[Time trends in prevalence of chronic diseases and multimorbidity not only due to aging: data from general practices and health surveys]. / Toename in chronische ziekten en multimorbiditeit.

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.

Do practice characteristics explain differences in morbidity estimates between electronic health record based general practice registration networks?

BACKGROUND: General practice based registration networks (GPRNs) provide information on population health derived from electronic health records (EHR). Morbidity estimates from different GPRNs reveal considerable, unexplained differences. Previous research showed that population characteristics could not explain this variation. In this study we investigate the influence of practice characteristics on the variation in incidence and prevalence figures between general practices and between GPRNs. METHODS: We analyzed the influence of eight practice characteristics, such as type of practice, percentage female general practitioners, and employment of a practice nurse, on the variation in morbidity estimates of twelve diseases between six Dutch GPRNs. We used multilevel logistic regression analysis and expressed the variation between practices and GPRNs in median odds ratios (MOR). Furthermore, we analyzed the influence of type of EHR software package and province within one large national GPRN. RESULTS: Hardly any practice characteristic showed an effect on morbidity estimates. Adjusting for the practice characteristics did also not alter the variation between practices or between GPRNs, as MORs remained stable. The EHR software package 'Medicom' and the province 'Groningen' showed significant effects on the prevalence figures of several diseases, but this hardly diminished the variation between practices. CONCLUSION: Practice characteristics do not explain the differences in morbidity estimates between GPRNs.

The influence of population characteristics on variation in general practice based morbidity estimations.

BACKGROUND: General practice based registration networks (GPRNs) provide information on morbidity rates in the population. Morbidity rate estimates from different GPRNs, however, reveal considerable, unexplained differences. We studied the range and variation in morbidity estimates, as well as the extent to which the differences in morbidity rates between general practices and networks change if socio-demographic characteristics of the listed patient populations are taken into account. METHODS: The variation in incidence and prevalence rates of thirteen diseases among six Dutch GPRNs and the influence of age, gender, socio economic status (SES), urbanization level, and ethnicity are analyzed using multilevel logistic regression analysis. Results are expressed in median odds ratios (MOR). RESULTS: We observed large differences in morbidity rate estimates both on the level of general practices as on the level of networks. The differences in SES, urbanization level and ethnicity distribution among the networks' practice populations are substantial. The variation in morbidity rate estimates among networks did not decrease after adjusting for these socio-demographic characteristics. CONCLUSION: Socio-demographic characteristics of populations do not explain the differences in morbidity estimations among GPRNs.

Novel empirical disability weights to assess the burden of non-fatal injury.

BACKGROUND: Disability weights are necessary to estimate the disability component (years lived with disability, YLDs) of disability-adjusted life years. The original global burden of disease approach to deriving disability weights ignores temporary consequences of injury. OBJECTIVES: To develop and apply novel empirical disability weights to improve estimates of the non-fatal burden of injury. METHODS: A set of 45 disability weights was derived for both permanent and temporary consequences of injury, using the annual profile approach. A population panel (n = 143) provided the values. The novel set of disability weights was then linked to epidemiological surveillance data on the incidence of injury in The Netherlands to calculate YLD resulting from permanent and temporary consequences of injury. RESULTS: The empirical disability weights for injury consequences varied from minor (corneal abrasion, 0.004) to very severe (quadriplegia, 0.719) health loss. Increasing disability weights by level of severity were found, as illustrated by concussion (0.02), versus moderate brain injury (0.193), versus severe brain injury (0.540). Application of these new disability weights showed a 36% increase in YLD as the result of unintentional injury. CONCLUSIONS: YLD calculations based on global burden of disease disability weights underestimate the size of the injury problem by ignoring temporary health consequences. Application of novel empirical disability weights, derived using the annual profile approach, may improve calculations on the burden of non-fatal injury.

Changes in the prevalence of chronic disease and the association with disability in the older Dutch population between 1987 and 2001.

BACKGROUND: most studies of older populations in developed countries show a decrease in the prevalence of disabilities, and an increase in chronic diseases over the past decades. Data in the Netherlands, however, mostly show an increase in the prevalence of chronic diseases and mixed results with regard to the prevalence of disability. This study aims at comparing changes in the prevalence, as well as the association between chronic diseases and disability between 1987 and 2001 in the older Dutch population using data representative of the general population. Most studies, so far, have only dealt with self-reported diseases, but in this study, we will use both self-reported and GP-registered diseases. STUDY DESIGN: data from the first (1987) and second (2001) Dutch National Survey of General Practice were used. In 1987, 103 general practices, compared to 104 in 2001, participated. Approximately 5% of the listed persons aged 18 years and over was asked to participate in an extensive health interview survey. An all-age random sample was drawn by the researchers from the patients listed in the participating practices (in 1987 n = 2, 708; in 2001 n = 3, 474). Both surveys are community based, with an age range between 55 and 97 years. Data on chronic diseases were based on GP registries and self-report. RESULTS: the prevalence of disability and of asthma/COPD, cardiac disease, stroke, and osteoarthritis decreased between 1987 and 2001, while the prevalence of diabetes increased. Changes were largely similar for GP-registered and self-reported diseases. Cardiac disease, asthma/COPD, and depression led to less disability, whereas low back pain and osteoarthritis led to more disability. CONCLUSIONS: in general, there were reductions in GP-registered chronic diseases as well as in self-reported diseases and disability. Results suggest that the disabling impact of fatal diseases decreased, while the impact of non-fatal diseases increased.

The health status of the Dutch population as assessed by the EQ-6D.

This study uses the Six-Dimensional EuroQol instrument (EQ-6D) to describe the health status of the Dutch population and investigates sociodemographic differences. The subjects participated in the second Dutch National Survey of General Practice, which was conducted in 2001. Five percent of all listed patients of 104 practices (99% of the Dutch are listed in a general practice) were invited for a health interview. Analyses were prepared for 9685 respondents aged 18 years or more. The EQ-6D is an extended EQ-5D (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) with a cognitive dimension. The EQ-6D construct validity was examined by comparing it with the SF-36, with good results. Most respondents reported no health problems, while 33% reported pain or discomfort. Women and elderly people generally reported more problems; only depression/anxiety was unrelated to age. Educational level was closely related to problems in all dimensions. The cognitive dimension of the EQ-6D, used for the first time in a general population, gave satisfactory results. This paper includes normative data by age and gender for both the EQ-6D and the EQ-5D. We conclude that the EQ-6D is an efficient tool for establishing the health status in the community, so that different population subgroups can be compared.

[Health and disease in the Netherlands: the Dutch National Public Health Compass as a source of information]. / Gezondheid en ziekte in Nederland; het Nationaal Kompas Volksgezondheid als informatiebron.

--The Dutch National Public Health Compass has been available on the Internet (www.nationaalkompas.nl) since 2001. This website, developed and managed by the National Institute for Public Health and the Environment, contains data and information on the population's health status, its determinants, prevention and care. The Compass brings together information from various data sources, research and expert opinions. --On the basis of this Compass, an overview has been made of the health of the Dutch population. --Both the life expectancy and the healthy life expectancy in the Netherlands increased after 1980. --Mortality from coronary heart disease, cerebrovascular accidents and lung cancer decreased, but they are still the most important causes of death. --Especially psychological disorders (alcohol dependence, anxiety disorders and depression), coronary heart disease and COPD are associated with a significant decrease in quality of life. --There are important health differences in the Netherlands between rich and poor, urban and rural areas, natives and immigrants. --The difference in life expectancy between men and women will decrease from more than 5 years in 2000 to less than 4 years in 2020. --A permanent facility for the provision of accurate public-health information is of great importance. The collaboration of registration holders and experts in maintaining the Compass is and will remain essential so that an integral overview of the health of the Dutch population can also be made in the future.

Health status and the challenges for prevention in The Netherlands.

In 2002, the third Public Health Status and Forecasts report was published, containing up-to-date information about Dutch public health and health care. A striking finding was that although life expectancy (LE) in The Netherlands increased between 1980 and 2000, the LE of men is rising less rapidly than the European Union (EU) average. The LE of Dutch women is stagnating and has now fallen below the EU average. These and many other unfavourable trends in the health status of the Dutch population were found to be largely due to unhealthy behaviour. One of the policy recommendations therefore was to strengthen the investments in prevention in order to reverse the stagnation in health status. In response to the findings, the Ministry of Health, Welfare and Sport published the National Prevention Paper. This Paper states that the Ministry, within the existing prevention policy, will pay more attention to healthy behaviour, stressing the responsibility of citizens as well as the societal responsibility of other parties, such as business communities, schools, health insurers and care suppliers. The prevention of specific diseases (diabetes, psychosocial problems, heart diseases, cancer, musculosceletal disorders, asthma and chronic obstructive pulmonary disease) has been given priority status. In this article, we present the major findings regarding the health status of the Dutch population and discuss the implications for prevention policy.

Health related quality of life in multiple musculoskeletal diseases: SF-36 and EQ-5D in the DMC3 study.

OBJECTIVE: To examine the health related quality of life of persons with one or more self reported musculoskeletal diseases, as measured by the short form 36 item health status survey (SF-36) and the Euroqol questionnaire (EQ-5D). METHODS: A sample of Dutch inhabitants aged 25 years or more (n = 3664) participated in a questionnaire survey. Twelve lay descriptions of common musculoskeletal diseases were presented and the subjects were asked whether they had ever been told by a physician that they had any of these. Their responses were used to assess the prevalence of these conditions. Commonly used scores of SF-36 and descriptive scores from EQ-5D are presented, along with standardised differences between disease groups and the general population. SUBJECTS: with musculoskeletal diseases had significantly lower scores on all SF-36 dimensions than those without musculoskeletal disease, especially for physical functioning (SF-36 score (SE), 75.2 (0.5) v 87.8 (0.5)); role limitations caused by physical problems (67.1 (0.9) v 85.8 (0.8)); and bodily pain (68.5 (0.5) v 84.1 (0.5)). The worst health related quality of life patterns were found for osteoarthritis of the hip, osteoporosis, rheumatoid arthritis, and fibromyalgia. Those with multiple musculoskeletal diseases had the poorest health related quality of life. Similar results were found for EQ-5D. CONCLUSIONS: All musculoskeletal diseases involve pain and reduced physical function. The coexistence of musculoskeletal diseases should be taken into account in research and clinical practice because of its high prevalence and its substantial impact on health related quality of life.

Levels of disability in major depression: findings from the Netherlands Mental Health Survey and Incidence Study (NEMESIS).

BACKGROUND: Information on the distribution of disability associated with major depression (MD) across different groups of patients is of interest to health policy and planning. We examined the associations of severity and type (a single or recurrent episode) of MD with disability in a Dutch general population sample. METHODS: We used data from the first wave (1996) of the Netherlands Mental Health Survey and Incidence Study (NEMESIS). MD 'severity' and 'type' were diagnosed with the help of the Composite International Diagnostic Interview according to DSM-III-R criteria. SF-36 scores, days ill in bed and days absent from work were taken as indicators of disability. The differences in these variables were studied by means of variance and regression analysis. RESULTS: Recurrent MD was found not to be associated with more disability than single episode MD. Higher 'severity' classes were associated with more disability. However, the degree of disability between 'moderate' and 'severe' MD differed only very slightly. The difference in disability between non-depressed and mildly depressed individuals had a larger effect than between each successive pair of 'severity' classes. CONCLUSIONS: Three groups of MD can be distinguished based on the associated degree of disability: 'mild', 'moderate to severe' and 'severe with psychotic features'. In the future, these groups can be used to describe the distribution of disability in the depressed population. The marked difference between 'mild' MD and no MD suggests that 'mild' cases should be considered relevant.

Physical disability in The Netherlands: prevalence, risk groups and time trends.

Physical disability represents an important health indicator of western populations. In this paper the prevalence of physical disabilities in The Netherlands is presented for four domains of disability-visual, hearing, mobility and activities of daily living (ADL) disability-with a focus on risk groups and time trends.Cross-sectional national health survey data (NetHIS) of 9 y, 1990-1998, presenting data on 62 352 persons of 16 y or over were used. All data were self-reported. About one-eighth of the research population had a physical disability, ie had at least major difficulty with one or more functions such as walking, seeing, hearing and washing. This figure increased from 1.7% in the age group of 16-24 y to 44.1% in the age group of 75 y or older. Risk groups were women, those living alone, those who were divorced or widowed and those with a low educational level. In the period 1990-1998, the prevalence did not change with the exception of the prevalence of mobility disability which dropped slightly with 0.2 percentage points per year due to decreasing prevalences among men. One conclusion is that the prevalence of disability is high and stable, and expected to increase in the future due to the ageing of the population.

Causes and consequences of comorbidity: a review.

A literature search was carried out to identify and summarize the existing information on causes and consequences of comorbidity of chronic somatic diseases. A selection of 82 articles met our inclusion criteria. Very little work has been done on the causes of comorbidity. On the other hand, much work has been done on consequences of comorbidity, although comorbidity is seldom the main subject of study. We found comorbidity in general to be associated with mortality, quality of life, and health care. The consequences of specific disease combinations, however, depended on many factors. We recommend more etiological studies on shared risk factors, especially for those comorbidities that occur at a higher rate than expected. New insights in this field can lead to better prevention strategies. Health care workers need to take comorbid diseases into account in monitoring and treating patients. Future studies on consequences of comorbidity should investigate specific disease combinations.

Which chronic conditions are associated with better or poorer quality of life?

The objective of the present study is to compare the QL of a wide range of chronic disease patients. Secondary analysis of eight existing data sets, including over 15,000 patients, was performed. The studies were conducted between 1993 and 1996 and included population-based samples, referred samples, consecutive samples, and/or consecutive samples. The SF-36 or SF-24 were employed as generic QL instruments. Patients who were older, female, had a low level of education, were not living with a partner, and had at least one comorbid condition, in general, reported the poorest level of QL. On the basis of rank ordering across the QL dimensions, three broad categories could be distinguished. Urogenital conditions, hearing impairments, psychiatric disorders, and dermatologic conditions were found to result in relatively favorable functioning. A group of disease clusters assuming an intermediate position encompassed cardiovascular conditions, cancer, endocrinologic conditions, visual impairments, and chronic respiratory diseases. Gastrointestinal conditions, cerebrovascular/neurologic conditions, renal diseases, and musculoskeletal conditions led to the most adverse sequelae. This categorization reflects the combined result of the diseases and comorbid conditions. If these results are replicated and validated in future studies, they can be considered in addition to information on the prevalence of the diseases, potential benefits of care, and current disease-specific expenditures. This combined information will help to better plan and allocate resources for research, training, and health care.

A national burden of disease calculation: Dutch disability-adjusted life-years. Dutch Burden of Disease Group.

OBJECTIVES: This study estimated the burden of disease due to 48 major causes in the Netherlands in 1994 in disability-adjusted life-years (DALYs), using national epidemiologic data and disability weights, and explored associated problems and uncertainties. METHODS: We combined data from Dutch vital statistics, registrations, and surveys with Dutch disability weights to calculate disease-specific health loss in DALYs, which are the sum of years of life lost (YLLs) and years lived with disability (YLDs) weighted for severity. RESULTS: YLLs were primarily lost by cardiovascular diseases and cancers, while YLDs were mostly lost by mental disorders and a range of chronic somatic disorders (such as chronic nonspecific lung disease and diabetes). These 4 diagnostic groups caused approximately equal numbers of DALYs. Sensitivity analysis calls for improving the accuracy of the epidemiologic data in connection with disability weights, especially for mild and frequent diseases. CONCLUSIONS: The DALY approach appeared to be feasible at a national Western European level and produced interpretable results, comparable to results from the Global Burden of Disease Study for the Established Market Economies. Suggestions for improving the methodology and its applicability are presented.

The contribution of chronic conditions and disabilities to poor self-rated health in elderly men.

BACKGROUND: The aim of the study was to investigate the contribution of chronic conditions and disabilities to poor self-rated health from the perspectives of the patient and the population: (a) What is the impact of seven somatic chronic conditions on self-rated health, independent of disabilities? and (b) To what extent can poor self-rated health be attributed to the selected chronic conditions and disabilities? METHODS: Data came from the 1990 (n = 509), 1993 (n = 381), and 1995 (n = 340) surveys of the Zutphen Elderly Study. Odds ratios (OR) and population attributable risks (PAR) were calculated to quantify the contribution of chronic conditions and disabilities to poor self-rated health. RESULTS: From the patient perspective, stroke was most strongly associated with poor self-rated health (OR = 3.5, 95% confidence interval: 1.8-6.9). From the population perspective, 63% of poor self-rated health could be attributed to the selected chronic conditions, with respiratory symptoms (28%), musculoskeletal complaints (24%), and coronary heart disease (13%) making the largest contribution. A total of 73% could be attributed to chronic conditions and disabilities. CONCLUSIONS: In this population of elderly men, stroke resulted in the largest losses in self-rated health in individual patients, whereas the largest contributions to poor self-rated health in the population were made by respiratory symptoms and musculoskeletal complaints.

Non-response bias in a study of cardiovascular diseases, functional status and self-rated health among elderly men.

OBJECTIVES: To investigate to what extent differences in health status between respondents and drop-outs affected the associations between cardiovascular diseases and functional status and self-rated health in a population-based longitudinal health survey in elderly men. METHODS: During the 1993 survey of the Zutphen Elderly Study, a non-response survey was carried out. The prevalence of myocardial infarction and stroke, disabilities in basic activities of daily living (BADL) and mobility, and self-rated health were compared between non-respondents (n = 99) and respondents (n = 381). Associations between myocardial infarction and stroke on the one hand and functional status and self-rated health on the other were calculated for the total population and for the respondents to assess the amount of under- or overestimation of these associations. RESULTS: The health of non-respondents was worse than that of respondents in terms of stroke, disabilities in BADL and mobility and self-rated health. Due to this selective non-response, the associations between cardiovascular diseases and functional status and self-rated health were biased. Although most of the associations were slightly overestimated, the most important bias was the underestimation by 57% of the association between stroke and disabilities in BADL [total population: odds ratios (OR) = 6.1, 95% confidence interval (CI) = 2.7-13.9; respondents only: OR = 2.6, CI = 0.7-9.9]. CONCLUSION: Selective non-response might lead to bias in the prevalence of disease, disabilities and self-rated health as well as in the associations between disease and functional status and self-rated health. The direction and magnitude of this bias varies according to type of disease and health outcome and is therefore difficult to predict. The need to minimize non-response and to investigate its implications is recommended in every study.

Reproducibility of performance-based and self-reported measures of functional status.

BACKGROUND: The reproducibility of a performance-based and a self-reported measure of functional status was investigated, as well as the impact of age and cognitive function on the reproducibility. METHODS: Of a random sample of 114 men of the 1995 survey of the Zutphen Elderly Study, 105 men (aged 79.9 +/- 4.5 years) participated in a test-retest study. They filled out a questionnaire on disabilities and carried out performance tests twice, in a 2-week interval. Four performance tests were administered (standing balance, walking speed, chair stand, and external shoulder rotation), and a summary performance score was constructed. The number of self-reported disabilities in basic activities of daily living, mobility, and instrumental activities of daily living were assessed. Kappa statistics and Pearson correlation coefficients between test and retest measurements were computed for the total group and stratified by age and cognitive function. RESULTS: Three performance tests and the summary performance score had fair to good reproducibility (walking speed: Pearsons r = .90, chair stand: r = .82, shoulder rotation: kappa = .49, summary score: kappa = .52). Only the test for standing balance was poorly reproducible (kappa = .29). The self-reported functional status was fairly to good reproducible (kappa = .63, r = .87). Self-reported functional status was significantly less reproducible in very old and cognitively impaired than in younger and nonimpaired individuals. CONCLUSIONS: In the elderly male subjects, performance tests and self-reported disabilities had moderate to good reproducibility, with the exception of the test for standing balance. In very old or cognitively impaired populations, self-reported functional status may have a lower reproducibility.

Age, time, and cohort effects on functional status and self-rated health in elderly men.

OBJECTIVES: This study investigated age-related changes in functional status and self-rated health in elderly men, taking into account changes over time and differences between birth cohorts. METHODS: The Zutphen Elderly Study is a longitudinal study of men born in the Netherlands between 1900 and 1920. Functional status and self-rated health were measured in 513 men in 1990, in 381 men in 1993, and in 340 men in 1995. Age, time, and cohort effects were analyzed in a mixed longitudinal model. RESULTS: Longitudinal analyses showed that during 5 years of follow-up, the proportion of men without disabilities decreased from 53% to 39%, whereas the percentage who rated themselves as healthy decreased from 50% to 35%. Cross-sectional analyses confirmed changes in functional status, suggesting an age effect. Time-series analyses confirmed changes in self-rated health, suggesting a time effect. No birth-cohort effects were found. CONCLUSIONS: Functional status deteriorates with age, whereas self-rated health is not related to age in men aged 70 years and older. The observed 5-year decline in self-rated health seemed to be due to a secular trend.

Ageing and the relationship between functional status and self-rated health in elderly men.

Functional status (measured as functional limitations or disabilities) is an important determinant of self-rated health in the elderly. Several issues which are not yet clear in this association are addressed in this study: (i) the modifying effect of age on the association; (ii) the effect of recent changes in disability level on the current level of self-rated health, and (iii) the effect of functional limitations on self-rated health, independent of disabilities. Data were derived from the 1990, 1993 and 1995 surveys of the Zutphen Elderly Study, a longitudinal health study in men born between 1900 and 1920. Analyses of repeated measurements were performed with self-rated health as dependent variable and disabilities, functional limitations, age, survey year, and interaction terms as independent variables. Odds ratios were calculated from these models. Men with disabilities in instrumental activities of daily living had no different health ratings than men without disabilities. Those with disabilities in mobility and basic activities of daily living, however, had an odds ratio on poor self-rated health of 4.7 (95% confidence interval: 2.7-7.9) and 8.9 (4.6-17.1) respectively. This association became weaker with increasing age, leading to an absence of a significant association in the oldest group. The current level of self-rated health was only associated with the current level of disabilities. Information on previous levels of disabilities did not contribute to current self-rated health. Functional limitations had a small, but significant, effect on self-rated health when disabilities were taken into account. This study helps in enhancing insight in the complex relationship between functional status and self-rated health in the elderly.

Measuring functional status: cross-sectional and longitudinal associations between performance and self-report (Zutphen Elderly Study 1990-1993).

We investigated cross-sectional as well as longitudinal associations between performance-based measures of functional status and self-reported measures of functional status. In the Zutphen Elderly Study, 494 men, born between 1900 and 1920, were examined in 1990, of whom 303 were reexamined in 1993. A performance score was constructed on the basis of four tests: standing balance, walking speed, ability to rise from a chair, and external shoulder rotation. Self-reported functional status was based on disabilities in basic activities of daily living, mobility, and instrumental activities of daily living. A hierarchic disability scale was constructed. Cross-sectional correlation coefficients between the performance score and the disability scale were 0.22 in 1990 and 0.39 in 1993. Correlations were highest between the test for walking speed and self-reported mobility and IADL, and between the test for external shoulder rotation and self-reported disabilities in basic activities of daily living. The correlation between the 3-year changes in performance and in self-report was 0.20 (p < 0.001). Both performance and self-report at baseline predicted performance and self-report after 3 years. Performance-based measures of functional status are cross-sectionally and longitudinally associated at modest levels with self-reported disabilities. Performance measures and self-reported measures are complementary, but do not measure the same construct.