Impact of Physician Owned Office Based Laboratories on Physician Practice Patterns and Outcomes after Percutaneous Vascular Interventions for Peripheral Artery Disease

Recent practices have shifted peripheral vascular interventions (PVI) of peripheral artery disease (PAD) from hospital-based facilities to physician owned office-based laboratories (OBLs). The transition to OBLs are due to a variety of factors such as technology advancement, increased efficiency, and financial incentives. We sought to evaluate impact of physicians “switching” to OBLs use from hospital-based facilities with regard to procedure volume and procedure type, patient outcomes, and Medicare reimbursements.
We identified patients with PVI for lower extremity PAD from 2006-2013 in a 20% Medicare sample, and identified physicians who transitioned from pre-dominantly hospital based facilities to OBLs (switch physicians) and compared them to those who did not utilize OBLs (control physicians). The main procedure outcomes included average number of PVI at 30-days and 1-year and atherectomy usage. Patient outcomes included major adverse limb events (MALE), above ankle amputation, hospitalizations, and mortality. Total costs at 30-days, 90-days and 1-year from initial PVI were also compared. We used a difference in difference model to control for time effects in a multi-variate regression model, reported as an odds ratio (OR) and 95% confidence interval (CI).
The cohort comprised 292 switch physicians who treated 7,134 patients (3,888 prior to OBLs and 3,246 patients after transitioning to OBLs), and 3,715 control physicians treating 54,213 patients (36,327 in the pre-period and 17,886 in the post-period). Patients treated by switch physicians had an increase in average (± SD) 30-day PVI rates from 1.10 ± 0.31 procedures per patient prior to OBL use to 1.16 ± 0.38 after transitioning to OBLs, P<.001. Similarly, average 1-year PVI rates increased from 1.39 ± 0.73 procedures per patient to 1.49 ± 0.81 after OBL use, P<.001. For control physicians 30-day PVI rates were similar in the pre-period (1.09 ± 0.31 procedures per patient) compared to the post period (1.09 ± 0.31), P=.99. Average 1-year PVI rates decreased from 1.33±0.67 in the pre-period to 1.31±0.64 in the post-period, P<.001. Transitioning to OBLs was associated with a 0.05 increase in PVI per patient at 30-days and 0.12 increase in PVI per patient at 1-year, P<.001. Similarly, switching to OBLs was associated with a 0.02 (95% CI 0.01-0.03, P=.002) increase in average atherectomy rates at 30-days and 0.03 (95% CI, 0.01 - 0.05, P=.008) increase at 1-year. Transitioning to OBLs was associated with a decreased risk decrease in hospitalization rates at 30-days (OR 0.64, 95% CI 0.57-0.74, P<.001) and 1-year (OR 0.72, 95% CI 0.65-0.81, P<.001) from the initial PVI. Transitioning to OBLs was also associated with a decreased risk in above ankle amputation at 30-days (OR 0.58, 95% CI 0.38-0.97, P=.009) and 1-year (OR 0.75, 95% CI 0.60-0.95, P=0.01). No statistical difference was observed for MALE and mortality rates at 30-days and 1-year as patients treated by both switch and control physicians experienced similar decreases. Transitioning to OBLs was associated with higher average costs: 30-day cost increased by 17% (95% CI 12%-22%, P<.001), 90-day costs increased by 12% (95% CI 7-17%, P<.001), and 1-year costs increased by 8% (95% CI 3-13%, P=.002) compared to patients treated by control physicians.
Transitioning to OBLs was associated higher 30-day and 1-year PVI rates and atherectomy rates with increases in total costs despite lower hospitalization rates. The clinical benefit of transitioning to OBLs was a greater decrease in above ankle amputation rates; however, MALE and mortality rates decreased at similar rates between switch and control physicians. This study demonstrates that financial incentives drives physician decision making in the treatment of patients with lower extremity PAD.

Keywords: Medicare
Peripheral Artery Disease
Financial Incentives
Thesis
Advisor: Laurence Baker
Matthew Mell