Primary care practice organization influences colorectal cancer screening performance

Health Services Research, June, 2007 by Elizabeth M. Yano, Lynn M. Soban, Patricia H. Parkerton, David A. Etzioni

Colorectal cancer (CRC) is a major source of preventable cancer morbidity and mortality, accounting for 10 percent of all U.S. cancer deaths (American Cancer Society 2004). Despite the availability of effective screening tests and widespread recognition of the importance of early detection through screening, CRC screening rates remain low (Coffield et al. 2001). In 2000, only 34 percent of the eligible U.S. population was screened for CRC within recommended time frames (Subramanian et al. 2004), while the average CRC screening rate was 47 percent among enrollees in commercial health plans and 50 percent among Medicare beneficiaries (NCQA 2004).

Most assessments of screening deficiencies have focused on patient factors (e.g., payment sources, knowledge deficits, preferences). While Medicare beneficiaries are more likely to be screened than those with private insurance, gaps in screening between high- and low-income individuals persist regardless of coverage type (Adams et al. 2004). Providers perceive the lack of patients' knowledge of screening's benefits and subsequent compliance with ordered tests as substantial barriers (Dulai et al. 2004). Patient attitudes have also been identified as important predictors of screening: individuals with positive attitudes toward screening are more apt to adhere to guidelines, while those who fear finding cancer, believe that cancer is fatal or believe their personal risk is low have lower adherence rates (Montano et al. 2004). Efforts to increase screening rates by educating patients have met with less than optimal effect (Zapka et al. 2003).

Primary care physicians play a critical role in promoting and ordering screening (Schwartz et al. 1991). Patients report lack of physician recommendation as the main reason they are not up-to-date (Klabunde et al. 2005). Nearly one-third of primary care physicians rely on single-sample in-office fecal occult blood testing (FOBT), the least accurate method of CRC screening, despite guidelines to the contrary (Nadel et al. 2005). Another third recommend repeat FOBT only after a positive test, again in sharp contrast to most recommended guidelines. Provider-level determinants of screening performance have historically focused on barriers to test use, including provider training, demographics, and beliefs about test performance (Sandler et al. 1989). While inadequate knowledge of CRC screening guidelines for average and high-risk patients is blamed for some of the variation, interventions to improve provider knowledge run the risk of being "necessary but not sufficient" given the general inadequacy of continuing medical education alone in invoking change (Davis et al. 1995; Gennarelli et al. 2005).

Organizational structure and care processes also have potent influences on quality of care (Casalino et al. 2003). Interventions that focus on changing organizational care processes demonstrate the largest effects on prevention performance, including colon cancer screening (Stone et al. 2002). Provider-reported barriers and facilitators in their practice environments (e.g., office reminder systems) have shown particular promise in determining CRC screening variation (Dulai et al. 2004). Other practice characteristics (e.g., practice size, availability of information technology for guidelines, and reminders) have been shown to be more consistently associated with delivery of preventive care than physician characteristics, though not for CRC screening (Pham et al. 2005). The importance of primary care structure in influencing receipt of CRC screening in the context of busy office practices has therefore gained increased attention. In fact, primary care practice "office processes" account for half of all comments among patients and providers regarding what fosters or hinders CRC screening (O'Malley et al. 2004).

In relatively sharp contrast to other public and private sector settings, the U.S. Department of Veterans Affairs (VA) health care facilities have raised screening rates to 68 percent of eligible patients through substantial restructuring toward primary care delivery, implementation of an electronic health record with decision support and practice management utilities (Evans, Nichol, and Perlin 2006), and an incentivized audit-and-feedback system of externally collected performance measures (Kizer 1999). Capitalizing on data resources within what is virtually the United States's only national health care system, we explored the contribution of primary care practice-level determinants of CRC screening variation, controlling for patient and area characteristics.

METHODS

Conceptual Model and Study Design

The conceptual model used to organize study measures adapts concepts from a hospital-based organizational taxonomy (Bazzoli et al. 1999) to a primary care perspective, aligning theory-driven constructs of centralization, integration, and differentiation with the strategic needs and structural attributes of primary care organizational features (Table 1). We further anchored this adapted taxonomy within an established conceptual framework for improving the quality of cancer care, delineating theoretical relationships between community, plan (or organization or medical group) and practice settings levels and their link to outcomes (Zapka et al. 2003).