Findings, Part A: reconfiguration of acute stroke services in Greater Manchester and London
Chapter 4 The impact of the centralisation of acute stroke care on the delivery of clinical
interventions
Overview
This chapter draws on a paper published by Ramsay et al.26Effects of centralising acute stroke services on stroke care provision in two large metropolitan areas in England. Stroke 2015;46(8):2244–51. Stroke is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0) License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is non-commercial, and no modifications or adaptations are made. See https://creativecommons.org/licenses/by-nc-nd/3.0/. Permission to adapt this material has been agreed with Wolters Kluwer.
What was already known about this subject?
l Provision of evidence-based stroke care is associated with better patient outcomes.
l Centralisation of acute stroke services in London and GM had a significantly different impact on clinical outcomes, with only the London changes associated with significantly greater reductions in mortality (see Chapter 3).
l There was limited evidence on the impact that centralisation of acute stroke care has on provision of evidence-based clinical interventions, and whether or not this might explain the changes in clinical outcomes observed.
What this chapter adds
l In London, where almost all patients were treated in a HASU, patients were more likely than elsewhere to receive evidence-based care in the first hours following arrival in hospital.
l GMA’s CSC/PSCs performed as effectively as HASUs in London, and significantly better than London on several important clinical interventions, but treated only 39% of stroke patients. This difference is explained in part by differing eligibility criteria in GM and London, but also because adherence to the model in GM was lower, with two-thirds of eligible patients treated in hyperacute units.
l As a result, only patients in London were significantly more likely than patients elsewhere to receive evidence-based care; stroke patients in GM were overall no more likely to receive evidence-based care in the first hours following arrival in hospital than patients in areas where no equivalent centralisation had taken place.
Background
Stroke care based on evidence of clinical effectiveness (e.g. access to stroke specialists, rapid scanning, assessment, treatments and therapies, referred to here as‘evidence-based clinical interventions’) is associated with better patient outcomes.21,25,53,81,82Benefits include reductions in mortality, LOS and disability, and increases in independence and QoL.
Some health systems have centralised their stroke services to create a smaller number of high-volume specialist services, aiming to improve patient access to evidence-based clinical interventions.7,9,10,83Recent research indicates that different models of centralisation are associated with different outcomes: although both GM and London centralisations were associated with significantly greater reductions in LOS, only the London centralisation was associated with a significantly greater reduction in stroke patient mortality than in the RoE.25This analysis attempts to explain the differences in clinical outcomes by analysing the London and GMA changes in terms of (1) their impact on the provision of evidence-based clinical interventions and/or (2) differences between the GM and London models’ eligibility criteria for admission to a hyperacute unit, and how reliably these criteria were followed.
Method
Design
This study used a controlled before-and-after design. It analysed risk-adjusted likelihood of stroke patients receiving evidence-based clinical interventions in GM and London, pre and post centralisation, compared with urban areas of England where acute stroke services had not been centralised (hereafter referred to as the‘comparator’).
Data
Patient-level data were drawn from two national audits organised by the Royal College of Physicians:
(1) pre centralisation, the National Sentinel Stroke Clinical Audit (Sentinel 2008), conducted from April to August 2008, was used; and (2) post centralisation, the SINAP, which ran from April 2010 to December 2012,72,84was used. Reflecting the implementation dates for the centralisations, the GM post-centralisation period was April 2010 to December 2012 inclusive, whereas London’s was July 2010 to December 2012 inclusive. Data collected in the two audits differed: Sentinel 2008 collected a‘snapshot’ of up to 60 patients per participating stroke service, whereas SINAP collected data for all patients receiving stroke care.
Consequently, post-centralisation data cover significantly more patients.
The analysis included data submitted by all hospitals providing acute stroke care in GM, London and a comparator area formed of hospitals providing acute stroke care in two parts of England (north-west England, excluding GM, and north-east England), where local documents showed that no equivalent centralisation had occurred. The comparator was limited to hospitals in urban settings equivalent to GM and London (classified as‘major urban’ by the UK ONS85); it covered 1.8 million people27and its level of participation in national audits was equivalent to GM and London (details available in Appendix 3). Although Sentinel 2008 had uniformly high participation across England,84participation in SINAP was variable in several areas of England, with many hospitals submitting few or no data.72These differing participation levels meant that the RoE could not act as the comparator. Consequently, data for approximately 56,100 stroke patients (7300‘before’, 48,700‘after’) were excluded. Data for all patients diagnosed with stroke (intracerebral haemorrhage or cerebral infarction) were included, both those occurring in hospital and those occurring outside hospital.
Patients with invalid data were excluded.
Measures
We analysed all evidence-based clinical interventions that had been measured consistently in both audits.59,86 These measures were calculated from arrival at hospital (or symptom onset if occurring in hospital), and assessed whether or not patients had their first brain scan within 3 hours and 24 hours of arrival (cut-off points were identified in the baseline audit national report reflecting the time to scan to support administration of thrombolysis, and national guidance to scan within 24 hours84); were admitted to a SU within 4 hours;
received antiplatelets within 48 hours (if ischaemic); and underwent physiotherapist, nutrition and formal swallow assessments within 72 hours (all if eligible).
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Statistical analysis
Descriptive statistics
Descriptive data were calculated at regional level for GM, London and the comparator, pre and post centralisation. Post centralisation, we categorised hospitals based on whether or not they were designated to provide hyperacute care. Consistent data were available on patient characteristics (age, sex, stroke type, worst level of consciousness, and whether the stroke occurred within or outside hospital) and the proportion of patients receiving each clinical intervention analysed.
Hospital-level variation
To understand the impact of the centralisations on patient volume and provision of care at hospital level, the unadjusted proportion of patients receiving evidence-based clinical interventions was calculated at hospital level for each area, both pre and post centralisation. Hospital-level proportions were plotted against the mean number of stroke patients submitted to the audits per day, and categorised by whether or not services were hyperacute.
Risk-adjusted likelihood of receiving evidence-based clinical interventions
Using patient-level data we used logistic regression to analyse whether or not patients received each evidence-based clinical intervention (yes/no) against region (whether or not they were treated in GM or London, with the comparator as the reference category), time period (whether or not they were treated in the‘after’ period, with being treated in the ‘before’ period as the reference category) and an interaction term between region and time period, controlling for age (in 5-year bands), sex, stroke diagnosis
(intracerebral haemorrhage/cerebral infarction), worst level of consciousness (fully conscious/semi-conscious/
drowsy/unconscious), and whether stroke occurred within or outside hospital (yes/no). All outcomes were binary (yes/no). We reported marginal effects, showing the adjusted predicted probability of each outcome in each region in each time period. Because the GM and London centralisations had different‘after’ periods (meaning the comparator data differed slightly), the regression analyses of the two centralisations were conducted separately. We reran our models stratifying by whether or not the patient was treated in a hyperacute or a non-hyperacute stroke service.
Following referral criteria for admission to hyperacute units in Greater Manchester and London
The proportion of patients treated in a HASU was calculated to examine whether or not the models selected in GM and London influenced the likelihood of receiving evidence-based clinical interventions; this was also used to measure how reliably the London hyperacute referral criteria were followed. To examine how reliably GM hyperacute referral criteria were followed, we compared patients’ time of symptom onset with time of arrival at hospital to calculate the proportion of patients who arrived at hospital within 4 hours of symptoms developing (and were thus eligible for hyperacute unit admission), and who were in fact admitted to a hyperacute unit.
Results
Descriptive statistics
Data for 38,623 acute stroke cases submitted to national audit were analysed, covering 51 hospitals pre centralisation (from a total of 189 hospitals participating in the audit across England) and 44 hospitals post centralisation (from a total of 171 hospitals across England). Table 7 presents the unadjusted data for GM and London compared with the comparator. Patient characteristics were similar in GM, London and the comparator in both pre- and post-centralisation time periods, and any potential effects of patient characteristics were controlled for in the regression analyses. Post centralisation, the proportion of patients receiving evidence-based clinical interventions increased in all three areas. It should be noted that denominators for these indicators varied from measure to measure owing to variable eligibility of patients or availability of data. Increases were most pronounced in care provided in the first hours following arrival at hospital (brain scan within 3 hours,
TABLE 7 Patient characteristics and unadjusted proportions of patients receiving evidence-based clinical interventions
Patient characteristics/
interventions
Region
GM London Comparator
Before After Before After Before After
Total patients (N) 653 10,295 1541 16,553 537 9044
Total hospitals 12 11 30 24 9 9
Case/day rate 0.63 0.97 0.58 1.03 0.80 1.07
HASU case/day rate 1.37 2.17
Non-HASU case/day rate 0.65 0.12
Mean age (years) 74.5 73.2 73.3 72.7 74.6 73.6
Proportion> 75 years (%) 55 50 51 50 53 51
Proportion female (%) 52 51 50 49 52 51
Stroke type (%)
Haemorrhage 13 11 14 11 11 11
Infarct 87 89 86 89 89 89
Worst consciousness (%)
Fully conscious 60 74 67 78 68 75
Semi-conscious 19 15 17 15 11 14
Drowsy 8 4 7 3 9 5
< 4 hours patients treated in hyperacute unit
> 4 hours patients treated in
hyperacute unit – 869/2154 THE IMPACT OF THE CENTRALISATION OF ACUTE STROKE CARE ON THE DELIVERY OF CLINICAL INTERVENTIONS
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admitted to a SU within 4 hours). The proportion of stroke patients receiving these clinical interventions was higher in London than in GM and the comparator, both pre and post centralisation, but the absolute difference was similar. Proportions of patients receiving evidence-based clinical interventions 24–72 hours after admission also increased in all three areas, but in all areas pre-centralisation levels commonly exceeded 80%, and post centralisation all proportions exceeded 90%. Generally, London had higher pre-centralisation levels and post-centralisation levels were similar– approaching the maximum – in each area.
Hospital-level variation
Pre centralisation, there was substantial between-hospital variation in the proportion of patients receiving evidence-based clinical interventions in all three areas (see Appendix 3). Post centralisation, hyperacute units in GM (CSC, PSCs) and London (HASUs) treated a higher volume of patients than elsewhere (see Table 7), and provided evidence-based clinical interventions to a higher proportion of their patients (Figure 4 and see Appendix 3, Figure 20).
Although the proportion of patients receiving evidence-based clinical interventions increased in GM and London’s non-hyperacute units and in the comparator area overall, patient volume increased less, and the proportion of patients receiving evidence-based clinical interventions tended to be lower and more variable than in the hyperacute units. When GM PSCs operated as DSCs, they performed in line with other DSCs (Figure 4a and see Appendix 3, Figure 20).
Risk-adjusted likelihood of receiving evidence-based clinical interventions
Trends in risk-adjusted proportions of patients receiving evidence-based clinical interventions (Tables 8 and 9) reflected the unadjusted findings (see Table 7). Post centralisation, on all clinical interventions analysed, London patients were overall significantly more likely to receive clinical interventions than comparator patients. GM patients were significantly more likely than comparator patients to receive two interventions (brain scan within 3 hours and 24 hours), significantly less likely to receive three interventions (admission to SU within 4 hours, and physiotherapist and swallow assessments within 72 hours), with no significant difference between GM and comparator patients on the two remaining interventions. London patients were overall significantly more likely than GM patients to receive six of the seven interventions (brain scan within 3 hours and 24 hours, admission to a SU within 4 hours, and physiotherapist, nutrition and swallow assessments within 72 hours), with the magnitude of differences ranging from 1.2% to 10.4% and with no significant difference on antiplatelets within 48 hours. Patients treated in hyperacute units, in both GM and London, were significantly more likely to receive clinical interventions than patients treated either
TABLE 7 Patient characteristics and unadjusted proportions of patients receiving evidence-based clinical interventions (continued)
Patient characteristics/
interventions
Region
GM London Comparator
Before After Before After Before After
Nutrition 72 hours 504/583
All measures reflect time from‘clock start’ (i.e. when patient first arrives at hospital or when symptoms are identified in in-patients).
Adapted from Ramsay et al.26with permission. Effects of centralising acute stroke services on stroke care provision in two large metropolitan areas in England. Stroke 2015;46(8):2244–51. Stroke is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0) License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is non-commercial, and no modifications or adaptations are made. See https://creativecommons.org/licenses/by-nc-nd/3.0/. Permission to adapt this material has been agreed with Wolters Kluwer. Table title and numbering updated for report.
in non-hyperacute units or in the comparator (with one exception, where comparator patients were significantly more likely to receive a physiotherapist assessment than GM hyperacute patients). Patients treated in GM hyperacute units were significantly more likely than London HASU patients to receive four clinical interventions:
brain scan within 3 hours, admission to SU within 4 hours, brain scan within 24 hours and antiplatelets within 48 hours (the magnitude of the differences ranged from 2.0% to 13.8%). Patients treated in GM hyperacute units were significantly less likely to receive a physiotherapist assessment within 72 hours than patients treated in London HASUs (magnitude 2.2%). There was no significant difference between GM and London hyperacute units in the number of patients receiving nutrition and formal swallow assessments within 72 hours.
0.0
FIGURE 4 Between-hospital variations in the proportion of patients admitted to a SU within 4 hours by area, post centralisation. (a) GM; (b) London; and (c) comparator. Adapted from Ramsay et al.26Effects of centralising acute stroke services on stroke care provision in two large metropolitan areas in England. Stroke 2015;46(8):2244–51.
All measures reflect time from‘clock start’ (i.e. when patient first arrives at hospital or when symptoms are identified in in-patients). Stroke is published on behalf of the American Heart Association, Inc., by Wolters Kluwer.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0) License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is non-commercial, and no modifications or adaptations are made.
See https://creativecommons.org/licenses/by-nc-nd/3.0/. Permission to adapt this material has been agreed with Wolters Kluwer. Figure title and numbering updated for report.
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TABLE 8 Risk-adjusted proportions of patients receiving evidence-based clinical interventions: GM vs. comparator
Intervention
Region, % likelihood (95% CI) GM
Comparator
Overall CSC/PSCs DSCs
Before After After After Before After
Brain scan 3 hours 25.0 (21.0 to 29.0) 65.2 (64.3 to 66.2) 85.5 (84.6 to 86.5) 52.2 (50.8 to 53.5) 29.0 (27.1 to 31.0) 62.3 (61.7 to 63.0) SU 4 hours 17.8 (14.6 to 21.0) 55.9 (54.9 to 57.0) 82.9 (81.8 to 83.9) 36.7 (35.3 to 38.1) 25.8 (24.0 to 27.7) 61.1 (60.5 to 61.7) Brain scan 24 hours 71.7 (68.2 to 75.1) 94.0 (93.5 to 94.4) 98.2 (97.8 to 98.5) 91.6 (90.9 to 92.2) 69.4 (67.2 to 71.5) 92.9 (92.5 to 93.2) Antiplatelets 48 hours 86.5 (83.8 to 89.2) 94.2 (93.7 to 94.7) 97.6 (97.1 to 98.1) 92.2 (91.5 to 93.0) 91.3 (90.0 to 92.7) 94.3 (93.9 to 94.6) Physiotherapist 72 hours 88.3 (85.7 to 90.8) 92.1 (91.5 to 92.7) 93.8 (93.0 to 94.7) 91.4 (90.7 to 92.2) 88.2 (86.6 to 89.8) 95.2 (94.9 to 95.5) Nutrition 72 hours 89.9 (87.7 to 92.0) 95.6 (95.3 to 96.0) 98.5 (98.2 to 98.8) 94.1 (93.6 to 94.7) 70.8 (68.6 to 73.0) 95.8 (95.5 to 96.1) Swallow 72 hours 87.7 (84.6 to 90.9) 94.0 (93.6 to 94.4) 98.6 (98.2 to 98.9) 91.6 (90.9 to 92.2) 82.3 (79.7 to 84.9) 96.0 (95.7 to 96.3) Notes
All measures reflect time from‘clock start’ (i.e. when patient first arrives at hospital or when symptoms are identified in in-patients).
Patients treated in hospitals hosting PSCs are categorised as treated in a PSC if admitted 07.00–19.00, Monday–Friday; out of hours, patients are categorised as treated in a DSC.
All interventions are timed from arrival at hospital (or symptom onset if occurring in-hospital).
Adapted with permission from Ramsay et al.26Effects of centralising acute stroke services on stroke care provision in two large metropolitan areas in England. Stroke 2015;46(8):2244–51.
Stroke is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0) License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is non-commercial, and no modifications or adaptations are made. See https://creativecommons.org/licenses/by-nc-nd/3.0/. Permission to adapt this material has been agreed with Wolters Kluwer. Table title and numbering updated for report.
10.3310/hsdr07070HEALTHSERVICESANDDELIVERYRESEARCH2019VOL.7NO.7
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TABLE 9 Risk-adjusted proportions of patients receiving evidence-based clinical interventions: London vs. comparator
Intervention
Region, % likelihood (95% CI) London
Comparator
Overall HASUs SUs
Before After After After Before After
Brain scan 3 hours 36.5 (34.0 to 39.1) 72.1 (71.4 to 72.8) 74.6 (73.8 to 75.3) 39.9 (36.9 to 42.9) 21.5 (18.9 to 24.0) 55.5 (54.8 to 56.3) SU 4 hours 29.6 (27.3 to 31.9) 66.3 (65.6 to 67.1) 69.1 (68.3 to 69.9) 28.6 (25.8 to 31.3) 18.7 (16.4 to 21.0) 54.4 (53.6 to 55.1) Brain scan 24 hours 77.9 (75.8 to 80.0) 95.2 (94.8 to 95.5) 96.2 (95.9 to 96.5) 83.4 (81.3 to 85.6) 62.4 (59.4 to 65.3) 91.5 (91.1 to 92.0) Antiplatelets 48 hours 94.1 (92.8 to 95.4) 94.8 (94.4 to 95.2) 95.3 (94.9 to 95.7) 89.6 (87.7 to 91.6) 85.4 (83.2 to 87.6) 93.8 (93.4 to 94.2) Physiotherapist 72 hours 88.9 (87.0 to 90.7) 95.4 (95.0 to 95.8) 96.0 (95.6 to 96.4) 86.3 (83.8 to 88.7) 87.9 (85.9 to 89.8) 93.4 (93.0 to 93.8) Nutrition 72 hours 74.1 (71.7 to 76.4) 98.3 (98.1 to 98.5) 98.6 (98.4 to 98.8) 94.7 (93.4 to 96.0) 84.2 (81.9 to 86.4) 93.3 (92.9 to 93.7) Swallow 72 hours 85.4 (82.8 to 88.0) 98.2 (97.9 to 98.4) 99.0 (98.8 to 99.1) 86.0 (83.6 to 88.5) 85.4 (82.5 to 88.3) 92.8 (92.4 to 93.3) Notes
All measures reflect time from‘clock start’ (i.e. when patient first arrives at hospital or when symptoms are identified in in-patients).
Adapted with permission from Ramsay et al.26Effects of centralising acute stroke services on stroke care provision in two large metropolitan areas in England. Stroke 2015;46(8):2244–51.
Stroke is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0) License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is non-commercial, and no modifications or adaptations are made. See https://creativecommons.org/licenses/by-nc-nd/3.0/. Permission to adapt this material has been agreed with Wolters Kluwer. Table title and numbering updated for report.
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To examine whether or not these differences reflected the greater proportion of patients in GM arriving within 4 hours, we reran this analysis focusing only on patients presenting within 4 hours of symptom onset and found that the differences between GM and London hyperacute units reduced substantially (see Appendix 3).
Access to care in hyperacute units in Greater Manchester and London
Post centralisation, 39% of GM patients were treated in a hyperacute unit, whereas 93% of London patients were (see Table 7). In addition, only 66% of GM stroke patients who presented within 4 hours of symptom onset were admitted to a hyperacute unit (see Table 7), meaning that 34% of patients who were eligible for hyperacute unit care were not admitted to one.
We reran our analyses using all available data for the RoE as the comparator; the results did not change appreciably (see Appendix 3).
Discussion
Principal findings
Post centralisation, the risk-adjusted likelihood of patients receiving evidence-based clinical interventions increased significantly in all areas. London patients were overall significantly more likely than patients elsewhere to receive the interventions. Importantly, hyperacute units in both GM and London were significantly more likely to provide interventions than non-hyperacute units in these areas, and in the comparator area overall.
Post centralisation, the risk-adjusted likelihood of patients receiving evidence-based clinical interventions increased significantly in all areas. London patients were overall significantly more likely than patients elsewhere to receive the interventions. Importantly, hyperacute units in both GM and London were significantly more likely to provide interventions than non-hyperacute units in these areas, and in the comparator area overall.