Claudia Bullock

Effect of Measurement on Sex Difference in Stroke Mortality

The 1994 to 1997 administrative data on 40 450 elderly Medicare beneficiaries and general population of 2 states were used to measure “case mortality” (deaths attributable to any cause among cases of acute stroke), “case fatality” (deaths caused by cerebrovascular diseases among cases of acute stroke), and “population mortality” (deaths caused by stroke in the elderly general population). Mortality was higher in men than in women according to all measures except population mortality caused by subarachnoid hemorrhage. There was no sex difference in 1-year case fatality. One-year all-cause mortality among cases of nonhemorrhagic stroke or all types of stroke was higher in men than in women. Similar sex differences were found in 4-year population mortality caused by nonhemorrhagic stroke or all types of stroke combined. The 3 measures differed with respect to sex difference in stroke mortality. How stroke is defined and how mortality is measured does affect sex difference.

Sex differences in carotid endarterectomy utilization and 30-day postoperative mortality.

Objective: To study trends, and sex and regional differences in utilization of the carotid endarterectomy (CEA) procedure and 30-day postoperative mortality from 1991 to 1999. Methods: Retrospective analysis of fee-for-service claims and mortality data for Medicare beneficiaries aged 65 years and older in the United States. Results: The male and female CEA rates and 30-day mortality increased with age up to the age of 79 years. From 1991 to 1995, the age-adjusted male and female CEA rates increased 72% from 26.6 and 14.2 procedures per 10,000 beneficiaries. Thereafter, the CEA rates slightly decreased except for the 80 years and older age group, which increased through 1999. In each year from 1991 to 1999, the age-adjusted male CEA rates were approximately 1.9 times higher than the corresponding female rates. From 1991 to 1998, the age-adjusted male and female 30-day mortality decreased 29.3% and 46.4% from 19.2 and 18.1 deaths per 1,000 procedures. From 1992 to 1997, except 1994, 30-day mortality was higher in men than in women. This sex difference was not present in the 65 to 69 years age group. There were small differences in CEA rates between two of the four regions of the United States in 3 of the 9 years. Conclusions: Increasing CEA rates with decreasing postoperative mortality suggest that CEA may have been more frequently performed on low-risk patients. The apparent sex differences in CEA rates may not be true differences.

Rise and fall of radical prostatectomy rates from 1989 to 1996.

OBJECTIVES To describe the changes in the rates of radical prostatectomy procedures, prostate-specific antigen (PSA) screening tests among Medicare beneficiaries, and the incidence of prostate cancer in the United States and to explain the exaggerated increase and decrease in the frequency of radical prostatectomy from 1989 to 1996. METHODS Medicare claims data on radical prostatectomy procedures and screening PSA tests and the National Cancer Institutes Surveillance, Epidemiology, and End Results prostate cancer incidence data were used to estimate the rates of PSA testing and radical prostatectomy among Medicare beneficiaries aged 65 to 74 years and 75 years and older (population rates). The age-specific true rates of the procedure were also estimated for the incident cases of prostate cancer (the population at risk of undergoing radical prostatectomy) among the beneficiaries. RESULTS The PSA test, prostate cancer incidence, and radical prostatectomy rates increased from 1989 to 1992. Thereafter, the incidence of prostate cancer, and the population and true rates of radical prostatectomy declined. The percentage of increase and decrease in the population rate of radical prostatectomy was approximately twice that in its true rate. CONCLUSIONS The radical prostatectomy rates based on all Medicare beneficiaries grossly exaggerated the changes in the use of the procedure. Where possible, true rates, using the population at risk as the denominator, should be used in the studies of diagnostic and therapeutic procedures, complications, and adverse effects.

Variation and changes in state-specific carotid endarterectomy and 30-day mortality rates, United States, 1991-2000

OBJECTIVES The objectives of this study were to investigate variations between states and changes in state-specific carotid endarterectomy (CEA) and 30-day mortality rates. Cross-sectional variations and changes over time in such measures may be indicative of improvement in the quality of care. METHODS We performed retrospective analyses of pre-existing administrative data on Medicare beneficiaries aged 65 years and older in the United States. Age-adjusted, state-specific CEA rates and 30-day postoperative mortality rates in 1991, 1995 and 2000 were examined, as well as changes in these rates from 1991 to 1995 and from 1995 to 2000. Stroke mortality in the general population of each state was used as a crude measure of the need for CEA procedure in the state. The Spearman rank correlation analysis was used to study correlations between rates. Oldhams method was used to avoid the effect of regression to the mean. RESULTS There were wide variations in the state-specific CEA rates, 30-day mortality, and in changes in these rates over time. The states with relatively low procedure rates in 1991 also had low rates in 1995 and 2000, and relatively higher increases in the rates. The states with relatively high 30-day mortality in 1991 or 1995 had lower increases or greater decreases in the rate. CEA rates were not correlated with any measure of surgical mortality, but they were correlated with stroke mortality in the general population. CONCLUSIONS The inter-state variation in CEA rates has not changed much since 1991, but variation in 30-day mortality decreased through 2000. The states with low procedure rates in 1991 did not have sufficient increase to catch up with the high-rate states by 1995, but they were prone to experience a higher increase in the subsequent 5 years. The validity of stroke mortality in a state as a measure of the need for CEA is questionable. Further research using clinical data is needed to better explain variations between states.

Adherence to Guidelines for and Disparities in Diabetes Care Utilization in Medicaid Children

1999-2002 Medicaid administrative data on 360 children with diabetes mellitus were used to study disparities in and utilization of health care in Missouri, United States. Measures of ambulatory care and its utilization were based on clinical guidelines. Their association with readmission in hospitals and emergency rooms were examined using multivariate analyses. Many children did not visit their doctors office, have blood tests for glycosylated hemoglobin, or monitor their blood glucose level. There were no sex or race differences in the utilization of ambulatory care or its outcome for all children, except for blood glucose test strip use. Older age and non-white race increased the odds of rehospitalization and three or more physician encounters decreased this risk. Non-white race increased the odds of visiting emergency rooms. In some subpopulations, there were age, sex, and race disparities in ambulatory care utilization. Adherence to diabetes care guidelines was associated with lower risk of re-hospitalization.

Evaluation of quality improvement interventions for reducing adverse outcomes of carotid endarterectomy.

Background:Clinical and health services interventions should be evaluated for their effectiveness. Objectives:The objectives of this study were to evaluate the effectiveness of quality improvement interventions for reducing the adverse outcome of the carotid endarterectomy (CEA) procedure, and to study the relationship between pre- and postintervention 30-day mortality and stroke rates. These interventions were implemented in 1997–1998 by the Peer Review Organizations (PRO) for 7 states. Research Design:In a quasiexperimental study, a control state was matched with each of the 7 intervention states. Pretest–posttest analyses compared the preintervention outcome rates in each intervention and control state with the corresponding postintervention rates. In a time (1991–2001) series analysis, the trends in the preintervention 30-day, 7-state mortality in intervention and control states were compared with the trends in the corresponding postintervention rates. Study Population:We studied Medicare beneficiaries aged 65 years and older who had a CEA procedure in 14 states during 1991–2001. Results:There was no correlation between the state-specific, preintervention 30-day mortality and the corresponding postintervention mortality. After interventions, there was no significant decline in 30-day mortality in any intervention or control state, or in all 7 intervention states combined or all control states combined. Similarly, the 30-day stroke rate did not decrease after interventions in any state. The trend in the 7-state, 30-day mortality also did not show further decline after interventions. Conclusion:After PRO interventions, the post-CEA 30-day mortality and stroke rates did not decrease in any individual intervention state or in all states combined.

Effectiveness of Interventions for Reducing the Frequency of Radical Prostatectomy Procedures in the Elderly: An Evaluation

Between 1993 and 1997, the Peer Review Organizations (PROs) implemented interventions for reducing radical prostatectomy rates in 50 selected hospitals in 10 states and all hospitals in an additional 4 states. Control hospitals and states were matched with the intervention hospitals and states. Prostate cancer incidence rates were used to estimate the number of Medicare beneficiaries aged 75 years and older with prostate cancer, the denominators for the procedure rates, in the hospital service area of each intervention and control hospital, and in each state and their controls. After interventions, significant reductions in the state-specific radical prostatectomy rates were achieved in the intervention hospitals in 2 states and in 1 of the 4 intervention states where statewide interventions had been implemented. Similar reductions were seen in the control hospitals in 3 other individual states and 8 states combined where hospital-based interventions were implemented. These changes in the procedure rates were most likely due to the national decline in the incidence of prostate cancer, not the PRO interventions.

Is there a sex or race difference in 30-day mortality after interruption of vena cava in a Medicare population?

PURPOSE Disparities in health care and its outcome often indicate an opportunity for improving the quality of health care. Sex and rare differences in short-term mortality following interruption of vena cava are not known. The objective of this study was to determine such differences. MATERIALS AND METHODS With use of Medicare administrative data, 1,823 interruption of vena cava procedures performed between 1994 and 1997 were identified among beneficiaries aged 65-99 years residing in Indiana and Kentucky. In Cox proportional hazard regression models, male-to-female and nonwhite-to-white 30-day mortality ratios were adjusted for age, sex or race, weighted Charlson comorbidity score, length of hospital stay, and fatal coexisting conditions (ascertained from death certificate data). RESULTS Altogether, 277 patients died within 30 days after the procedure. Women were older than men. The comorbidity score was associated with male sex and mortality. There was no significant race difference in unadjusted or adjusted 30-day mortality after interruption of the vena cava. Unadjusted mortality was higher in men than in women (odds ratio, 1.49; 95% confidence interval [CI]=1.15, 1.92). Although adjustment for age, race, Charlson score, and length of hospital stay reduced the magnitude of sex difference, it remained significant. Further adjustment for fatal coexistent conditions reduced the sex difference to an insignificant level (odds ratio, 1.22; 95% CI=0.96, 1.56). CONCLUSIONS There was no significant sex or race difference in adjusted 30-day mortality after interruption of vena cava procedure in the elderly Medicare beneficiary population of two states.