What is the association between continuity of primary care and cancer screening in a health system where patients have free movement between practices?

Problem

Continuity of care is considered a core component of high performing primary health systems, and previous research has reported an association between increased continuity of care and higher quality care, including increased participation in cancer screening. However most existing research is cross-sectional and does not inform about potential causality. This research considers the association between continuity of care and cancer screening services in Australian general practice, using a large longitudinal database of Australian adults. Australian primary care is characterised by unrestricted access to primary care services, and the absence of practice enrolment. It is common for patients to attend multiple general practitioners (GPs) and also attend multiple practices. This research seeks to understand whether there is an association between increased continuity of primary care and rates of screening for breast and cervical cancer, and whether this association holds at a general practice level (site continuity of care), as well as with an individual general practitioner (personal continuity of care).

Approach

This research uses longitudinal data from the Australian Longitudinal Study on Women's Health (ALWSH) - a large study of over 50,000 Australian women running for over twenty years. This research considers the association between self-reported continuity of care (with a practice and with an individual GP) and mammography and Pap testing rates. Panel data regression and instrumental variable analyses are reported to control for the endogeneity of continuity of care within the model.

Findings

Even after controlling for patient demographics, burden of disease and individual heterogeneity, results show that women with continuity of care with either a practice or provider are statistically significantly more likely to have recommended cancer screening (mammography and Pap testing) than those women without continuity of care. An instrumental variable analysis controlling for the endogeneity of continuity of care provides consistent results and supports the relationship between increased personal continuity of care and increased Pap testing.

Consequences

Continuity of care with a practice and with an individual GP are both associated with increased rates of cancer screening in this sample of Australian women. Failing to consider the endogeneity of continuity of care may downwardly bias estimates of association between continuity of care and health outcomes, and lead to underestimation of the potential benefits of continuity of care.