Association Between Increased Hospital Reimbursement for Cardiac Rehabilitation and Utilization of Cardiac Rehabilitation by Medicare Beneficiaries: An Interrupted Time Series

Abstract

Background: Although cardiac rehabilitation (CR) is a Class I Guideline recommendation, and has been shown to be a cost-effective intervention after a cardiac event, it has been reimbursed at levels insufficient to cover hospital operating costs. In January 2011, Medicare increased payment for CR in hospital outpatient settings by ≈180%. We evaluated the association between this payment increase and participation in CR of eligible Medicare beneficiaries to better understand the relationship between reimbursement policy and CR utilization.

Methods: From a 5% Medicare claims sample, we identified patients with acute myocardial infarction, coronary artery bypass surgery, percutaneous coronary intervention, or cardiac valve surgery between January 1, 2009 and September 30, 2012, alive 30 days after their event, with continuous enrollment in Medicare fee-for-service, Part A/B for 4 months. Trends and changes in CR participation were estimated using an interrupted time series approach with a hierarchical logistic model, hospital random intercepts, adjusted for patient, hospital, market, and seasonality factors. Estimates were expressed using average marginal effects on a percent scale.

Results: Among 76 695 eligible patients, average annual CR participation was 19.5% overall. In the period before payment increase, adjusted annual participation grew by 1.1 percentage points (95% CI, 0.48-2.4). No immediate change occurred in CR participation when the new payment was implemented. In the period after payment increase, on average, 20% of patients participated in CR annually. The annual growth rate in CR participation slowed in the post-period by 1.3 percentage points (95% CI, -2.4 to -0.12) compared with the prior period. Results were somewhat sensitive to time window variations.

Conclusions: The 2011 increase in Medicare reimbursement for CR was not associated with an increase in participation. Future studies should evaluate whether payment did not reach a threshold to incentivize hospitals or if hospitals were not sensitive to reimbursement changes.

Keywords: cardiac rehabilitation; hospital; myocardial infarction; outpatient; percutaneous coronary intervention.

Figure 1.

Flowchart Showing Extraction Criteria for Cardiac Rehabilitation (CR) Eligible Sample.

Figure 2.

Mean Unadjusted Percent Cardiac Rehabilitation Participation Rate by Month. Unadjusted mean percent cardiac rehabilitation (CR) participation by month. The gray circles represent the mean percent of CR-eligible patients who participated in at least one CR session within four months of their index event. The solid vertical line represents the date the payment increase was implemented, January 1, 2011. The dashed vertical line represents the start of the lead-in period. Patients whose index events occurred between September 1, 2010 and December 31, 2010 were excluded during this lead-in period because their 4-month episodic window spanned the date the new payment was implemented.

Figure 3.

Average Predicted Cardiac Rehabilitation Participation by Month with Fitted Model, from 2009 to 2012. Adjusted trends evaluated at the mean of the covariates and coefficients from the mixed effects regression model are presented. The solid vertical line represents the date the payment for cardiac rehabilitation increase was implemented, January 1, 2011. The dashed vertical line represents the start of the lead-in period. Patients whose index events occurred between September 1, 2010 and December 31, 2010 were excluded during this lead-in period because their 4-month episodic window spanned the date the new payment was implemented. Model predictions were estimated using covariate means at each timepoint. Large blue circles represent the values predicted by the model for the periods before and after the payment increase, which includes the fixed covariate effects and hospital (group) random effects. Small gray circles represent values predicted if the payment had not increased (counterfactual). To plot the systematic relationship between payment and CR participation, we predicted the fixed covariate effect without the hospital random effects for the adjusted regression model (blue) and the counterfactual (grey).