Resource use trajectories for aged medicare beneficiaries with complex coronary conditions

Abstract

Objective: To use coronary revascularization choice to illustrate the application of a method simulating a treatment's effect on subsequent resource use.

Data sources: Medicare inpatient and outpatient claims from 2002 to 2008 for patients receiving multivessel revascularization for symptomatic coronary disease in 2003-2004.

Study design: This retrospective cohort study of 102,877 beneficiaries assessed survival, days in institutional settings, and Medicare payments for up to 6 years following receipt of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).

Methods: A three-part estimator designed to provide robust estimates of a treatment's effect in the setting of mortality and censored follow-up was used. The estimator decomposes the treatment effect into effects attributable to survival differences versus treatment-related intensity of resource use.

Principal findings: After adjustment, on average CABG recipients survived 23 days longer, spent an 11 additional days in institutional settings, and had cumulative Medicare payments that were $12,834 higher than PCI recipients. The majority of the differences in institutional days and payments were due to intensity rather than survival effects.

Conclusions: In this example, the survival benefit from CABG was modest and the resource implications were substantial, although further adjustments for treatment selection are needed.

Figure 1

Unadjusted Survival, Days Spent in an Institutional Setting, and Medicare Payments after Revascularization with Percutaneous Coronary Intervention (PCI) or Coronary Artery Bypass Grafting (CABG)

Figure 2

Adjusted Estimates of Incremental Survival and Resource Use after Revascularization with Percutaneous Coronary Intervention (PCI) versus Coronary Artery Bypass Grafting (CABG). (Incremental differences are cumulative from time of the initial revascularization procedure. Vertical bars indicate 95 percent pointwise confidence intervals, displayed at 2-month intervals for clarity)

Figure 3

Decomposition of Adjusted Estimates of Incremental Difference between Coronary Artery Bypass Grafting and Percutaneous Coronary Intervention into Portion Attributable to Differences in the Intensity of Service Use among Survivors (Intensity Effect) and Portion Attributable to Changes in Duration of Survival (Survival Effect). (Incremental differences are cumulative from time of initial revascularization procedure. Vertical bars indicate 95 percent pointwise confidence intervals, displayed at 2-month intervals for clarity)