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Biomedical subjects

A R Localio

Publications and source records attributed to A R Localio.

At least 19 recordsLinked to original sources
PubMed2004

Incidence of adverse events and negligence in hospitalized patients: results of the Harvard Medical Practice Study I. 1991.

BACKGROUND: As part of an interdisciplinary study of medical injury and malpractice litigation, we estimated the incidence of adverse events, defined as injuries caused by medical management, and of the subgroup of such injuries that resulted from negligent or substandard care. METHODS: We reviewed 30121 randomly selected records from 51 randomly selected acute care, non-psychiatric hospitals in New York State in 1984. We then developed population estimates of injuries and computed rates according to the age and sex of the patients as well as the specialties of the physicians. RESULTS: Adverse events occurred in 3.7% of the hospitalizations (95% confidence interval 3.2 to 4.2), and 27.6% of the adverse events were due to negligence (95% confidence interval 22.5 to 32.6). Although 70.5% of the adverse events gave rise to disability lasting less than 6 months, 2.6% caused permanently disabling injuries and 13.6% led to death. The percentage of adverse events attributable to negligence increased in the categories of more severe injuries (Wald test chi(2) = 21.04, p<0.0001). Using weighted totals we estimated that among the 2671863 patients discharged from New York hospitals in 1984 there were 98609 adverse events and 27179 adverse events involving negligence. Rates of adverse events rose with age (p<0.0001). The percentage of adverse events due to negligence was markedly higher among the elderly (p<0.01). There were significant differences in rates of adverse events among categories of clinical specialties (p<0.0001), but no differences in the percentage due to negligence. CONCLUSIONS: There is a substantial amount of injury to patients from medical management, and many injuries are the result of substandard care.

Adolescent↗
PubMed2001

Adjustments for center in multicenter studies: an overview.

Increasingly, investigators rely on multicenter or multigroup studies to demonstrate effectiveness and generalizability. Authors too often overlook the analytic challenges in these study designs: the correlation of outcomes and exposures among patients within centers, confounding of associations by center, and effect modification of treatment or exposure across center. Correlation or clustering, resulting from the similarity of outcomes among patients within a center, requires an adjustment to confidence intervals and P values, especially in observational studies and in randomized multicenter studies in which treatment is allocated by center rather than by individual patient. Multicenter designs also warrant testing and adjustment for the potential bias of confounding by center, and for the presence of effect modification or interaction by center. This paper uses examples from the recent biomedical literature to highlight the issues and analytic options.

Bias↗
PubMed2001

The effects of contemporary use of coronary stents on in-hospital mortality. Registry Committee of the Society for Cardiac Angiography and Interventions.

OBJECTIVES: This study was designed to determine the effect of coronary stents on in-hospital mortality. BACKGROUND: Despite extensive use of stents for percutaneous coronary interventions (PCIs), their effect on serious in-hospital events, especially mortality, is not well defined. METHODS: A cohort study was performed using 16,811 consecutive native-vessel PCI procedures performed on patients in the Society for Cardiac Angiography & Interventions Registry from July 1, 1996, through December 31, 1998. Patients undergoing balloon-only angioplasty were compared with those receiving a planned or unplanned stent. Procedures with other devices were excluded. Multivariable analyses adjusted for detailed clinical characteristics and for individual laboratory. RESULTS: Stents were associated with a significant reduction in in-hospital mortality (0.3%) compared with balloon procedures (0.6%; multivariable odds ratio [OR] 0.55; 95% confidence interval [CI] 0.34, 0.89; p = 0.014). The risk of emergency coronary bypass also was reduced by stenting (0.3% vs. 0.7%; multivariable OR 0.47; 95% CI: 0.29, 0.76; p = 0.002). Adjustment for the use of glycoprotein IIb/IIIa inhibitors did not change the results, and the effects of stenting relative to balloon procedures were similar in those procedures with and without glycoprotein IIb/IIIa blockade (p = 0.94). CONCLUSIONS: This study suggests that coronary stenting, compared with balloon procedures, reduces in-hospital mortality, independent of the clinical setting.

Adult↗
PubMed2001

Validation of the ICD/AIS MAP for pediatric use.

OBJECTIVE: To determine the performance of the ICD/AIS MAP (EJ MacKenzie et al) as a method of classifying injury severity for children. METHODS: Data on all children less than 16 years of age admitted to all designated trauma centers in Pennsylvania from January 1994 through October 1996 were obtained from the state trauma registry. The ICD/AIS MAP was used to convert all injury related ICD-9-CM diagnosis codes into abbreviated injury scale (AIS) score and injury severity score (ISS). Agreement between trauma registry AIS and ISS scores and MAP generated scores was assessed using the weighted kappa (kappaw) coefficient for ordered data and the intraclass correlation coefficient for continuous data. RESULTS: Agreement in ISS scores was excellent, both overall (intraclass correlation coefficient = 0.86, 95% confidence interval (CI) 0.84 to 0.89)), and when grouped into three levels of severity (kappaw= 0.86, 95% CI 0.85 to 0.87). Agreement in AIS scores across all body regions and ages was also excellent, (kappaw= 0.86 (95% CI 0.83 to 0.87). Agreement increased with age (kappaw= 0.78 for children <2 years; kappaw= 0.86 for older children) and varied by body region, though was excellent across all regions. CONCLUSIONS: The performance of the ICD/AIS MAP in assessing severity of pediatric injuries was equal to or better than previous assessments of its performance on primarily adult patients. Its performance was excellent across the pediatric age range and across nearly all body regions of injury.

Adolescent↗
PubMed2000

Effects of coronary stents on cardiovascular outcomes in broad-based clinical practice.

BACKGROUND: Although stents have been shown to reduce the need for repeated percutaneous coronary intervention (PCI) in randomized trials, the effects of stents in broad-based, diverse clinical practice have not been well studied, nor has their effect on subsequent myocardial infarction or cardiac death. METHODS: A retrospective cohort study was performed that included all 43 hospitals performing PCI in Pennsylvania in the last quarter of 1995, with the use of the Pennsylvania Health Care Cost Containment Council database. All 5258 patients who underwent PCI, excluding those with previous PCI within the preceding 6 months, were included. The primary outcomes were in-hospital events (death or coronary bypass), 6-month revascularization rates, and 6-month rates of cardiac death or myocardial infarction. RESULTS: A total of 1240 patients (24%) had a stent procedure. Compared with nonstent procedures, stents reduced the risk of in-hospital events (multivariable odds ratio adjusted for patient and hospital level differences, 0.63; 95% confidence interval, 0.41-0.97), primarily because of a 52% reduction in the need for coronary bypass. Stents also reduced the need for follow-up revascularization procedures (multivariable hazard ratio, 0.72; 95% confidence interval, 0.59-0. 87), primarily because of a 31% reduction in repeated PCI. However, stents had no effect on 6-month rate of myocardial infarction or cardiac death (multivariable hazard ratio, 0.97; 95% confidence interval, 0.71-1.33). CONCLUSIONS: Using stents decreases the need for repeated PCI in broad-based clinical practice, confirming results from randomized trials. However, this study did not detect any effect on subsequent myocardial infarction or cardiac death.

Adult↗
PubMed2000

Contraceptive requirements for clinical research.

OBJECTIVE: To survey the type and frequency of use of contraceptive requirements for entry into clinical trials. METHODS: We reviewed 410 protocols submitted between January 1994 and January 1997 to one Institutional Review Board. RESULTS: Contraception or sterility for women was required in 171 (41.7%) protocols without explanation and 146 (35.6%) based on study drug. Eight and one half percent hd no exclusions. Signature certification of contraceptive use was required in 138 protocols; 230 required certification of understanding requirements; and 101 required two signatures. Signature certification documenting no pregnancy at enrollment was required in 234 protocols. There were no requirements for signatures from male subjects. Celibacy or sexual orientation were not recognized as reasons for waiver from signature requirements. CONCLUSION: The broad application of contraceptive requirements potentially creates disproportionate burdens and access by gender to participation in clinical research. Careful elucidation of methods, timing, and the consent process in order to avoid potential fetal risk and encourage inclusion of hormonally intact women will improve research and access.

Clinical Protocols↗
PubMed2000

Trends in incidence of pediatric injury hospitalizations in Pennsylvania.

OBJECTIVES: This study analyzed short-term trends in pediatric injury hospitalizations. METHODS: We used a population-based retrospective cohort design to study all children 15 years or younger who were admitted to all acute care hospitals in Pennsylvania with traumatic injuries between 1991 and 1995. RESULTS: Injuries accounted for 9% of all acute hospitalizations for children. Between 1991 and 1995, admissions of children with minor injuries decreased by 29% (P < .001). However, admissions for children with moderate (P = .69) or serious (P = .41) injuries did not change. CONCLUSIONS: Significant declines in pediatric admissions for minor injuries were noted and may reflect both real reductions in injury incidence and changes in admission practices over the period of the study.

Abbreviated Injury Scale↗
PubMed1999

Empirical Bayes estimation of random effects parameters in mixed effects logistic regression models.

We extend an approach for estimating random effects parameters under a random intercept and slope logistic regression model to include standard errors, thereby including confidence intervals. The procedure entails numerical integration to yield posterior empirical Bayes (EB) estimates of random effects parameters and their corresponding posterior standard errors. We incorporate an adjustment of the standard error due to Kass and Steffey (KS; 1989, Journal of the American Statistical Association 84, 717-726) to account for the variability in estimating the variance component of the random effects distribution. In assessing health care providers with respect to adult pneumonia mortality, comparisons are made with the penalized quasi-likelihood (PQL) approximation approach of Breslow and Clayton (1993, Journal of the American Statistical Association 88, 9-25) and a Bayesian approach. To make comparisons with an EB method previously reported in the literature, we apply these approaches to crossover trials data previously analyzed with the estimating equations EB approach of Waclawiw and Liang (1994, Statistics in Medicine 13, 541-551). We also perform simulations to compare the proposed KS and PQL approaches. These two approaches lead to EB estimates of random effects parameters with similar asymptotic bias. However, for many clusters with small cluster size, the proposed KS approach does better than the PQL procedures in terms of coverage of nominal 95% confidence intervals for random effects estimates. For large cluster sizes and a few clusters, the PQL approach performs better than the KS adjustment. These simulation results agree somewhat with those of the data analyses.

Adult↗
PubMed1999

Detection of Björk-Shiley convexo-concave heart valve outlet strut single leg separations: consensus image acquisition and interpretation using two different cineradiographic imaging technologies.

BACKGROUND: Conventional cineradiology has been used clinically to detect partially broken outlet struts (single leg separations, SLSs) in normally functioning Björk-Shiley convexo-concave (C/C) heart valves. The value of radiographic screening has, however, been debated in the medical literature. This study uses the same radiographic technique in sheep implanted with known-status C/C valves in combination with a newly developed geometric image magnification radiography system. This study was designed to test whether sensitivity and specificity of radiographic screening of C/C valves in detecting SLSs could be improved through the combination of readers and imaging modalities. METHODS: Twenty-one sheep with mitral C/C valves were studied on both systems. Five were used for extensive scanning training. When operators were expert on both systems, 16 blinded study valves (4 intact and 12 with outlet strut SLSs) were scanned twice on both systems, first on a modified conventional and then a prototype geometric image magnification (Feinfocus(TM)) cineradiographic system by two expert physicians working together. RESULTS: Among the 32 scanned valves, the two combined expert physicians were required to evaluate 40 intact legs and 24 with an SLS. For all SLS valves, the conventional and Feinfocus systems separately detected 50 (12/24) and 54% (13/24), respectively. When the two systems were combined, the final consensus score was correct in 67% (16/24) of all SLS valves. CONCLUSIONS: Combined modality, paired expert physicians detected 67% of all SLSs. The Feinfocus system might be best reserved for those patients in whom the Siemens screening study demonstrates in minimally suspicious (grade 2) or suspicious (grade 3) appearance of a C/C valve outlet strut leg.

Animals↗
PubMed1999

Reliability and validity of estimating the NIH stroke scale score from medical records.

BACKGROUND AND PURPOSE: The aim of our study was to determine whether the National Institutes of Health Stroke Scale (NIHSS) can be estimated retrospectively from medical records. The NIHSS is a quantitative measure of stroke-related neurological deficit with established reliability and validity for use in prospective clinical research. Recently, retrospective observational studies have estimated NIHSS scores from medical records for quantitative outcome analysis. The reliability and validity of estimation based on chart review has not been determined. METHODS: Thirty-nine patients were selected because their NIHSS scores were formally measured at admission and discharge. Handwritten notes from medical records were abstracted and NIHSS scores were estimated by 6 raters who were blinded to the actual scores. Estimated scores were compared among raters and with the actual measured scores. RESULTS: Interrater reliability was excellent, with an intraclass correlation coefficient of 0.82. Scores were well calibrated among the 6 raters. Estimated NIHSS scores closely approximated the actual scores, with a probability of 0.86 of correctly ranking a set of patients according to 5-point interval categories (as determined by the area under the receiver-operator characteristic curve). Patients with excellent outcomes (NIHSS score of </=5) could be identified with sensitivity of 0.72 and specificity of 0.89. There were no significant differences between these parameters at admission and discharge. CONCLUSIONS: For the purposes of retrospective studies of acute stroke outcome, the NIHSS can be abstracted from medical records with a high degree of reliability and validity.

Cerebrovascular Disorders↗
PubMed1998

In vivo accuracy of two radiographic systems in the detection of Björk-Shiley convexo-concave heart valve outlet strut single leg separations.

OBJECTIVE: Modified cineradiographic systems have been used clinically to detect partially broken outlet struts in normally functioning Björk-Shiley convexo-concave heart valves. Almost all such valves were explanted, presuming that full failure would likely follow. Inasmuch as the clinical setting only rarely permits examination of normally rated valves, the accuracy of radiographic detection cannot be clinically defined. This study uses the clinical radiographic technique in sheep implanted with known-status convexo-concave valves, comparing its accuracy and that of a newly developed, geometric image magnification radiography system. METHODS: Twenty-one sheep with mitral convexo-concave valves were studied on both systems. Five were used for extensive training. When operators were expert with both systems, images of four intact valves and 12 valves with outlet strut single leg separations, along with a seventeenth single leg separation valve used for calibration, were integrated into 112 image sets organized into a balanced incomplete block design for evaluation by eight trained, blinded reviewers. RESULTS: Cineradiography sensitivity was 24% versus 31% for direct image magnification. The odds ratio for detection of single leg separation by direct image magnification versus cineradiography was 2.0 (95% confidence interval, 0.76 to 5.9; p = 0.13). Cineradiography specificity was 93% versus 90% for direct image magnification. Sensitivity and specificity varied markedly by reviewer, with sensitivity ranging from 8% to 55% and specificity from 51% to 100% for the combined technologies. CONCLUSIONS: The data support the need for more intensive training for convexo-concave valve imaging and further investigation of unconventional radiographic technologies. Clinical cineradiography of convexo-concave valves may detect as little as 25% of valves having a single leg separation, underestimating the prevalence of single leg separations and thereby implying more rapid progression to full fracture than is actually the case.

Animals↗
PubMed1998

Anticoagulation therapy in patients with venous thromboembolic disease.

OBJECTIVE: To determine, in a representative sample of patients drawn from a variety of hospitals, the degree of adherence to consensus recommendations for anticoagulation among patients with deep vein thrombosis or pulmonary embolism. DESIGN: Cross-sectional review of a population-based random sample. SETTING: Twenty-one randomly selected Pennsylvania hospitals. PATIENTS: Of 357 randomly selected Medicare beneficiaries discharged from study hospitals with a diagnosis of deep venous thrombosis or pulmonary embolism during 1992, 43 charts were not reviewed for administrative reasons, 31 were miscoded or not treated with intravenous administration of heparin, and 13 were excluded for other reasons, leaving 270 in the final sample. MEASUREMENTS AND MAIN RESULTS: Overall, 179 patients (66%, 95% confidence interval [CI] 59%, 72%) received therapeutic anticoagulation (two consecutive partial thromboplastin times more than 1.5 times control) within 24 hours of starting heparin. Platelet counts were checked at least once during the first week of heparin therapy in 66% (95% CI 58%, 74%). At least 5 days of heparin therapy was given to 84% (95% CI 79%, 87%). Among 266 (99%) of the patients receiving warfarin, 193 (72%; 95% CI 63%, 80%) received heparin until the prothrombin time ratio or International Normalized Ratio was therapeutic. Patients who were started on warfarin therapy within 2 days of heparin had decreased length of stay (geometric mean 8.2 vs 9.7 days, p = .003). Compliance varied among hospitals. CONCLUSIONS: In a wide variety of hospitals, we found fair, but variable, compliance with consensus recommendations for anticoagulation of patients with venous thromboembolic disease. Simple interventions to improve compliance with these recommendations might improve quality of care and reduce costs.

Aged↗
PubMed1997

Radiographic detection of single-leg fracture in Björk-Shiley Convexo-Concave prosthetic valves: a phantom model study.

Cineradiography can identify patients with single-leg fractured Björk-Shiley Convexo-Concave valves, although little is known about the sensitivity and specificity of this technique. We evaluated three normal and six (0 microm gap) single-leg fractured Björk-Shiley valves that were placed in a working phantom model. Valves were randomly imaged a total of 33 times and duplicated into a 120-valve series with a 1:9 ratio of abnormal/normal valves. Six reviewers independently graded each valve and demonstrated markedly different rates of identifying the fractured valves. Average sensitivity at the grade that clinically results in valve explanation was 47%. Among the normal valves, a correct identification was made 96% (range 91% to 99%) of the time. Present radiographic technology may have significant difficulty in identifying true single-leg fracture in Björk-Shiley valves with limb separations that are common among clinically explanted valves.

Angiocardiography↗
PubMed1997

Cost-effectiveness analysis of helicopter EMS for trauma patients.

STUDY OBJECTIVE: To evaluate the cost-effectiveness of helicopter EMS for trauma patients. METHODS: We applied a cost-effectiveness analysis from the service provider's perspective to cost and effectiveness estimates. The cost estimates comprise direct operating costs and additional survivors' hospital costs. The effectiveness estimates were calculated with the TRISS methodology from literature sources and data from a cohort of patients transported by helicopter during 1994 and 1995. Sensitivity analysis and discounting were used. Cost per life saved and discounted cost per year of life in 1995 US dollars were the main outcome measures. RESULTS: The reported literature survival benefit ranges from 1 to 12 additional survivors per 100 patients flown. Transport costs were $2,214 per patient, and each additional survivor's hospitalization averaged $15,883. For the base case (5 additional survivors per 100 patients flown), cost per life was $60,163 and discounted cost per year of life $2,454. Sensitivity analysis revealed that discounted cost per year of life could be as high as $9,677 or as low as $1,400 and that it was most dependent on the surviving benefit. These results are comparable to a reported median discounted cost per year of life of %19,000 for other commonly used lifesaving medical interventions. CONCLUSION: Assuming that helicopter air medical transport provides a substantial survival benefit for trauma patients, our findings suggest that this service is a cost-effective option for the treatment of trauma patients. The magnitude of the survival benefit is the most important factor determining cost-effectiveness.

Air Ambulances↗
PubMed1997

The public release of hospital and physician mortality data in Pennsylvania. A case study.

OBJECTIVES: Using the public reports of the Pennsylvania Health Care Cost Containment Council on coronary artery bypass graft surgery for 1990 to 1992 as a case study, the authors assess the sensitivity of results to the choice of data and statistical methodology. METHODS: Using the Council's public-release data, surgical mortality and utilization were reanalyzed by standard linear models, empirical Bayes methods, Monte Carlo simulations, and hierarchical statistical models. RESULTS: Statistical power calculations demonstrate that the annual volume of bypass surgery for many hospitals and for most surgeons is too small for meaningful mortality comparisons. The number of hospitals and physicians designated as mortality "outliers" in the Council's reports results in part from a failure to adjust critical P values for multiple comparisons. Hierarchical statistical models implemented by mixed effects logistic regression, by contrast, can detect true differences in performance without producing false outliers. Mortality analyses are sensitive to the choice of comorbidities used for severity adjustment of a mortality model. Small-area analyses indicate large differences in the rates of bypass surgery across Pennsylvania, with lower population-based rates of surgery associated with higher population-based inpatient mortality. CONCLUSIONS: Analyses of mortality by operative procedure, rather than by patient diagnosis, should consider the potential for selection bias caused by the decision to elect surgery. The clinical and statistical issues of operative mortality are sufficiently complex to merit review by independent experts before public release of hospital and physician performance measures.

Cardiology Service, Hospital↗
PubMed1996

Identifying adverse events caused by medical care: degree of physician agreement in a retrospective chart review.

OBJECTIVE: To 1) assess the degree of agreement among physicians on the cause of previously flagged adverse outcomes and 2) relate the findings to systems of quality assurance and performance assessment and proposals for no-fault compensation for medical injuries. DESIGN: Observational study of 7533 pairs of "structured implicit" reviews (subjective opinions based on guidelines) of medical records done by 127 physicians working independently. SETTING: Random sample of 51 inpatient facilities in New York State. PATIENTS: Random sample of inpatient medical records from the selected facilities. MEASUREMENTS: 1) Number of agreed-upon adverse events compared with the number of cases of extreme disagreement and 2) internally and indirectly standardized rates at which physician reviewers found adverse events (injuries to patients caused at least in part by medical management). RESULTS: In 12.9% of cases (971 of 7533), the two physicians in a pair had extreme disagreement about the occurrence of an adverse event. These cases outnumbered those in which both reviewers found an adverse event (10%; n = 757). Agreement was highest for wound infections and lowest for adverse events attributed to failure to diagnose or lack of therapy. The amount of experience the physicians had in reviewing records tended to increase the level of agreement. Even after standardization to the results of the entire sample, individual physicians' rates of finding at least slight evidence of an adverse event varied widely (range, 9.9% to 43.7%) (P < 0.001). CONCLUSIONS: Structured implicit reviews produced disagreement on the causes of adverse patient outcomes. If systems of quality assurance, performance audits, or no-fault patient compensation are to succeed, methods for overcoming the common tendency toward disagreement among experts must be developed.

Humans↗
PubMed1996

Measuring defensive medicine using clinical scenario surveys.

For more than two decades, advocates of malpractice system reform have claimed that the most damaging and costly result of the U.S. medical malpractice system is the practice of defensive medicine, in which physicians order tests and procedures primarily because of fear of malpractice liability. In this article, we discuss the issues raised by different definitions of defensive medicine and propose a working definition to guide measurement of the concept. We also consider the strengths and weaknesses of available approaches for measuring defensive medicine. Finally, we describe an empirical approach to measuring defensive medicine using clinical scenario surveys. The results suggest that, if physicians actually practice as they say they would in these surveys, defensive medicine does exist, although not to the extent suggested by anecdotal evidence or direct physician surveys. The results also suggest that defensive medicine varies considerably across clinical situations. In all of the scenarios, many physicians chose aggressive patient management styles even though conservative management was considered medically acceptable by the expert panels that developed the scenarios. In most cases, medical indications, not malpractice concerns, motivated clinical choices. Our results highlight the limitations of surveys as a method of measuring the extent of defensive medicine. The implications of managed care and health care reform for defensive medicine are also discussed.

Attitude of Health Personnel↗