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PubMed1998

Risk-adjusted capitation payments: developing a diagnostic cost groups classification for the Dutch situation.

In many countries market-oriented health care reforms are high on the political agenda. A common element of these reforms is that the consumers may choose among competing health insurers or health plans, which are largely financed through premium-replacing capitation payments. Since 1993, Dutch sickness funds receive risk-adjusted capitation payments based on demographic factors. It has been shown that the predictive accuracy of a demographic capitation model improves when it is extended with diagnostic information from prior hospitalizations, in the form of Diagnostic Costs Groups (DCGs). In this study a DCG classification is developed using Dutch cost data of sickness fund members of all ages. The study also dealt with the question of how to handle high discretion diagnoses. For the Dutch situation high discretion diagnoses may be defined as those diagnoses for which day case treatment is a possible alternative for a hospital admission. Grouping persons with a hospital admission for high discretion diagnoses together with people without an admission resulted in a slight reduction of the predictive accuracy of the DCG model. Adequate risk-adjustment is critical to the success of market-oriented health care reforms. The use of diagnostic information from prior hospitalizations seems a promising option for improving the capitation formula.

Capitation Fee↗
PubMed2003

Conceptual, methodological, and statistical challenges in brain imaging studies of developmentally based psychopathologies.

Brain imaging studies in developmentally based psychopathologies most often use magnetic resonance imaging (MRI) to study regional volumes, task-related activity, neurometabolite concentrations, or the paths of fiber tracts within the brain. Methodological challenges for the use of MRI in studying these disorders include understanding the ultrastructural correlates of brain structure and function that are below the limits of resolution of this imaging modality and developing better methods for approximating the anatomical boundaries of the cytoarchitectonic units that are defined by those ultrastructural characteristics. Conceptual challenges include distinguishing findings that represent pathophysiologically central causes from compensatory and epiphenomenal effects, a difficulty that stems directly from the inherently correlational nature of imaging data. The promise of functional imaging studies must capitalize on the specificity of the cognitive and behavioral probes that are used to illuminate core features of the pathophysiology of developmental disorders, while recognizing the assumptions and limitations of the subtraction paradigms that are used to isolate the brain functions of interest. Statistical challenges include incorporating adequate statistical models for scaling effects within the brain, as well as modeling important demographic correlates that contribute to the substantial interindividual variability inherent in most imaging data. Statistical analyses need to consider the substantial intercorrelation of measures across the brain and the importance of correcting for multiple statistical comparisons, as well as the need for improved methods for brain warping and for assessing effective connectivity in functional imaging studies.

Brain↗
PubMed2002

Risk and promotive effects in the explanation of persistent serious delinquency in boys.

Risk and promotive effects were investigated as predictors of persistent serious delinquency in male participants of the Pittsburgh Youth Study (R. Loeber, D. P. Farrington, M. Stouthamer-Loeber, & W. B. van Kammen, 1998), living in different neighborhoods. Participants were studied over ages 13-19 years for the oldest sample and 7-13 years for the youngest sample. Risk and promotive effects were studied in 6 domains: child behavior, child attitudes, school and leisure activities, peer behaviors, family functioning, and demographics. Regression models improved when promotive effects were included with risk effects in predicting persistent serious delinquency. Disadvantaged neighborhoods, compared with better neighborhoods, had a higher prevalence of risk effects and a lower prevalence of promotive effects. However, predictive relations between risk and promotive effects and persistent serious delinquency were linear and similar across neighborhood socioeconomic status.

Adolescent↗
PubMedDate not supplied

A population exposure model for particulate matter: case study results for PM(2.5) in Philadelphia, PA.

A population exposure model for particulate matter (PM), called the Stochastic Human Exposure and Dose Simulation (SHEDS-PM) model, has been developed and applied in a case study of daily PM(2.5) exposures for the population living in Philadelphia, PA. SHEDS-PM is a probabilistic model that estimates the population distribution of total PM exposures by randomly sampling from various input distributions. A mass balance equation is used to calculate indoor PM concentrations for the residential microenvironment from ambient outdoor PM concentrations and physical factor data (e.g., air exchange, penetration, deposition), as well as emission strengths for indoor PM sources (e.g., smoking, cooking). PM concentrations in nonresidential microenvironments are calculated using equations developed from regression analysis of available indoor and outdoor measurement data for vehicles, offices, schools, stores, and restaurants/bars. Additional model inputs include demographic data for the population being modeled and human activity pattern data from EPA's Consolidated Human Activity Database (CHAD). Model outputs include distributions of daily total PM exposures in various microenvironments (indoors, in vehicles, outdoors), and the contribution from PM of ambient origin to daily total PM exposures in these microenvironments. SHEDS-PM has been applied to the population of Philadelphia using spatially and temporally interpolated ambient PM(2.5) measurements from 1992-1993 and 1990 US Census data for each census tract in Philadelphia. The resulting distributions showed substantial variability in daily total PM(2.5) exposures for the population of Philadelphia (median=20 microg/m(3); 90th percentile=59 microg/m(3)). Variability in human activities, and the presence of indoor-residential sources in particular, contributed to the observed variability in total PM(2.5) exposures. The uncertainty in the estimated population distribution for total PM(2.5) exposures was highest at the upper end of the distribution and revealed the importance of including estimates of input uncertainty in population exposure models. The distributions of daily microenvironmental PM(2.5) exposures (exposures due to time spent in various microenvironments) indicated that indoor-residential PM(2.5) exposures (median=13 microg/m(3)) had the greatest influence on total PM(2.5) exposures compared to the other microenvironments. The distribution of daily exposures to PM(2.5) of ambient origin was less variable across the population than the distribution of daily total PM(2.5) exposures (median=7 microg/m(3); 90th percentile=18 microg/m(3)) and similar to the distribution of ambient outdoor PM(2.5) concentrations. This result suggests that human activity patterns did not have as strong an influence on ambient PM(2.5) exposures as was observed for exposure to other PM(2.5) sources. For most of the simulated population, exposure to PM(2.5) of ambient origin contributed a significant percent of the daily total PM(2.5) exposures (median=37.5%), especially for the segment of the population without exposure to environmental tobacco smoke in the residence (median=46.4%). Development of the SHEDS-PM model using the Philadelphia PM(2.5) case study also provided useful insights into the limitations of currently available data for use in population exposure models. In addition, data needs for improving inputs to the SHEDS-PM model, reducing uncertainty and further refinement of the model structure, were identified.

Activities of Daily Living↗
PubMed1998

Does a secular trend exist in the distribution of occlusal patterns?

The existence of a secular trend in the distribution of occlusal patterns was studied in two generations of children. Study models and demographic data of a sample of 265 children from the previous generation (group A) and recordings of clinical examinations of 988 children from the present generation (group B) served as the data base for this study. Children in whom caries affected the occlusion and those in the deciduous dentition stage were excluded. Thus, occlusal analysis was performed for 102 children in group A and 703 in group B. A dramatic decrease was found in the prevalence of caries affecting the occlusion. No difference existed between the two groups with respect to molar and canine anteroposterior relationships. However, there was a decrease in the prevalence of normal occlusion accompanied by an increase of Class I malocclusion.

Adolescent↗
PubMed2003

Autoantibodies to the islet cell antigen SOX-13 are associated with duration but not type of diabetes.

AIMS: The autoantigen SOX-13 of the SRY-related high mobility group box is a low-frequency reactant in sera from patients with Type 1 diabetes. We further investigated the potential diagnostic role of anti-SOX-13, and in particular its ability to distinguish Type 1 from Type 2 diabetes, in two large, well-characterized cohorts. METHODS: SOX-13 autoantibody status was ascertained using a radioimmunoprecipitation assay in (i) a random sample of 546 participants in an Australian community-based study (the Fremantle Diabetes Study; FDS) of whom 119 had Type 1 and 427 Type 2 diabetes, and (ii) a sample of 333 subjects with Type 2 diabetes from the United Kingdom Prospective Diabetes Study (UKPDS) stratified by age, anti-glutamic acid decarboxylase (GAD) and islet cell antibody (ICA) status, and requirement for insulin therapy within 6 years of diagnosis. RESULTS: The frequencies of anti-SOX-13 in the FDS subjects were 16.0% and 14.8% for Type 1 and Type 2 patients, respectively, and levels were similar. In the UKPDS subjects, the frequency was 4.5%. In a logistic regression model involving demographic, anthropometric and metabolic variables, only diabetes duration was significantly associated with anti-SOX-13 positivity, especially for duration > 5 years (P < 0.002). When the coexistence of autoantibodies was assessed in the two study samples, there were no significant associations between anti-SOX-13 and ICA, anti-GAD or ICA512/IA-2. CONCLUSIONS: Whilst the frequency of anti-SOX-13 may be increased in some populations of diabetic patients, this reactivity does not usefully distinguish Type 1 from Type 2 diabetes. However, the association with diabetes duration suggests that anti-SOX-13 may be a non-specific marker of tissue damage associated with chronic hyperglycaemia.

Adult↗
PubMed2001

[Validation of an observer-based rating set compared to a standardized written psychological test for the diagnosis of depression and anxiety in a university preadmission test center].

INTRODUCTION: Depression and anxiety can be a major factor of perioperative stress and might contribute to patients dissatisfaction with medical care if they remain unrecognized. There are several methods to diagnose depression and anxiety like standardized written psychological tests or self report scales. Because these tests are not always suitable for routine use in a busy preadmission test center we evaluated an observer-based rating set for the diagnosis of depression and anxiety. MATERIAL AND METHODS: 70 patients of a university hospital preadmission test center were tested with the HADS-D-Test and the observer-based rating set after approval of the institutional review board and written informed consent. Test-data were compared using a logistic regression model and demographic variables were analyzed using t-Test. ANOVA and Pearson correlation. RESULTS: The prevalence of depression in our study population was 11.11% (14.75% in male, 9.76% in female) and the prevalence of anxiety was 7.14% (6.9% in male and 7.32% in female). The correlation between the observer-based rating items and the HADS-D-diagnosis was statistically highly significant. The observer based items "unsteady eye movements" and "general worrisome mood" proved to be especially sensitive for anxiety and the items "sorrowful mood" and "impression of resignation" were sensitive for depression without any influence of the experience of the anesthesiologist. A higher prevalence of depression and anxiety was found in patients with ASA-class III compared to those with ASA-classes I and II while age and type of surgery had no significant influence. CONCLUSIONS: Based on our observations depression and anxiety are a relevant factor of preoperative morbidity assessment. Observer-based items are a reliable tool to detect those patients which might need special assistance and therapy in the perioperative period to reduce stress associated with high preexisting levels of depression and anxiety.

Adult↗
PubMed2000

Association of patients' perception of health status and exercise electrocardiogram, myocardial perfusion imaging, and ventricular function measures.

BACKGROUND: Patients' viewpoint of their health status is increasingly used as an important outcome measure of the success of treatments. Because clinicians rarely formally measure patients' health-related quality of life, the question arises whether noninvasive testing for ischemia can provide similar information regarding physical functioning and general health perception. METHODS: We measured physical functioning and general health status with the Medical Outcomes Study Short Form (SF-36) survey in 195 consecutive patients (68% male, mean age 55.6 +/- 11.1 years) referred for exercise testing with myocardial perfusion imaging. The survey was completed immediately before the exercise test. RESULTS: In the multivariate analysis, the strongest predictor of physical functioning and general health perception was metabolic equivalents. However, the best model, including demographic, clinical, and test variables, predicted only 14% of the variation in physical functioning and 10% of the variability in general health perception. CONCLUSIONS: The variation in physical functioning and general health perception, as measured by the SF-36, among patients referred for exercise testing is not predicted well by the results of the test. As expected, several test results are significantly associated with physical functioning and general health perception; however, there was substantial overlap among individual patients, suggesting that the parameters are poor surrogates for the actual assessment of the domains. If these domains are deemed important to tracking patient outcomes, then they should supplement the current assessments of these patients.

Adult↗
PubMed1994

A consistency algorithm based on information theory.

"This paper provides a geometric-mean solution to the consistency problem of multidimensional demographic projection models, based on the constrained minimization of an entropy function. A comparison with the existing harmonic-mean solution yields many similarities and almost no differences....However, one major advantage of the geometric mean is that its corresponding distance function is firmly based on (information) theory." (SUMMARY IN FRE)

Evaluation Studies as Topic↗
PubMed1999

The use of microsatellite variation to infer population structure and demographic history in a natural model system.

To assess the reliability of genetic markers it is important to compare inferences that are based on them to a priori expectations. In this article we present an analysis of microsatellite variation within and among populations of island foxes (Urocyon littoralis) on California's Channel Islands. We first show that microsatellite variation at a moderate number of loci (19) can provide an essentially perfect description of the boundaries between populations and an accurate representation of their historical relationships. We also show that the pattern of variation across unlinked microsatellite loci can be used to test whether population size has been constant or increasing. Application of these approaches to the island fox system indicates that microsatellite variation may carry considerably more information about population history than is currently being used.

Animals↗
PubMed2006

Positive selection versus demography: evolutionary inferences based on an unusual haplotype structure in Drosophila simulans.

Coalescent simulations were used to investigate the possible role of population subdivision and history in shaping nucleotide variation in a recombining 88-kb genomic fragment of Drosophila simulans displaying an unusual large-scale haplotype structure. The multilocus analysis, based on summary statistics using specific demographic null models under recombination, indicates that the observed levels of linkage disequilibrium differed significantly from the values expected under different bottleneck and population admixture scenarios. These results indicate that demography alone may not account for the observed pattern of variation and support the previous claim that the data are better described by a model in which an adaptive mutation has not yet gone to fixation.

Animals↗
PubMed2002

Hyperlactataemia and lactic acidosis during antiretroviral therapy: relevance, reproducibility and possible risk factors.

OBJECTIVE: To evaluate the prevalence, outcome and possible risk factors for hyperlactataemia and lactic acidosis in HIV-positive persons receiving antiretroviral therapy. METHODS: Cross-sectional and longitudinal data from a prospectively collected clinical database. Associations with antiretroviral regimen, clinical and laboratory parameters were assessed using univariate and multivariate Cox's proportional hazards model. RESULTS: Patients naive to therapy and patients on current therapy for a minimum of 4 months were assessed. Median lactate was 1.1 mol/l in 253 untreated individuals and 1.4 mmol/l in 1239 patients stable on therapy for at least 4 months. At least two on-therapy samples were available for 750 of the 1239 individuals, taken a median 92 days apart. Lactate measurement showed a low positive predictive value of 38.9% but a high negative predictive value (98%) for normal values. Lactate was elevated > or = 2.4 mmol/l in 102 individuals on at least one occasion. In the multivariate Cox's proportional hazards model, no demographic characteristics were associated with hyperlactataemia. Didanosine-containing regimens doubled the relative hazard of hyperlactataemia compared with those sparing didanosine. Abacavir-containing regimens reduced the hazard of hyperlactataemia. Choice of thymidine analogue did not influence risk. Hyperlactataemia was associated with acid-base disturbance. Use of didanosine and female sex were over-represented amongst nine patients with severe hyperlactataemia (> 5 mmol/l) or lactic acidosis. CONCLUSIONS: Screening of lactate is of limited use in asymptomatic individuals on antiretroviral therapy. Raised lactate represents part of a spectrum of lactate and acid-base disturbance that infrequently includes lactic acidosis. Didanosine appears associated with an increased risk of hyperlactataemia.

Acidosis, Lactic↗
PubMed2006

Exploring factors that influence child use of dental services and toothbrushing in New Zealand.

OBJECTIVES: To explore factors contributing to dental service use and toothbrushing among Mäori, Pacific and New Zealand European or Other (NZEO) children in New Zealand. METHODS: Data were obtained from the 2002 National Child Nutrition Survey. Models representing demographic, socio-economic status (SES), lifestyle, dietary, food security and oral health paradigms were tested using logistic regression. RESULTS: Mäori and Pacific children were more likely to not attend for dental care (OR: 1.99 and 2.05 respectively) than NZEO children when age, sex and time lived in New Zealand were accounted for. The addition of household (OR: 1.93 and 2.05 respectively) or lifestyle (OR: 1.95 and 1.81 respectively) factors resulted in minimal OR changes for Mäori or Pacific child dental attendance, whereas addition of dietary (OR: 1.44 and 1.23 respectively) and food security (OR: 1.43 and 1.32 respectively) items reduced the ORs of Mäori and Pacific child dental attendance so they no longer differed significantly to NZEO children. Addition of dental factors increased the ORs of Mäori and Pacific children not utilizing dental services compared with NZEO children (OR: 2.30 and 2.13 respectively). Mäori and Pacific children were more likely to not brush teeth (OR: 3.86 and 1.49 respectively) than NZEO children when age, sex and time lived in New Zealand were accounted for. Addition of dietary factors resulted in a 36% OR reduction of Mäori children not brushing (OR: 2.57), while addition of household SES (OR: 1.06), lifestyle (OR: 1.14), dietary (OR: 0.71) or food security factors (OR: 1.19) reduced the ORs of Pacific children so they were no longer significantly different to NZEO children. CONCLUSIONS: Mäori and Pacific children were more likely to have not received dental care (variance largely explained by dietary and food security factors) and Mäori children were more likely to not brush their teeth (variance largely explained by dietary items) than NZEO children.

Adolescent↗
PubMed2026

Patient expectations assessed before randomisation and after the first treatment session, and their associations with pain outcome at 3 months in patients with tennis elbow: a secondary analysis of a randomised controlled feasibility trial in Norwegian secondary care.

OBJECTIVE: To evaluate patients' expectations of pain improvement before randomisation (T1) and after the first treatment (T2), and to examine how expectations at these two time points were associated with pain outcome measured at 3&#x2009;months (T3). DESIGN: Exploratory secondary analyses of a three-arm, randomised controlled feasibility trial in patients with tennis elbow comparing heavy slow resistance training, shock wave therapy and advice (1:1:1). SETTING: Outpatient clinic at Oslo University Hospital. PARTICIPANTS: Adults with lateral epicondylalgia, commonly known as tennis elbow. MAIN OUTCOME MEASURES: Expected pain was rated on a Numeric Rating Scale (NRS, 0-10) at T1 and T2. Present pain (NRS, 0-10) was reported at 3&#x2009;months (T3). Changes in expectations from T1 to T2 were summarised descriptively. Univariable linear regressions assessed associations between T3 pain and expectations at T1 and T2, treatment group and baseline factors. Explained variance was quantified by R2. Multivariable models including demographics and baseline pain were evaluated via adjusted R2. RESULTS: Fifty-four participants were included. In the shock wave group, nine (47%) came to expect greater improvement from T1 to T2; by contrast, in the advice group, seven (41%) expected less improvement. Expectations at T1 were not associated with T3 pain, whereas expectations at T2 were positively associated with T3 pain (b=0.61, 95%&#x2009;CI 0.33 to 0.89, p<0.01, R2=0.27), suggesting that higher expected pain at T2 was associated with higher reported pain at T3. Adding education and baseline pain increased explained variance modestly (R2 from 0.27 to 0.32). CONCLUSION: In this study, expectations measured after randomisation and one treatment session were associated with pain at 3&#x2009;months for patients with tennis elbow. Larger, prospectively designed studies should investigate how postrandomisation expectations relate to clinical outcomes in non-blinded musculoskeletal trials. TRIAL REGISTRATION NUMBER: NCT04803825.

Humans↗
PubMed1999

Do the factors associated with successful contact tracing of patients with gonorrhoea and Chlamydia differ?

OBJECTIVE: To assess and compare factors which may be associated with successful contact tracing in patients with gonorrhoea and chlamydia. STUDY DESIGN: Prospective observational study of patients attending a genitourinary medicine clinic with a diagnosis of gonorrhoea or chlamydia. Multivariate analysis model including demographic, socioeconomic, and behavioural variables. RESULTS: The attendance of at least one sexual contact was associated with naming more contacts for patients with gonorrhoea (OR 1.44, 95% CI 1.04-2.01). A history of gonorrhoea was associated with successful contact tracing for patients with chlamydia (OR 1.46, 95% CI 1.12-1.9). Successful contact tracing, as defined by at least one confirmed contact attendance after the index case, was not associated with age, sex, sexual orientation, history of chlamydia, use of condoms, marital status, ethnicity, or socioeconomic status for either gonorrhoea or chlamydia. CONCLUSIONS: Differences in the composition of the core groups infected with gonorrhoea and chlamydia are not explained by differences in contact tracing success. In the clinic setting studied, the outcome of contact tracing was not associated with a variety of demographic, socioeconomic, and behaviour factors.

Adult↗
PubMed2026

Population genomics of Plasmodium malariae from 4 African countries.

BACKGROUNDMalaria caused by Plasmodium malariae is geographically widespread and sometimes associated with prolonged infection, yet little is known about its genomic epidemiology.METHODSWe performed hybrid capture and whole-genome sequencing of 77 isolates collected from Cameroon (n = 7), the Democratic Republic of the Congo (n = 16), Nigeria (n = 4), and Tanzania (n = 50) between 2015 and 2021, analyzing parasite genetic population structure and demography.RESULTSThere is no evidence of geographic population structure. Nucleotide diversity was significantly lower than in colocalized P. falciparum isolates, while linkage disequilibrium was significantly higher. Genome-wide selection scans identified no erythrocyte invasion ligands or antimalarial resistance orthologs as top hits; however, targeted analyses of these loci revealed evidence of selective sweeps around 4 erythrocyte invasion ligands and 6 antimalarial resistance orthologs. Demographic inference modeling suggests that African P. malariae is recovering from a bottleneck.CONCLUSIONP. malariae is genomically atypical among human Plasmodium spp. and lacks strong population structure in Africa. The low diversity has potential impacts on understanding persistent versus new infection through genomic epidemiology.FUNDINGBill & Melinda Gates Foundation (grant 002202), USAID/PMI through Jhpiego and CDC, NIH (T32AI007151, T32AI070114, R01AI107949, R01AI129812, R21 AI148579, R01AI137395, R21AI152260, R01AI132547, and K24AI134990), and the DELTAS Africa initiative (DELGEME grant 107740/Z/15/Z).

Plasmodium malariae↗
PubMed1998

Predicting psychological distress among former Soviet immigrants.

This study investigated whether age, gender, marital status, education, employment, length of time in the U.S. and immigration demands (novelty, occupation, language, discrimination, loss, and not feeling at home) were predictors of psychological distress in a sample of 1,647 former Soviet immigrants. Multiple regression analysis indicated that the combined model of demographic and demand of immigration variables was significant. Results indicated that women, older immigrants, those with less than a college education, and those with greater immigration demands related to novelty, language, discrimination, loss, and not feeling at home were most distressed.

Adult↗