Association of Physician Referrals with Timely Cancer Care Using Tumor Registry and Claims Data

Abstract

More Americans are being screened for and more are surviving colorectal cancer due to advanced treatments and better quality of care; however, these benefits are not equitably distributed among diverse or older populations. Differential care delivery outcomes are driven by multiple factors, including access to timely treatment that comes from high-quality care coordination. Providers help ensure such coordinated care, which includes timely referrals to specialists. Variation in referrals between providers can also result in differences in treatment plans and outcomes. Patients who are more often referred between the same diagnosing and treating providers may benefit from more timely care compared to those who are not. Our objective is to examine patterns of referral, or patient-sharing networks (PSNs), and our outcome, treatment delay of 30-days (yes/no). We hypothesize that if a patient is in a PSN they will have lower odds of a 30-day treatment initiation delay. Our observational population-based analysis using the National Cancer Institute (NCI)-linked tumor registry and Medicare claims database includes records for 27,689 patients diagnosed with colorectal cancer from 2001 to 2013, and treated with either chemotherapy, radiotherapy, or surgery. We modeled the adjusted odds of a delay and found 17.04% of patients experienced a 30-day delay in initial treatment. Factors that increased odds of a delay were lack of membership in a PSN (adjusted odds ratio [AOR]: 2.20; 95% confidence interval [CI]: 1.71-2.84), racial/ethnic minority status, and having multiple comorbidities. Provider characteristics significantly associated with greater odds of a delay were if dyads were not in the same facility (AOR: 1.95; 95% CI: 1.81-2.10), if providers were different genders, most notably male (diagnosing) and female (treating) [AOR: 1.23; 95% CI: 1.08-1.40, p = 0.0015]. PSNs appear to be associated with reduced of a care delay. The associations observed in our study address the demand for developing multilevel interventions to improve the delivery and coordination of high-quality of care for older cancer patients.

Keywords: cancer and aging; communication; health care delivery; health disparities; patient–provider communication; systems science.

FIG. 1.

Illustration of PSNs. Diagnosing providers: A, B, C and Treating Providers 1 and 2 share patients indicated by white circles. Dyad A-1 shares 2 patients; dyad B1 shares 1; Dyad B2 shares 1; and Dyad C2 shares 1. PSN, patient-sharing network.

FIG. 2.

TTI Illustration of time interval under study to develop outcome variable (30-day Delay). TTI, time to treatment initiation.

FIG. 3.

The Kolmogorov-Smirnov (KS) curves compares the number of days it takes each group (PSN=1, non-PSN=0) to initiate treatment. The PSN group (indicated with a red line) demonstrates a larger proportion initiating treatment (in days) sooner than the non-PSN group (blue line). The time each group takes to initial treatment differs significantly as indicated by p<.0001. This test confirmed our PSN group cut-offs were appropriate. KS, Kolmogorov-Smirnov (asymptotic test).