Relative cost effectiveness of the SPHERE intervention in selected patient subgroups with existing coronary heart disease

Abstract

Heterogeneity exists within the patient population with coronary heart disease and the cost effectiveness of treatment may vary across subgroups within the overall population. This study compares the cost effectiveness of a secondary prevention intervention for a combined patient population relative to three selected subgroups: patients aged over 70 years; patients with a diagnosis other than angina only (that is, patients with a history of myocardial infarction, coronary artery bypass graft and/or percutaneous transluminal coronary angioplasty); and patients with diabetes. The results for the general population have been published elsewhere, but ongoing budget constraints require consideration of the appropriateness of targeting resources to patient subgroups. We adopt a probabilistic model to combine within trial and beyond trial impacts of treatment to estimate the lifetime health care costs and quality-adjusted life years of two primary care-based secondary prevention strategies: SPHERE Intervention--tailored practice and patient care plans and Control--standardised usual care. In all cases, the intervention was associated with mean cost savings and mean QALYs gains, when compared to the control, though statistical significance was never achieved. However, the probability of the intervention being cost effective was higher than 85% in all analyses across a range of potential cost-effectiveness threshold values. There is no compelling statistical evidence to support the targeting of specific subgroups across the general population. However, if affordability constraints are binding, the results do allow a tentative ranking of priorities based on the probabilistic subgroup analysis.

Cost effectiveness of group follow-up after structured education for type 1 diabetes: a cluster randomised controlled trial

“…While the clinical study showed no significant difference in terms of HbA 1c , group-based peer support was shown to be cost saving relative to usual care. A second Irish RCT evaluating primary care clinics for the secondary prevention of coronary heart disease in Irish general practice reported significant reductions in hospital admissions and costs of care relative to usual care [31,32]. While further evidence is required, these results suggest a tentative pattern of beneficial resource implications from more proactive approaches to chronic disease management in the community.…”

Economic implications of cardiovascular disease management programs: moving beyond one-off experiments

“…Cluster randomization has been suggested as an option to help reduce 'contamination' bias by providing a pragmatic experimental approach [42]. In our systematic reviews [5,6], cluster randomization was applied to two source trials [43,44] in three publications [9,10,44]; the other approaches included the use of separate investigative sites [38] or separate delivery personnel [36] for each arm, although this in itself can introduce bias. While it is plausible that the control group in open-label studies better approximates the usual care practice than the 'blinded' control group in double-blind trials [41], even this merit may be offset if what constitutes 'usual care' is not clearly described.…”

“…Considering the potentially weak durability of behavior-based components observed in the trials [36,37] (e.g., motivational interviewing, goal setting, self-management education), the items assumed in the model should be routinely included in a sensitivity analysis. In our model-based review [6], four articles (44%) [9,10,16,38] specifically assessed the impact of the assumed durability of the intervention effect beyond the duration of a trial. One of these was Article 6 (Issue B), in which the beneficial effects of the CHD intervention were assumed to persist for 4 years post-trial, and thereafter to be the same across groups over their lifetimes (base-case) [9].…”

“…The published studies we used as examples pertain to HF and CHD. These conditions often involve costly hospitalizations or emergency services, which many CVD-MPs aim to reduce through counseling, education, self-management skills or social support as part of secondary prevention efforts [7][8][9][10]. Our discussion of the net intervention effect and generalizability (Section II) focuses on the degree to which the study findings are attributable to an intervention of interest and whether the inference can be made to the patient domain beyond the study populations.…”

Heterogeneity in cost-effectiveness of lifestyle counseling for metabolic syndrome risk groups -primary care patients in Sweden

“…patients with higher risk factor levels might potentially experience larger decreases in disease risk after an intervention than patients with a lower risk level. The risk factor levels of patients might thus affect the effectiveness and hence the cost-effectiveness [11] of an intervention. The issue might be even more crucial for lifestyle interventions, as the potential benefits from the lifestyle modifications might differ according to individual ability to respond to the treatment as well as the individual baseline risk level.…”