2007 HSR&D National Meeting Abstract
3088 — Dual Use of VA and Medicare Services by Veterans with Prostate Cancer
Sohn M (MCHSPR) , Brent T
(CCDOR), Hur K
(MCHSPR), Zhang H
(MCHSPR), Wilt T
To examine factors that affect the use of Medicare services by VHA users for prostate cancer diagnosis.
The VHA Medical SAS Inpatient and Outpatient Datasets for 1999 – 2002 and all Medicare claims files for the same years were used to identify those who were diagnosed with prostate cancer by VHA or Medicare providers during the four years. The study sample consists of all male veterans who have used VHA services at least once in the current or the prior year and were 65 years old or older at the start of each year. 29 co-existing conditions were identified by the Elixhauser method.
The number of elderly VHA users diagnosed with prostate cancer was 140,408 in 1999 and 222,683 in 2002. The percent of patients diagnosed with prostate cancer in the VHA alone steadily decreased from 38% in 1999 to 28% in 2000, while almost 50% were diagnosed by Medicare providers alone. Multivariate analyses show that, holding constant individual characteristics such as age, race, and co-morbidities, accessibility characteristics including enrollment priority, distance to the VHA outpatient clinics, and the number of physicians per patient were all significantly predictive of prostate cancer diagnosis by Medicare providers alone. An increase of one physician per 1,000 patients in a VISN was associated with 15% lower probability of being diagnosed exclusively by a Medicare provider (Odds Ratio = 0.844; 95% Confidence Interval, 0.831 – 0.857; p < 0.001).
Where a VHA user is diagnosed with prostate cancer depends significantly on his individual characteristics as well as his accessibility to VHA services. This study shows that the number of physicians per unique patients treated in a VISN was significantly and negatively associated with prostate cancer diagnosis by a Medicare provider, suggesting that the limited capacity in the VHA may turn elderly veterans increasingly to Medicare providers for prostate cancer diagnosis.
This study suggests that the capacity limitations and waiting time in the VHA may be a factor in veterans’ decision to seek care in Medicare and confirms the importance of reducing waiting times for appointments in the VHA.