Incentivised Chronic Disease Management and the Inverse Equity Hypothesis: Findings from a Longitudinal Analysis of Scottish Primary Care Practice-level Data

Background: The inverse equity hypothesis asserts that new health policies initially widen inequality, then attenuate inequalities over time. Since 2004, the UK's pay-for-performance scheme for chronic disease management (CDM) in primary care general practices (the Quality and Outcomes Framework) has permitted practices to except (exclude) patients from attending annual CDM reviews, without financial penalty. Informed dissent (ID) is one component of exception rates, applied to patients who have not attended due to refusal or non-response to invitations. 'Population achievement' describes the proportion receiving care, in relation to those eligible to receive it, including excepted patients. Examination of exception reporting (including ID) and population achievement enables the equity impact of the UK pay-for-performance contract to be assessed. We conducted a longitudinal analysis of practice-level rates and of predictors of ID, overall exceptions and population achievement for CDM to examine whether the inverse equity hypothesis holds true.

Methods: We carried out a retrospective, longitudinal study using routine primary care data, analysed by multilevel logistic regression. Data were extracted from 793 practices (83% of Scottish general practices) serving 4.4 million patients across Scotland from 2010/2011 to 2012/2013, for 29 CDM indicators covering 11 incentivised diseases. This provided 68,991 observations, representing a total of 15 million opportunities for exception reporting.

Results: Across all observations, the median overall exception reporting rate was 7.0% (7.04% in 2010-2011; 7.02% in 2011-2012 and 6.92% in 2012-2013). The median non-attendance rate due to ID was 0.9% (0.76% in 2010-2011; 0.88% in 2011-2012 and 0.96% in 2012-2013). Median population achievement was 83.5% (83.51% in 2010-2011; 83.41% in 2011-2012 and 83.63% in 2012-2013). The odds of ID reporting in 2012/2013 were 16.0% greater than in 2010/2011 (p < 0.001). Practices in Scotland's most deprived communities were twice as likely to report non-attendance due to ID (odds ratio 2.10, 95% confidence interval 1.83-2.40, p < 0.001) compared with those in the least deprived; rural practices reported lower levels of non-attendance due to ID. These predictors were also independently associated with overall exceptions. Rates of population achievement did not change over time, with higher levels (higher remuneration) associated with increased rates of overall and ID exception and more affluent practices.

Conclusions: Non-attendance for CDM due to ID has risen over time, and higher rates are seen in patients from practices located in disadvantaged areas. This suggests that CDM incentivisation does not conform to the inverse equity hypothesis, because inequalities are widening over time with lower uptake of anticipatory care health checks and CDM reviews noted among those most in need. Incentivised CDM needs to include incentives for engaging with the 'hard to reach' if inequalities in healthcare delivery are to be tackled.