Comparing registered and resident populations in Primary Care Networks in England: an observational study

Summary

Two years after the introduction of PCNs, most GP practices in England are part of a PCN. There is a wide range in the registered population size of PCNs, with only 56.1% in the 30 000–50 000 range originally recommended by NHS England. Assigning geographically defined PCN catchment areas resulted in similar average population sizes, but there was large variation across England in the overlap between the registered and resident catchment populations. In one-quarter of areas, <60% of people registered to a GP practice in the PCN were resident within the PCN catchment area, while in others this approached 100%. LSOAs in urban areas tended to have less overlap between registered and resident populations compared with those in rural areas, as did LSOAs in more deprived versus less deprived areas. However, within urban and rural areas, there were differences in the associations with deprivation, with lower percentages registered in more deprived compared with less deprived urban areas, but a trend towards higher percentages registered in more deprived areas. This may in part reflect differing patterns of mobility in rural and urban areas across the socioeconomic gradient.

Strengths and limitations

A strength of the work is the use of data covering all patient registrations to GPs in England, stratified by every LSOA, allowing the comparison of both registration and residence patterns. A limitation of the data is the inclusion only of patients who are registered to a GP practice. Some vulnerable patient groups, such as Travellers and people experiencing homelessness, are less likely to be registered with GPs and so may not be represented by the findings.²⁰ Second, the LSOA of residence of a patient is derived from their address as registered with their GP, and therefore may not be up to date. If some patients move further from their practice and do not re-register or update their address, the concordance observed in this study could be expected to be an overestimate of the true agreement between primary care registration and residence. The aim of the study was to compare registration patterns across the country, and according to urban and rural status and socioeconomic deprivation, but not to measure the causal effects of these factors on registrations. The associations seen in this study will be at least partially explained by sociodemographic factors, which impact on patient preference for proximity to and choice of GP practice; for example, if younger people are less likely to update their address than older people after moving, or those in employment choose to register at a location close to their place of work rather than residence, consistent with a previous study finding higher over-registration in London than other parts of England.²¹

Comparison with existing literature

The size of PCNs based on registered patients are similar to a previous study using data from January 2020, which identified a similar number of PCNs (n = 1250) and median size, indicating little change in the intervening period up to April 2021.² This study also found that 40% of PCNs were outside of the recommended size range. A second study using a data-driven approach to defining PCN catchment areas in London also suggested that larger PCN size may be more reflective of underlying patient registration patterns.¹⁴

To the authors' knowledge, this is the first study that has defined a geographical catchment for PCNs. However, geographical catchments have been described in secondary care settings and different methods have been proposed. The FPTP method was chosen as it results in the assignment of every LSOA to one and only one PCN; other approaches, such as a proportional flow method may assign an LSOAs to more than one catchment or leave others unassigned.¹²

Implications for research and practice

With the formation of ICSs, which have well-defined geographical footprints, there is a need to understand how PCNs will fit into local ICS ‘neighbourhoods’.^7,22 This work highlights that around one-quarter of people registered to a GP practice in a PCN are not living within the nominal catchment area of their PCN, but also that there is significant variation nationally, meaning that some PCNs may be differently able to achieve the objective of providing care to a geographic community of patients. In some parts of the country, most patients live outside the bounds of the geographic catchment of their registered PCN. Instead, these PCN communities may be imagined as overlapping extensively with one another and without a discrete geographic identity. In such areas, the challenge of accountability of individual PCNs and collaboration with local place-based services is likely to be greater than in areas with little overlap. Identifying patterns of overlap at a local level may inform strategies for collaboration both between neighbouring PCNs and individual GP practices within PCNs where overlap is particularly great.

The finding that PCNs in urban areas, and particularly those in more deprived urban areas, tend to have less overlap between registered and catchment populations than those in rural, and less deprived areas, highlights the possibility of inequities in care provision. This indicates a need to consider local context, including population movement and registration patterns in policy decisions and commissioning of integrated care services. These findings also suggest that in urban areas, and more socioeconomically deprived urban areas in particular, the implementation of larger PCNs consisting of more practices may facilitate better matching between the registered patients of a PCN and its catchment residents.

With increasing use of remote consultations during the COVID-19 pandemic, further research is needed to understand patient and practice priorities around the importance of proximity to their GP practice, and whether preferences have changed over time. The Babylon GP At Hand PCN, for example, was providing a significant number of remote consultations before the pandemic^23,24 and was found in the present study to have a much larger registered population than catchment population, indicating a wide geography over which patients are registered. With a move to greater digital health care during the pandemic, if GP practices register more patients ‘out-of-area’, a similar pattern may be replicated across other PCNs over time and become a hurdle to further integration of care. Some healthcare services, such as mental health teams and district nursing, may only accept patients resident within a defined geography, and so a widely dispersed patient population will increase the number of organisations a GP practice within a PCN needs to work with, potentially resulting in higher workloads, inhibiting organisational continuity of care and integration of services, and ultimately impacting on patient care.

In conclusion, as of April 2021, most GP practices in England have formed part of a PCN. The study finds substantial variation across the country in the overlap between people and place in PCNs. Lower overlap was more common in urban and more deprived areas, which is likely to exacerbate existing health inequalities. Low overlap in some areas will significantly hamper the ability of PCNs to integrate with community services and ICSs, and with greater use of remote consultations during the COVID-19 pandemic, there is a risk that this overlap erodes over time.