Ralph B D'Agostino

VU University Medical Center, Amsterdamo, North Holland, Netherlands

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Publications (8)50.89 Total impact

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    ABSTRACT: Different research groups sometimes carry out comparable studies. Combining the data can make it possible to address additional research questions, particularly for small observational studies such as those frequently seen in palliative care research. We present a systematic approach to pool individual subject data from observational studies that addresses differences in research design, illustrating the approach with two prospective observational studies on treatment and outcomes of lower respiratory tract infection in US and Dutch nursing home residents. Benefits of pooling individual subject data include enhanced statistical power, the ability to compare outcomes and validate models across sites or settings, and opportunities to develop new measures. In our pooled dataset, we were able to evaluate treatments and end-of-life decisions for comparable patients across settings, which suggested opportunities to improve care. In addition, greater variation in participants and treatments in the combined dataset allowed for subgroup analyses and interaction hypotheses, but required more complex analytic methods. Pitfalls included the large amount of time required for equating study procedures and variables and the need for additional funding.
    Palliative Medicine 10/2008; 22(6):750-9. · 2.61 Impact Factor
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    ABSTRACT: Generalizability of clinical predictors for mortality from lower respiratory infection (LRI) in nursing home residents has not been assessed for residents with dementia. In prospective cohort studies of LRI in 61 nursing homes in the Netherlands (n = 541) and 36 nursing homes in Missouri, USA (n = 564), we examined 14-day and 1- and 3-month mortality in residents with dementia who were treated with antibiotics. A logistic model predicting 14-day mortality derived from Dutch data included eating dependency, elevated pulse, decreased alertness, respiratory difficulty, insufficient fluid intake, high respiratory rate, male gender, and pressure sores. After adjusting coefficients with the heuristic shrinkage factor, the 14-day model showed good discrimination and calibration in both datasets. The apparent c-statistic for the original Dutch model was 0.80 (after correction for optimism, it was 0.75); the c-statistic was 0.74 in the U.S. validation population. The models predicting 1- and 3-month mortality showed moderate performance. A scoring system for estimating 14-day mortality performed equally well as the original model. We identified a set of credible clinical predictors that are easily assessed and demonstrated validity in identifying residents at low risk of dying from LRI across different nursing home populations. This tool should inform decision-making for families and doctors.
    Journal of Clinical Epidemiology 10/2006; 59(9):970-9. · 5.48 Impact Factor
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    ABSTRACT: Lower respiratory infection (LRI) is the leading cause of hospitalization for nursing home residents, but hospitalization is costly and may cause complications. We sought to compare mortality and cost between episodes of LRI initially treated in the hospital versus the nursing home after controlling for illness severity and the probability of hospitalization. This was a prospective cohort study of nursing home residents with LRIs. We identified 1406 episodes of LRI in 36 nursing homes in central Missouri and the St. Louis area between August 15, 1995, and September 30, 1998. Economic analysis was restricted to 1033 episodes identified after March 31, 1997. We adjusted for the higher probability of initial hospitalization in sicker residents using measures of illness severity and a hospitalization propensity score. The propensity score was derived from a logistic regression model that included patient, physician, and facility variables. Estimated costs were attributed to initial treatment setting. After controlling for the probability of hospitalization and illness severity, hospitalization was not a significant mortality predictor (odds ratio 0.89, 95% confidence interval 0.52-1.52). Mean daily cost was $138.24 for initial nursing home treatment and $419.75 for the hospital. After controlling for illness severity and propensity for hospitalization, hospital treatment is not associated with either increased or decreased risk for mortality for nursing home residents with LRIs. For residents with low and medium mortality risk, nursing home treatment is likely to be safe and less costly.
    Medical Care 10/2004; 42(9):860-70. · 3.23 Impact Factor
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    ABSTRACT: Scant information exists about the risk of functional decline following treatment of acute illness in the nursing home (NH) setting. The aim of this study was to determine the incidence of short-term (30-day) functional decline among survivors of NH-acquired lower respiratory tract infection (LRI) and the factors that predict such decline, including the role of initial hospitalization. We used a prospective cohort design to study 781 episodes of LRI in 1044 NH residents in 36 NHs in central Missouri and the St. Louis metropolitan area. Functional decline was defined as a 3-point increase on the Minimum Data Set (MDS) activities of daily living (ADL) long form scale. Of 781 LRI cases who survived to 30 days, the incidence of ADL decline was 28.8%. In a logistic regression model that used generalized estimating equations to adjust for clustering, variables associated with ADL decline included the following: chronic feeding tube use (AOR = 4.54, 95% confidence interval, or CI, 1.61, 12.80), decubitus ulcer (adjusted odds ratio [AOR] = 2.29, 95% CI 1.35, 3.90), shortness of breath (AOR = 2.18, 95% CI 1.44, 3.30), short-term memory problems (AOR = 2.07, 95% CI 1.33, 3.23), decline in self-performance of toilet use in the 24 hours prior to evaluation (AOR = 1.65, 95% CI 1.29, 2.12), age (AOR = 1.02, 95% CI 1.00, 1.05), and baseline ADL score. Addition of treatment variables to the model showed that initial hospitalization was also associated with ADL decline (AOR = 1.90, 95% CI 1.20, 3.00). Residents with ADL decline at 30 days were less likely to recover to their baseline ADL status at 90 days. Many NH residents who survive to 30 days following LRI develop new functional limitations, and such individuals are at risk for ADL decline at 90 days. A limited number of clinical variables may predict short-term functional decline. Initial hospitalization for acute treatment of LRI may increase the risk of subsequent ADL decline among individuals who survive to 30 days.
    The Journals of Gerontology Series A Biological Sciences and Medical Sciences 02/2003; 58(1):60-7. · 4.31 Impact Factor
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    ABSTRACT: Lower respiratory tract infection (LRI) is a leading cause of mortality and hospitalization in nursing home residents. Treatment decisions may be aided by a clinical prediction rule that identifies residents at low and high risk of mortality. To identify patient characteristics predictive of 30-day mortality in nursing home residents with an LRI. Prospective cohort study of 1406 episodes of LRI in 1044 residents of 36 nursing homes in central Missouri and the St Louis, Mo, area between August 15, 1995, and September 30, 1998. Thirty-day all-cause mortality. Thirty-day mortality was 14.7% (n = 207). In a logistic analysis, using generalized estimating equations to adjust for clustering, we developed an 8-variable model to predict 30-day mortality, including serum urea nitrogen, white blood cell count, body mass index, pulse rate, activities of daily living status, absolute lymphocyte count of less than 800/microL (0.8 x 10(9)/L), male sex, and deterioration in mood over 90 days. In validation testing, the model exhibited reasonable discrimination (c =.76) and calibration (nonsignificant Hosmer-Lemeshow goodness-of-fit statistic, P =.54). A point score based on this model's variables fit to the entire data set closely matched observed mortality. Fifty-two percent of residents had low (score of 0-4) or relatively low (score of 5-6) predicted 30-day mortality, with 2.2% and 6.2% actual mortality, respectively. Our model distinguishes nursing home residents at relatively low risk for mortality due to LRI. If independently validated, our findings could help physicians identify nursing home residents in need of different therapeutic approaches for LRI.
    JAMA The Journal of the American Medical Association 12/2001; 286(19):2427-36. · 29.98 Impact Factor
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    ABSTRACT: Subtle presentation and the frequent lack of on-site physicians complicate the diagnosis of pneumonia in nursing home residents. We sought to identify clinical findings (signs, symptoms, and simple laboratory studies) associated with radiographic pneumonia in sick nursing home residents. This was a prospective cohort study. The residents of 36 nursing homes in central Missouri and the St. Louis area with signs or symptoms suggesting a lower respiratory infection were included. We compared evaluation findings by project nurses with findings reported from chest radiographs. Among 2334 episodes of illness in 1474 nursing home residents, 45% of the radiograph reports suggested pneumonia (possible=12%; probable or definite = 33%). In 80% of pneumonia episodes, subjects had 3 or fewer respiratory or general symptoms. Eight variables were significant independent predictors of pneumonia (increased pulse, respiratory rate =30, temperature =38 degrees C, somnolence or decreased alertness, presence of acute confusion, lung crackles on auscultation, absence of wheezes, and increased white blood count). A simple score (range = -1 to 8) on the basis of these variables identified 33% of subjects (score > or =3) with more than 50% probability of pneumonia and an additional 24% (score of 2) with 44% probability of pneumonia. Pneumonia in nursing home residents is usually associated with few symptoms. Nonetheless, a simple clinical prediction rule can identify residents at very high risk of pneumonia. If validated in other studies, physicians could consider treating such residents without obtaining a chest radiograph.
    The Journal of family practice 11/2001; 50(11):931-7. · 0.67 Impact Factor
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    ABSTRACT: Although lower respiratory tract infections are a leading cause of death in frail elderly patients, few studies have compared treatments and outcomes. We assessed the effects of different antibiotic treatment strategies on survival of elderly nursing home residents with lower respiratory tract infections in the United States and the Netherlands, where treatment approaches are quite different. We combined data from 2 prospective cohort studies of lower respiratory tract infections conducted in 36 nursing homes in the United States and 61 in the Netherlands. We included residents whose infections were treated with antibiotics: 806 in the United States and 415 in the Netherlands. Outcome measures were 1-month and 3-month mortality. We used logistic regression to adjust for differing illness severity. Dutch residents had higher mortality than US residents (28.1% vs 15.1% at 1 month, respectively; P <.001). After adjusting for illness severity with logistic regression, the differences between the Dutch and US populations were not significant (odds ratio 1.34; 95% confidence interval, 0.94-1.90). Predicted mortality was overestimated for more severely ill US residents at 1 month but not at 3 months. No antibiotic regimen was consistently associated with increased or decreased mortality. Despite differences in illness severity and treatment, adjusted mortality did not differ between the 2 countries. Although we cannot exclude a short-term survival benefit from more aggressive treatment in the United States, differences in baseline health appear prognostically more important than the type of antibiotic treatment.
    The Annals of Family Medicine 3(5):422-9. · 4.61 Impact Factor