Investigating the impact of primary care payments on underdiagnosis in dementia: A difference-in-differences analysis

In England, two primary care incentive schemes were introduced to increase dementia diagnosis rates to two-thirds of expected levels. This study assesses the effectiveness of these schemes.

We used a difference-in-differences framework to analyse the individual and collective impacts of the incentive schemes: (1) Directed Enhanced Service 18 (DES18: facilitating timely diagnosis of and support for dementia) and (2) the Dementia Identification Scheme (DIS). The dataset included 7529 English general practices, of which 7142 were active throughout the 10-year study period (April 2006 to March 2016). We controlled for a range of factors, including a contemporaneous hospital incentive scheme for dementia. Our dependent variable was the percentage of expected cases that was recorded on practice dementia registers (the "rate").

From March 2013 to March 2016, the mean rate rose from 51.8% to 68.6%. Both DES18 and DIS had positive and significant effects. In practices participating in the DES18 scheme, the rate increased by 1.44 percentage points more than the rate for non-participants; DIS had a larger effect, with an increase of 3.59 percentage points. These combined effects increased dementia registers nationally by an estimated 40 767 individuals. Had all practices fully participated in both schemes, the corresponding number would have been 48 685.

The primary care incentive schemes appear to have been effective in closing the gap between recorded and expected prevalence of dementia, but the hospital scheme had no additional discernible effect. This study contributes additional evidence that financial incentives can motivate improved performance in primary care.