Pathology of short-term dorsal fin tag-attachments in tagged and re-stranded short-beaked common dolphins Delphinus delphis on Cape Cod, MA

Odontocetes are difficult to study in the wild, making tagging and remote tracking a valuable practice. However, evaluations of host responses at tagging sites have been primarily limited to visual observations in the field. Here we explore the macro- and microscopic pathology of dorsal fin tag attachments in 13 stranded and released short-beaked common dolphins Delphinus delphis from Cape Cod, MA that later re-stranded and died or were euthanized 1-28 d post-tagging. Tags were attached to stranded dolphins' dorsal fins using 2 methods: core biopsy or piercing. Grossly, the piercing method resulted in epidermal compression into the dermis. One tag site had a necrotic border 28 d after application. Grossly, the biopsy method resulted in minimal to no tissue reaction. Two tag sites had granulation tissue accumulation 4 and 12 d after tagging. Histopathologic findings for all tag types and animals consisted of focal epithelial loss, dermal edema, perivascular edema, inflammation and hyperplasia, and inter- and extracellular edema in the adjacent epidermis. Minor expected pathological changes given the procedure were also observed: superficial epidermal necrosis in 3 cases, and superficial bacterial colonization in 2 cases. There was no evidence of sepsis and tagging was not related to cause of re-stranding or death in any case. These gross and histopathologic findings support previous observational conclusions in small delphinids that with appropriate sterile technique, the impacts of single pin dorsal fin tagging on the animal can be minimal and localized. Of the 2 methods, core biopsy may be a better tagging method.

Using Blood Gas Analysis and Capnography to Determine Oxygenation Status in Bottlenose Dolphins (Tursiops truncatus) Following the Deepwater Horizon Oil Spill

Following the Deepwater Horizon (DWH) oil spill in 2010, poor pulmonary health and reproductive failure in bottlenose dolphins (Tursiops truncatus) in the northern Gulf of Mexico were well-documented. One postulated etiology for the increased fetal distress syndrome and pneumonia found in affected perinatal dolphins was maternal hypoxia caused by lung disease. The objective of this study was to evaluate the utility of blood gas analysis and capnography in determining oxygenation status in bottlenose dolphins with and without pulmonary disease. Blood and breath samples were collected from 59 free-ranging dolphins in Barataria Bay, Louisiana (BB), during a capture-release health assessment program, and from 30 managed dolphins from the U.S. Navy Marine Mammal Program in San Diego, CA. The former was the oil-exposed cohort and the latter served as a control cohort with known health histories. Capnography and select blood gas parameters were compared based on the following factors: cohort, sex, age/length class, reproductive status, and severity of pulmonary disease. Animals with moderate-severe lung disease had higher bicarbonate concentrations (p = 0.005), pH (p < 0.001), TCO₂ (p = 0.012), and more positive base excess (p = 0.001) than animals with normal-mild disease. Capnography (ETCO₂) was found to have a weak positive correlation with blood PCO₂ (p = 0.020), with a mean difference of 5.02 mmHg (p < 0.001). Based on these findings, indirect oxygenation measures, including TCO₂, bicarbonate, and pH, show promise in establishing the oxygenation status in dolphins with and without pulmonary disease.

REVIEW: Assessing North Atlantic right whale health: threats, and development of tools critical for conservation of the species

Whaling has decimated North Atlantic right whales Eubalaena glacialis (NARW) since the 11th century and southern right whales E. australis (SRW) since the 19th century. Today, NARWs are Critically Endangered and decreasing, whereas SRWs are recovering. We review NARW health assessment literature, NARW Consortium databases, and efforts and limitations to monitor individual and species health, survival, and fecundity. Photographs are used to track individual movement and external signs of health such as evidence of vessel and entanglement trauma. Post-mortem examinations establish cause of death and determine organ pathology. Photogrammetry is used to assess growth rates and body condition. Samples of blow, skin, blubber, baleen and feces quantify hormones that provide information on stress, reproduction, and nutrition, identify microbiome changes, and assess evidence of infection. We also discuss models of the population consequences of multiple stressors, including the connection between human activities (e.g. entanglement) and health. Lethal and sublethal vessel and entanglement trauma have been identified as major threats to the species. There is a clear and immediate need for expanding trauma reduction measures. Beyond these major concerns, further study is needed to evaluate the impact of other stressors, such as pathogens, microbiome changes, and algal and industrial toxins, on NARW reproductive success and health. Current and new health assessment tools should be developed and used to monitor the effectiveness of management measures and will help determine whether they are sufficient for a substantive species recovery.

Gross and histopathologic diagnoses from North Atlantic right whale Eubalaena glacialis mortalities between 2003 and 2018

Seventy mortalities of North Atlantic right whales Eubalaena glacialis (NARW) were documented between 2003 and 2018 from Florida, USA, to the Gulf of St. Lawrence, Canada. These included 29 adults, 14 juveniles, 10 calves, and 17 of unknown age class. Females represented 65.5% (19/29) of known-sex adults. Fourteen cases had photos only; 56 carcasses received external examinations, 44 of which were also necropsied. Cause of death was determined in 43 cases, of which 38 (88.4%) were due to anthropogenic trauma: 22 (57.9%) from entanglement, and 16 (42.1%) from vessel strike. Gross and histopathologic lesions associated with entanglement were often severe and included deep lacerations caused by constricting line wraps around the flippers, flukes, and head/mouth; baleen plate mutilation; chronic extensive bone lesions from impinging line, and traumatic scoliosis resulting in compromised mobility in a calf. Chronically entangled whales were often in poor body condition and had increased cyamid burden, reflecting compromised health. Vessel strike blunt force injuries included skull and vertebral fractures, blubber and muscle contusions, and large blood clots. Propeller-induced wounds often caused extensive damage to blubber, muscle, viscera, and bone. Overall prevalence of NARW entanglement mortalities increased from 21% (1970-2002) to 51% during this study period. This demonstrates that despite mitigation efforts, entanglements and vessel strikes continue to inflict profound physical trauma and suffering on individual NARWs. These cumulative mortalities are also unsustainable at the population level, so urgent and aggressive intervention is needed to end anthropogenic mortality in this critically endangered species.

Mortality trends of stranded marine mammals on Cape Cod and southeastern Massachusetts, USA, 2000 to 2006

To understand the cause of death of 405 marine mammals stranded on Cape Cod and southeastern Massachusetts between 2000 and 2006, a system for coding final diagnosis was developed and categorized as (1) disease, (2) human interaction, (3) mass-stranded with no significant findings, (4) single-stranded with no significant findings, (5) rock and/or sand ingestion, (6) predatory attack, (7) failure to thrive or dependent calf or pup, or (8) other. The cause of death for 91 animals could not be determined. For the 314 animals that could be assigned a cause of death, gross and histological pathology results and ancillary testing indicated that disease was the leading cause of mortality in the region, affecting 116/314 (37%) of cases. Human interaction, including harassment, entanglement, and vessel collision, fatally affected 31/314 (10%) of all animals. Human interaction accounted for 13/29 (45%) of all determined gray seal Halichoerus grypus mortalities. Mass strandings were most likely to occur in northeastern Cape Cod Bay; 97/106 (92%) of mass stranded animals necropsied presented with no significant pathological findings. Mass strandings were the leading cause of death in 3 of the 4 small cetacean species: 46/67 (69%) of Atlantic white-sided dolphin Lagenorhynchus acutus, 15/21 (71%) of long-finned pilot whale Globicephala melas, and 33/54 (61%) of short-beaked common dolphin Delphinus delphis. These baseline data are critical for understanding marine mammal population health and mortality trends, which in turn have significant conservation and management implications. They not only afford a better retrospective analysis of strandings, but ultimately have application for improving current and future response to live animal stranding.

Associations among hospital capacity, utilization, and mortality of US Medicare beneficiaries, controlling for sociodemographic factors

OBJECTIVE

To explore whether geographic variations in Medicare hospital utilization rates are due to differences in local hospital capacity, after controlling for socioeconomic status and disease burden, and to determine whether greater hospital capacity is associated with lower Medicare mortality rates.

DATA SOURCES/STUDY SETTING

The study population: a 20 percent sample of 1989 Medicare enrollees. Measures of resources were based on a national small area analysis of 313 Hospital Referral Regions (HRR). Demographic and socioeconomic data were obtained from the 1990 U.S. Census. Measures of local disease burden were developed using Medicare claims files.

STUDY DESIGN

The study was a cross-sectional analysis of the relationship between per capita measures of hospital resources in each region and hospital utilization and mortality rates among Medicare enrollees. Regression techniques were used to control for differences in sociodemographic characteristics and disease burden across areas.

DATA COLLECTION/EXTRACTION METHODS

Data on the study population were obtained from Medicare enrollment (Denominator File) and hospital claims files (MedPAR) and U.S. Census files.

PRINCIPAL FINDINGS

The per capita supply of hospital beds varied by more than twofold across U.S. regions. Residents of areas with more beds were up to 30 percent more likely to be hospitalized, controlling for ecologic measures of socioeconomic characteristics and disease burden. A greater proportion of the population was hospitalized at least once during the year in areas with more beds; death was also more likely to take place in an inpatient setting. All effects were consistent across racial and income groups. Residence in areas with greater levels of hospital resources was not associated with a decreased risk of death.

CONCLUSIONS

Residence in areas of greater hospital capacity is associated with substantially increased use of the hospital, even after controlling for socioeconomic characteristics and illness burden. This increased use provides no detectable mortality benefit.

Effect of hospital volume on in-hospital mortality with pancreaticoduodenectomy

BACKGROUND

Reports of better results at national referral centers than at low-volume community hospitals have prompted calls for regionalizing pancreaticoduodenectomy (the Whipple procedure). We examined the relationship between hospital volume and mortality with this procedure across all US hospitals.

METHODS

Using information from the Medicare claims database, we performed a national cohort study of 7229 Medicare patients more than 65 years old undergoing pancreaticoduodenectomy between 1992 and 1995. We divided the study population into approximate quartiles according to the hospital's average annual volume of pancreaticoduodenectomies in Medicare patients: very low (< 1/y), low (1-2/y), medium (2-5/y), and high (5+/y). Using multivariate logistic regression to account for potentially confounding patient characteristics, we examined the association between institutional volume and in-hospital mortality, our primary outcome measure.

RESULTS

More than 50% of Medicare patients a undergoing pancreaticoduodenectomy received care at hospitals performing fewer than 2 such procedures per year. In-hospital mortality rates at these low- and very-low-volume hospitals were 3- to 4-fold higher than at high-volume hospitals (12% and 16%, respectively, vs 4%, P < .001). Within the high-volume quartile, the 10 hospitals with the nation's highest volumes had lower mortality rates than the remaining high-volume centers (2.1% vs 6.2%, P < .01). The strong association between institutional volume and mortality could not be attributed to patient case-mix differences or referral bias.

CONCLUSIONS

Although volume-outcome relationships have been reported for many complex surgical procedures, hospital experience is particularly important with pancreaticoduodenectomy. Patients considering this procedure should be given the option of care at a high-volume referral center.

Variation profiles of common surgical procedures

BACKGROUND

Rates of many surgical procedures vary widely across both large and small geographic regions. Although variation in health care use has long been described, few studies have systematically compared variation profiles across surgical procedures. The goal of this study was to examine current patterns of regional variation in the rates of common surgical procedures.

METHODS

The study population consisted of patients enrolled in Medicare in 1995, excluding those enrolled in risk-bearing health maintenance organizations. Patients ranged in age from 65 to 99 years. Using data from hospital discharge abstracts, we calculated rates of 11 common inpatient procedures for each of 306 US hospital referral regions (HRRs). To assess the relative variability of each procedure, we determined the number of low and high outlier regions (HRRs with rates < 50% or > 150% the national average) and the ratio of highest to lowest HRR rates.

RESULTS

Procedures differed markedly in their variability. Rates of hip fracture repair, resection for colorectal cancer, and cholecystectomy varied only 1.9- to 2.9-fold across HRRs (0, 0, and 4 outlier regions, respectively). Coronary artery bypass grafting, transurethral prostatectomy, mastectomy, and total hip replacement had intermediate variation profiles, varying 3.5- to 4.7-fold across regions (8, 10, 16, and 17 outlier regions, respectively). Lower extremity revascularization, carotid endarterectomy, back surgery, and radical prostatectomy had the highest variation profiles, varying 6.5- to 10.1-fold across HRRs (25, 32, 39, and 56 outlier regions, respectively).

CONCLUSIONS

Although the use of many surgical procedures varies widely across geographic areas, rates of "discretionary" procedures are most variable. To avoid potential overuse or underuse, efforts to increase consensus in clinical decision making should focus on these high variation procedures.

Influence of patient preferences and local health system characteristics on the place of death. SUPPORT Investigators. Study to Understand Prognoses and Preferences for Risks and Outcomes of Treatment

OBJECTIVE

To examine the degree to which variation in place of death is explained by differences in the characteristics of patients, including preferences for dying at home, and by differences in the characteristics of local health systems.

DESIGN

We drew on a clinically rich database to carry out a prospective study using data from the observational phase of the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT component). We used administrative databases for the Medicare program to carry out a national cross-sectional analysis of Medicare enrollees place of death (Medicare component).

SETTING

Five teaching hospitals (SUPPORT); All U.S. Hospital Referral Regions (Medicare).

STUDY POPULATIONS

Patients dying after the enrollment hospitalization in the observational phase of SUPPORT for whom place of death and preferences were known. Medicare beneficiaries who died in 1992 or 1993.

MAIN OUTCOME MEASURES

Place of death (hospital vs non-hospital).

RESULTS

In SUPPORT, most patients expressed a preference for dying at home, yet most died in the hospital. The percent of SUPPORT patients dying in-hospital varied by greater than 2-fold across the five SUPPORT sites (29 to 66%). For Medicare beneficiaries, the percent dying in-hospital varied from 23 to 54% across U.S. Hospital Referral Regions (HRRs). In SUPPORT, variations in place of death across site were not explained by sociodemographic or clinical characteristics or patient preferences. Patient level (SUPPORT) and national cross-sectional (Medicare) multivariate models gave consistent results. The risk of in-hospital death was increased for residents of regions with greater hospital bed availability and use; the risk of in-hospital death was decreased in regions with greater nursing home and hospice availability and use. Measures of hospital bed availability and use were the most powerful predictors of place of death across HRRs.

CONCLUSIONS

Whether people die in the hospital or not is powerfully influenced by characteristics of the local health system but not by patient preferences or other patient characteristics. These findings may explain the failure of the SUPPORT intervention to alter care patterns for seriously ill and dying patients. Reforming the care of dying patients may require modification of local resource availability and provider routines.

Hospital readmission rates for cohorts of Medicare beneficiaries in Boston and New Haven

BACKGROUND

Geographic variations in the use of hospital services are associated with differences in the availability of hospital beds. There continues to be uncertainty about the extent to which unmeasured case-mix differences explain these findings. Previous research showed that the number of occupied beds per capita in Boston was substantially higher than the number of occupied beds per capita in New Haven, Connecticut, and that overall rates of hospital utilization were higher for Boston residents than for New Haven residents.

METHODS

We used Medicare claims data to study cohorts of Medicare beneficiaries 65 years of age or older and residing in Boston or New Haven who were initially hospitalized for one of five indications (acute myocardial infarction, stroke, gastrointestinal bleeding, hip fracture, or potentially curative surgery for breast, colon, or lung cancer). Residents of Boston or New Haven who were discharged between October 1, 1987, and September 30, 1989, were enrolled in the cohort corresponding to the earliest such admission and followed for up to 35 months.

RESULTS

The relative rate of readmission in Boston as compared with New Haven was 1.64 (95 percent confidence interval, 1.53 to 1.76) for all cohorts combined, with a similarly elevated rate for each of the five clinical cohorts and each age, sex, and race subgroup examined. Hospital-specific readmission rates varied substantially among the hospitals in Boston and were higher than those in New Haven. No relation was found between mortality (during the first 30 days after discharge or over the entire study period) and either community or hospital-specific readmission rates.

CONCLUSIONS

Regardless of the initial cause of the admission, Medicare beneficiaries who were initially hospitalized in Boston had consistently higher rates of readmission than did Medicare beneficiaries hospitalized in New Haven. Differences in the severity of illness are unlikely to explain these findings. One possible explanation is a threshold effect of hospital-bed availability on decisions to admit patients.

Dobutamine stress echocardiography: detection of coronary artery disease in patients with dilated cardiomyopathy

OBJECTIVES

This study attempted to determine the safety and accuracy of dobutamine stress echocardiography for detection of coronary artery disease in patients with dilated cardiomyopathy.

BACKGROUND

Detection of regional wall motion abnormalities at rest does not reliably distinguish ischemic from nonischemic cardiomyopathy. Previous studies have shown that dobutamine stress echocardiography safely and accurately identifies coronary artery disease in patients without dilated cardiomyopathy.

METHODS

Seventy patients with dilated cardiomyopathy underwent dobutamine stress echocardiography. Echocardiograms were obtained at baseline and at low (5 to 10 micrograms/kg body weight per min) and peak doses of dobutamine. Rest and stress left ventricular wall motion scores were derived from analysis of regional wall motion. Fifty-four subjects underwent coronary angiography.

RESULTS

Dobutamine infusion was terminated after achievement of the target heart rate or maximal protocol dose in 49 patients (70%), ischemia in 12 (17%), arrhythmia in 4 (6%) and side effects in 5 (7%). No patient had prolonged ischemia or sustained arrhythmia. Of those with angiographic studies, 40 had significant coronary artery disease (> or = 50% diameter stenosis). Use of the change in global wall motion score index from low to peak dose resulted in a sensitivity of 83% for dobutamine stress echocardiography and a specificity of 71% for detection of coronary artery disease. Sensitivity for detection of triple-, double- and single-vessel disease was 100%, 83% and 69%, respectively.

CONCLUSIONS

Dobutamine stress echocardiography safely provides diagnostic information in patients with dilated cardiomyopathy. This technique has high sensitivity for multivessel coronary artery disease but only moderate specificity.

Standardized rates of recurrent outcomes

Longitudinal studies are often concerned with estimating the rate of an event that may recur. Examples are nonmelanoma skin cancer rates, screening rates for breast cancer using mammography and hospital admission rates. We propose simple estimators for directly and indirectly standardized summary rates and relative rates of recurrent events and their variances. We also develop an estimator of the excess rate in an area if the rate in another area applied. For non-recurrent events, the estimators are identical to the usual standardized summary rates. The estimators are independent of the underlying distribution of the event of interest and allow for unequal follow-up times and event rate heterogeneity among individuals. The method is not computationally intensive and does not require specialized software. We illustrate the application of the method in a retrospective cohort study of hospital utilization patterns of Medicare enrollees in Boston and New Haven over a three and a half year period.

Estimating the variance of standardized rates of recurrent events, with application to hospitalizations among the elderly in New England

Usual approaches for estimating the variance of a standardized rate may not be applicable to rates of recurrent events. Where individuals are prone to repeated health events, Greenwood and Yule (J R Stat Soc [A], 1920;83:255-79) advocated use of the negative binomial distribution to account for departures from the assumption of randomness of recurrent events required by the Poisson distribution. In this paper, the authors implemented the negative binomial distribution in the computation of annual hospitalization rates within certain hospital market areas. Data used were from 1,549,915 New England residents aged 65 years or more who were enrolled in Medicare between October 1, 1988, and September 30, 1989, and who had 458,593 hospital admissions during that year. New England was partitioned into 170 hospital market areas ranging in population size from 162 to 70,821 elderly Medicare enrollees. The negative binomial distribution demonstrated substantially better fits than the Poisson distribution to the numbers of hospitalizations within hospital market areas. Estimated standard errors for indirectly standardized rates based on the negative binomial distribution were 25-51 percent higher than estimated standard errors that assumed an underlying Poisson distribution. Using regression analysis to smooth overdispersion parameters across hospital market areas produced similar results. The approach described in this paper may be useful in estimation of confidence intervals for standardized rates of recurrent events when these events do not recur randomly.

Restrictive hemodynamic patterns after cardiac transplantation: relationship to histologic signs of rejection

Hemodynamic and echocardiographic data from 33 consecutive patients undergoing cardiac transplantation were correlated with endomyocardial biopsy results to determine whether reversible restrictive hemodynamics accompany histologic evidence of transplant rejection. During the study period 251 biopsy specimens were obtained during periods of no histologic evidence of transplant rejection and 52 episodes of mild, 20 episodes of moderate, and one episode of severe rejection. Right atrial mean pressure increased significantly during episodes of moderate transplant rejection (9.9 +/- 6.2 mm Hg, p less than 0.001) compared with pressures obtained during periods when there was no evidence of rejection (4.6 +/- 3.2 mm Hg), mild rejection (5.8 +/- 3.9 mm Hg), or resolving rejection (4.3 +/- 3.4 mm Hg). Y descent was elevated during moderate rejection (9.6 +/- 4.2 mm Hg, p less than 0.001) compared with pressures during episodes of no rejection (5.6 +/- 2.5 mm Hg), mild rejection (6.6 +/- 2.7 mm Hg), and resolving rejection (5.8 +/- 3.1 mm Hg) and showed a wave morphology consistent with a restrictive hemodynamic pattern. Pulmonary capillary wedge pressure was increased during moderate rejection (14.4 +/- 6.4 mm Hg) when compared with pressures obtained during episodes of no rejection (10.2 +/- 5.8 mm Hg) or resolving rejection (10.2 +/- 5.4 mm Hg) (p less than 0.02). Sensitivity for a right atrial mean pressure of 11 mm Hg indicating moderate rejection was 41% with a specificity of 96%. Sensitivity for Y descent (greater than or equal to 10 mm Hg) was 52% and specificity was 94%.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparing clinical information with claims data: some similarities and differences

How well can hospital discharge abstracts be used to estimate patient health status? This paper compares information on comorbidity obtained from hospital discharge abstracts for patients undergoing prostatectomy or cholecystectomy at a Winnipeg teaching hospital with clinical data on preoperative medical conditions prospectively collected during an Anesthesia Follow-up study. The diagnostic information on cardiovascular disease, respiratory disease, and metabolic disorders showed considerable agreement, ranging from 65 to over 90% correspondence across the two data sets. Certain conditions noted by the anesthesiologist were often absent from the claims data; cardiovascular disease was recorded in the clinical data but absent from the claims for 31% of prostatectomy and 17% of cholecystectomy cases. Such patients were less likely to have been assigned a high score on the ASA Physical Status measure or to have high-risk diagnoses on the hospital file. Similar findings resulted from comparing the two sources in their ability to predict such adverse outcomes as mortality and readmission to hospital: the anesthesia file generally included less serious comorbidity.

Innovation, centralization, and growth. Coronary artery bypass graft surgery in Manitoba

Innovation and diffusion of new surgical procedures are limited in Manitoba, Canada by restrictions on which hospitals are allowed to perform particular surgical programs. Programs centralizing performance of certain operations in a few hospitals have the potential for controlling costs and quality of care but may limit access for individuals living in other areas. Such issues are highlighted in this analysis of coronary artery bypass graft surgery in Manitoba. Patterns of growth and access are first examined; then regional variations in rates of bypass surgery are compared with rates for coronary angiography and valve surgery. Physician reluctance to refer patients to Winnipeg appears to be responsible for the lower rates of these procedures in Western Manitoba. The implications for studies of centralization/regionalization of medical services, physician decision-making, and diffusion of technology are explored.

Risk adjustment in claims-based research: the search for efficient approaches

Claims-based indices of comorbidity and severity, as well as other measures derived from routinely collected administrative data, are developed and tested. The extent to which risk adjustments using claims can be improved by adding information from one well-known measure based on chart review and patient examination (the American Society of Anesthesiologists' (ASA) Physical Status score) is also examined. Readmissions and mortality after three common surgical procedures are the outcomes studied using multiple logistic regression. Claims-based measures of comorbidity, derived both from hospital discharge abstracts at the time of surgery and from hospitalizations in the 6 months before surgery, provided reasonably good predictions of postsurgical readmissions and mortality. In the most complete logistic regression models, the Somers' Dyx measure of fit (a rank correlation coefficient) ranged from 0.23 to 0.38 for readmissions and from 0.46 to 0.72 for mortality. In 5 out of 6 cases, these predictions were not improved by including the prospectively-collected ASA Physical Status score. Such difficulties in improving risk adjustment by more intensive data collection are discussed in terms of their research implications.

Assessing data quality: a computerized approach

With the growing reliance on large health care data bases, the need to verify data quality increases as well. Because of the considerable costs involved in checks using primary data collection, a computerized methodology for performing such checks is suggested. The technique seems appropriate for any situation where two data collection systems (i.e. hospital discharge abstracts and physician claims for payment) relate to the same event, such as a patient's hospitalization. After reviewing other approaches, this paper suggests linking physician claims for performing particular surgical procedures with hospital discharge abstracts for the stay in which the surgery took place. Physician and hospital data for adults age 25 and over in Manitoba from 1 April, 1979 to 31 March, 1984 were used to address the questions: 1. How well can the two data sets be linked? 2. Given linkage of the two data sets, how much agreement is there as to procedure and diagnosis? Linkage between hospital and physician data was excellent (over 95%) for 5 out of 11 surgical procedures (hysterectomy, prostatectomy, total hip replacement, coronary artery bypass surgery, and heart valve replacement); there was over 90% perfect agreement for three other procedures (cholecystectomy, cataract surgery and total knee replacement). Problems with matching the Manitoba Health Services Commission tariffs (on physician claims) with ICD-9-CM operation codes (on hospital data) led to only 77% perfect agreement for vascular surgery and 84% for gallbladder and biliary tract operations other than cholecystectomy; over 10% of the cases linked on surgeon and date but not on the designated procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Becoming more efficient at outcomes research

This paper discusses several practical problems in research design: Is it worth doing a relatively "quick and dirty" study or is a more thorough study using all available information necessary? All the desired information may either not be available or be time-consuming to collect. What are the likely biases in going ahead and doing the research with the data base "in hand"? Such issues are important because of the limited resources for technology assessment (in terms of money, number of researchers, and research interest) and the great number of unstudied technologies.

Monitoring adverse outcomes of surgery using administrative data

In this article, we document a stabilization in adverse outcomes associated with hysterectomies, cholecystectomies, and prostatectomies performed between 1972-73 and 1982-83 in Manitoba, Canada. The proportion of surgery performed by high-volume surgeons and by surgical specialists increased slightly over the decade. However, given the already low rates of adverse outcomes, these changes did not translate into significant decreases in the postoperative mortality rate or in the rate of related hospital readmissions. Reducing the proportion of adverse outcomes would be facilitated by identifying institutions with poorer than expected outcomes.

Software for health care analysts: a modular approach

The many concerns about the cost and quality of health care suggest the need to facilitate planners' using existing data bases for utilization review, program evaluation, and technology assessment. Despite both the availability of relevant data and widespread improvements in computing power, integrated computer software to permit analyses by nonspecialists has not previously been developed. This paper discusses the features of a health policy information system which aids working with hospital discharge abstracts, medical claims, cancer registries, and vital statistics files. Analyses of small area utilization, length of stay, in-hospital mortality, and readmissions are facilitated by this package. This information system, named the Health Applications System, includes an analysis module, three information management modules, and a set of record linkage modules. The modules were developed using the macroprocessor in the fourth-generation SAS system. Features of the software and their implications for data analysis are discussed.