How health system factors affect primary care practitioners' decisions to refer patients for further investigation: protocol for a pan-European ecological study.

backgroundThere is wide variation in the overall one-year relative cancer survival rates across Europe, and this is thought to indicate national variations in stage of disease at diagnosis. However, there is little evidence to explain how different national systems influence a primary care practitioner's (PCP's) referral decisions, and how these relate to the variation in survival rates. This study investigates the health system factors that influence the thinking of PCPs when faced with patients who may have cancer, how they compare across European countries, and how they relate to national one-year relative cancer relative survival rates.

methodsAn online quantitative questionnaire with closed-ended questions is used in a cross-sectional survey of 1250 PCPs in Europe, in 25 local health areas in 20 countries. Descriptive data are elicited for each country, including respondents' demographic details. An exploratory factor analysis will identify factors underlying the decision to refer patients for further investigations. Between-country variation in these factors will then be further investigated and presented as means with 95% confidence intervals. A regression model will be fitted for the vignettes using one-year relative survival as the outcome, with the proportion of PCPs opting to investigate as a single explanatory variable. Weighted regression will be used to explore which health system factors are associated with opting to investigate and with one-year relative survival. Linear correlations will be estimated between the proportions opting to investigate and national survival rates. When comparing between countries, weighted linear regression will be used to adjust for different sample sizes in each country. DISCUSSION: This study investigates which system factors affect PCPs' decisions to refer and investigate patients who may have cancer, how they compare across 20 European countries, and how these factors relate to cancer survival rates. Knowledge of the extent and variability of the health system factors that affect referral decisions will inform future health service design, policy and research.