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)
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.
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 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.
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.
Per capita hospital expenditures in the United States exceed those in Canada, but little research has examined differences in outcomes. We used insurance databases to compare postsurgical mortality for 11 specific surgical procedures, both before and after adjustment for case mix, among residents of New England and Manitoba who were over 65 years of age. For low- and moderate-risk procedures, 30-day mortality rates were similar in both regions, but 6-month mortality rates were lower in Manitoba. For the two high-risk procedures, concurrent coronary bypass/valve replacement and hip fracture repair, both 30-day and 6-month mortality rates were lower in New England. Although no consistent pattern favoring New England for cardiovascular surgery was found, the increased mortality following hip fracture in Manitoba was found for all types of repair and all age groups. We conclude that for low- and moderate-risk procedures, the higher hospital expenditures in New England were not associated with lower perioperative mortality rates.
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.