Inequalities and inequities in the types of chronic pain services available in areas of differing deprivation across England

Socioeconomic disadvantage

Socioeconomic disadvantage can be described at both an individual-level (socioeconomic status (SES)) and an area-level (deprivation). SES is a composite measure which considers an individual’s income, education and occupation. However, the standard measure of deprivation of the 32,844 ‘small areas’ in England (average population of 1,500) is the Index of Multiple Deprivation (IMD) which has 7 contributing domains (income, education, employment, health, crime, living environment and barriers to housing/service) [1].

Chronic pain epidemiology

Many chronic diseases are more prevalent amongst those who are socioeconomically disadvantaged [2], and chronic pain is no exception to this. 2017 Health Survey for England [3] revealed that the prevalence of chronic pain is higher in more deprived compared to less deprived areas. Similarly, a 2021 meta-analysis [4] of 45 international studies found that there is a moderate increase in the risk of chronic pain for those of low (OR=1.32; 95% CI: 1.21, 1.44) and medium (OR=1.16; 95% CI: 1.09, 1.23) SES compared to those of high SES.

Furthermore, patients in deprived areas experience more severe and disabling pain [5], [6], [7], [8] as well as suffer greater mental distress [5] compared to their counterparts in less deprived areas. 2017 Health Survey for England [3] found that people who experience high interference chronic pain (pain that moderately or severely limits daily, social and work-related activities, Von Korff Graded Chronic Pain Scale [9]) are twice as likely to live in the most deprived quintile (30%) compared to the least deprived quintile (15%).

Chronic pain service provision in England

In England, healthcare services are provided by NHS England, which is a subdivision of the NHS, a national tax funded healthcare system that is free at the point of delivery. NHS England has organisational units (NHS Trusts) that each serve specific geographical areas. The same area can be served by several Trusts providing different services. The National Institute of Health and Care Excellence (NICE) is the public body of the Department of Health which publishes healthcare guidelines and quality standards.

The National Pain Audit 2010–2014 [10, 11] investigated NHS-provided pain clinics across England and Wales. Among other shortcomings, it found that only 56% of clinics were meeting the minimum multidisciplinary standard (presence of a psychologist, physiotherapist, and physician) and very few clinics were meeting recommended evidence-based waiting times [11]. However, the audit did not report the specific services offered within pain clinics or how the provision of these services varied according to the level of deprivation of an area. The Inverse Care Law [12] states that healthcare services and professionals are often sparse where they are most in need. To our knowledge, no research has been published exploring if the Inverse Care Law [12] applies in the context of services for chronic pain in England and if so, to what extent.

Aim

To examine how the types of services available for chronic pain patients vary between England NHS Trusts, serving areas of differing deprivation.

Defining ‘ideal’ provision of chronic pain services

Firstly, a list of primary chronic pain services that NHS Trusts should ideally provide was generated. All recommendations made in the management section of NICE guidelines for primary chronic pain [13] excluding the pharmacological therapies (outside main aim of this study), were included in the list. The 3-tier grading system of pain services outlined in NHS England standards for specialised pain services [14] and the types of members for pain multidisciplinary teams (MDTs) recommended in Faculty of Pain Medicine Core Standards for Pain Management Services [15] were also included.

Two refinements were then made to produce the final list of primary chronic pain services that NHS Trusts should ideally provide (Table 1). Psychological therapies were removed because the provider of such services (psychologist) was also on the list. The categories Tier 2 and Tier 3 on the list were merged because of difficulty in determining the level of speciality of a service using chosen data collection methods.

Next, services for patients with secondary chronic pain were added to the list. For this, NICE guidelines on the 8 commonest causes of secondary chronic pain in the UK were considered [16]. These are headache, low back pain and sciatica, rheumatoid arthritis, osteoarthritis, spondyloarthritis, endometriosis, neuropathic pain and irritable bowel syndrome [16]. All pain-related service recommendations, excluding pharmacological therapies and surgical interventions (outside main aim of this study), were included in the list.

One refinement was then made to produce the final list (Table 2); manual therapy was removed since physiotherapists, who most commonly provide this intervention in the NHS, were on the list.

Trust selection and data collection

England NHS Trusts from the NHS provider directory [17] were numbered from 1 to 217. Random numbers were then generated, and duplicate numbers were removed as they arose until there were 100 different numbers (representing 46% of England NHS Trusts). Next, numbers corresponding to Trusts that either no longer exist or solely provide mental health or ambulance or limited community services were removed, leaving 63 Trusts. Trust websites were then searched, and it was recorded whether each of the ideal chronic pain services (listed in Table 2) were being provided or not. For 34 Trusts, the website had enough information to determine this. Then pain receptionists and/or secretaries from remaining 29 Trusts were contacted to clarify which services were being provided. Pain receptionists and/or secretaries were contacted because unlike healthcare professionals, they were easily accessible via telephone numbers available on Trust websites. Healthcare professionals would have had to be contacted via email, to which non-response is more likely.

Three Trusts were unreachable so where information about a service was missing from their websites, it was assumed that the service was not provided. The process of trust selection and data collection is summarised in Figure 1.

Calculating deprivation scores

Next, deprivation score of the area that each Trust covered was recorded. For this, a mean of the IMD 2019 scores [1] of the ‘small areas’ that the Trust covered [18] was calculated. Mean was weighted on population size [19].

Tertiary Trusts provide care for their local area as well as highly specialised services for areas beyond this. However, only the IMD 2019 scores of the local ‘small areas’ were considered in the above calculation. Given that some of these Trusts receive referrals nationally, it was not possible to include IMD 2019 scores of all areas covered by these Trusts. Furthermore, this would not demonstrate the true accessibility of services because access to highly specialised services in tertiary care hides whether there is adequate secondary care service provision locally. Finally, the provision of cordotomy and neuromodulation, two interventions only provided in tertiary Trusts were not evaluated, again making the distinction between secondary and tertiary Trusts unnecessary.

Statistical analysis

Analyses were performed using GraphPad Prism (version 9.1.2 for Windows). Spearman’s Correlation Coefficient was calculated to assess the relationship between deprivation level of areas and number of types of chronic pain services provided available. Mann–Whitney U and Kruskal–Wallis tests were used to compare IMD 2019 scores of Trust areas with and without each service in Table 2.

Figure 1:

Summary of process of NHS Trust selection and data collection. Data was collected in June and July 2021.

Limitations and future work

Websites were used for data collection which may not be regularly updated. However, they provided an important dimension to the results. Patients who are looking to access the pain service and General Practitioners wanting to refer patients often use the websites. Therefore, an inadequate website could reduce the use of services despite them being available.

Guidelines on only the eight commonest causes of secondary chronic pain were considered.

Only the provision of services was recorded; their quality or effectiveness was not investigated. Future work could use validated pain severity and quality-of-life questionnaires pre- and post-treatment to evaluate outcomes in areas of differing deprivation.

Additionally, future research and practice interventions should consider that a service being available does not necessarily mean that it is accessible. For example, a group at a tertiary paediatric chronic pain service [22] found that proportionately fewer children from deprived areas were being referred to the service. These children were also less likely to attend appointments. Furthermore, the National Pain Audit found that low numbers of non-English speaking patients were accessing the pain services.

Despite the above limitations, this study still makes an important first step in uncovering some of the inequalities and inequities that exist in the provision of chronic pain services in England. This research hopes to prompt further investigation into the true magnitude and impact of these issues and consequent improvement to the provision of chronic pain services in England, particularly in deprived areas.

Similar research across Europe is recommended to inform effective policy decisions to combat the widespread health disparities in chronic pain [4], [5], [6], [7], [8].