|
Long-term healthcare and cost outcomes of disease management in a large, randomized, community-based population with heart failure |
Galbreath A D, Krasuski R A, Smith B, Stajduhar K C, Kwan M D, Ellis R, Freeman G L |
|
|
Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology A disease management (DM) programme for patients with congestive heart failure (CHF) was examined. The DM programme was administered by telephone. Calls were initially made weekly, with a transition to monthly for the duration of the intervention. The frequency of calls could be adjusted for acuity or need. All the patients were mailed educational material on CHF which emphasised the patient's role in management through daily weight, activity level, sodium intake and medication compliance. Smokers were offered smoking cessation instruction, including both written material and verbal reinforcement from disease managers. Patient education included instruction in appropriate cardiac diet (low fat, low sodium, restricted fluids), medication compliance, exercise, and appropriate reaction to signs of the onset of a CHF exacerbation. The patients were given a 24-hour-a-day, 7-day-a-week, toll-free telephone number that they could call with questions about CHF management. They were also assigned a disease manager, a registered nurse with specialised cardiac training, who provided patient education and medication management in conjunction with the primary care provider (PCP).
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients with systolic and diastolic CHF. Systolic dysfunction was broadly defined as an ejection fraction of less than or equal to 49%. Criteria for diastolic dysfunction included any of left ventricular hypertrophy (interventricular septal or posterior wall thickness >/= 1.2 cm), E-to-A reversal, or other abnormal transmitral flow pattern.
Setting The setting was primary and secondary care. The economic study was carried out in the USA.
Dates to which data relate The effectiveness and resource use data were gathered from 1999 and 2003. The price year was not reported.
Source of effectiveness data The effectiveness evidence was derived from a single study.
Link between effectiveness and cost data The costing was performed retrospectively on the same sample of patients as that used in the clinical study.
Study sample Potential patients were identified through lists generated from the databases of the authors' institution and other partner medical centres. The patients were contacted by letter and offered an opportunity to participate. A screening questionnaire, conducted by telephone, contained nine questions about history suggestive of CHF signs or symptoms. A positive answer to any question was considered suggestive of CHF, and these patients proceeded to screening echocardiography. Overall, 1,069 patients were enrolled. There were 359 patients (28% female) in the control group and 710 patients (29% female) in the experimental group. The mean ages of the patients were 70.8 (+/- 9.9) years (control group) and 71.0 (+/- 10.4) years (experimental group), respectively. It was not stated whether any patients refused to participate or were excluded for any reason from the study sample. Power calculations showed that a total sample size of 1,058 would yield 80% power to detect clinically and economically significant differences across the primary and secondary outcomes.
Study design This was a single-centre, randomised, controlled clinical trial that was carried out at the University of Texas Health Science Center at San Antonio in Texas. The participants were randomised in a 2:1 ratio between the experimental and control groups. The length of follow-up was 18 months and the patients were assessed every 6 months. The authors stated that some patients were lost to the follow-up assessment. The number of missing patients varied depending on the outcome measure. No blinding was performed.
Analysis of effectiveness The analysis of the clinical study was conducted on an intention to treat basis. The primary outcome measures used were survival, cardiac event-free survival, all-cause mortality, performance on a 6-minute walk test, and improvement in functional therapeutic class. In the sub-group of systolic heart failure patients, two additional outcomes were used. These were improvement in ejection fraction and adherence to guideline-based medications (defined as percentage on a combination of diuretic, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker or hydralazine/nitrite combination, and a beta-blocker). Overall survival analyses were conducted using the Kaplan-Meier technique. Cox regression, adjusted for study group membership, was used to ascertain whether the effect of the intervention differed across key demographic and clinical sub-groups. The study groups were generally comparable at baseline, but there was a slightly higher average diastolic blood pressure (1.8 mmHg) in the experimental group which was statistically significant, (p=0.032).
Effectiveness results Patients in the intervention group lived approximately 76 days longer than patients in the control group (mean survival 526.9 days versus 450.5 days). However, although there was a trend toward fewer events in the treatment group, cardiac event-free survival was not significantly different between the groups.
When the analysis was restricted to the sub-group of patients with systolic dysfunction, significant differences in mortality rate and cardiac event-free survival were found, (p=0.012).
A Cox regression analysis of all-cause mortality showed that hazard ratios for experimental group membership were 1.32 for asymptomatic patients (NYHA Class I; p non significant), 0.76 for patients in NYHA Class II, (p non significant), and 0.54 for patients in NYHA classes III and IV, (p=0.048).
When survival data were analysed for only the patients with systolic heart failure, the benefit derived by the intervention group was lengthened to 81 days (445 days for control group versus 526 days for intervention group). For this sub-group, a substantially stronger effect on mortality was observed among patients in NYHA Classes III and IV (hazard ratio 0.37; p=0.004). However, for patients with diastolic heart failure, no difference in mortality rate or in cardiac event-free survival was obtained from the intervention.
The analysis of the 6-minute walk test was restricted to 217 patients with complete clinical data. No statistically significant difference between the groups was observed.
The analysis of the ejection fraction was performed for patients with systolic heart failure. It was limited to those with both an initial and final ejection fraction recorded (n=502 patients). There was a small improvement in both groups, with ejection fraction being greater for the control group. However, at 18 months, the differences between the groups did not reach statistical significance. It was also noted that NYHA score improvements were significantly more likely in the DM patients than in the control patients.
Among patients with systolic dysfunction, at the end of the trial, 43.3% of the control patients and 54.4% of the patients in the treatment group were on guideline-recommended medications. Thus, DM significantly increased the fraction of patients with systolic heart failure who were prescribed guideline-based therapy.
Clinical conclusions The effectiveness analysis showed that DM improved life expectancy, but not objective measures of functional capacity, among patients with CHF.
Measure of benefits used in the economic analysis The health outcomes were left disaggregated and no summary benefit measure was used in the economic evaluation. In effect, a cost-consequences analysis was performed.
Direct costs The perspective adopted in the study was not explicitly stated. Limited information on the cost analysis was provided. The health services included in the economic evaluation were those related to inpatient and outpatient visits, medications and diagnostic tests. The cost of administering the DM intervention was not included. The quantities of resources used were extensively reported, whereas the unit costs were not given. Resource consumption was estimated on the basis of 92% of the patients included in the clinical trial (nearly 53,000 health-related encounters). Data audits were performed on a randomly selected 5% of all charts as an assessment of review accuracy, with an inter-rater reliability of 96.8%. The source of the costs was unclear, although charges might have been estimated from the authors' institution. Discounting was not relevant as the costs were incurred during less than two years. The price year was not reported.
Statistical analysis of costs A series of repeated-measures analyses of variance was used to assess whether utilisation outcomes differed between study groups and/or over time.
Indirect Costs The indirect costs were not included in the economic evaluation.
Sensitivity analysis Sensitivity analyses were not carried out.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The total health care costs were:
$3,711.65 in the control group and $3,602.67 in the experimental group between month 0 and month 6,
$3,230.43 in the control group and $2,919.38 in the experimental group between month 6 and month 12, and
$3,001.26 in the control group and $3,277.05 in the experimental group between month 12 and month 18.
The costs were not statistically different between the groups.
Synthesis of costs and benefits A synthesis of the costs and benefits was not relevant since a cost-consequences analysis was performed.
Authors' conclusions In a large, community-based population with chronic heart failure (CHF), disease management (DM) provided a significant improvement in survival, most notably in patients with systolic dysfunction, particularly those in NYHA Classes III and IV. However, DM did not reduce hospitalisations or cost and did not increase exercise performance. Overall, DM had little impact on patients with diastolic dysfunction.
CRD COMMENTARY - Selection of comparators The selection of the comparator (management by the PCP) was appropriate as it reflected standard care at the authors' institution. You should decide whether this is a valid comparator in your own setting.
Validity of estimate of measure of effectiveness The effectiveness evidence came from a large clinical trial, which was appropriate for the study question. Power calculations were performed to determine the appropriateness of the sample size. The study groups were quite well matched at baseline, although diastolic blood pressure was not comparable between the groups. Statistical analyses were carried out to test the significance of differences between the groups. The length of follow-up was appropriate. The authors stated that the analysis of clinical outcomes was conducted on an intention to treat basis. However, the analysis of some secondary outcomes was restricted to a smaller sample of patients with available clinical data. Sub-group analyses were also carried out. The evidence came from a single centre, thus caution is required when extrapolating the results of the analysis to other settings. The use of a large sample of patients ensured that the patients enrolled in the trial were representative.
Validity of estimate of measure of benefit No summary benefit measure was used in the analysis because a cost-consequences analysis was conducted. Please refer to the comments in the 'Validity of estimate of measure of effectiveness' field (above).
Validity of estimate of costs The information on the cost analysis was limited. The authors stated that a full report on the cost-effectiveness of DM was ongoing. The cost items were presented as macro-categories, and a detailed breakdown of the resources was not provided. The unit costs were not reported. Resource consumption was assessed prospectively alongside the clinical trial. Some statistical analyses were used to assess the comparability of costs between the groups. The price year was not reported, which will hinder reflation exercises in other settings. The impact of variations in the cost estimates was not addressed. It was noted that the use of self-reported data for the assessment of resource consumption could have led to an underestimation of the actual resource use.
Other issues The authors noted that their findings did not confirm those from other studies that had shown reduced resource use and health care costs associated with DM. It was pointed out that such discrepancies might have arisen because of the larger and stronger design of the current study. However, other studies had shown that DM increased the overall health care costs. The issue of the generalisability of the study results to other settings was not widely addressed, and sensitivity analyses were not performed. The authors stated that a unique strength of their analysis was the inclusion of both systolic and diastolic patients, who were appropriately classified by echocardiography. The study referred to patients with CHF and this was reflected in the authors' conclusions.
Implications of the study The study results suggested that DM programmes are most useful when targeted at patients with the worst functional class.
Source of funding Supported by a grant from the US Department of Defense, US Army Medical Research Acquisition Activity.
Bibliographic details Galbreath A D, Krasuski R A, Smith B, Stajduhar K C, Kwan M D, Ellis R, Freeman G L. Long-term healthcare and cost outcomes of disease management in a large, randomized, community-based population with heart failure. Circulation 2004; 110(23): 3518-3526 Other publications of related interest Mejhert M, Kahan T, Persson H, Edner M. Limited long term effects of a management programme for heart failure. Heart 2004;90:1010-5.
Riegel B, Carlson B, Glaser D, Hoagland P. Which patients with heart failure respond best to multidisciplinary disease management? J Card Fail 2000;6:290-9.
Laramee AS, Levinsky SK, Sargent J, Ross R, Callas P. Case management in a heterogeneous congestive heart failure population. Arch Intern Med 2003;163:809-17.
Indexing Status Subject indexing assigned by NLM MeSH Aged; Cost-Benefit Analysis; Delivery of Health Care /economics /methods; Diastole; Disease Management; Endpoint Determination; Female; Health Services /utilization; Heart Failure /economics /epidemiology /prevention & Hospitalization /statistics & Humans; Life Expectancy; Male; Medical Records Systems, Computerized; Patient Care Team; Patient Education as Topic; Survival Rate; Systole; control; numerical data AccessionNumber 22005000024 Date bibliographic record published 31/03/2006 Date abstract record published 31/03/2006 |
|
|
|