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Derek C Angus

Publications and source records attributed to Derek C Angus.

88 records · Page 5Linked to original sources
PubMed2003

Cost-effectiveness of inhaled nitric oxide in the treatment of neonatal respiratory failure in the United States.

OBJECTIVE: Two recent randomized controlled trials (RCTs) reported that inhaled nitric oxide (iNO) decreased the incidence of extracorporeal membrane oxygenation (ECMO) or death in term and near-term newborns with hypoxic respiratory failure. Our objective was to estimate the cost-effectiveness ratio of iNO in this population. METHODS: We studied 1000 simulation cohorts (n = 483 for each cohort) of term/near-term newborns with hypoxemic respiratory failure. We conducted our study following US Public Health Service Panel on Cost-Effectiveness in Health and Medicine guidelines, adopting the US societal perspective. We constructed a decision tree reflecting iNO use, subsequent ECMO use, death, and long-term neurologic and respiratory morbidity in survivors, as determined from the combined outcomes of the 2 RCTs (n = 483). We estimated costs on the basis of length-of-stay data for the initial episode of care from 1 of the RCTs, unit costs from administrative data sets, and current pricing for iNO. We ran a Monte Carlo simulation to generate estimates of differences in costs and effects at 1 year, along with the stochastic uncertainty around these estimates. We expressed effects as quality-adjusted survival, assuming quality of life = 1 with no comorbidity, 0.7 with 1 comorbidity, and 0.49 (0.7 x 0.7) with 2 comorbidities. We constructed a base case, in which iNO was initiated at tertiary care ECMO centers (mimicking the RCTs) and a Public Health Service Panel on Cost-effectiveness in Health and Medicine reference case, in which iNO was initiated at the local hospital before transfer (mimicking real-world practice). We exposed our assumptions to a sensitivity analysis. RESULTS: Direct application of the trial results (base case) suggested that iNO was both more effective and cheaper (cost savings of 1880 dollars per case despite acquisition costs of 5150 dollars, predominantly as a result of decreased need for ECMO), with 84.6% probability that the cost-effectiveness ratio was better than 100,000 dollars per quality-adjusted life-year. Under the reference case, iNO was also more effective (though slightly less so) and was even cheaper (cost savings of 4400 dollars per case), with 71.6% probability that iNO was cheaper and more effective and 91.6% probability that the cost effectiveness ratio was better than 100,000 dollars per quality-adjusted life-year. Sensitivity analyses showed these estimates to be sensitive to patient selection and the price of iNO but insensitive to assumptions regarding quality of life. CONCLUSIONS: From a US societal perspective, iNO has a favorable cost-effectiveness profile when initiated either at ECMO centers or at local hospitals in term/near-term neonates with hypoxemic respiratory failure.

Cost-Benefit Analysis↗
PubMed2002

The epidemiology of severe sepsis in children in the United States.

Despite extensive research into the etiology and treatment of severe sepsis, little is known about its epidemiology in children. We sought to determine the age- and sex-adjusted incidence, outcome, and associated hospital costs of severe sepsis in United States children using 1995 hospital discharge and population data from seven states (24% of the United States population). Of 1,586,253 hospitalizations in children who were 19 years old or less, 9,675 met International Classification of Diseases, 9th revision, clinical modification-based severe sepsis criteria or 42,364 cases of pediatric severe sepsis per year nationally (0.56 cases per 1,000 population per year). The incidence was the highest in infants (5.16 per 1,000), fell dramatically in older children (0.20 per 1,000 in 10 to 14 year olds), and was 15% higher in boys than in girls (0.60 versus 0.52 per 1,000, p < 0.001). Hospital mortality was 10.3%, or 4,383 deaths nationally (6.2 per 100,000 population). Half of the cases had underlying disease (49.0%), and over one-fifth (22.9%) were low-birth-weight newborns. Respiratory infections (37%) and primary bacteremia (25%) were the most common infections. The mean length of stay and cost were 31 days and $40,600, respectively. Estimated annual total costs were 1.97 billion US dollars nationally. Severe sepsis is a significant health problem in children and is associated with the use of extensive healthcare resources. Infants are at highest risk, especially those with a low birth weight.

Adolescent↗
PubMed2002

Physician staffing patterns and clinical outcomes in critically ill patients: a systematic review.

CONTEXT: Intensive care unit (ICU) physician staffing varies widely, and its association with patient outcomes remains unclear. OBJECTIVE: To evaluate the association between ICU physician staffing and patient outcomes. DATA SOURCES: We searched MEDLINE (January 1, 1965, through September 30, 2001) for the following medical subject heading (MeSH) terms: intensive care units, ICU, health resources/utilization, hospitalization, medical staff, hospital organization and administration, personnel staffing and scheduling, length of stay, and LOS. We also used the following text words: staffing, intensivist, critical, care, and specialist. To identify observational studies, we added the MeSH terms case-control study and retrospective study. Although we searched for non-English-language citations, we reviewed only English-language articles. We also searched EMBASE, HealthStar (Health Services, Technology, Administration, and Research), and HSRPROJ (Health Services Research Projects in Progress) via Internet Grateful Med and The Cochrane Library and hand searched abstract proceedings from intensive care national scientific meetings (January 1, 1994, through December 31, 2001). STUDY SELECTION: We selected randomized and observational controlled trials of critically ill adults or children. Studies examined ICU attending physician staffing strategies and the outcomes of hospital and ICU mortality and length of stay (LOS). Studies were selected and critiqued by 2 reviewers. We reviewed 2590 abstracts and identified 26 relevant observational studies (of which 1 included 2 comparisons), resulting in 27 comparisons of alternative staffing strategies. Twenty studies focused on a single ICU. DATA SYNTHESIS: We grouped ICU physician staffing into low-intensity (no intensivist or elective intensivist consultation) or high-intensity (mandatory intensivist consultation or closed ICU [all care directed by intensivist]) groups. High-intensity staffing was associated with lower hospital mortality in 16 of 17 studies (94%) and with a pooled estimate of the relative risk for hospital mortality of 0.71 (95% confidence interval [CI], 0.62-0.82). High-intensity staffing was associated with a lower ICU mortality in 14 of 15 studies (93%) and with a pooled estimate of the relative risk for ICU mortality of 0.61 (95% CI, 0.50-0.75). High-intensity staffing reduced hospital LOS in 10 of 13 studies and reduced ICU LOS in 14 of 18 studies without case-mix adjustment. High-intensity staffing was associated with reduced hospital LOS in 2 of 4 studies and ICU LOS in both studies that adjusted for case mix. No study found increased LOS with high-intensity staffing after case-mix adjustment. CONCLUSIONS: High-intensity vs low-intensity ICU physician staffing is associated with reduced hospital and ICU mortality and hospital and ICU LOS.

Adult↗
PubMed2002

Severe community-acquired pneumonia: use of intensive care services and evaluation of American and British Thoracic Society Diagnostic criteria.

Despite careful evaluation of changes in hospital care for community-acquired pneumonia (CAP), little is known about intensive care unit (ICU) use in the treatment of this disease. There are criteria that define CAP as "severe," but evaluation of their predictive value is limited. We compared characteristics, course, and outcome of inpatients who did (n = 170) and did not (n = 1,169) receive ICU care in the Pneumonia Patient Outcomes Research Team prospective cohort. We also assessed the predictive characteristics of four prediction rules (the original and revised American Thoracic Society criteria, the British Thoracic Society criteria, and the Pneumonia Severity Index [PSI]) for ICU admission, mechanical ventilation, medical complications, and death (as proxies for severe CAP). ICU patients were more likely to be admitted from home and had more comorbid conditions. Reasons for ICU admission included respiratory failure (57%), hemodynamic monitoring (32%), and shock (16%). ICU patients incurred longer hospital stays (23.2 vs. 9.1 days, p < 0.001), higher hospital costs (21,144 dollars vs. 5,785 dollars, p < 0.001), more nonpulmonary organ dysfunction, and higher hospital mortality (18.2 vs. 5.0%, p < 0.001). Although ICU patients were sicker, 27% were of low risk (PSI Risk Classes I-III). Severity-adjusted ICU admission rates varied across institutions, but mechanical ventilation rates did not. The revised American Thoracic Society criteria rule was the best discriminator of ICU admission and mechanical ventilation (area under the receiver operating characteristic curve, 0.68 and 0.74, respectively) but none of the prediction rules were particularly good. The PSI was the best predictor of medical complications and death (area under the receiver operating characteristic curve, 0.65 and 0.75, respectively), but again, none of the prediction rules were particularly good. In conclusion, ICU use for CAP is common and expensive but admission rates are variable. Clinical prediction rules for severe CAP do not appear adequately robust to guide clinical care at the current time.

Adolescent↗
PubMed2002

Hospitalized community-acquired pneumonia in the elderly: age- and sex-related patterns of care and outcome in the United States.

Community-acquired pneumonia (CAP) is a frequent cause of hospital admission and death among elderly patients, but there is little information on age- and sex-specific incidence, patterns of care (intensive care unit admission and mechanical ventilation), resource use (length of stay and hospital costs), and outcome (mortality). We conducted an observational cohort study of all Medicare recipients, aged 65 years or older, hospitalized in nonfederal U.S. hospitals in 1997, who met ICD-9-CM-based criteria for CAP. We identified 623,718 hospital admissions for CAP (18.3 per 1,000 population > or = 65 years), of which 26,476 (4.3%) were from nursing homes and of which 66,045 (10.6%) died. The incidence rose five-fold and mortality doubled as age increased from 65-69 to older than 90 years. Men had a higher mortality, both unadjusted (odds ratio [OR]: 1.21 [95% CI: 1.19-1.23]) and adjusted for age, location before admission, underlying comorbidity, and microbiologic etiology (OR: 1.15 [95% CI: 1.13-1.17]). Mean hospital length of stay and costs per hospital admission were 7.6 days and $6,949. For those admitted to the intensive care unit (22.4%) and for those receiving mechanical ventilation (7.2%), mean length of stay and costs were 11.3 days and $14,294, and 15.7 days and $23,961, respectively. Overall hospital costs were $4.4 billion (6.3% of the expenditure in the elderly for acute hospital care), of which $2.1 billion was incurred by cases managed in intensive care units. We conclude that in the hospitalized elderly, CAP is a common and frequently fatal disease that often requires intensive care unit admission and mechanical ventilation and consumes considerable health care resources. The sex differences are of concern and require further investigation.

Age Distribution↗
PubMed2002

Renal failure in the ICU: comparison of the impact of acute renal failure and end-stage renal disease on ICU outcomes.

BACKGROUND: Acute renal failure (ARF) is associated with a persistent high mortality in critically ill patients in intensive care units (ICUs). Most studies to date have focused on patients with established, intrinsic ARF or relatively severe ARF due to multiple factors. None have examined outcomes of dialysis-dependent chronic renal failure [end-stage renal disease (ESRD)] patients in the ICU. We examined the incidence and outcomes of ARF in the ICU using a standard definition and compared these to outcomes of ICU patients with either ESRD or no renal failure. We sought to determine the impact of renal dysfunction and/or loss of organ function on outcome. METHODS: We prospectively scored 1530 admissions to eight ICUs over a 10-month period for illness severity at ICU admission using the Acute Physiological and Chronic Health Evaluation (APACHE III) evaluation tool. Patients were defined as having ARF based on the definition of Hou et al (Am J Med 74:243-248,1983) designed to detect significant measurable declines in renal function based on serum creatinine. ESRD patients were identified as being chronically dialysis-dependent prior to ICU admission and the remainder had no renal failure. Clinical characteristics at ICU admission and ICU and hospital outcomes were compared between the three groups. RESULTS: We identified 254 cases of ARF, 57 cases of ESRD and 1219 cases of no renal failure for an incidence of ARF of 17%. Roughly half the ARF patients had ARF at ICU admission and the remainder developed ARF during their ICU stay. Only 11% of ARF patients required dialysis support. ARF patients had significantly higher acute illness severity scores than those with no renal failure, whereas patients with ESRD had intermediate severity scores. ICU mortality was 23% for patients with ARF, 11% for those with ESRD, and 5% for those with no renal failure. There was no difference in outcome between patients who had ARF at ICU admission and those who developed ARF in the ICU. Patients with ARF severe enough to require dialysis had a mortality of 57%. APACHE III predicted outcome very well in patients with no renal failure and patients with ARF at the time of scoring but underpredicted mortality in those who developed ARF after ICU admission and overestimated mortality in patients with ESRD. CONCLUSIONS: ARF is common in ICU patients and has a persistent negative impact on outcomes, although the majority of ARF is not severe enough to require dialysis support. The mortality of patients with ARF from all causes is almost exactly similar to that noted using the same criteria two decades ago. More profound ARF requiring dialysis continues to have an even greater mortality. Nevertheless, acute declines in renal function are associated with a mortality that is not well explained simply by loss of organ function. The majority of ARF patients who did not require dialysis still had a considerably higher mortality than the ESRD patients, all of whom required dialysis; while ARF patients who did require dialysis had a much higher morality than ESRD patients. APACHE III performs well and captures the mortality of patients with ARF at the time of scoring. Development of ARF after scoring has a profound effect on standardized mortality. We were unable to identify a unique mortality associated with ARF, but the presence of measurable renal insufficiency continues to be a sensitive marker for poor outcome.

APACHE↗
PubMed2002

The first international consensus conference on continuous renal replacement therapy.

BACKGROUND: Management of acute renal failure (ARF) in the critically ill is extremely variable and there are no published standards for the provision of renal replacement therapy in this population. We sought to review the available evidence, make evidence-based practice recommendations, and delineate key questions for future study. METHODS: We undertook an evidence-based review of the literature on continuous renal replacement therapy (CRRT) using MEDLINE searches. We determined a list of key questions and convened a 2-day consensus conference to develop summary statements via a series of alternating breakout and plenary sessions. In these sessions, we identified supporting evidence and generated practice guidelines and/or directions for future research. RESULTS: Of the 46 questions considered, we found consensus for 20. We found inadequate evidence for 21 questions and for the remaining five we found data but no consensus. Full versions of workgroup findings are available on the Internet at http://www.ADQI.net. CONCLUSIONS: Despite limited data, broad areas of consensus exist for use of CRRT and guideline development appears feasible. Equally broad areas of disagreement also exist and additional basic and applied research in acute renal failure is needed.

Acute Kidney Injury↗
PubMed2002

A new conceptual framework for ICU performance appraisal and improvement.

PURPOSE: This study examined the use of outcomes for the purposes of ICU evaluation and improvement. We reviewed the strengths and weaknesses of an outcomes-centered approach to intensive care unit (ICU) evaluation and present a more comprehensive conceptual framework for ICU evaluation and improvement. MATERIALS AND METHODS: Data was collected from 2 sources: (1) a structured review of the literature, with relevant articles identified using Medline, and (2) 85 semistructured interviews of health care professionals (eg, physicians) and health care administrators (eg, chief executive officer). The interviewees came from 4 institutions: a 900-bed East Coast teaching medical center, a 600-bed East Coast teaching medical center, a 590-bed East Coast teaching medical center, and a 435-bed West Coast private community hospital. A nonrandomized, purposeful sample was used. RESULTS: A conceptual framework for ICU evaluation is presented that identifies and defines 3 different types of variables: performance (eg, appropriateness of care, effectiveness of care), outcome (eg, resource use, mortality), and process (eg, timeliness of treatment, work environment). The framework emphasizes performance variables and the relationships between performance, outcome, and process of care variables, as a logical focus for ICU evaluation and improvement. CONCLUSIONS: Performance variables offer distinct advantages over outcome variables for ICU evaluation. Their use, however, will require additional development of current evaluation tools and methods. They provide the ability to identify the value an ICU adds to patient care in a hospital or to an episode of illness, and to evaluate integrated systems for providing care.

Chief Executive Officers, Hospital↗
PubMed2002

Does acute organ dysfunction predict patient-centered outcomes?

BACKGROUND: Long-term patient-centered outcomes after acute illness may be associated with baseline health status, the development of acute organ dysfunction (AOD), or both. STUDY OBJECTIVE: To determine whether AOD (occurring in the first 30 days) was independently associated with 90-day survival, functional status, and health-related quality of life (HRQL) after controlling for baseline health status in patients who were hospitalized with community-acquired pneumonia (CAP) and survived to day 30. DESIGN: Prospective observational study. SETTING: Four hospitals in Pennsylvania, Massachusetts, and Nova Scotia, Canada, between October 1991 and March 1994. PATIENTS: One thousand three hundred thirty-nine patients who were hospitalized with CAP. INTERVENTIONS: Baseline and 90-day quality-of-life and functional status questionnaires. MEASUREMENTS AND RESULTS: We determined the 90-day survival rate in all patients (n = 1,339) and the functional status and HRQL in subsets of 261 and 219 patients, respectively. AOD occurred in one or more organ system in 639 patients (47.7%) and in two or more organ systems in 255 patients (19.1%). In univariate analyses, greater AOD was associated with a higher mortality rate (p < 0.0001), a lower HRQL (p = 0.006), and lower functional status (p = 0.009) at 90 days. However, after adjusting for baseline HRQL, AOD was not associated with mortality (p = 0.47) or HRQL (p = 0.14) at 90 days and was only weakly associated with 90-day functional status (p = 0.02). CONCLUSIONS: Although patients who develop AOD are at risk for late adverse outcomes, their risk is due predominantly to poor baseline status prior to illness and not to the organ dysfunction per se. Therefore, AOD does not appear to have significant long-term ramifications for patient-centered outcomes.

Adolescent↗
PubMed2001

Continuous versus intermittent renal replacement therapy: a meta-analysis.

OBJECTIVE: Patients with critical illness commonly develop acute renal failure requiring mechanical support in the form of either continuous renal replacement therapy (CRRT) or intermittent hemodialysis (IRRT). As controversy exists regarding which modality should be used for most patients with critically illness, we sought to determine whether CRRT or IRRT is associated with better survival. DESIGN: We performed a meta-analysis of all prior randomized and observational studies that compared CRRT with IRRT. Studies were identified through a MEDLINE search, the authors' files, bibliographies of review articles, abstracts and proceedings of scientific meetings. Studies were assessed for baseline characteristics, intervention, outcome and overall quality through blinded review. The primary end-point was hospital mortality, assessed by cumulative relative risk (RR). MEASUREMENTS AND RESULTS: We identified 13 studies ( n=1400), only three of which were randomized. Overall there was no difference in mortality (RR 0.93 (0.79-1.09), p=0.29). However, study quality was poor and only six studies compared groups of equal severity of illness at baseline (time of enrollment). Adjusting for study quality and severity of illness, mortality was lower in patients treated with CRRT (RR 0.72 (0.60-0.87), p<0.01). In the six studies with similar baseline severity, unadjusted mortality was also lower with CRRT (RR 0.48 (0.34 -0.69), p<0.0005). CONCLUSIONS: Current evidence is insufficient to draw strong conclusions regarding the mode of replacement therapy for acute renal failure in the critically ill. However, the life-saving potential with CRRT suggested in our secondary analyses warrants further investigation by a large, randomized trial.

Critical Care↗
PubMedDate not supplied

A clinically based discrete-event simulation of end-stage liver disease and the organ allocation process.

BACKGROUND: The optimal allocation of scarce donor livers is a contentious health care issue requiring careful analysis. The objective of this article was to design a biologically based discrete-event simulation to test proposed changes in allocation policies. METHODS: The authors used data from multiple sources to simulate end-stage liver disease and the complex allocation system. To validate the model, they compared simulation output with historical data. RESULTS: Simulation outcomes were within 1% to 2% of actual results for measures such as new candidates, donated livers, and transplants by year. The model overestimated the yearly size of the waiting list by 5% in the last year of the simulation and the total number of pretransplant deaths by 10%. CONCLUSION: The authors created a discrete-event simulation model that represents the biology of end-stage liver disease and the health care organization of transplantation in the United States.

Adolescent↗
PubMedDate not supplied

Incorporating biological natural history in simulation models: empirical estimates of the progression of end-stage liver disease.

OBJECTIVE: To develop an empiric natural-history model that can predict quantitative changes in the laboratory values and clinical characteristics of patients with end-stage liver disease (ESLD), to be used to calibrate an individual microsimulation model. METHODS: The authors report the development of a stochastic model that uses cubic splines to interpolate between observed laboratory values over time in a cohort of 1997 patients with ESLD awaiting liver transplantation at the University of Pittsburgh Medical Center. The splines were recursively sampled to provide a stochastic, quantitative natural history of each candidate's disease. RESULTS: The model was able to simulate the types of erratic disease trajectories that occur in individual patients and was able to preserve the statistical properties of the natural history of ESLD in cohorts of real patients. Moreover, the model was able to predict pretransplant survival rates (87% at 1 year), which were statistically similar to rates observed in the authors' local cohort (92%). CONCLUSIONS: Cubic splines can be used to generate quantitative natural histories for individual patients with ESLD and may be useful for developing clinically robust microsimulation models of other diseases.

Disease Progression↗