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Biomedical subjects

R E Park

Publications and source records attributed to R E Park.

At least 19 recordsLinked to original sources
PubMed1998

The reproducibility of a method to identify the overuse and underuse of medical procedures.

BACKGROUND: To assess the overuse and underuse of medical procedures, various methods have been developed, but their reproducibility has not been evaluated. This study estimates the reproducibility of one commonly used method. METHODS: We performed a parallel, three-way replication of the RAND-University of California at Los Angeles appropriateness method as applied to two medical procedures, coronary revascularization and hysterectomy. Three nine-member multidisciplinary panels of experts were composed for each procedure by stratified random sampling from a list of experts nominated by the relevant specialty societies. Each panel independently rated the same set of clinical scenarios in terms of the appropriateness of the relevant procedure on a risk-benefit scale ranging from 1 to 9. Final ratings were used to classify the procedure in each scenario as necessary or not necessary (to evaluate underuse) and inappropriate or not inappropriate (to evaluate overuse). Reproducibility was measured by overall agreement and by the kappa statistic. The criteria for underuse and overuse derived from these ratings were then applied to real populations of patients who had undergone coronary revascularization or hysterectomy. RESULTS: The rates of agreement among the three coronary-revascularization panels were 95, 94, and 96 percent for inappropriate-use scenarios and 93, 92, and 92 percent for necessary-use scenarios. Agreement among the three hysterectomy panels was 88, 70, and 74 percent for inappropriate-use scenarios. Scenarios involving necessary use of hysterectomy were not assessed. The three-way kappa statistic to detect overuse was 0.52 for coronary revascularization and 0.51 for hysterectomy. The three-way kappa statistic to detect underuse of coronary revascularization was 0.83. Application of individual panels' criteria to real populations of patients resulted in a 100 percent variation in the proportion of cases classified as inappropriate and a 20 percent variation in the proportion of cases classified as necessary. CONCLUSIONS: The appropriateness method is far from perfect. Appropriateness criteria may be useful in comparing levels of appropriate procedures among populations but should not by themselves be used to direct care for individual patients.

Delphi Technique↗
PubMed1998

Delphi-panel analysis of appropriateness of high-dose therapy and bone marrow transplants in adults with acute lymphoblastic leukemia in first remission.

BACKGROUND: There is controversy over whether high-dose therapy and a bone marrow transplant is better than conventional-dose chemotherapy in adults with acute lymphoblastic leukemia (ALL) in first remission. This decision may depend on which type of donor is available: an HLA-identical sibling, an alternative donor transplant (HLA-matched related or unrelated people other than HLA-identical siblings), or autotransplant. OBJECTIVE: To determine the appropriate use of high-dose therapy and bone marrow transplants in ALL in first remission. Develop a treatment algorithm. PANELISTS: Nine leukemia experts from diverse geographic sites and practice settings. EVIDENCE: Boolean MEDLINE searches of acute lymphoblastic leukemia and chemotherapy and/or transplants. CONSENSUS PROCESS: We used a modified Delphi-panel group judgment process. Age, white blood cell (WBC) count, cytogenetics and immune type were permuted to define 48 clinical settings. Each panelist rated appropriateness of high-dose therapy and a transplant versus conventional-dose chemotherapy on a 9-point ordinal scale (1, most inappropriate; 9, most appropriate) considering three types of donors: (1) HLA-identical siblings; (2) alternative donors; and (3) autotransplants. An appropriateness index was developed based on median rating and amount of disagreement. Relationship of appropriateness indices to the permuted clinical variables was considered by analysis of variance and recursive partitioning. Preference between donor types was analyzed by comparing mean appropriateness indices of comparable settings and a treatment algorithm was developed. CONCLUSIONS: In people with an HLA-identical sibling donor, transplants were rated appropriate in those with unfavorable cytogenetics and uncertain in all other settings. An HLA-identical sibling donor was always preferred to an alternative donor or autotransplant. In people without an HLA-identical sibling but with an alternative donor, this type of transplant was rated appropriate in those with unfavorable cytogenetics. However, an autotransplant was preferred over an alternative donor transplant in all other settings where a transplant was rated uncertain. In people without an HLA-identical sibling or alternative donor, autotransplants were rated uncertain in all settings except in those with not unfavorable cytogenetics, WBC < 100 x 10(9) l(-1) and T- or pre-B-cell type where they were rated inappropriate.

Adolescent↗
PubMed1998

The development of indications for the preoperative use of recombinant erythropoietin.

OBJECTIVE: To develop indications for the preoperative use of recombinant erythropoietin (rHuEPO) alone and in conjunction with preoperative autologous donation (PAD). DESIGN: A 2-round modified Delphi-consensus process. PARTICIPANTS: Nine physicians representing multiple clinical specialties, practice environments and geographic locations. METHOD: From evidence tables and a literature summary (MEDLINE database from January 1985 to August 1996) provided and using the RAND-UCLA appropriateness method, the physicians developed 264 indications for the preoperative use of rHuEPO by permuting 7 clinical factors (age, history of transfusion or antibody incompatibility, hemoglobin level, anemia of chronic disease, expected blood loss, presence of cardiovascular or cardiopulmonary disease and patient anxiety). These indications were rated on a 9-point appropriateness scale. Median scores and measures of agreement were determined. OUTCOME MEASURES: The significance of cost constraints or cost and blood supply constraints and the impact of each clinical factor on the ratings as judged by statistical analysis. RESULTS: Of the 264 indications, 54% were rated appropriate, 18% uncertain and 28% inappropriate. Expected blood loss had the greatest impact on the ratings (high expected blood loss had a 5.9 point more appropriate rating on the 9-point scale than low expected blood loss [p < 0.0001]). Preoperative hemoglobin level also significantly influenced the ratings (p < 0.0001). Compared with the clinical context, the ratings under the cost constraint were 1.0 less appropriate (p < 0.0001) for rHuEPO alone and 1.2 less appropriate for rHuEPO and PAD (p < 0.0001). The ratings for patients with moderate expected blood loss were significantly influenced by the cost constraint (less appropriate). CONCLUSIONS: Expected blood loss and preoperative hemoglobin level were the best indicators of rHuEPO appropriateness. Different contexts modify the appropriateness ratings of an expensive drug like rHuEPO.

Blood Loss, Surgical↗
PubMed1997

Adjusting cesarean delivery rates for case mix.

OBJECTIVES: (1) To describe the issues in developing a clinical predictor of cesarean delivery that could be used to adjust reported cesarean rates for case mix, and (2) to compare its performance to other, simpler predictors using clinical and statistical criteria. DATA SOURCES: Singleton births greater than 2,500 grams in Washington State in 1989 and 1990 for whom mothers and infant hospital discharge records could be matched to birth certificate data. DESIGN: Statistical analysis of retrospective merged hospital and birth certificate data, which were used to develop variables and models to predict the probability that any particular delivery would be a cesarean. PRINCIPAL FINDINGS: Merged data led to better predictor variables than those based on one source. A simple four-category hierarchical classification into births with prior cesarean, breech but no prior cesarean, first birth, and other explains 30 percent of the variance in individual cesarean rates. The full clinical model fit the data well and explained 37 percent of the variance. Multiparas without serious complications comprised 35 percent of the mothers and averaged less than 2 percent cesareans. A hospital's predicted cesarean rate depends strongly on the proportion of its births that are first births. CONCLUSION: Government and private agencies have reported cesarean rates as measures of hospital performance. Depending on data and resources available, both simple and complex measures of case mix can be used to adjust reported rates. These adjustments should not include all variables related to the rates. Proper adjustments may not alter hospital rankings greatly, but they will improve the validity and acceptability of the reports.

Birth Certificates↗
PubMed1996

The appropriateness of coronary artery bypass graft surgery in academic medical centers. Working Group of the Appropriateness Project of the Academic Medical Center Consortium.

OBJECTIVE: To compare the appropriateness of use of coronary artery bypass graft (CABG) surgery in Academic Medical Center Consortium hospitals as judged 1) according to criteria developed by an expert panel, 2) according to revisions of those criteria made by cardiac surgeons from the Academic Medical Center Consortium, and 3) by review of cases by the surgeons responsible for those cases. DESIGN: Retrospective, randomized medical record review. SETTING: 12 Academic Medical Center Consortium hospitals. PATIENTS: Random sample of 1156 patients who had had isolated CABG surgery in 1990. MAIN OUTCOME MEASURES: 1) Percentage of patients with indications for which CABG surgery was classified as appropriate, Inappropriate, or of uncertain appropriateness and 2) percentage of cases in which CABG surgery was judged inappropriate or uncertain for which ratings changed after local case review. RESULTS: Data were retrieved from medical records by trained abstractors using an explicit data collection instrument. Cases in which CABG surgery was judged to be inappropriate or uncertain were individually reviewed by the responsible surgeons. According to the expert panel ratings, 83% of the CABG operations (95% CI, 81% to 85%) were necessary, 9% (CI, 8% to 10%) were appropriate, 7% (CI, 5% to 8%) were uncertain, and 1.6% (CI, 0.6% to 2.5%) were inappropriate. These rates are almost identical to those found in a previous study that was done in New York State and that used the same criteria (in that study, 91% of operations were classified as necessary or appropriate, 7% were classified as uncertain, and 2.4% were classified as inappropriate). Rates of inappropriate procedures varied from 0% to 5% among the 12 member hospitals (P = 0.02). The Academic Medical Center Consortium cardiac surgeons revised 568 (24%) of the indications used by the expert panel. However, because those revisions altered the appropriateness ratings in both directions and affected only 50 cases (4%), the net effect of the revisions was slight: The rate of inappropriate CABG surgery increased from 1.6% to 1.9%. Local review found that data collection errors had caused erroneous ratings in 12.5% of 64 cases in which surgery had been classified as inappropriate or uncertain. CONCLUSIONS: The Academic Medical Center Consortium hospitals had low rates of inappropriate and uncertain use of CABG surgery, regardless of the criteria used for assessment. Even though surgeons from the Consortium revised the appropriateness ratings extensively, their revisions had a negligible effect on the overall assessment of appropriateness. However, because of potential data collection errors, appropriateness criteria should be used for individual case audits only if supplemented by subsequent physician review.

Academic Medical Centers↗
PubMed1996

Variations by specialty in physician ratings of the appropriateness and necessity of indications for procedures.

The authors compare the appropriateness ratings and mutual influence of panelists from different specialties rating a comprehensive set of indications for six surgical procedures. Nine-member panels rated each procedure: abdominal aortic aneurysm surgery, carotid endarterectomy, cataract surgery, coronary angiography, and coronary artery bypass graft surgery/percutaneous transluminal coronary angioplasty (common panel). Panelists individually rated the appropriateness of indications at home and then discussed and re-rated the indications during a 2-day meeting. Subsequently, they rated the necessity of those indications scored by the group as appropriate. There were 45 panelists, including specialists (either performers of the procedure or members of a related specialty) and primary care providers, all drawn from nominations by their respective specialty societies. Main outcome measures included: individual panelists' mean ratings over all indications, mean change and conformity scores between rounds of ratings, and the percentage of audited actual procedures rated appropriate or necessary. Performers had the highest mean ratings, followed by physicians in related specialties, trailed by primary care providers. One fifth of all actual procedures were for indications rated appropriate by performers and less than appropriate by primary care providers. At the panel meetings, primary care providers and related specialists showed no greater tendency to be influenced by other panelists than did performers. Multispecialty panels provide more divergent viewpoints than panels composed entirely of performers. This divergence means that fewer actual procedures are deemed performed for appropriate or necessary indications.

Angioplasty, Balloon, Coronary↗
PubMed1994

Comparison of the appropriateness of coronary angiography and coronary artery bypass graft surgery between Canada and New York State.

OBJECTIVE: To compare the appropriateness of coronary angiography and coronary artery bypass graft (CABG) use between the United States and Canada. DESIGN: Retrospective randomized medical record review. SETTING: All hospitals performing coronary angiography and/or CABG surgery in two Canadian provinces (Ontario and British Columbia); in New York State, 15 randomly selected hospitals that provide coronary angiography and 15 randomly selected hospitals that provide CABG surgery. PATIENTS: All patients were randomly selected. For coronary angiography, 533 patients in Canada and 1333 patients in New York were selected; for CABG, 556 patients in Canada and 1336 patients in New York were selected. MAIN OUTCOME MEASURES: Percentage of patients in each country who had coronary angiography or CABG for necessary, appropriate, uncertain, or inappropriate indications as rated by criteria developed separately in each country and the complications of those procedures. RESULTS: For coronary angiography, 9% of Canadian cases and 10% of New York cases were rated inappropriate using Canadian criteria compared with 5% and 4%, respectively, using US criteria. For CABG, 4% of Canadian cases and 6% of New York cases were rated inappropriate by Canadian criteria compared with 3% and 2%, respectively, using US criteria. A lower proportion of procedures were performed on persons aged 75 years or older in Canada than in New York for both coronary angiography (5% vs 11%; P < .001) and CABG (6% vs 14%; P < .001). Women were also represented in lower proportions among angiography cases in Canada than in New York (28% vs 35%; P = .023). Canadian patients with left main coronary disease waited significantly longer between angiography and CABG than did New York patients (P < .0001). CONCLUSIONS: Rates of inappropriate use of cardiac procedures were low in Canada and New York, which suggests that the regionalization of cardiac procedures that characterizes both health care systems contributes to better clinical decision making. Differences in the use of cardiac procedures among the elderly in the two countries merits further comparative examination.

Aged↗
PubMed1994

Measuring the necessity of medical procedures.

This is a report on the extension of the concept of the appropriateness of a procedure to the necessity, or crucial importance, of that procedure. To state that a procedure is crucial means that withholding the procedure would be deleterious to the patient's health. Appropriateness and necessity ratings for six procedures were obtained using a modified Delphi panel process developed in earlier work. Panels were composed of practicing clinicians who were recognized leaders in their fields. The panels included both performers and nonperformers of the procedure under discussion. For most procedures and panelists, necessity was related to appropriateness, but was distinct from it. The proportion of indications for which the procedure was crucial varied in clinically consistent ways both among and within procedures. However, panelists did not achieve a consensus on necessity. Further research is suggested to refine the method to promote consensus and to validate further the ratings of necessity. In conclusion, necessity ratings can be used together with appropriateness ratings to address not only the overuse of procedures, but also to indicate limited access to care through underuse of procedures.

Angioplasty, Balloon, Coronary↗
PubMed1994

The effect of alternative case-mix adjustments on mortality differences between municipal and voluntary hospitals in New York City.

OBJECTIVE: This study investigated how mortality differences between groups of municipal versus voluntary hospitals are affected by case-mix adjustment methods. DATA SOURCES AND STUDY SETTING: We sampled about 10,000 random admissions from administrative data for patients hospitalized with each of six conditions in hospitals in New York City during 1984-1987. STUDY DESIGN: We developed logistic regression models adjusting for age and gender, for principal diagnosis, for "limited other diagnoses" (secondary diagnoses that were very unlikely to result from care received), for "full other diagnoses" (all secondary diagnoses irrespective of whether they might have been due to care received), for previous diagnoses, and for other variables. PRINCIPAL FINDINGS: For five of the six conditions, when the limited other diagnoses adjustment was used there was higher mortality in the municipal hospitals (p < .05), with 3.3 additional deaths/100 admissions for myocardial infarction, 1.2 for pneumonia, 8.3 for stroke, 2.8 for head trauma, and 0.8 for hip repair. However, when the full other diagnoses adjustment was used, differences remained significant only for stroke (4.3 additional deaths/100 admissions) and head trauma (1.3) (p < .05). CONCLUSIONS: Estimates of mortality differences between New York City municipal and voluntary hospitals are substantially affected by which secondary diagnoses are used in case-mix adjustment. Judgments of quality should not be based on administrative data unless models can be developed that validly capture level of sickness at admission.

Adolescent↗
PubMed1993

The appropriateness of use of coronary artery bypass graft surgery in New York State.

OBJECTIVE: To determine the appropriateness of use of coronary artery bypass graft surgery in New York State. DESIGN: Retrospective randomized medical record review. SETTING: Fifteen randomly selected hospitals in New York State that provide coronary artery bypass graft surgery. PATIENTS: Random sample of 1338 patients undergoing isolated coronary artery bypass graft surgery in New York State in 1990. MAIN OUTCOME MEASURES: Percentage of patients who had bypass surgery for appropriate, inappropriate, or uncertain indications; operative (30-day) mortality; and complications. RESULTS: Nearly 91% of the bypass operations were rated appropriate; 7%, uncertain; and 2.4%, inappropriate. This low inappropriate rate differs substantially from the 14% rate found in a previous study of patients operated on in 1979, 1980, and 1982. The difference in rates was not due to more lenient criteria but to changes in practice, the most important being that the fraction of patients receiving coronary artery bypass grafts for one- and two-vessel disease fell from 51% to 24%. Individual hospital rates of inappropriateness (0% to 5%) did not vary significantly. Rates of appropriateness also did not vary by hospital location, volume, or teaching status. Operative mortality was 2.0%; 17% of patients suffered a complication. Complication rates varied significantly among hospitals (P < .01) and were higher in downstate hospitals. CONCLUSIONS: The rates of inappropriate and uncertain use of coronary artery bypass graft surgery in New York State were very low. Rates of inappropriate use did not vary significantly among hospitals, or according to region, volume of bypass operations performed, or teaching status.

Coronary Artery Bypass↗
PubMed1993

The appropriateness of use of percutaneous transluminal coronary angioplasty in New York State.

OBJECTIVE: To determine the appropriateness of use of percutaneous transluminal coronary angioplasty (PTCA) in New York State. DESIGN: Retrospective randomized medical record. SETTING: Fifteen randomly selected hospitals in New York State that provide PTCA. PATIENTS: Random sample of 1306 patients undergoing PTCA in New York State in 1990. MAIN OUTCOME MEASURES: Percentage of patients who underwent PTCA for indications rated appropriate, uncertain, and inappropriate. RESULTS: The majority of patients received PTCA for chronic stable angina, unstable angina, and in the post-myocardial infarction period (up to 3 weeks). Fifty-eight percent of PTCAs were rated appropriate; 38%, uncertain; and 4%, inappropriate. The inappropriate rate varied by hospital from 1% to 9% (P = .12); the uncertain rate, from 26% to 50% (P = .02); and the combined inappropriate and uncertain rate, from 29% to 57% (P < .001). There was no difference in appropriateness when the institutions were grouped by volume (fewer than 300 procedures annually or at least 300 procedures annually), location (upstate vs downstate), or by teaching status. CONCLUSIONS: Few PTCAs were performed for inappropriate indications in New York State. However, the large number of procedures performed for indications that were rated uncertain as to their net benefit requires further study and justification at both clinical and policy levels.

Adult↗
PubMed1993

The appropriateness of use of coronary angiography in New York State.

OBJECTIVE: To determine the appropriateness of use of coronary angiography in New York State. DESIGN: Retrospective randomized medical record review. SETTING: Fifteen randomly selected hospitals in New York State that provide coronary angiography. PATIENTS: Random sample of 1335 patients undergoing coronary angiography in New York State in 1990. MAIN OUTCOME MEASURES: Percentage of patients who underwent coronary angiography for appropriate, uncertain, or inappropriate indications. RESULTS: Approximately 76% of coronary angiographies were rated appropriate; 20%, uncertain; and 4%, inappropriate. Inappropriate use did not vary significantly between the elderly (ie, patients aged 65 years and older) and nonelderly, 4.7% and 3.9%, respectively. Although the rate of inappropriate use varied from 0% to 9% among hospitals, the difference was not significant. Rates of appropriateness did not vary by hospital location (upstate vs downstate), volume (fewer than 750 procedures annually or at least 750 procedures annually), teaching status, or whether revascularization was available at the hospital where angiography was performed. CONCLUSIONS: Although coronary angiography was used for few inappropriate indications in New York State, many procedures were performed for uncertain indications in which the benefit and risk were approximately equal or unknown.

Adult↗
PubMed1993

Mortality differences between New York City municipal and voluntary hospitals, for selected conditions.

To determine if mortality differences between municipal and voluntary hospitals in New York City persist after adjustment for computerized administrative data (age, sex, principal diagnosis, and secondary diagnosis), six conditions in those hospitals from 1984 through 1987 were studied. Unadjusted mortality was significantly higher in municipal hospitals for myocardial infarction, stroke, and head trauma, and lower for congestive heart failure and pneumonia. Adjustment using administrative data eliminated differences for myocardial infarction, congestive heart failure, and pneumonia, but not for stroke and head trauma. We conclude that adjustment using administrative data eliminates some but not all mortality differences between municipal and voluntary hospitals. Medical record review is needed to determine why these differences persist.

Diagnosis-Related Groups↗
PubMed1992

Assigning appropriateness ratings for diagnostic upper gastrointestinal endoscopy using two different approaches.

Methods that combine information in the medical literature with expert clinical judgment are needed to determine the appropriateness of use of a procedure. The purpose of this study is to better understand the reliability and construct validity of this process by comparing ratings of appropriateness for diagnostic upper gastrointestinal endoscopy that were developed using different approaches by two independent groups. Both the RAND/UCLA Health Services Utilization Study (HSUS) and the American Society for Gastrointestinal Endoscopy (ASGE) combined scientific data with expert physician judgment to rate the appropriateness of specific clinical indications for the use of upper gastrointestinal endoscopy. This study applies the ratings developed by each group to a nationally representative sample of 1,585 endoscopies performed on people 65 years of age and older in 1981. HSUS developed indications that could be used to rate all 1,585 procedures; ASGE indications were less comprehensive and applied to 70% (n = 1,115) of procedures. Of those rated by both groups, appropriateness category ratings agreed for 94% of the procedures. However, the procedures not rated by ASGE were unevenly distributed across HSUS appropriateness ratings. Twelve percent of procedures rated as appropriate by HSUS were not rated by ASGE, but 80% of procedures rated as equivocal by HSUS and 73% rated as inappropriate by HSUS were not rated by ASGE, for those procedures rated by both approaches there was good agreement; however, a more explicit and comprehensive method may be required if equivocal and inappropriate use of a procedure is to be identified.

Aged↗
PubMed1992

dorsal-twist interactions establish snail expression in the presumptive mesoderm of the Drosophila embryo.

The first step in the differentiation of the Drosophila mesoderm is the activation of two regulatory genes, twist (twi) and snail (sna), in ventral regions of early embryos. sna is a transcriptional repressor that is uniformly expressed throughout the presumptive mesoderm. Its sharp lateral limits help to establish the boundary between the mesoderm and neuroectoderm. Genetic studies suggest that sna is a target of the dorsal (dl) morphogen, and this interaction provides a model for determining how a morphogen gradient establishes a sharp, on/off threshold response. We present evidence that dl and twi directly activate sna expression. Site-directed mutagenesis of dl- and twi-binding sites within defined regions of the sna promoter suggest that the two proteins (containing the Rel and helix-loop-helix domains, respectively) function multiplicatively to ensure strong, uniform expression of sna, particularly in ventral-lateral regions where there are diminishing amounts of dl. These results are consistent with the possibility that the sharp sna borders are formed by multiplying the shallow dl gradient and the steeper twi gradient.

Animals↗
PubMed1992

The dorsal gradient morphogen regulates stripes of rhomboid expression in the presumptive neuroectoderm of the Drosophila embryo.

rhomboid (rho) encodes a putative transmembrane receptor that is required for the differentiation of the ventral epidermis. It is initially expressed before the completion of cellularization in lateral stripes within the presumptive neuroectoderm. Here, we present evidence that the maternal morphogen dorsal (dl) acts in concert with basic helix-loop-helix (b-HLH) proteins, possibly including twist (twi), to activate rho in both lateral and ventral regions. Expression is blocked in ventral regions (the presumptive mesoderm) by snail (sna), which is also a direct target of the dl morphogen. A 300-bp region of the rho promoter (the NEE), which is sufficient for neuroectoderm expression, contains a cluster of dl and b-HLH activator sites that are closely linked to sna repressor sites. Mutations in these binding sites cause genetically predicted changes in the levels and limits of rho expression. In particular, the disruption of sna-binding sites causes a derepression of the pattern throughout ventral regions, providing evidence that sna is directly responsible for establishing the mesoderm/neuroectoderm boundary before gastrulation. The tight linkage of activator and repressor sites in the rho NEE is similar to the arrangement of binding sites observed in the even-skipped stripe 2 element, which is regulated by bicoid (bcd). This suggests that the dl and bcd morphogens use a similar mechanism to make stripes in the Drosophila embryo.

Animals↗