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Cost-Effectiveness of a Peer and Practice Staff Support Intervention | Page 2

Published Online: March 20, 2014
Christopher S. Hollenbeak, PhD; Mark G. Weiner, MD; and Barbara J. Turner, MD, MSED
The 280 intervention (N = 136) and control (N = 144) subjects were well balanced on demographics and clinical conditions (Table 2). Complete data to estimate CHD risk were available for 212 (94 intervention and 118 control)subjects and complete end point data were available for 247 (116 intervention and 131 control) subjects. Sixty-eight percent of intervention subjects (N = 79) were compliant with an effective “dose” intervention (ie, at least 2 peer coach calls and 1 practice visit) and included in the compliance subgroup analysis.

Baseline cost-effectiveness results (Table 3) show that the average cost over 6 months of the intervention was $435 for intervention subjects and $74 for control subjects. The intervention was successful in reducing both SBP and CHD risk. SBP fell by 7.2 mm Hg among intervention subjects, compared with only 0.77 mm Hg for control subjects (P = .0011). The average difference in CHD risk among intervention subjects fell by 0.046% but rose by 0.034% among control subjects (P = .07). The ICERs were $453,419 per predicted CHD event avoided over 6 months and $55 per mm Hg reduced in 6 months.

The uncertainty analysis for these ICERs (Figures 1A and 1B) shows a high probability that the intervention would rensult in a reduction in systolic blood pressure. The probability that the intervention is cost-effective is 25%, 50%, and 75% if the decision maker is willing to pay $45.20, $55.40, and $70.80, respectively, to reduce SBP by 1 mm Hg for at least 6 months (Figure 1B). For CHD risk, the CEAC suggests that the probability that the intervention is cost-effective for reducing CHD risk is 25%, 50%, and 75% if the decision maker is willing to pay $324,000, $449,000, and $674,000, respectively, to avoid 1 CHD event over 6 months (Figures 1C and 1D).

Similar results were observed for the subgroup of patients who were compliant with the intervention (Table 3). The average cost of the intervention over 6 months was $442 for compliant intervention subjects and $74 for control subjects. SBP fell 8.5 mm Hg among intervention subjects, compared with only 0.77 mm Hg for control subjects. The average difference in CHD risk among compliant subjects decreased by 0.07% and increased by 0.03% among control subjects. The ICERs were $48 per mm Hg reduced in 6 months and $350,134 per predicted CHD event avoided over 6 months. The CEACs for the compliant subgroup, presented in Figure 1 (G and H), suggest that the probability that the intervention is cost-effective in reducing SBP is 25%, 50%, and 75% if the decision maker is willing to pay $34, $40, and $48, respectively, to reduce SBP by 1 mm Hg for at least 6 months. The probability that the intervention is cost-effective in reducing CHD risk is 25%, 50%, and 75% if the decision maker is willing to pay $274,000, $351,000, and $476,000, respectively, to avoid 1 additional CHD event in 6 months (Figures 1E and 1F).

Long-term cost-effectiveness results are presented in Table 4. Assuming that the intervention was given every year over the patient’s lifetime (10-year horizon), the intervention was more costly ($7324 vs $5584), but also more effective, both in terms of YLS (8 vs 7) and QALYs (6.3 vs 6.2). This yields ICERs for the intervention of $12,373 per incremental YLS and $10,866 per incremental QALY saved.

DISCUSSION

This study finds that a combined community and office staff behavioral health intervention to reduce hypertension and risk of CHD among African American primary care patients with uncontrolled hypertension and other CHD risks is potentially cost-effective at reducing SBP in the short term, and in terms of cost per YLS and QALY in the long term, but not cost-effective for reducing CHD risk in the short term (6 months). There are 2 explanations for the relatively high within-trial ICER to prevent CHD events. First, substantial costs are expended for the initial training of peer coaches and practice team members. With a more mature program, these may be reduced, yielding lower cost-effectiveness ratios. We conducted qualitative interviews with our peer coaches and identified key characteristics that motivated sustained participation and may be used to find a cohort of committed, long-term peer coaches.16 Second, the number of predicted CHD events avoided was low, as would be expected for a short (6-month) time frame. Extrapolating for 4 years, we found that predicted CHD risk would be reduced by 12% (0.73% absolute reduction from 6.1% baseline risk). Of course, additional costs would need to be incurred as well.

Another practical concern in regard to the high ICER for preventing 1 CHD event is that our within-trial analysis takes the provider or healthcare system’s perspective, so the provider must cover the cost of the additional services to prevent this event. At this point in the United States, peer coaches are not routinely covered by payers and behavioral health visits with mid-level staff would not be reimbursed unless payment for care were changed from fee-for-service to another bundled scheme, such as one under the medical home model. Indeed, providers are not rewarded directly for avoiding CHD events. Only in a setting such as a national healthcare system would this expense be clearly beneficial from the provider perspective. On the other hand, pay-forperformance measures in the United States do evaluate BP control for persons with hypertension, so a $47 expense per mm Hg reduction in BP in persons whose control continues to be inadequate despite treatment might presently be attractive to a provider.

Our within-trial cost-effectiveness results regarding the role of lay counselors in CHD risk reduction are much higher than those from other countries. Barton et al studied the costeffectiveness of lay health trainers in a randomized trial conducted in Liverpool, where the intervention involved offering information, advice, and support aimed at changing beliefs and behaviors in order to reduce risk of cardiovascular disease.18 The intervention had an estimated ICER of £14,480 (approximately $22,709 per QALY) over 6 months. However, there was only a 39.5% chance that it would be cost-effective at a WTP threshold of £20,000, and at no WTP threshold was it cost-effective with a probability greater than 50%. A costeffectiveness analysis of an Australian cluster-randomized trial of telephone counseling addressing diet and physician activity in 434 adult participants with type 2 diabetes mellitus or hypertension reported that the cost per QALY gained in 2008 Australian dollars was $29,375.19 Although these studies use different metrics for cost-effectiveness assessment, collectively they paint a much more favorable picture for the use of lay counselors to reduce cardiovascular risk than our withintrial analysis. Extrapolating the trial results using the Markov model suggested that our intervention was cost-effective, even under the conservative assumption that the intervention would have to be repeated every year.

This study targeted a highly vulnerable population— African Americans—who have a greatly increased CHD risk in the United States.21 CHD risk factor screening and counseling interventions that target low-income older persons in the community who are uninsured, such as the WISEWOMAN study, have found that, in the best-case analysis, it costs US $4400 per discounted life-year gained, but a sensitivity analysis revealed substantial uncertainty around this estimate.22 Nonetheless, these data suggest that patients in healthcare delivery settings and persons in the community with poor access to care may benefit from interventions to reduce CHD risks that exact a great toll on minority populations. Of course, the financial resources required for these interventions may not be insignificant.

Limitations

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Issue: March 2014
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