In April this year, Public Health England (PHE) published estimated rates of atrial fibrillation (AF) for local CCGs in England,1 claiming that ‘Healthcare professionals can use this resource to estimate the number of people with atrial fibrillation in their local area. The data also shows the variation in the condition across the local area. This can help with planning and commissioning local services.’1
Unfortunately, these estimates are grossly inflated. They bear little resemblance to local reality and may be misused to erroneously claim that GPs are underestimating prevalence by up to 100%.
PHE used a small study from 2010 in northern Sweden with a population of 76 000 to estimate the rates in an ethnically diverse population of 50 million people in England. Twenty per cent to 50% of people in some urban CCGs are from BAME groups with lower AF prevalence than white populations. Bradford AF prevalence was reduced by 70% in South Asians in comparison with the white population.2
The Swedish study was conducted over 7 years and included all cases of AF, including all transient hospital inpatient cases that occurred in one in three cardiac operations. When the authors analysed cases identified in a single year rather than over 7 years, numbers were reduced by half. A Scottish study based on GP diagnoses showed that the annual prevalence was less than half that in Sweden. AF in people over 85 was 22% in Sweden and 7.1% in Scotland.3
Comparing PHE estimates based on Sweden with the QOF 2018/2019 data from general practice in London boroughs shows overestimates of between 28% and 100% (Table 1), the higher figures being most pronounced in boroughs with large black or South Asian populations.
These data from Sweden are not reliable for the estimation of annual AF prevalence as determined by GPs and substantially overestimate annual reports of prevalence in these populations. Commissioners and GPs should beware of the gap between flawed estimates and the reality of their local community prevalence.
- © British Journal of General Practice 2020