide a unique opportunity to study the influence of socio-economic and environmental factors acting in pregnancy, birth and infancy on the development of dental caries in later life. This paper describes a feasibility study which established the processes required, and outcomes of, successful linkage of oral health data collected by the 2013 three-year-old national dental epidemiology survey with the Born in Bradford birth cohort database. The necessary processes included achieving research permissions and ethical approval; creation of a data sharing agreement; ensuring data security and encrypted data transfer. With regard to the outcomes, a robust a priori statistical plan was developed. 152 three-year-old children were examined for the 2013 dental epidemiology survey in Bradford, and of those, 69 parents consented to data linkage believing that their child was part of the Born in Bradford cohort. However, only 36 of these 69 children were participating in the cohort. Of these, six children had obvious dentinal caries experience (dmft >0). There was insufficient power with such small numbers, to examine the association between birthweight and dental caries at the age of three-years-old. Key learning points from this feasibility study have informed the design of a larger study to link the 2014/5 five-year-old dental epidemiology surveys with the Born in Bradford cohort. This paper reveals the important methodological considerations for future data linkages between routine health data and research data

Identifying MAIS3+ injury severity collisions in UK Police collision records

Objective This study represents the first stage of a project to identify serious injury, at the level of MAIS3+ (excluding fatal collisions) from within the police collision data. The resulting data will then be used to identify the vehicle drivers concerned and in later studies these will be culpability-scored and profiled to allow targeting of interventions. Method UK Police collision data known as STATS19 for the county of Cambridgeshire (UK) was linked using Stata with Trauma Audit and Research Network (TARN) hospital trauma patient data for the same geographical area for the period April 2012 to March 2017. Linking was two-stage; firstly, a deterministic process followed by a probabilistic process. Results The linked records represent an individual trauma patient from TARN data linked to an individual trauma casualty from STATS19 data. Full collision data for the incident resulting in the trauma casualty was extracted. The resulting subset of collisions has the MAIS3+ injury criteria applied. From the 10,498 recorded collisions the deterministic linking process was successful in linking 257 MAIS3+ trauma patients to collision injury subjects from 232 separate collisions with the probabilistic process linking a further 22 MAIS3+ subjects from 21 collision events. The combined collision data for the 253 collisions involved 434 motor vehicle drivers. Conclusions We produced viable results from the available data to identify MAIS3+ collisions from the overall collision data

Does administrative data reflect individual experience? Comparing an index of poverty with individually collected data on financial well-being in a multi-ethnic community

The Income Deprivation Affecting Children Index (IDACI) uses administrative data to count children living in households in receipt of both in-work and out-of-work means-tested benefits and provides small area ranking as an indicator of child poverty in neighbourhoods. Benefit take-up rates within an area will affect its reliability. We aimed to examine benefit take-up rates and compare area ranking by the IDACI with ranking using individually reported data across areas of varying ethnic composition. Mothers living in areas with high minority ethnic density were less likely to report claiming a benefit than those in majority White or mixed areas, despite reporting lower incomes. The correlation between self-reported material difficulties and worsening IDACI rank was much lower in areas characterised by minority ethnic populations. Further investigation into the performance of area-based deprivation measures in areas with high minority ethnic density is needed

Maternal health inequalities and GP provision: investigating variation in consultation rates for women in the Born in Bradford cohort

Background The ‘Five Year Forward View’ (NHS England) calls for a radical upgrade in public health provision. Inequalities in maternal health may perpetuate general patterns of health inequalities across generations; therefore equitable access to GP provision during maternity is important. This paper explores variation in GP consultation rates for disadvantaged mothers. Method Data from the Born in Bradford cohort (around 12,000 women), combined with GP records and GP practice variables, were modelled to predict GP consultation rates, before and after adjusting for individual health and GP provision. Results Observed GP consultation rates are higher for women in materially deprived neighbourhoods and Pakistani women. However these groups were found to consult less often after controlling for individual health. This difference, around one appointment per year, is ‘explained’ by the nature of GP provision. Women in practices with a low GP to patient ratio had around 9 fewer consultations over the six year period compared to women in practices with the highest ratio. Conclusions Equitable access to GP services, particularly for women during the maternal period, is essential for tackling deep-rooted health inequalities. Future GP funding should take account of neighbourhood material deprivation to focus resources on areas of the greatest need

Introduction and evaluation of a 'pre-ART care' service in Swaziland: an operational research study

Objective: To implement and evaluate a formal pre-antiretroviral therapy (ART) care service at a district hospital in Swaziland. Design: Operational research. Setting: District hospital in Southern Africa. Participants: 1171 patients with a previous diagnosis of HIV. A baseline patient group consisted of the first 200 patients using the service. Two follow-up groups were defined: group 1 was all patients recruited from April to June 2009 and group 2 was 200 patients recruited in February 2010. Intervention: Introduction of pre-ART care-a package of interventions, including counselling; regular review; clinical staging; timely initiation of ART; social and psychological support; and prevention and management of opportunistic infections, such as tuberculosis. Primary and secondary outcome measures: Proportion of patients assessed for ART eligibility, proportion of eligible patients who were started on ART and proportion receiving defined evidence-based interventions (including prophylactic co-trimoxazole and tuberculosis screening). Results: Following the implementation of the pre-ART service, the proportion of patients receiving defined interventions increased; the proportion of patient being assessed for ART eligibility significantly increased (baseline: 59%, group 1: 64%, group 2: 76%; p=0.001); the proportion of ART-eligible patients starting treatment increased (baseline: 53%, group 1: 81%, group: 2, 81%; p<0.001) and the median time between patients being declared eligible for ART and initiation of treatment significantly decreased (baseline: 61 days, group 1: 39 days, group 2: 14 days; p<0.001). Conclusions: This intervention was part of a shift in the model of care from a fragmented acute care model to a more comprehensive service. The introduction of structured pre-ART was associated with significant improvements in the assessment, management and timeliness of initiation of treatment for patients with HIV