Estimating Morbidity Rates Based on Routine Electronic Health Records in Primary Care: Observational Study.

BACKGROUND: Routinely recorded electronic health records (EHRs) from general practitioners (GPs) are increasingly available and provide valuable data for estimating incidence and prevalence rates of diseases in the population. This paper describes how we developed an algorithm to construct episodes of illness based on EHR data to calculate morbidity rates. OBJECTIVE: The goal of the research was to develop a simple and uniform algorithm to construct episodes of illness based on electronic health record data and develop a method to calculate morbidity rates based on these episodes of illness. METHODS: The algorithm was developed in discussion rounds with two expert groups and tested with data from the Netherlands Institute for Health Services Research Primary Care Database, which consisted of a representative sample of 219 general practices covering a total population of 867,140 listed patients in 2012. RESULTS: All 685 symptoms and diseases in the International Classification of Primary Care version 1 were categorized as acute symptoms and diseases, long-lasting reversible diseases, or chronic diseases. For the nonchronic diseases, a contact-free interval (the period in which it is likely that a patient will visit the GP again if a medical complaint persists) was defined. The constructed episode of illness starts with the date of diagnosis and ends at the time of the last encounter plus half of the duration of the contact-free interval. Chronic diseases were considered irreversible and for these diseases no contact-free interval was needed. CONCLUSIONS: An algorithm was developed to construct episodes of illness based on routinely recorded EHR data to estimate morbidity rates. The algorithm constitutes a simple and uniform way of using EHR data and can easily be applied in other registries.

The Public Health Status and Foresight report 2014: Four normative perspectives on a healthier Netherlands in 2040.

Policy-oriented foresight reports aim to inform and advise decision-makers. In value-laden areas such as public health and healthcare, deliberative scenario methods are clearly needed. For the sixth Dutch Public Health Status and Forecasts-report (PHSF-2014), a new approach of co-creation was developed aiming to incorporate different societal norms and values in the description of possible future developments. The major future trends in the Netherlands were used as a starting point for a deliberative dialogue with stakeholders to identify the most important societal challenges for public health and healthcare. Four societal challenges were identified: 1) To keep people healthy as long as possible and cure illness promptly, 2) To support vulnerable people and enable social participation, 3) To promote individual autonomy and freedom of choice, and 4) To keep health care affordable. Working with stakeholders, we expanded these societal challenges into four corresponding normative scenarios. In a survey the normative scenarios were found to be recognizable and sufficiently distinctive. We organized meetings with experts to explore how engagement and policy strategies in each scenario would affect the other three societal challenges. Possible synergies and trade-offs between the four scenarios were identified. Public health foresight based on a business-as-usual scenario and normative scenarios is clearly practicable. The process and the outcomes support and elucidate a wide range of strategic discussions in public health.

Do conceptualisations of health differ across social strata? A concept mapping study among lay people.

OBJECTIVES: The legitimacy of policies that aim at tackling socioeconomic inequalities in health can be challenged if they do not reflect the conceptualisations of health that are valued in all strata. Therefore, this study analyses how different socioeconomic groups formulate their own answers regarding: what does health mean to you? DESIGN: Concept mapping procedures were performed in three groups that differ in educational level. All procedures followed exactly the same design. SETTING: Area of the city of Utrecht, the Netherlands. PARTICIPANTS: Lay persons with a lower, intermediate and higher educational level (±15/group). RESULTS: The concept maps for the three groups consisted of nine, eight and seven clusters each, respectively. Four clusters occurred in all groups: absence of disease/disabilities, health-related behaviours, social life, attitude towards life. The content of some of these differed between groups, for example, behaviours were interpreted as having opportunities to behave healthily in the lower education group, and in terms of their impact on health in the higher education group. Other clusters appeared to be specific for particular groups, such as autonomy (intermediate/higher education group). Finally, ranking ranged from a higher ranking of the positively formulated aspects in the higher education group (eg, lust for life) to that of the negatively formulated aspects in the lower education group (eg, having no chronic disease). CONCLUSION: Our results provide indications to suggest that people in lower socioeconomic groups are more likely to show a conceptualisation of health that refers to (1) the absence of health threats (vs positive aspects), (2) a person within his/her circumstances (vs quality of own body/mind), (3) the value of functional (vs hedonistic) notions and (4) an accepting (vs active) attitude towards life.

Estimating incidence and prevalence rates of chronic diseases using disease modeling.

BACKGROUND: Morbidity estimates between different GP registration networks show large, unexplained variations. This research explores the potential of modeling differences between networks in distinguishing new (incident) cases from existing (prevalent) cases in obtaining more reliable estimates. METHODS: Data from five Dutch GP registration networks and data on four chronic diseases (chronic obstructive pulmonary disease [COPD], diabetes, heart failure, and osteoarthritis of the knee) were used. A joint model (DisMod model) was fitted using all information on morbidity (incidence and prevalence) and mortality in each network, including a factor for misclassification of prevalent cases as incident cases. RESULTS: The observed estimates vary considerably between networks. Using disease modeling including a misclassification term improved the consistency between prevalence and incidence rates, but did not systematically decrease the variation between networks. Osteoarthritis of the knee showed large modeled misclassifications, especially in episode of care-based registries. CONCLUSION: Registries that code episodes of care rather than disease generally provide lower estimates of the prevalence of chronic diseases requiring low levels of health care such as osteoarthritis. For other diseases, modeling misclassification rates does not systematically decrease the variation between registration networks. Using disease modeling provides insight in the reliability of estimates.

Time Trends in Prevalence of Chronic Diseases and Multimorbidity Not Only due to Aging: Data from General Practices and Health Surveys.

INTRODUCTION: Chronic diseases and multimorbidity are common and expected to rise over the coming years. The objective of this study is to examine the time trend in the prevalence of chronic diseases and multimorbidity over the period 2001 till 2011 in the Netherlands, and the extent to which this can be ascribed to the aging of the population. METHODS: Monitoring study, using two data sources: 1) medical records of patients listed in a nationally representative network of general practices over the period 2002-2011, and 2) national health interview surveys over the period 2001-2011. Regression models were used to study trends in the prevalence-rates over time, with and without standardization for age. RESULTS: An increase from 34.9% to 41.8% (p<0.01) in the prevalence of chronic diseases was observed in the general practice registration over the period 2004-2011 and from 41.0% to 46.6% (p<0.01) based on self-reported diseases over the period 2001-2011. Multimorbidity increased from 12.7% to 16.2% (p<0.01) and from 14.3% to 17.5% (p<0.01), respectively. Aging of the population explained part of these trends: about one-fifth based on general practice data, and one-third for chronic diseases and half of the trend for multimorbidity based on health surveys. CONCLUSIONS: The prevalence of chronic diseases and multimorbidity increased over the period 2001-2011. Aging of the population only explained part of the increase, implying that other factors such as health care and society-related developments are responsible for a substantial part of this rise.

[Living longer, with more disease and less disability; trends in public health 2000-2030]. / Langer leven, meer ziekte, minder beperkingen; trends in de volksgezondheid van 2000 tot 2030.

The Dutch Public Health Status and Foresight report 2014 explores the future of public health in the Netherlands, using a trend scenario and four future scenarios. The trend scenario provides projections until 2030, based on the trends over the last decades and assuming the policy stays the same. After many years the unfavourable trends in lifestyle seem to have ended: the percentage of smokers is decreasing and the percentage of people who are overweight is no longer increasing. Life expectancy will continue to increase, but the differences between socioeconomic groups will not become smaller. Demographic changes (rise in the ageing population) and improvements in health care will contribute to an increase in the number of chronically ill which will increase from 5.3 million in 2011 to 7 million in 2030. However, most people with a chronic disease feel healthy, have no disabilities and participate fully in society. Health care expenditures rose from 9.5% of the GDP in 2000 to 14% in 2012. How this growth will continue in the next years is uncertain.

[A trend scenario and four perspectives for 2040: the Dutch Public Health Status and Forecast 2014]. / Een trendscenario en vier perspectieven voor 2040: de Volksgezondheid Toekomst Verkenning 2014.

In the Dutch Public Health Status and Forecast report (PHSF), the Dutch National Institute for Public Health and the Environment explores the future of public health and health care in the Netherlands until 2040. The PHSF-2014 will consist of four parts: (a) a description of public health in the Netherlands now and in the past; (b) future trends, based on model calculations and expert opinions; (c) future scenarios based on four normative perspectives on public health; and (d) opportunities and dilemmas in the prevention of future problems. In this first article of a short series on the PHSF-2014, we briefly explain these four parts of the study. In the next article, we will describe the most important future trends until 2030. In the final article, we will summarize the conclusions of the PHSF-2014.

[59 important health problems; a selection of diseases for public health monitoring]. / 59 belangrijke volksgezondheidsproblemen: een selectie van ziekten voor het monitoren van de volksgezondheid.

Listing the top diseases is important for an overview of population health. These lists reduce the thousands of diseases to a compact selection that enables policy makers and researchers to set priorities in public health and health care. The Dutch National Institute for Public Health and the Environment uses such a selection for the Public Health Status and Forecast, a four-yearly overview of population health. This document forms the basis of the policy report on public health policy of the Ministry of Health, Welfare and Sport. The previous selection is 20 years old. The new selection not only reflects changing disease patterns, but also changing public discussions. The selection is still based on mortality and morbidity, but also on costs and participation in society, two subjects that are high on the public agenda.

Quality aspects of Dutch general practice-based data: a conceptual approach.

BACKGROUND: General practice-based data, collected within general practice registration networks (GPRNs), are widely used in research. The quality of the data is important but the recording criteria about what type of information is collected and how this information should be recorded differ between GPRNs. OBJECTIVE: We aim to identify aspects that describe the quality of general practice-based data in the Netherlands. METHODS: To investigate the quality aspects, we used the method of concept mapping, a structured conceptualization process for a complex multi-dimensional topic. We explored the ideas of representatives from 10 Dutch GPRNs on the quality of general practice-based data in five steps: preparation, generation of statements, structuring, representation and interpretation. In a brainstorm session, 10 experts generated statements about good data quality from general practice, which we completed with information from the literature. In total, 18 experts participated in the ranking and clustering of the statements. These results were analysed using ARIADNE software, using a combination of principal component analysis and cluster analysis techniques. Finally, the clusters were labelled based on their content. RESULTS: A total of 72 statements were analysed, which resulted in a two-dimensional picture with six clusters, 'complete health record', 'coding of information', 'episode oriented recording', 'diagnostic validity', 'recording agreements' and 'residual category'. CONCLUSIONS: The quality of general practice-based data can be considered on five content-based aspects. These aspects determine the quality of recording.

Multimorbidity and comorbidity in the Dutch population - data from general practices.

BACKGROUND: Multimorbidity is increasingly recognized as a major public health challenge of modern societies. However, knowledge about the size of the population suffering from multimorbidity and the type of multimorbidity is scarce. The objective of this study was to present an overview of the prevalence of multimorbidity and comorbidity of chronic diseases in the Dutch population and to explore disease clustering and common comorbidities. METHODS: We used 7 years data (2002-2008) of a large Dutch representative network of general practices (212,902 patients). Multimorbidity was defined as having two or more out of 29 chronic diseases. The prevalence of multimorbidity was calculated for the total population and by sex and age group. For 10 prevalent diseases among patients of 55 years and older (N = 52,014) logistic regressions analyses were used to study disease clustering and descriptive analyses to explore common comorbid diseases. RESULTS: Multimorbidity of chronic diseases was found among 13% of the Dutch population and in 37% of those older than 55 years. Among patients over 55 years with a specific chronic disease more than two-thirds also had one or more other chronic diseases. Most disease pairs occurred more frequently than would be expected if diseases had been independent. Comorbidity was not limited to specific combinations of diseases; about 70% of those with a disease had one or more extra chronic diseases recorded which were not included in the top five of most common diseases. CONCLUSION: Multimorbidity is common at all ages though increasing with age, with over two-thirds of those with chronic diseases and aged 55 years and older being recorded with multimorbidity. Comorbidity encompassed many different combinations of chronic diseases. Given the ageing population, multimorbidity and its consequences should be taken into account in the organization of care in order to avoid fragmented care, in medical research and healthcare policy.

The disabling effect of diseases: a study on trends in diseases, activity limitations, and their interrelationships.

OBJECTIVES: Data from the Netherlands indicate a recent increase in prevalence of chronic diseases and a stable prevalence of disability, suggesting that diseases have become less disabling. We studied the association between chronic diseases and activity limitations in the Netherlands from 1990 to 2008. METHODS: Five surveys among noninstitutionalized persons aged 55 to 84 years (n = 54,847) obtained self-reported data on chronic diseases (diabetes, heart disease, peripheral arterial disease, stroke, lung disease, joint disease, back problems, and cancer) and activity limitations (Organisation for Economic Co-operation and Development [OECD] long-term disability questionnaire or 36-item Short Form Health Survey [SF-36]). RESULTS: Prevalence rates of chronic diseases increased over time, whereas prevalence rates of activity limitations were stable (OECD) or slightly decreased (SF-36). Associations between chronic diseases and activity limitations were also stable (OECD) or slightly decreased (SF-36). Surveys varied widely with regard to disease and limitation prevalence rates and the associations between them. CONCLUSIONS: The hypothesis that diseases became less disabling from 1990 to 2008 was only supported by results based on activity limitation data as assessed with the SF-36. Further research on how diseases and disability are associated over time is needed.

Disability weights for suicidal thoughts and non-fatal suicide attempts.

BACKGROUND: Although there are disability weights available for a wide range of health states, these do not include suicidality. This makes it difficult to evaluate the severity of suicidality in comparison with other health states. The aim of this study therefore is to estimate disability weights for suicidal thoughts and for mental distress involved in non-fatal suicide attempts. METHODS: A Dutch expert panel of sixteen medical practitioners who were knowledgeable about suicidality estimated disability weights (DWs) for twelve health states by interpolating them on a calibrated Visual Analogue Scale. The DWs for ten of these health states had been estimated in previous studies and were used to determine the external consistency of the panel. The other two concerned health states for suicidal thoughts and non-fatal suicide attempts. The resulting DWs could vary between 0 (best imaginable health state) and 1 (worst imaginable health state). RESULTS: Both internal (Cronbach's α = 0.98) and external consistency of the panel were satisfactory. The DWs for suicidal thoughts and non-fatal suicide attempts were estimated to be 0.36 and 0.46 respectively. LIMITATIONS: The panel was relatively small, which resulted in broad confidence intervals. CONCLUSIONS: Suicidal thoughts are considered to be as disabling as alcohol dependence and severe asthma. The mental distress involved in non-fatal suicide attempts is thought to be comparable in disability to heroin dependence and initial stage Parkinson's. These results demonstrate the severity of suicidality.

[Multimorbidity and comorbidity in the Dutch population--data from general practices]. / Multimorbiditeit en comorbiditeit in de Nederlandse bevolking--gegevens van huisartsenpraktijken.

OBJECTIVE: To present an overview of the prevalence of multimorbidity and comorbidity of chronic diseases in the Dutch population. DESIGN: Data analysis. METHODS: Data from the Netherlands Information Network of General Practice (LINH), a large representative network of general practices over a period of 7 years (2002-2008) were analysed. Multimorbidity was defined as a patient having been diagnosed with two or more of 29 chronic diseases in the general practitioner's electronic medical records system. The prevalence of chronic diseases and multimorbidity was calculated for the total population and subsequently by sex and age groups. For the 10 most prevalent diseases in the elderly, clustering and comorbidity of chronic diseases in patients 55 years and older were analysed. RESULTS: Almost 13% of the total Dutch population and 37% of patients 55 years and older had 2 or more chronic diseases. More than 70% of the patients aged 55 years and older who had 1 of the 10 specific chronic diseases also had an additional chronic disease. Most disease pairs occurred more frequently than expected based on independency (clustering), particularly the combinations depression and anxiety disorder, coronary heart disease and heart failure, and COPD and heart failure. The five most common combinations of conditions associated with a certain disease concerned only a limited portion (30%) of all disease comorbidity. This means that 70% of patients with a chronic disease had 1 or more additional diseases not included in the 5 most frequently occurring diseases. CONCLUSION: Multimorbidity was identified in over two-thirds of the elderly with frequently occurring chronic diseases. Comorbidity encompassed many different combinations of chronic diseases. In light of an ageing population, multimorbidity should increasingly be taken into account when delivering healthcare, in medical research and in defining healthcare policies.

Trends in activity limitations: the Dutch older population between 1990 and 2007.

BACKGROUND: It is not clear whether recent increases in life expectancy are accompanied by a concurrent postponement of activity limitations. The objective of this study was to give best estimates of the trend in the prevalence of activity limitations among the non-institutionalized population aged 55-84 years over the period 1990-2007 in The Netherlands. METHODS: We examined self-reports on 12 measures of moderate or severe activity limitations in stair climbing, walking and getting dressed as assessed by OECD long-term disability questionnaire or Short Form-36 (SF-36) items, using original data from five population-based cross-sectional and longitudinal surveys (n = 54,847 respondents). To account for heterogeneity between surveys, we used meta-analyses to study time trends. RESULTS: Time trends of 10 out of the 12 activity limitation variables studied were stable. The prevalence of at least moderate activity limitations in stair climbing [odds ratio (OR) = 1.03)] and getting dressed (OR = 1.04) based on OECD items increased over the study period. Age- and gender-stratified time trend analyses showed consistent patterns. CONCLUSIONS: No declines were observed in the prevalence of activity limitations in the Dutch older population over the period 1990-2007. The increase in life expectancy in this period is accompanied by a stable prevalence of most activity limitations.

Don't get the message: the effect of a warning text before visiting a proanorexia website.

OBJECTIVE: This study examined the effect of the placement of a warning text before visiting proanorexia websites on actual access of these websites. METHOD: A separate webpage with a warning text aiming at first-time visitors was placed before each proanorexia website hosted by a Dutch Internet provider. During the research period of 1 year, the numbers of hits at the warning webpage were registered together with the numbers of hits at the underlying proanorexia website. RESULTS: Of the total number of hits registered at the warning webpage, about two-third of the visitors were registered at the underlying proanorexia website. This indicates that about one-third of the visitors did not continue their visit to a proanorexia website after being exposed to the warning text. DISCUSSION: Placement of a warning text before proanorexia websites appears a promising strategy in holding back potential visitors.

What factors explain the differences in morbidity estimations among general practice registration networks in the Netherlands? A first analysis.

BACKGROUND: Information on the incidence and prevalence of diseases is a core indicator for public health. There are several ways to estimate morbidity in a population (e.g., surveys, healthcare registers). In this paper, we focus on one particular source: general practice based registers. Dutch general practice is a potentially valid source because nearly all non-institutionalized inhabitants are registered with a general practitioner (GP), and the GP fulfils the role as "gatekeeper". However, there are some unexplained differences among morbidity estimations calculated from the data of various general practice registration networks (GPRNs). OBJECTIVE: To describe and categorize factors that may explain the differences in morbidity rates from different GPRNs, and to provide an overview of these factors in Dutch GPRNs. RESULTS: Four categories of factors are distinguished: "healthcare system", "methodological characteristics", "general practitioner", and "patient". The overview of 11 Dutch GPRNs reveals considerable differences in factors. CONCLUSION: Differences in morbidity estimation depend on factors in the four categories. Most attention is dedicated to the factors in the "methodology characteristics" category, mainly because these factors can be directly influenced by the GPRN.

Disability weights for comorbidity and their influence on health-adjusted life expectancy.

BACKGROUND: Comorbidity complicates estimations of health-adjusted life expectancy (HALE) using disease prevalences and disability weights from Burden of Disease studies. Usually, the exact amount of comorbidity is unknown and no disability weights are defined for comorbidity. METHODS: Using data of the Dutch national burden of disease study, the effects of different methods to adjust for comorbidity on HALE calculations are estimated. The default multiplicative adjustment method to define disability weights for comorbidity is compared to HALE estimates without adjustment for comorbidity and to HALE estimates in which the amount of disability in patients with multiple diseases is solely determined by the disease that leads to most disability (the maximum adjustment method). To estimate the amount of comorbidity, independence between diseases is assumed. RESULTS: Compared to the multiplicative adjustment method, the maximum adjustment method lowers HALE estimates by 1.2 years for males and 1.9 years for females. Compared to no adjustment, a multiplicative adjustment lowers HALE estimates by 1.0 years for males and 1.4 years for females. CONCLUSION: The differences in HALE caused by the different adjustment methods demonstrate that adjusting for comorbidity in HALE calculations is an important topic that needs more attention. More empirical research is needed to develop a more general theory as to how comorbidity influences disability.

Mental health in the Dutch population and in general practice: 1987-2001.

BACKGROUND: In the last 15 years, both the demand for and supply of specialised mental health care increased considerably in the Netherlands. Increased demand may reflect a change in psychological morbidity, but may also be a consequence of increased supply. Specialised health care in the Netherlands is accessible only through referral by a GP, and so it is important to consider the role of primary care in the diagnosis of mental health problems. AIM: The aim of this study is to achieve a better understanding of the development of mental health status in the Dutch population and the consequent help-seeking behaviour in primary care. METHOD: Using two comparable morbidity studies carried out in the Dutch population and in primary care, we compared data from 1987 and 2001 to assess the following: possible differences in mental health between 1987 and 2001; possible differences in prevalence of mental disorder as diagnosed by GPs in 1987 and 2001; possible differences in the sociodemographic determinants of mental health and mental disorder in primary care between 1987 and 2001. RESULTS: Our results show an increase in mental and social problems in the population between 1987 and 2001. However, GPs diagnosed fewer patients as having a mental disorder in 2001 than they did in 1987. The risk of mental disorders or social problems in several sociodemographic groups remained largely the same, as did the chance of receiving a psychological or social diagnosis. CONCLUSION: We conclude that, while mental disorder in the population is increasing, the role of primary care has changed. Although GPs diagnose a lower percentage of mental problems as such, they refer an increasingly larger proportion of these to secondary care.

Has the burden of depression been overestimated?

OBJECTIVE: To investigate whether high estimates of the burden of depression could be attributed to an overestimation of disability weights (reflecting more severe disability). METHODS: We derived disability weights that were tailored to prevalence data. Empirical disability data from a Dutch community survey was used to describe three classes of severity of depression and their proportional prevalence. We obtained valuations from experts for each class and calculated the overall disability weight for depression. FINDINGS: Expert valuations were similar to those of previous studies. The overall disability weight for depression was similar to other studies except the 1994 Dutch Burden of Disease Calculation, which it exceeded by 73%. The lower Dutch 1994 disability weight resulted from an overestimation of the proportion of mild cases of depression by experts (60% versus 27% observed in the empirical data used in the present study). CONCLUSION: This study found no indication that disability associated with depression was overestimated. The Dutch example showed the importance of tailoring disability weights to epidemiological data on prevalence.