No abstract

This study aims to identify the extent of terminal digit bias in routinely recorded blood pressures (BP) across a number of different general practices and report on changes in terminal digit bias over a 10-year period. It also explores the effect this may have had on the mean recorded BP in this population. BP records were taken from The Health Improvement Network database containing anonymized patient records from information entered by UK general practices in the financial years 1996-1997 to [2005][2006]. The proportion of measurements ending in zero and the mean BP readings were calculated for each practice and for each year of data. Over this 10-year period the percentage of systolic BPs with zero terminal digits fell from 71.2 to 36.7% and mean recorded BP fell from 152.3 to 145.3 mm Hg. Correcting the BPs to remove terminal digit bias indicates a 2-3 mm Hg underestimation of the mean population systolic BP over this period. The between-practice variation in the percentage of zero terminal digit readings increased from 3.5 to 6.5 s.d. Although it is welcome to see a reduction in terminal digit bias, it is worrying to see the increase in variation between practices. There is evidence that terminal digit bias may lead to potential misclassification and inappropriate treatment of hypertensive patients. The increase in variation observed may therefore lead to an increased variation in the quality of care given to patients.

Background: Historically there has been a wide variation in the proportion of inadequate smears between general practices. Cervical screening in the UK is undergoing a fundamental change by moving from conventional to liquid based cytology (LBC). The main driver for this change has been a predicted reduction in the proportions of inadequate samples. This study investigates the effect of LBC on the variation in the proportion of inadequate samples between general practices using Shewhart's theory of variation and control charts.

Background: Inadequate cervical smears cannot be analysed, can cause distress to women, are a financial burden to the NHS and may lead to further unnecessary procedures being undertaken. Furthermore, the proportion of inadequate smears is known to vary widely amongst providers. This study investigates this variation using Shewhart's theory of variation and control charts, and suggests strategies for addressing this.

Although the majority of publications on the epidemiology of hypertension are on North American and European populations, high blood pressure and its health consequences are worldwide phenomena. For several reasons, good epidemiological data on blood pressure in the population are essential to understanding high blood pressure.Firstly, epidemiological studies inform our understanding of the extent of the problem. What are mean blood pressures in a population? How many individuals are likely to require treatment for hypertension? An understanding of the extent of the problem is essential if we are to plan and develop health services to deal with the clinical needs that are associated with high blood pressure. This includes the management of hypertension, the treatment of stroke and the treatment of cardiovascular disease.Secondly, epidemiological monitoring can tell us whether blood pressures in a given population are increasing or decreasing. Alongside demographic data this information gives us a picture of where we are going in terms of health service needs. Rising average blood pressures in a population mean that greater numbers of persons will need treatment for hypertension. It also means that there are likely to be more cardiovascular diseases to treat in the future. This is particularly true if other risk factors are changing in the population, for example if the population is ageing, smoking is on the increase or average cholesterol levels are rising.Thirdly, such data are important if we are to understand what factors cause high blood pressure. This includes both the proximal factors -such as obesity or salt intake -and the distal factors -such as socio-economic or cultural conditions that influence diet and lifestyle -which underlie the proximal factors. In the long term, insight into the causes of high blood pressure offers the best chance of informing policies that will reduce average blood pressures in the population as a whole.There are many potential sources of bias in population surveys of blood pressure. Efforts must be made to ensure the sample is representative of the population as a whole. The measurement technique must be highly standardised: even small differences in measurement technique can make important differences in the mean blood pressures in a population survey. Minh et al.'s 1 paper on the prevalence and socio-economic determinants of hypertension in a rural population in Vietnam goes some way towards minimising these sources of bias. As a result of this it is an important contribution to our understanding of blood pressure in South East Asian populations. Vietnam is a country of some 80 million people (about the same population as Germany), yet there are few epidemiological studies of its people's blood pressure. Their study found lower mean blood pressures than in Western Europe and a lower prevalence of hypertension in farmers than other workers. Few of those that were hypertensive were on treatment. The findings of the study are valuable both as a description of the epidemiology...