Economic evaluation of systemic treatments for cytomegalovirus retinitis in patients with AIDS

OBJECTIVE

To determine the cost of using systemic therapy to treat newly diagnosed cytomegalovirus (CMV) retinitis in persons with AIDS.

DESIGN

Incidence-based simulation model of CMV treatment from a government payer perspective.

SETTING

Swiss healthcare system.

PATIENTS AND PARTICIPANTS

Patients with AIDS and newly diagnosed CMV retinitis.

INTERVENTIONS

Patients were assigned to 1 of 4 treatment regimens for induction and maintenance therapy: (i) intravenous (IV) cidofovir induction and maintenance (cidofovir IV/IV); (ii) IV foscarnet induction and maintenance (foscarnet IV/IV); (iii) IV ganciclovir induction and maintenance (ganciclovir IV/IV); and (iv) IV ganciclovir induction and oral (PO) ganciclovir maintenance (ganciclovir IV/PO). Following a second relapse, patients were assigned to one of the other regimens.

MAIN OUTCOME MEASURES

Time to first and subsequent progression, duration of maintenance treatment and direct medical expenditures [1998 Swiss francs (SwF)] .

RESULTS

The median time to first progression was longest for cidofovir IV/IV, followed by foscarnet IV/IV, ganciclovir IV/IV and ganciclovir IV/PO. Mean survival was 13 months and mean costs for this period in the base case were lowest in those initially treated with cidofovir (SwF146,742), followed by initial treatment with foscarnet IV/IV (SwF194,809), ganciclovir IV/PO (SwF195,190) and ganciclovir IV/IV (SwF243,964). Costs were most sensitive to changes in efficacy estimates.

CONCLUSIONS

Of the regimens studied, initiation of treatment with systemic cidofovir appears least costly over a 13-month period.

Parameter solicitation for planning cost effectiveness studies with dichotomous outcomes

When economic endpoints are included alongside clinical effectiveness measures in randomized clinical trials (RCT), they are summarized together by the incremental cost effectiveness ratio (ICER). Adding economic endpoints to an RCT complicates the planning of experiments because investigators must now solicit their beliefs about costs, but even more challenging, they must also specify their association with effectiveness. Solicitation of correlations between costs and effects can be unintuitive, and so potentially highly inaccurate. This is unfortunate because power is highly sensitive to the association between costs and effects. Mis-specification in this association may lead to substantially underpowered or overpowered studies. We show that when clinical effectiveness measures are dichotomous, specification of the correlation between costs and effects can be avoided by instead describing their association with a mixture model. This representation leads to simple and highly intuitive parameter specifications. It may also be used to generate realistic raw data that can be used to evaluate experiment power with simulation. We give particular attention to evaluating and interpreting power when Fieller's theorem method (FTM) is used to calculate confidence for, and test hypotheses about, the ICER. Data from a previously published clinical trial are used to demonstrate the use of this new method to calculate sample size for a cost effectiveness study.

Simulation modeling of outcomes and cost effectiveness

Modeling will continue to be used to address important issues in clinical practice and health policy issues that have not been adequately studied with high-quality clinical trials. The apparent ad hoc nature of models belies the methodologic rigor that is applied to create the best models in cancer prevention and care. Models have progressed from simple decision trees to extremely complex microsimulation analyses, yet all are built using a logical process based on objective evaluation of the path between intervention and outcome. The best modelers take great care to justify both the structure and content of the model and then test their assumptions using a comprehensive process of sensitivity analysis and model validation. Like clinical trials, models sometimes produce results that are later found to be invalid as other data become available. When weighing the value of models in health care decision making, it is reasonable to consider the alternatives. In the absence of data, clinical policy decisions are often based on the recommendations of expert opinion panels or on poorly defined notions of the standard of care or medical necessity. Because such decision making rarely entails the rigorous process of data collection, synthesis, and testing that is the core of well-conducted modeling, it is usually not possible for external audiences to examine the assumptions and data that were used to derive the decisions. One of the modeler's most challenging tasks is to make the structure and content of the model transparent to the intended audience. The purpose of this article is to clarify the process of modeling, so that readers of models are more knowledgeable about their uses, strengths, and limitations.

Quality of life in survivors of colorectal carcinoma

BACKGROUND

Colon carcinoma is a common malignancy that accounts for a substantial share of all cancer-related morbidity and mortality. However, little is known with regard to general and disease specific quality of life in survivors of colorectal carcinoma, particularly from community-based samples of cases across stage and survival times from diagnosis.

METHODS

Subjects with colorectal carcinoma were recruited from the National Cancer Institute's Surveillance, Epidemiology, and End Results cancer registry. Subjects completed two self-administered surveys: the Functional Assessment of Cancer Therapy Scales for Colorectal Cancer (FACT-C) and the Health Utilities Index (HUI) Mark III.

RESULTS

One hundred seventy-three respondents (average age: 70.4 years, 71.4% female) completed the survey. In the first 3 years after diagnosis, quality of life was lower and varied substantially among respondents. After 3 years, respondents in all TNM stages of disease except Stage IV reported a relatively uniform and high quality of life. Pain, functional well-being, and social well-being were affected most substantially across all stages and times from diagnosis. Low income status was associated with worse outcomes for pain, ambulation, and social and emotional well-being. Only emotional well-being scores improved significantly over time in both surveys.

CONCLUSIONS

Those individuals who achieve a long term remission from colorectal carcinoma may experience a relatively high quality of life, although deficits remain for several areas, particularly in those of low socioeconomic status. Sampling design may have excluded the most severely ill patients.

Clinical and economic effects of pulmonary artery catheterization in nonemergent coronary artery bypass graft surgery

OBJECTIVE

To examine the association between use of pulmonary artery catheterization with hospital outcomes and costs in nonemergent coronary artery bypass graft (CABG) surgery.

DESIGN

Retrospective cohort study.

SETTING

Fifty-six community-based hospitals in 26 states.

PARTICIPANTS

A total of 13,907 patients undergoing nonemergent CABG surgery between January 1, 1997, and December 31, 1997.

MEASUREMENTS AND MAIN RESULTS

Discharge abstracts for each patient were examined. Stratified and multivariate analyses were used to assess the impact of pulmonary artery catheters (PACs) on in-hospital mortality, length of stay in the intensive care unit, total length of stay, and hospital costs. Outcomes were adjusted for patient demographic factors, hospital characteristics, and hospital volume of PAC use in the year of analysis. Fifty-eight percent of the patients received a PAC. After adjustment, the relative risk of in-hospital mortality was 2.10 for the PAC group compared with the patients who did not receive a PAC (95% confidence interval [CI], 1.40 to 3.14; p < 0.001). The mortality risk was significantly higher in hospitals with the lowest third of PAC use (odds ratio, 3.35; 95% CI, 1.74 to 6.47; p < 0.001) and not significantly increased in the highest two thirds of users (odds ratio, 1.62; 95% CI, 0.99 to 2.66; p = 0.09). Days spent in critical care were similar; however, total length of hospital stay was 0.26 days longer in the PAC group (p < 0.001). Hospital costs were $1,402 higher in the PAC group.

CONCLUSION

In the setting of nonemergent CABG surgery, pulmonary artery catheterization was associated with an increased risk of in-hospital mortality, greater length of stay, and higher total costs, particularly in hospitals with low volume of PAC use.

Healthcare charges and use in commercially insured children enrolled in managed care health plans in Washington State

OBJECTIVE

To determine the relative importance of enrollee, physician, medical group, and healthcare plan characteristics as determinants of healthcare use and expenditures in commercially insured children < 18 years of age enrolled in managed care health plans. We focused on the effects of age and benefit level, the two most important predictors of cost and utilization in our study of adults.

METHODS

This study included 67,432 commercially insured children who were between 1 and 18 years of age, and were cared for by 790 primary care physicians, who practiced in 60 medical care groups in Washington State. Plan enrollment and utilization data for 1994 were linked to a survey of medical care groups contracting with three managed care health plans. Benefit level for each enrollee was defined as low, medium, or high and was based on cost sharing by the health plan for hospitalization, outpatient care, and emergency department services. The three outcome measures included estimated total per member per year charges, number of ambulatory visits, and hospital days.

RESULTS

In multivariate analysis, enrollee age was the most important determinant of total charges, with younger children incurring higher charges and utilization. For children 5 years and younger, mean total per member per year charges were $617 in the low-benefit category and $878 in the high category (p < .0001). These differences were less apparent for children 6-12 years ($355 versus $420, p = .012), and were not statistically significant for children 13 years and older ($503 versus $552, p = .14). The annual number of visits increased with benefit level for children of all ages.

CONCLUSIONS

Enrollee age and benefit level were the most important determinants of healthcare use and expenditures in children enrolled in managed care health plans.

A controlled time-series trial of clinical reminders: using computerized firm systems to make quality improvement research a routine part of mainstream practice

OBJECTIVE

To explore the feasibility of conducting unobtrusive interventional research in community practice settings by integrating firm-system techniques with time-series analysis of relational-repository data.

STUDY SETTING

A satellite teaching clinic divided into two similar, but geographically separated, primary care group practices called firms. One firm was selected by chance to receive the study intervention. Forty-two providers and 2,655 patients participated.

STUDY DESIGN

A nonrandomized controlled trial of computer-generated preventive reminders. Net effects were determined by quantitatively combining population-level data from parallel experimental and control interrupted time series extending over two-month baseline and intervention periods.

DATA COLLECTION

Mean rates at which mammography, colorectal cancer screening, and cholesterol testing were performed on patients due to receive each maneuver at clinic visits were the trial's outcome measures.

PRINCIPAL FINDINGS

Mammography performance increased on the experimental firm by 154 percent (0.24 versus 0.61, p = .03). No effect on fecal occult blood testing was observed. Cholesterol ordering decreased on both the experimental (0.18 versus 0.1 1, p = .02) and control firms (0.13 versus 0.07, p = .03) coincident with national guidelines retreating from recommending screening for young adults. A traditional uncontrolled interrupted time-series design would have incorrectly attributed the experimental-firm decrease to the introduction of reminders. The combined analysis properly indicated that no net prompting effect had occurred, as the difference between firms in cholesterol testing remained stochastically stable over time (0.05 versus 0.04, p = .75). A logistic-regression analysis applied to individual-level data produced equivalent findings. The trial incurred no supplementary data collection costs.

CONCLUSIONS

The apparent validity and practicability of our reminder implementation study should encourage others to develop computerized firm systems capable of conducting controlled time-series trials.

Suboptimal medical therapy in COPD: exploring the causes and consequences

Effective outpatient management of COPD requires prescription of and adherence to appropriate therapies. Although practice guidelines for outpatient management of COPD are widely available, evidence suggests that these guidelines are not being implemented widely in clinical practice. Furthermore, several studies have shown that patient compliance with recommended therapy is poor. This paper discusses several reasons why implementation of practice guidelines and adherence with prescribed therapies may be poor. Potential clinical and economic consequences of suboptimal management are reviewed. Although the evidence suggests that improved compliance with guideline-recommended practice will improve symptoms and disease-specific quality of life, further work needs to be done to establish the cost-effectiveness of chronic therapies for COPD relative to other chronic conditions. Without such data, managed care organizations will be reluctant to allocate scarce resources toward expensive guideline implementation programs for individuals with this condition.

The economic burden of COPD

COPD is one of the leading causes of morbidity and mortality worldwide and imparts a substantial economic burden on individuals and society. Despite the intense interest in COPD among clinicians and researchers, there is a paucity of data on health-care utilization, costs, and social burden in this population. The total economic costs of COPD morbidity and mortality in the United States were estimated at $23.9 billion in 1993. Direct treatments for COPD-related illness accounted for $14.7 billion, and the remaining $9.2 billion were indirect morbidity and premature mortality estimated as lost future earnings. Similar data from another US study suggest that 10% of persons with COPD account for > 70% of all medical care costs. International studies of trends in COPD-related hospitalization indicate that although the average length of stay has decreased since 1972, admissions per 1,000 persons per year for COPD have increased in all age groups > 45 years of age. These trends reflect population aging, smoking patterns, institutional factors, and treatment practices.

Patient-level estimates of the cost of complications in diabetes in a managed-care population

OBJECTIVE

To develop incidence-based estimates of the cost of several diabetes-related complications.

DESIGN AND SETTING

This was a retrospective cohort study in a large health maintenance organisation. A total of 8905 patients with type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes mellitus and 36,520 age- and gender-matched controls without diabetes were observed from 1992 to 1995. Incidence rates of 6 major diabetes-related complications were computed for both populations. Annual health expenditures in the first and second year following diagnosis were computed for each complication. For comparison, annual costs were derived for individuals without diabetes or the complication of interest.

MAIN OUTCOME MEASURES AND RESULTS

Over 3 years of observation, incidence rates for the groups with and without diabetes were as follows: myocardial infarction 9.0 versus 3.2%; stroke 8.7 versus 3.8%; hypertension 26.2 versus 16.9%; end-stage renal disease 5.9 versus 1.4%; foot ulcer 7.9 versus 1.1%; and eye disease 44.3 versus 2.8%. Expressed as a multiple of the average annual cost of care for those without diabetes [$US3400/year (1995 dollars) for those over 65 years of age] and the related complication of interest, excess expenditures for those with diabetes were as follows for the first year following diagnosis: no complications 1.59; myocardial infarction 4.1; stroke 3.5; hypertension 2.56; end-stage renal disease 4.32; foot ulcer 4.0; and eye disease 2.46. For younger cohorts (less prevalent in the sample), incremental costs for each complication were generally greater than in the older group.

CONCLUSIONS

The high incidences and costs may support the value of aggressive early intervention for patients with diabetes. These data will be useful for pharmacoeconomic modelling of the cost effectiveness of new and existing therapies for this condition.

Would you like suspenders to go with that belt? An analysis of optimal combinations of cost sharing and managed care

When and why would it be efficient for a managed care insurance plan using managerial limits to add patient cost sharing? This paper uses a diagrammatic model to indicate that the use of patient point-of-service cost sharing can cause the managerial limits or guidelines to be less restrictive in limiting high value care for cases of severe illness. The model shows that cost-sharing is more likely to improve efficiency the greater the variation in illness severity and the smaller the degree of moral hazard. The model is extended to the case in which provider cost sharing is also used.

A review of quality-of-life evaluations in prostate cancer

Prostate cancer is a highly prevalent malignancy in older men. Because the disease and its treatments have the potential to cause substantial morbidity in affected individuals, prostate cancer has been the subject of great interest for quality-of-life (QOL) researchers. In this article, we review published QOL studies that have focused on individuals with prostate cancer. Generic survey instruments have generally been found to be insensitive to changes in health-related quality of life (HR-QOL) related to prostate cancer and its treatments. Domain-specific survey instruments (such as those focusing on sexual function) have been more sensitive, but fail to capture all relevant impacts. At least 9 disease-specific instruments have been developed to measure the HR-QOL impact of prostate cancer. These instruments generally focus on specific symptoms related to the disease and its treatment--urinary function, bowel function, sexual function, physical function, psychological function and pain--however, the domains covered are not consistent from instrument to instrument, and the domains of emphasis within each instrument are rarely the same. In addition, no single instrument has been applied to all major therapies for prostate cancer across men at different ages and stages of disease. Finally, HR-QOL evaluations in some patient groups, such as those with advanced disease, have received relatively little attention to date. As a result of the proliferation of prostate cancer-specific survey instruments and inconsistencies in their design and application, decision-makers face great difficulties evaluating HR-QOL across disease stages and comparing the HR-QOL impacts of alternative therapies, including conservative management ('watchful waiting'). In order for these tools to be useful for patient management and policy-making, coordination of instrument development efforts with the goal of consolidating the number of measures used is urgently needed.

Cervical spine screening with CT in trauma patients: a cost-effectiveness analysis

PURPOSE

To investigate the cost-effectiveness of computed tomography (CT) relative to radiography for cervical spine screening in trauma patients.

MATERIALS AND METHODS

A decision analysis model was constructed to compare the incremental cost-effectiveness of radiography and CT as primary cervical spine screening modalities in trauma patients. Analyses were performed from a societal perspective, and probability and cost estimates from the literature and institutional experience were used. In separate cost-effectiveness analyses, hypothetical cohorts of trauma patients from three defined clinical scenarios were considered: high, moderate, and low risk for cervical spine fracture. Outcome measures included cases of paralysis prevented, total cost of screening strategies, and incremental cost-effectiveness ratios.

RESULTS

In high-risk patients, screening with CT is a dominant strategy that prevents cases of paralysis and saves money for society. In moderate-risk patients, screening with CT is cost-effective with reference-case assumptions and within the range of most sensitivity analyses. In the low-risk group, CT screening helps prevent cases of paralysis, but the incremental cost-effectiveness ratio is high (> $80,000 per quality-adjusted life year).

CONCLUSION

CT is the preferred cervical spine screening modality in trauma patients at high and moderate risk for cervical spine fracture.

On the use of survival analysis techniques to estimate medical care costs

Measurement of treatment costs is important in the evaluation of medical interventions. Accurate cost estimation is problematic, when cost records are incomplete. Methods from the survival analysis literature have been proposed for estimating costs using available data. In this article, we clarify assumptions necessary for validity of these techniques. We demonstrate how assumptions needed for valid survival analysis may be violated when these methods are applied to cost estimation. Our observations are confirmed through simulations and empirical data analysis. We conclude that survival analysis approaches are not generally appropriate for the analysis of medical costs and review several valid alternatives.

The use of automated data to identify complications and comorbidities of diabetes: a validation study

We evaluated the accuracy of administrative data for identifying complications and comorbidities of diabetes using International Classification of Diseases, 9th edition, Clinical Modification and Current Procedural Terminology codes. The records of 471 randomly selected diabetic patients were reviewed for complications from January 1, 1993 to December 31, 1995; chart data served to validate automated data. The complications with the highest sensitivity determined by a diagnosis in the medical records identified within +/-60 days of the database date were myocardial infarction (95.2%); amputation (94.4%); ischemic heart disease (90.3%); stroke (91.2%); osteomyelitis (79.2%); and retinal detachment, vitreous hemorrhage, and vitrectomy (73.5%). With the exception of amputation (82.9%), positive predictive value was low when based on a diagnosis identified within +/-60 days of the database date but increased with relaxation of the time constraints to include confirmation of the condition at any time during 1993-1995: ulcers (88.5%); amputation (85.4%); and retinal detachment, vitreous hemorrhage and vitrectomy (79.8%). Automated data are useful for ascertaining potential cases of some diabetic complications but require confirmatory evidence when they are to be used for research purposes.

An economic evaluation of the JNC hypertension guidelines using data from a randomized controlled trial. Joint National Committee

BACKGROUND

We wanted to determine the clinical cost of managing hypertension when following the Joint National Committee on Hypertension (JNC) guidelines, including drug therapy, the cost of monitoring for and treating side effects, compliance, and the cost of switching after therapeutic failures.

METHODS

The base-case analysis considers antihypertensive agents from four therapeutic classes that were recently evaluated in a large randomized trial: enalapril, amlodipine, acebutolol, and chlorthalidone. Clinical evaluation, therapy, and monitoring for hypertension are modeled with an incidence-based Markov model. Clinical inputs include agent efficacy, side effects, and compliance with dosing schedules. JNC-recommended clinical and laboratory monitoring schedules are followed for each agent. Switches between classes occur for therapeutic failures. Drug and medical care costs are valued in 1995 US dollars.

RESULTS

Although patients whose hypertension was initially treated with amlodipine achieved control more readily than patients who were given the other agents, the initial costs to achieve and maintain hypertension control were lowest for chlorthalidone ($641), followed by acebutolol ($920), amlodipine ($946), and enalapril ($948). Maintenance costs were lowest for chlorthalidone. For all agents except chlorthalidone, drug costs were the largest component of overall costs, followed by the costs of office visits, laboratory monitoring, and switching between classes for therapeutic failures.

CONCLUSIONS

By following JNC guidelines, a slightly higher percentage of patients will achieve hypertension control with a newer class calcium channel blocker (amlodipine) but at a substantially higher cost than with a generic diuretic (chlorthalidone).

Incidence, outcomes, and cost of foot ulcers in patients with diabetes

OBJECTIVE

To determine the incidence of foot ulcers in a large cohort of patients with diabetes, the risk of developing serious complications after diagnosis, and the attributable cost of care compared with that in patients without foot ulcers.

RESEARCH DESIGN AND METHODS

Retrospective cohort study of patients with diabetes in a large staff-model health maintenance organization from 1993 to 1995. Patients with diabetes were identified by algorithm using administrative, laboratory, and pharmacy records. The data were used to calculate incidence of foot ulcers, risk of osteomyelitis, amputation, and death after diagnosis of foot ulcer, and attributable costs in foot ulcer patients compared with patients without foot ulcers.

RESULTS

Among 8,905 patients identified with type 1 or type 2 diabetes, 514 developed a foot ulcer over 3 years of observation (cumulative incidence 5.8%). On or after the time of diagnosis, 77 (15%) patients developed osteomyelitis and 80 (15.6%) required amputation. Survival at 3 years was 72% for the foot ulcer patients versus 87% for a group of age- and sex-matched diabetic patients without foot ulcers (P < 0.001). The attributable cost for a 40- to 65-year-old male with a new foot ulcer was $27,987 for the 2 years after diagnosis.

CONCLUSIONS

The incidence of foot ulcers in this cohort of patients with diabetes was nearly 2.0% per year. For those who developed ulcers, morbidity, mortality, and excess care costs were substantial compared with those for patients without foot ulcers. The results appear to support the value of foot-ulcer prevention programs for patients with diabetes.

Recruiting adults with osteoarthritis into an aquatic exercise class: strategies for a statewide intervention

OBJECTIVE

Although research suggests that regular exercise can be helpful in reducing the dysfunction and discomfort of osteoarthritis, promoting exercise among older adults within this population is neither straightforward nor easily accomplished. This article describes the various methods, and their relative success rates, that were employed to recruit older adults throughout the state of Washington into an aquatic exercise program.

METHODS

Strategies included a recruitment letter distributed to Arthritis Foundation (AF) members in Washington state, local media news coverage, physician referrals, and advertisements in local papers and newsletters.

RESULTS

The most successful methods for enrolling participants were through the AF recruitment letters and local television coverage. The AF recruitment letter was the most expensive method of generating responses, while the television coverage was the least expensive.

CONCLUSIONS

Collaborating with a well-reputed community-based organization and capitalizing on available publicity resources are important strategies researchers can use to gain access to a difficult and geographically dispersed population.

Estimated growth of lung volume reduction surgery among Medicare enrollees: 1994 to 1996

OBJECTIVE

To estimate the number of lung volume reduction surgery procedures performed on Medicare enrollees from 1994 to 1996.

DESIGN

Statistical analysis of national Medicare claims data.

PATIENTS

All Medicare enrollees with emphysema hating claims records for pulmonary resection procedures from January 1, 1993, through December 31, 1996.

MAIN OUTCOME MEASURE

Estimated number of lung volume reduction procedures performed per month from July 1994 through December 1996.

RESULTS

An estimated 1,212 lung volume reduction procedures were performed on Medicare enrollees between July 1994 and December 1995 (95% confidence interval, 1,012 to 1,408). Nearly one half of these procedures were performed in the last 3 months of 1995. At the time Health Care Financing Administration announced that it would suspend reimbursement for the procedure (December 1995), lung volume reduction surgery was being performed in 37 states. The number of claims per month decreased from a peak of 169 in December 1995, to 11 in March 1996. Average Medicare reimbursement per procedure was $31,398.

CONCLUSIONS

Lung volume reduction surgery for patients increased rapidly following its reintroduction in 1994. The growth of lung volume reduction surgery demonstrates that widespread adoption and utilization of a surgical procedure can occur in the absence of data from controlled clinical trials. Medicare expenditures for lung volume reduction surgery were an estimated $30 million to $50 million. Performing the surgery for all current Medicare patients who meet the appropriate clinical criteria would cost an estimated $1 billion.

The limited state of technology assessment for medical devices: facing the issues

Medical devices are an integral part of clinical practice and account for a substantial proportion of the national health budget. Clinical testing and regulation of medical devices, however, is vastly different from and inferior to the testing and regulation of drugs. As managed care organizations begin to exert controls on device use, providers are being caught between the policies of their organizations and the demands of device manufacturers and patients, who want wider access to devices. We outline several reasons for the poor state of medical device evaluations and the dangers of using devices without adequate information, and include the recently developed device assessment and reporting guidelines created by the Task Force on Technology Assessment of Medical Devices.