Use of Medicare services by elderly residents of Puerto Rico

OBJECTIVES: We describe hospitalization rates among Medicare beneficiaries resident in Puerto Rico compared to beneficiaries in the mainland U.S., in 1999. METHODS: A cross-sectional analysis using Medicare Denominator and hospitalization files. RESULTS: The rate ratio (PR/U.S.) of age, gender-adjusted hospitalizations among elderly Medicare beneficiaries with Part A coverage was 0.78, compared with 0.92 among beneficiaries with both Part A and Part B coverage. Among the latter, the rate ratios were 0.78 for surgical admissions, 1.08 for low-variation medical conditions, and 0.97 for high variation medical conditions. They were higher for younger elderly beneficiaries. CONCLUSIONS: Rates of hospitalization in Puerto Rico may be lower, the same or exceed those of the mainland U.S. depending on the age of the beneficiary and the type of hospitalization.

Transurethral resection of the prostate among medicare beneficiaries: 1984 to 1997. For the Patient Outcomes Research Team for Prostatic Diseases.

PURPOSE: We examine the epidemiology and associated risks of transurethral resection of the prostate among Medicare beneficiaries for the period 1984 to 1997. MATERIALS AND METHODS: We used hospital claims for transurethral resection of the prostate from a 20% national sample of Medicare beneficiaries for the period 1991 to 1997. Risk of mortality and reoperation were evaluated using life table methods and compared to those for the period 1984 to 1990. We also examined the association between surgical volume and adverse outcomes following resection using unique urologist identifier codes from the 1997 part B Medicare claims. RESULTS: Compared to 1984 to 1990, age adjusted rates of transurethral resection for benign prostatic hyperplasia (BPH) during 1991 to 1997 declined by approximately 50% for white (14.6 to 6.72/1,000) and 40% for black (11.8 to 6.58/1,000) men. Of the men who underwent resection for BPH during the recent period 53% were 75 years old or older but 30-day mortality in men 70 years old or older was significantly lower than that in 1984 to 1990. Since 1987 the 5-year risk for reoperation following transurethral resection for BPH has remained 5%. For resection performed in 1997 we observed no statistically significant association between urologist surgical volume and risks of reoperation or 30-day mortality. CONCLUSIONS: Compared to the peak period of its use in the 1980s, older men are now undergoing transurethral resection of the prostate. Nevertheless, outcomes for men 65 years old or older continue to be good.

How well does a single question about health predict the financial health of Medicare managed care plans?

CONTEXT: Responses to simple questions that predict subsequent health care utilization are of interest to both capitated health plans and the payer. OBJECTIVE: To determine how responses to a single question about general health status predict subsequent health care expenditures. DESIGN: Participants in the 1992 Medicare Current Beneficiary Survey were asked the following question: "In general, compared to other people your age, would you say your health is: excellent, very good, good, fair or poor?" To obtain each participant's total Medicare expenditures and number of hospitalizations in the ensuing year, we linked the responses to this question with data from the 1993 Medicare Continuous History Survey. SAMPLE: Nationally representative sample of 8775 noninstitutionalized Medicare beneficiaries 65 years of age and older. MAIN OUTCOME MEASURES: Annual age- and sex-adjusted Medicare expenditures and hospitalization rates. RESULTS: Eighteen percent of the beneficiaries rated their health as excellent, 56% rated it as very good or good, 17% rated it as fair, and 7% rated it as poor. Medicare expenditures had a marked inverse relation to self-assessed health ratings. In the year after assessment, age- and sex-adjusted annual expenditures varied fivefold, from $8743 for beneficiaries rating their health as poor to $1656 for beneficiaries rating their health as excellent. Hospitalization rates followed the same pattern: Respondents who rated their health as poor had 675 hospitalizations per 1000 beneficiaries per year compared with 136 per 1000 for those rating their health as excellent. CONCLUSIONS: The response to a single question about general health status strongly predicts subsequent health care utilization. Self-reports of fair or poor health identify a group of high-risk patients who may benefit from targeted interventions. Because the current Medicare capitation formula does not account for health status, health plans can maximize profits by disproportionately enrolling beneficiaries who judge their health to be good. However, they are at a competitive disadvantage if they enroll beneficiaries who view themselves as sick.

Can we afford comprehensive, supportive care for the very old?

OBJECTIVE: To address the question, "Is there enough overuse of Medicare reimbursement to hospitals that reallocation of excess could provide sufficient funds to enhance home care and community services?" DESIGN: Simulation using data from the Medicare Current Beneficiary Survey (MCBS) to estimate dollars that might be reallocated from hospital reimbursement. PARTICIPANTS: A total of 3577 persons aged 80 and older in a stratified sample of Medicare beneficiaries interviewed in September 1992 in the MCBS. MEASUREMENTS: We ranked the United States hospital service areas' (HSAs) Medicare hospital discharge rates. We assigned the beneficiaries in the MCBS to the HSAs based on their residence zip codes. The hospitalization expenditures and mortality rates of MCBS respondents living in HSAs in each quartile were compared. RESULTS: By reducing hospital utilization to the mean level now used by the lowest quartile of HSAs, $560 would be saved per Medicare beneficiary aged 80 or older (P=.004) with no difference in mortality rates. These savings could purchase 40 visiting nurse visits per year for those in need. Potential savings would be $152 per Medicare beneficiary if hospital utilization were reduced from that used by the highest quartile to the level of the lower three quartiles of HSAs, enough to purchase about 11 additional visiting nurse visits. CONCLUSION: This simulation suggests that the very old might safely receive less hospital care. Because relatively few older people need home and community services in a year, these per capita savings could be reallocated to purchase many services for those having the greatest need.

Benchmarking the US physician workforce. An alternative to needs-based or demand-based planning.

OBJECTIVE: To propose population-based benchmarking as an alternative to needs- or demand-based planning for estimating a reasonably sized, clinically active physician workforce for the United States and its regional health care markets. DESIGN: Cross-sectional analysis of 1993 American Medical Association and American Osteopathic Association physician masterfiles. POPULATION: The resident population of the 306 hospital referral regions in the United States. MAIN OUTCOME MEASURES: Per capita number of clinically active physicians by specialty adjusted for age and sex population differences and out-of-region health care utilization. The measured physician workforce was compared with 4 benchmarks: the staffing within a large (2.4 million members) health maintenance organization (HMO), a hospital referral region dominated by managed care (Minneapolis, Minn), a hospital referral region dominated by fee-for-service (Wichita, Kan), and the proposed "balanced" physician supply (50% generalists). RESULTS: The proportion of the US population residing in hospital referral regions with a higher per capita generalist workforce than the benchmark was 96% for the HMO benchmark, 60% for Wichita, and 27% for Minneapolis. The specialist workforce exceeded all 3 benchmarks for 74% of the population. The per capita workforce of generalists was not related to the proportion of generalists among regions (Pearson correlation coefficient=0.06; P=.26). CONCLUSIONS: Population-based benchmarking offers practical advantages to needs- or demand-based planning for estimating a reasonably sized per capita workforce of clinically active physicians. The physician workforce within the benchmarks of an HMO and health care markets indicates the varying opportunities for regional physician employment and services. The ratio of generalists to specialists does not measure the adequacy of the supply of the generalist workforce either nationally or for specific regions. Research measuring the relationship between physician workforces of different sizes and population outcomes will guide the selection of future regional benchmarks.

Estimating treatment benefits for the elderly: the effect of competing risks.

To fully involve patients in treatment decisions, physicians need to communicate future health prospects that patients will have both with and without newly diagnosed disease. These prospects depend not only on the risks patients face from the new disease but also on the risks they face from other causes. Nowhere is an understanding of these competing risks more relevant than in the care of the elderly. In this study, we use the declining exponential approximation for life expectancy (DEALE) to provide a framework to help clinicians gauge the effect of competing risks as a function of age. Because older patients have many competing risks for death, the absolute effect of a new diagnosis on life expectancy is often relatively small. Consequently, the potential gain in survival even from perfect therapy may also be small. Moreover, no therapy is perfect, and the risks of therapy often increase with age. In the elderly, the combination of a high burden of competing risks and high rates of treatment-related complications conspires to reduce the net benefit of numerous interventions. We conclude that, compared with younger patients, the elderly should request only the more clearly effective treatments and should be willing to tolerate fewer associated complications before they agree to initiate therapy.

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.

Studying outcomes and hospital utilization in the elderly. The advantages of a merged data base for Medicare and Veterans Affairs hospitals.

That veterans aged 65 years and older are eligible to receive care either in the Veteran Affairs (VA) health care system or in the private sector under Medicare confounds the analysis of veterans' health services utilization and outcomes in two ways. First, changes in eligibility or financial barriers to access with regard to either system influence veterans' decisions about where to seek needed care. Second, analyses of VA care for elderly veterans that rely solely on VA data sources underestimate both overall utilization and treatment complications. Similarly, failure to consider the contribution of health care delivery in the VA system may confound analyses of health care utilization by the Medicare-eligible population. To study the magnitude of such confounding influences, we linked the Medicare and VA health care administrative databases for residents of New England and New York. Results indicated that, for ten surgical procedures commonly performed in the elderly, as well as for hospitalizations resulting from acute myocardial infarction and hip fracture, VA patients receive from 17.6% to 37.4% of hospital care outside the VA system. Private hospitalizations account for 5.5% to 19.5% of the care received by veterans within 6 months after an initial episode of care in a VA hospital. It was also found that initial hospitalizations for study conditions in the VA accounted for 3.6% of all such hospitalizations among elderly Medicare-eligible men. Although overall hospital utilization appears to be underestimated in VA data sources, it was found that ascertaining mortality from sources available within the VA produced excellent results when compared with deaths recorded in the Medicare enrollment files. A national, merged VA-Medicare data base is feasible and would enhance the validity of analyses of health care delivery both for elderly veterans and for the Medicare population.

Hip fracture incidence and mortality in New England.

We used Medicare data to conduct a population-based study of osteoporotic hip fracture incidence and outcomes among New England residents. To reduce bias and improve data reliability, we combined data from multiple files; we found that 6% of cases would have been missed had we relied on hospital claims alone. Hip fracture incidence (per 1,000 person-years) increased for white females from 2.2 for ages 65-69 to 31.8 for ages 90-94 and for white males from 0.9 for ages 65-69 to 20.8 for ages 90-94. Incidence among blacks was lower in all age/sex groups. The female/male relative risk was greater among whites than among blacks. Case fatality following hip fracture was 12.5% at 90 days and 23.7% at 1 year and was higher among males, older patients, and those who had documented comorbidity or who were residents of nursing homes.

Overcoming potential pitfalls in the use of Medicare data for epidemiologic research.

We used Medicare data bases and US Census data to address two questions critical to the use of Medicare files for epidemiologic research. First, we examined the degree to which the population enrolled in the Medicare program is similar to the elderly resident population of the United States, as estimated by the US Census. We found small differences in the total population estimates but substantial differences by age and race. Second, we found that among Medicare enrollees, physician claims identify a small proportion of hip fracture cases which are not documented in the hospital discharge files. This proportion varies by age, region, and state within the United States. Calculation of rates based on Medicare hospital discharge data, and probably other hospital discharge data sets as well, must take these limitations into account. Use of all available Medicare data files can overcome these limitations.

Postsurgical mortality in Manitoba and New England.

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.

Risk of carotid endarterectomy in the elderly.

We used the Medicare claims files to describe operative mortality for 2,089 New England residents over the age of 65 who underwent carotid endarterectomy in 1984 and 1985. For patients ages 65 to 69, the risk of death within 30 days of surgery was 1.1 percent, (95% confidence interval = 0.5, 2.1), for those ages 70 to 74, 2.8 percent (1.7, 4.4), for those ages 75 to 79, 3.2 percent (1.8, 5.2), and for those over age 80, 4.7 percent (2.3, 8.5). Nearly 80 percent of patients underwent surgery at hospitals performing 40 or fewer carotid endarterectomies per year on the Medicare population. The adjusted odds ratio for 30 day mortality for patients undergoing surgery in these low-volume hospitals was 2.8 (95% CI = 1.1, 7.2) compared to higher volume hospitals. Although the Medicare claims data provided only limited data about post-operative strokes, analysis of post-operative stroke risk supported these findings.

Hospital use and mortality among Medicare beneficiaries in Boston and New Haven.

We compared rates of hospital use and mortality in fiscal year 1985 among Medicare enrollees in Boston and New Haven, Connecticut. Adjusted rates of discharge, readmission, length of stay, and reimbursement were 47, 29, 15, and 79 percent higher, respectively, in Boston; 40 percent of Boston's deaths occurred in hospitals as compared with 32 percent of New Haven's. High-variation medical conditions (those for which there is little consensus about the need for hospitalization) accounted for most of these differences. By contrast, discharge rates for low-variation medical conditions (which tend to reflect the incidence of disease) were similar. Inpatient case-fatality rates were lower in Boston than in New Haven (RR = 0.85; 95 percent confidence interval, 0.78 to 0.92), but when all deaths (regardless of place of death) were measured, the mortality rates in Boston and New Haven were nearly identical (RR = 0.99; 95 percent confidence interval, 0.93 to 1.05). We conclude that the lower rate of hospital use by Medicare enrollees in New Haven was not associated with a higher overall mortality rate. Population-based as well as hospital-based statistics are needed to evaluate differences in hospital mortality rates for high-variation medical conditions.

Small area analysis: methodology and application.

The data derived from small area analysis type studies carried out in Iowa, Maine and other states is the focus of wide attention from many of the health care delivery system constituencies. These studies look at local patterns of practice. Results of such studies dramatically highlight the wide variances in rates of hysterectomies, prostatectomies or admissions for pulmonary disease between one population area and the next. These variances lead to some provocative discussions of their causes and relationships. Much has already been debated in the health care forum about the meanings of the data, and much more commentary can be expected as consumer groups, UR/QA professionals, those paying health care costs and the federal government join the discussions. In hopes of offering insight into small area analysis, JAMRA presents the following article.