Development of a comorbidity index using physician claims data

Important comorbidities recorded on outpatient claims in administrative datasets may be missed in analyses when only inpatient care is considered. Using the comorbid conditions identified by Charlson and colleagues, we developed a comorbidity index that incorporates the diagnostic and procedure data contained in Medicare physician (Part B) claims. In the national cohorts of elderly prostate (n = 28,868) and breast cancer (n = 14,943) patients assessed in this study, less than 10% of patients had comorbid conditions identified when only Medicare hospital (Part A) claims were examined. By incorporating physician claims, the proportion of patients with comorbid conditions increased to 25%. The new physician claims comorbidity index significantly contributes to models of 2-year noncancer mortality and treatment received in both patient cohorts. We demonstrate the utility of a disease-specific index using an alternative method of construction employing study-specific weights. The physician claims index can be used in conjunction with a comorbidity index derived from inpatient hospital claims, or employed as a stand-alone measure.     

Evaluation of three algorithms to identify incident breast cancer in Medicare claims data

OBJECTIVE: To test the validity of three published algorithms designed to identify incident breast cancer cases using recent inpatient, outpatient, and physician insurance claims data. DATA: The Surveillance, Epidemiology, and End Results (SEER) registry data linked with Medicare physician, hospital, and outpatient claims data for breast cancer cases diagnosed from 1995 to 1998 and a 5 percent control sample of Medicare beneficiaries in SEER areas. STUDY DESIGN: We evaluate the sensitivity and specificity of three algorithms applied to new data compared with original reported results. Algorithms use health insurance diagnosis and procedure claims codes to classify breast cancer cases, with SEER as the reference standard. We compare algorithms by age, stage, race, and SEER region, and explore via logistic regression whether adding demographic variables improves algorithm performance. PRINCIPAL FINDINGS: The sensitivity of two of three algorithms is significantly lower when applied to newer data, compared with sensitivity calculated during algorithm development (59 and 77.4 percent versus 90 and 80.2 percent, p<.00001). Sensitivity decreases as age increases, and false negative rates are higher for cases with in situ, metastatic, and unknown stage disease compared with localized or regional breast cancer. Substantial variation also exists by SEER registry. There was potential for improvement in algorithm performance when adding age, region, and race to an indicator variable for whether the algorithm determined a subject to be a breast cancer case (p<.00001). CONCLUSIONS: Differential sensitivity of the algorithms by SEER region and age likely reflects variation in practice patterns, because the algorithms rely on administrative procedure codes. Depending on the algorithm, 3-5 percent of subjects overall are misclassified in 1998. Misclassification disproportionately affects older women and those diagnosed with in situ, metastatic, or unknown-stage disease. Algorithms should be applied cautiously to insurance claims databases to assess health care utilization outside SEER-Medicare populations because of uneven misclassification of subgroups that may be understudied already.     

Characteristics of high staff intensive Medicare psychiatric inpatients

Previous analyses of the costs of Medicare psychiatric inpatients have been limited by the use of claims and provider cost reports that fail to quantify differences in patient characteristics and routine costs. This article uses new primary data from 66 psychiatric inpatient units in 40 facilities nationwide to measure the times staff spend in therapeutic and other activities caring for Medicare patients. Patient days are divided into two groups of very high and low staff intensity and patient characteristics compared in each group. Results identify key patient characteristics associated with high staffing days, including old age, dementia and cognitive impairment, severe psychiatric diagnosis, deficits in activities of daily living (ADLs), and assaultive or agitated behaviors. Policy implications and suggested enhancements are made with regard to the proposed CMS case-mix classification system based on claims data alone.     

Comorbidity risk-adjustment strategies are comparable among persons with hip fracture

OBJECTIVE: To determine the magnitude and importance of declines in model performance associated with altering the data source and time frame from which comorbid conditions were identified in claims-based risk adjustment among persons with hip fracture. STUDY DESIGN AND SETTING: Medicare claims data were used to identify incident hip fracture cases in 1999. Three risk-adjustment instruments were evaluated: one by Iezzoni, the Charlson Index (Romano adaptation), and the Clinical Classification Software (CCS). Several implementation strategies, defined by altering data source (MedPar and/or Part B claims) and time frame (index hospitalization and/or 1-year preperiod), were assessed for each instrument. Logistic regression was used to predict 1-year mortality, and model performance was compared. RESULTS: Each instrument had modest ability to predict 1-year mortality after hip fracture. The CCS performed best overall (c=0.76), followed by the Iezzoni (c=0.73) and Charlson models (c=0.72). Although each instrument performed most favorably when applied to both inpatient and outpatient claims and when comorbidities were considered during the preperiod, varying data source and time frame had trivial effects on model performance. CONCLUSION: The similar predictive ability of the three risk-adjustment instruments suggests that ease of implementation be a key consideration in choosing an approach for hip fracture populations.     

An Algorithm for the Use of Medicare Claims Data to Identify Women with Incident Breast Cancer

Objective. To develop and validate a clinically informed algorithm that uses solely Medicare claims to identify, with a high positive predictive value, incident breast cancer cases.
Data Source. Population-based Surveillance, Epidemiology, and End Results (SEER) Tumor Registry data linked to Medicare claims, and Medicare claims from a 5 percent random sample of beneficiaries in SEER areas.
Study Design. An algorithm was developed using claims from 1995 breast cancer patients from the SEER-Medicare database, as well as 1995 claims from Medicare control subjects. The algorithm was validated on claims from breast cancer subjects and controls from 1994. The algorithm development process used both clinical insight and logistic regression methods.
Data Extraction. Training set: Claims from 7,700 SEER-Medicare breast cancer subjects diagnosed in 1995, and 124,884 controls. Validation set: Claims from 7,607 SEER-Medicare breast cancer subjects diagnosed in 1994, and 120,317 controls.
Principal Findings. A four-step prediction algorithm was developed and validated. It has a positive predictive value of 89 to 93 percent, and a sensitivity of 80 percent for identifying incident breast cancer. The sensitivity is 82–87 percent for stage I or II, and lower for other stages. The sensitivity is 82–83 percent for women who underwent either breast-conserving surgery or mastectomy, and is similar across geographic sites. A cohort identified with this algorithm will have 89–93 percent incident breast cancer cases, 1.5–6 percent cancer-free cases, and 4–5 percent prevalent breast cancer cases.
Conclusions. This algorithm has better performance characteristics than previously proposed algorithms. The ability to examine national patterns of breast cancer care using Medicare claims data would open new avenues for the assessment of quality of care.     

Real-World Cost of Care for Commercially Insured versus Medicare Patients with Metastatic Pancreatic Cancer Who Received Guideline-Recommended Therapies

BackgroundMuch of the literature about the costs of metastatic pancreatic cancer is focused on the Medicare population, but the cost in the commercially insured population is not well-documented. Differences in treatment patterns between commercially insured and Medicare patients with metastatic pancreatic cancer can provide insights into healthcare utilization and the total cost of care.ObjectiveTo compare the total cost of care for commercially insured versus Medicare patients with metastatic pancreatic cancer who are receiving National Comprehensive Cancer Network (NCCN)-recommended treatment regimens.MethodsWe identified 3904 patients (mean age at diagnosis, 56 years) with metastatic pancreatic cancer using International Classification of Diseases, Ninth/Tenth Revision diagnosis codes in claims data in the 2014–2018 MarketScan commercial database and 28,063 patients (mean age at diagnosis, 73 years) with metastatic pancreatic cancer in the 2014–2017 Medicare Parts A, B, and D 100% research identifiable data files. We calculated the total cost of care and resource utilization by NCCN-recommended (category 1) treatment regimen, including 5-fluorouracil, leucovorin, oxaliplatin, and irinotecan (FOLFIRINOX); gemcitabine plus nab-paclitaxel; gemcitabine monotherapy; and liposomal irinotecan. All patients had ≥2 claims with a pancreatic cancer diagnosis more than 30 days apart and ≥1 subsequent claims with a secondary malignancy diagnosis for metastatic disease.ResultsThe mean total cost of care was 186% higher in the commercially insured cohort than in the Medicare cohort. Excluding gemcitabine monotherapy, the total cost of care for patients with metastatic pancreatic cancer was similar between the regimens used in each cohort, ranging from $95,426 to $116,325 in the commercial insurance group and from $39,777 to $40,390 in the Medicare group. The components of hospital-based inpatient and outpatient costs varied between similar regimens in both cohorts. The inpatient admission patterns of patients'' regimens were consistent across the 2 cohorts, with patients receiving gemcitabine monotherapy or liposomal irinotecan having the lowest overall number of admissions in each cohort.ConclusionsThe treatment patterns varied across the regimens but were largely consistent between the commercially insured and the Medicare patients who received the same regimen for metastatic pancreatic cancer; the ratio of total cost of care was 3:1 (commercially insured to Medicare). The total costs of care were similar across the regimens in each cohort, but the components of the total cost varied. These results can inform clinical guidelines and pathways for pancreatic cancer therapy as new evidence and treatment options emerge, and in the context of increasing value-based care models.     

Medicare breast surgery fees and treatment received by older women with localized breast cancer

OBJECTIVE: To determine whether area-level Medicare physician fees for mastectomy and breast conserving surgery were associated with treatment received by Medicare beneficiaries with localized breast cancer and to compare these results with an earlier analysis conducted using small areas (three-digit zip codes) as the unit of observation. DATA SOURCE: Medicare claims and physician survey data for a national sample of elderly (aged 67 or older) Medicare beneficiaries with localized breast cancer treated in 1994 (unweighted n = 1,787). STUDY DESIGN: Multinomial logistic regression analysis was used to estimate a model of treatment received as a function of Medicare fees, controlling for other area economic factors, patient demographic and clinical characteristics, physician experience, and region. PRINCIPAL FINDINGS: In 1994, average Medicare fees (adjusted for the effects of modifiers and procedure mix) for mastectomy (MST) and breast conserving surgery (BCS) were 904 dollars and 305 dollars, respectively. Holding other fees and factors fixed, a 10 percent increase in the BCS fee increased the odds of breast conserving surgery with radiation therapy relative to mastectomy to 1.34 (p = 0.02), while a 10 percent decrease in the MST fee increased the odds of breast conserving surgery with radiation therapy to 1.86 (p < 0.01). CONCLUSIONS: Among older women with localized breast cancer, financial incentives appear to influence the use of mastectomy and breast conserving surgery with radiation therapy. This finding is consistent with the hypothesis that physicians are responsive to financial incentives when the alternative procedures have clinically equivalent outcomes and the patient's clinical condition does not dominate the treatment choice. We also find that the fee effects derived from this analysis of individual data with more precise measurement of both diagnosis and treatment are qualitatively similar to the results of the small-area analysis. This suggests that the earlier study was not severely affected by ecological bias or other data limitations inherent in Medicare claims data.     

Effects of competition on Medicare administrative costs.

This paper examines the effects of introducing competitive contracting into the Medicare: Part B program. The administrative costs of contractors (carriers) who process Medicare claims for medical services are examined to determine relative efficiencies of firms operating under either competitive or non-competitive contracts. Pooled time-series cross-sectional data are used to estimate an average total cost function. Findings are that (1) appreciable cost reductions were obtained by the introduction of competition, (2) economies of scale are present in Medicare claims processing, and (3) carriers who are non-profit organizations (i.e. Blue Shield plans) do not exhibit higher costs than comparable commercial insurance companies.     

More Comprehensive Care Among Family Physicians is Associated with Lower Costs and Fewer Hospitalizations

PURPOSEComprehensiveness is lauded as 1 of the 5 core virtues of primary care, but its relationship with outcomes is unclear. We measured associations between variations in comprehensiveness of practice among family physicians and healthcare utilization and costs for their Medicare beneficiaries.METHODSWe merged data from 2011 Medicare Part A and B claims files for a complex random sample of family physicians engaged in direct patient care, including 100% of their claimed care of Medicare beneficiaries, with data reported by the same physicians during their participation in Maintenance of Certification for Family Physicians (MC-FP) between the years 2007 and 2011. We created a measure of comprehensiveness from mandatory self-reported survey items as part of MC-FP examination registration. We compared this measure to another derived from Medicare’s Berenson-Eggers Type of Service (BETOS) codes. We then examined the association between the 2 measures of comprehensiveness and hospitalizations, Part B payments, and combined Part A and B payments.RESULTSOur full family physician sample consists of 3,652 physicians providing the plurality of care to 555,165 Medicare beneficiaries. Of these, 1,133 recertified between 2007 and 2011 and cared for 185,044 beneficiaries. There was a modest correlation (0.30) between the BETOS and self-reported comprehensiveness measures. After adjusting for beneficiary and physician characteristics, increasing comprehensiveness was associated with lower total Medicare Part A and B costs and Part B costs alone, but not with hospitalizations; the association with spending was stronger for the BETOS measure than for the self-reported measure; higher BETOS scores significantly reduced the likelihood of a hospitalization.CONCLUSIONSIncreasing family physician comprehensiveness of care, especially as measured by claims measures, is associated with decreasing Medicare costs and hospitalizations. Payment and practice policies that enhance primary care comprehensiveness may help “bend the cost curve.”     

Use of surveillance, epidemiology, and end results-medicare data to conduct case-control studies of cancer among the US elderly

Cancer is an important cause of morbidity in the elderly, and many medical conditions and treatments influence cancer risk. The Surveillance, Epidemiology, and End Results (SEER)-Medicare database can be used to conduct population-based case-control studies that elucidate the etiology of cancer among the US elderly. SEER-Medicare links data on malignancies ascertained through SEER cancer registries to claims from Medicare, the US government insurance program for people over age 65 years. Under one approach described herein, elderly cancer cases are ascertained from SEER data (1987-2005). Matched controls are selected from a 5% random sample of Medicare beneficiaries. Risk factors of interest, including medical conditions and procedures, are identified by using linked Medicare claims. Strengths of this design include the ready availability of data, representative sampling from the US elderly population, and large sample size (e.g., under one scenario: 1,176,950 cases, including 221,389 prostate cancers, 185,853 lung cancers, 138,041 breast cancers, and 124,442 colorectal cancers; and 100,000 control subjects). Limitations reflect challenges in exposure assessment related to Medicare claims: restricted range of evaluable risk factors, short time before diagnosis/selection for ascertainment, and inaccuracies in claims. With awareness of limitations, investigators have in SEER-Medicare data a valuable resource for epidemiologic research on cancer etiology.     

Where do elderly veterans obtain care for acute myocardial infarction: Department of Veterans Affairs or Medicare?

OBJECTIVE: To examine Department of Veterans Affairs (VA) and Medicare hospitalizations for elderly veterans with acute myocardial infarction (AMI), their use of cardiac procedures in both systems, and patient mortality. DATA SOURCES: Merging of inpatient discharge abstracts obtained from VA Patient Treatment Files (PTF) and Medicare MedPAR Part A files. STUDY DESIGN: A retrospective cohort study of male veterans 65 years or older who were prior users of the VA medical system (veteran-users) and who were initially admitted to a VA or Medicare hospital with a primary diagnosis of AMI at some time from January 1, 1988 through December 31, 1990 (N = 25,312). We examined the use of cardiac catheterization, coronary bypass surgery, and percutaneous transluminal coronary angioplasty in the 90 days after initial admission for AMI in both VA and Medicare systems, and survival at 30 days, 90 days, and one year. Other key measures included patient age, race, marital status, comorbidities, cardiac complications, prior utilization, and the availability of cardiac technology at the admitting hospital. PRINCIPAL FINDINGS: More than half of veteran-users (54 percent) were initially hospitalized in a Medicare hospital when they suffered an AMI. These Medicare index patients were more likely to receive cardiac catheterization (OR 1.24, 95% C.I. 1.17-1.32), coronary bypass surgery (OR 2.01, 95% C.I. 1.83-2.20), and percutaneous transluminal coronary angioplasty (OR 2.56, 95% C.I. 2.30-2.85) than VA index patients. Small proportions of patients crossed over between systems of care for catheterization procedures (VA to Medicare = 3.3%, and Medicare to VA = 5.1%). Many VA index patients crossed over to Medicare hospitals to obtain bypass surgery (27.6 percent) or coronary angioplasty (12.1 percent). Mortality was not significantly different between veteran-users who were initially admitted to VA versus Medicare hospitals. CONCLUSIONS: Dual-system utilization highlights the need to look at both systems of care when evaluating access, costs, and quality either in VA or in Medicare systems. Policy changes that affect access to and utilization of one system may lead to unpredictable results in the other.     

Limited validity of diagnosis codes in Medicare claims for identifying cancer metastases and inferring stage

PurposeResearchers are using diagnosis codes from health claims to identify metastatic disease in cancer patients. The validity of this approach has not been established.MethodsWe used the linked 2005–2007 Surveillance, Epidemiology and End Results (SEER)–Medicare data to assess the validity of metastasis codes at diagnosis from claims compared with stage reported by SEER cancer registries. The cohort included 80,052 incident breast, lung, and colorectal cancer patients aged 65 years and older. Using gold-standard SEER data, we evaluated sensitivity, specificity, positive predictive value, and negative predictive value of claims-based stage, survival by stage classification, and patient factors associated with stage misclassification using multivariable regression.ResultsFor patients with a registry report of distant metastatic cancer, the sensitivity, specificity, and positive predictive value of claims never simultaneously exceeded 80% for any cancer: lung (42.7%, 94.8%, and 88.1%), breast (51.0%, 98.3%, and 65.8%), and colorectal (72.8%, 93.8%, and 68.5%). Misclassification of stage from Medicare claims was significantly associated with inaccurate estimates of stage-specific survival (P < .001). In adjusted analysis, patients who were older, black, or living in low-income areas were more likely to have their stage misclassified in claims.ConclusionsDiagnosis codes in Medicare claims have limited validity for inferring cancer stage and metastatic disease.     

Mortality,Health Care Use,and Costs of Clostridioides difficile Infections in Older Adults

ObjectivesEstimate mortality, cost, and health care resource utilization for Medicare beneficiaries aged ≥65 years who suffered a primary Clostridioides difficile infection (CDI) episode only or any recurrent CDI, and understand how outcomes covary with death.DesignRetrospective observational claims analysis.Setting and ParticipantsPatients aged ≥65 years who had an inpatient or outpatient CDI diagnosis claim to Medicare and continuous enrollment in Medicare parts A, B, and D during the 12-month pre- and post-index periods.MethodsUsing 100% Medicare Fee-for-Service claims data for 2009–2017, primary (pCDI, n = 345,893) and recurrent (rCDI: n = 151,596) CDI episodes were identified. Demographic and clinical characteristics, mortality, health care resource utilization, and costs (per patient per month) were summarized for 12 months before and up to 12 months after episode start. Regression models were estimated for hospitalization risk, hospital length of stay (LOS), and cost to adjust for comorbidities.ResultsCDI-associated deaths were almost 10 times higher after recurrent CDI (25.4%) than primary CDI (2.7%). Compared with survivors, decedents were older, had higher Charlson Comorbidity Index scores, and were more likely Black. Adjusting for comorbidities, during follow-up, decedents had higher hospitalization rates [pCDI: odds ratio (OR) = 1.83, P < .001; rCDI: OR = 2.58, P < .001], and recurrent CDI decedents had more intensive care unit use (OR = 2.34, P < .001) compared with survivors. Decedents also had a longer length of stay (pCDI: +3.2 days, P < .001; rCDI: +2.6 days, P < .001), and higher total cost (pCDI: +303%, P < .001; rCDI: +297%, P < .001).Conclusions and ImplicationsCDI is an important contributing diagnosis to all-cause mortality, particularly for recurrences. Prior to death, older Medicare beneficiaries who experienced CDI received longer, more intensive, and more costly care compared with survivors. Clinicians should be particularly attentive to prevention, identification, and appropriate treatment of CDI in older adults. Better treatments to reduce primary C difficile infection and recurrences in this vulnerable population can lower both mortality and economic burden.     

Despite 'welcome to medicare' benefit, one in eight enrollees delay first use of part B services for at least two years

Much research has focused on the possible overuse of health care services within Medicare, but there is also substantial evidence of underuse. In recent years, Congress has added a "welcome to Medicare" physician visit and a number of preventive services with no cost sharing to the Medicare benefit package to encourage early and appropriate use of services. We examined national longitudinal data on first claims for Part B services-the portion of Medicare that covers physician visits-to learn how people used these benefits. We found that 12 percent of people, or about one in eight, who enrolled in Medicare at age sixty-five waited more than two years before making their first use of care covered by Part B. In part, this delay reflected patterns of use before enrollment, in that people who sought preventive care before turning sixty-five continued to do so after enrolling in Medicare. Enrollees with Medigap coverage, higher household wealth, and a higher level of education typically received care under Part B sooner than others, whereas having greater tolerance for risk was more likely to lead enrollees to delay use of Part B services. Men had a lower probability of using Part B services early than women; blacks and members of other minority groups were less likely to use services early than whites. Although the "welcome to Medicare" checkup does not appear to have had a positive effect on use of services soon after enrollment, the percentage of beneficiaries receiving Part B services in the first two years after enrollment has steadily increased over time. Whether or not delays in receipt of care should be a considerable public policy concern may depend on what factors are leading specific categories of enrollees to delay care and how such delays affect health.     

Age and Gender Differences in Medicare Expenditures and Service Utilization at the End of Life for Lung Cancer Decedents

PURPOSE: Gender and age differences in medical care are well documented. We examined age and gender differences in Medicare expenditures for lung cancer decedents in the last year of life (LYOL) through a cross-sectional study of Medicare administrative and claims data. METHODS: Participants were aged Medicare beneficiaries (>or=68) with lung cancer, who were covered by Parts A and B for 36 months before death (1996-1999; n = 13,120). Regression techniques were used to estimate age and gender differences in mean Medicare utilization and expenditures in the LYOL overall and by type of service, conditional on use: inpatient, outpatient, physician, skilled nursing facility (SNF), home health, and hospice, controlling for demographic, clinical, geographic, and supply characteristics. RESULTS: Women were more likely than men to use inpatient, SNF, home health, and hospice services. Women's average expenditures were approximately dollars 1,900 greater than men's, with differences attributed to higher average expenditures for SNF, home health, and hospice. Older cohorts used fewer inpatient and outpatient services and used more SNF and hospice services in their LYOL. Average Medicare expenditures were significantly lower in older cohorts (dollars 8,487 less for those age >or=85 at death than for those 68-74). Adjusting for age explains most of the gender differences in average Medicare expenditures. Remaining gender differences vary across age cohorts, with larger gender differences in social-supportive service expenditures among those 68-74 and 75-84 and outpatient and physician services among those 75-84 and >or=85. DISCUSSION AND CONCLUSIONS: Our findings suggest that gender disparities in expenditures are generally small at the end of life for lung cancer decedents, particularly among the older cohorts. As expected, the bigger observed differences are by age although the direction of the association is not consistent across types of service. Higher expenditures for women on social-supportive services may reflect fewer informal supports for older women compared with men.     

Biosimilar Uptake in Medicare Part B Varied Across Hospital Outpatient Departments and Physician Practices: The Case of Filgrastim

ObjectivesTo examine the uptake of filgrastim-sndz (Zarxio), the first biosimilar to launch in the United States, in the Medicare Part B fee-for-service program from its launch in September 2015 to December 2017 and compare characteristics of patients and facilities that used filgrastim-sndz or originator filgrastim (Neupogen).MethodsThe 20% sample of Medicare Part B fee-for-service administrative claims data was used to extract information on claims for any filgrastim product between January 1, 2015 and December 31, 2017.ResultsThe utilization of filgrastim-sndz in Medicare Part B increased sharply between January and August 2016, surpassing filgrastim by November 2017, contributing to a 30% decrease in overall spending on this drug since 2015. Uptake was faster and larger in physician practices compared with hospital outpatient departments. About 77% of patients receiving filgrastim-sndz were new users. Utilization patterns indicated that product selection occurred at the facility level, rather than being at the discretion of the prescribing physician or driven by patient characteristics.ConclusionUptake of biosimilar filgrastim in the Medicare Part B program occurred despite multiple challenges to the adoption of biosimilars in the US market, suggesting that substantial potential savings could be generated by improving biosimilar uptake. Our findings indicated that physician practices and hospital outpatient departments have distinctive biosimilar uptake patterns. Thus policy makers aiming to contain Medicare Part B spending might consider focusing on incentivizing biosimilar uptake among hospital outpatient departments.     

Disparities in breast cancer treatment among American Indian, Hispanic and non-Hispanic White Women Enrolled in Medicare

Because racial/ethnic disparities in breast cancer survival have persisted, we investigated differences in breast cancer treatment among American Indian, Hispanic, and non-Hispanic White (NHW) women. Surveillance, Epidemiology and End Results data linked to Medicare claims in New Mexico and Arizona (1987-1997) among enrollees aged 65 and older were used to identify treatment, treatment interval, and mortality risk associated with delays in care. We identified 2,031 women (67 American Indian, 333 Hispanic and 1,631 NHW women with time to treatment information. Treatment intervals from diagnosis to surgery (all stages, 18 versus 4 days, p.     

Health-risk-assessment tools used to predict costs in defined populations

With the Balanced Budget Act of 1997 mandating that the Health Care Financing Administration (HCFA) implement risk-adjusted payment mechanisms for Medicare managed care plans (Medicare + Choice) by January 2000, risk-adjustment tools will play an important role in future capitated reimbursement. This is because there is growing evidence that healthier-than-average beneficiaries select Medicare + Choice. The risk adjustment that HCFA has adopted is initially based on primary inpatient diagnosis from hospitalizations in the previous year. Other payers are likely to adopt similar payment mechanisms. This article reviews nineteen risk-adjustment research papers, including the tool adopted for Medicare + Choice, some of which are likely to form the basis for subsequent HCFA risk-adjustment methods. In general, claims-based models are more powerful in predicting total costs than survey-based or demographics-based models. Survey-based models, although expensive and not as powerful claims-based models, can be used when claims data are unavailable. One of the most popular survey-based tools, SF-36, is likely to become increasingly important because HCFA will be using it to measure quality outcomes from Medicare + Choice plans and will make the results public. All of the models reviewed have limitations, but can be expected to be building blocks for future risk-based capitated reimbursement.     

Strategies for improving comorbidity measures based on Medicare and Medicaid claims data

Claims-based measures of comorbid illness severity have generally relied on the diagnoses listed for a single hospitalization. Unfortunately, such diagnostic information is often limited because patients have not been hospitalized during periods of interest, because of incomplete coding of diagnoses on claims forms, or because listed diagnoses represent complications of the hospitalization rather than pre-existing comorbid conditions. To address these limitations, we developed and tested four comorbidity index scores for patients with breast cancer, each based on different sources of health services claims from Medicare and Medicaid: hospitalization for breast cancer surgery; outpatient care prior to the hospitalization; other inpatient care prior to the hospitalization; and all sources combined. Varying the number and type of sources of diagnostic information yielded only very small improvements in the prediction of mortality at 1 and 3 years. Surprisingly, even simpler measures of comorbidity (crude number of diagnoses) and of prior health care utilization (total days spent in the hospital) performed at least as well in predicting mortality as did the more complex index scores which assigned points and weights for specific conditions. The greatest improvement in explanatory power was observed when another source of clinical information (cancer stage derived from a population-based cancer registry) was used to supplement claims information. Expanding the source of claims diagnoses and focusing on time periods prior to an index hospitalization are insufficient for substantially improving the explanatory power of claims-based comorbidity indices. Other improvements suggested by our results should include: increasing the completeness and accuracy of claims diagnoses; supplementing diagnoses with health care utilization information in claims data; and supplementing claims data with other sources of clinical information.     

Preventive services for the elderly: would coverage affect utilization and costs under Medicare?

OBJECTIVES. This study was undertaken to determine whether adding a benefit for preventive services to older Medicare beneficiaries would affect utilization and costs under Medicare. METHODS. The demonstration used an experimental design, enrolling 4195 older, community-dwelling Medicare recipients. Medicare claims data for the 2 years in which the preventive visits occurred were compared for the intervention (n = 2105) and control (n = 2090) groups. Monthly allowable charges for Part A and Part B services and number of hospital discharges and ambulatory visits were compared. RESULTS. There were no significant differences in the charges between the groups owing to the intervention, although total charges were somewhat lower for the intervention group even when the cost of the intervention was included. Charges for both groups rose significantly as would be expected for an aging population. A companion paper describes a modest health benefit. CONCLUSIONS. There appears to be a modest health benefit with no negative cost impact. This finding gives an early quantitative basis for the discussion of whether to extend Medicare benefits to include a general preventive visit from a primary care clinician.