The Islington study has shown that a prompting system which coordinates structured care of non insulin treated diabetic patients between general practitioners, optometrists and hospital clinics is an effective w ay to ensure adequate medical care in the community. The standard of care provided by this approach was comparable to that provided in the hospital diabetic clinics of the DGH. In respect of its higher take-up rate by patients, prompted care was
m ore effective than hospital clinic care; this was reflected in the lower lost to follow-up rate in the prompted group than in the hospital clinic group. Professional and patient compliance w ith the prompting regime proved high and the system as a whole was acceptable to all the parties involved.
The process of care findings in this study represent the most important achievement of prompted diabetic care but, as mentioned in Chapter 6, these measures in themselves can only be viewed as an imperfect guide to the standard of medical care patients received. Because the providers of care in this study were a diverse group there are likely to have been considerable differences in the knowledge and skills of the doctors who provided care to the two groups of patients. Despite this qualification, the process of care levels achieved by prompted structured care in Islington are a marked improvement on those of previous U K studies. In the Cardiff trial 14% of community care patients received regular GP review and only 5% received yearly blood glucose estimations (Hayes and Harries 1984). In Kirkcaldy, two thirds of patients received a diabetes review by their general practitioner in the first or second year of a two year study, and only 50% had annual blood glucose assessments (Porter 1979, 1982). In a non randomised study in Ipswich, amongst a group of 209 diabetics discharged to GP care w i t h agreed standards of follow-up, only 25% of patients had their urine tested or blood
glucose level estimated by their GP in the previous two years (Day et al 1987).
Prompted care in Islington ensured very high levels of specific diabetes clinical assessments, such as weighing, blood pressure, foot examination, and retinal examination. There was no evidence of a tail off in these process of care rates in the second year of the study as had been noted in the community care group in Kirkcaldy (Porter 1979). All prompted GP reviews were performed in the context of information concerning recent blood glucose, HbAj and albuminuria estimations. This level of clinical assessment compares favourably w i t h the most comprehensive levels reported from hospital clinics, and from GP mini-clinic care (Yudkin et al 1980, Williams et al 1989, Kemple and Hayter 1991, Parnell et al 1993). There were no differences between the two groups in the number of changes of diabetic treatment category, nor in the proportion of patients admitted to hospital for a diabetes-related reason. Though previous studies have documented a higher mortality in the community group (Hayes & Harries 1984, Porter 1979 ), this was not the case in Islington.
A number of the clinical outcome measures reported in this trial, for example, the proportion of patients w i t h diabetic complications at the end of the study period (see Table 9), need to be interpreted in the light of their being the product of observations by a wide variety of doctors working in routine care settings, and not trained to minimise inter- and intra-observer variability. In addition, even if all patients had been examined at the beginning and end of the trial by a single observer, a median study length of two years is too short a follow-up period in w hich to expect demonstrable differences in diabetic complication rates (Fuller 1983, Jarrett 1983). Subject to these provisos, there were no significant differences between the two study groups in the proportion of
patients recorded as developing the following diabetic
complications: lower limb neuropathy, ischaemic heart disease, albuminuria k + , or onset of stroke. The small increase in diastolic blood pressure in the hospital clinic group, w i t h a small fall in
the prompted group at the end of the study, are of questionable significance. Reference has already been made to the greater proportion of prompted patients, by the end of the trial, reported to have lower limb ischaemia. This could have been the result of poorly developed GP skills in detecting foot pulses, or the result of a greater initial risk of ischaemia due to the higher level of ischaemia documented in the prompted group at the start of the study
(see Table 3).
Mean plasma glucose and HbAj values, unlike complication rates, are not subject to observer error and provide useful proxy measures of outcome. The results of this study are in keeping with the findings of Singh et al from Wolverhampton who found no loss in glycaemic control in a non randomised discharge of both Type I & II patients to GP mini-clinic care. The Islington results, though starting at higher initial levels, are also comparable t o ^ ^ h o s e recently
announced from the Wirral by Baldwin et al(^^^(^^9^^. In a non ) S randomised study, this group found only slight deterioration in
fasting blood glucose levels in 220 Type II diabetic patients discharged to GP care with 4 monthly computer prompted requests for fasting blood glucose and GP review, but with annual review in the hospital clinic. In the discharged patients, fasting blood glucose levels rose from an initial mean value of 7.6mmol/L to 8.1mmol/L, though mean HbAj fell non-significantly from 8.3% to 7.9% after two years follow-up. In Islington, the rise of mean random plasma glucose within groups (of 1.3 mmol/L in controls and 1.6 mmol/L) may have been due to a drift in the mean interval between blood test and last meal and was not matched by a significant rise in mean HbAi within group.
The Islington results are also comparable to those of Harvey et al (1992) in Aberdeen who found no evidence of loss of glycaemic control and no alteration in the rate of onset of diabetic complications in a group of 258 (Type I and II) patients randomly discharged from conventional hospital clinic care to a system of shared care with GPs. In this study, which also incorporated annual diabetic review in the hospital clinic for the shared care group.
the loss to follow-up rate in the shared care group was zero compared to 14 in the hospital group (p<0.001). These results and those in Islington contrast, however, w i t h the findings from Cardiff (Hayes & Harries 1984) where, at the end of the trial, the available measures of HbA^ indicated worse glycaemic control in the community
care group, although there were no pre-randomisation HbAj
me a s u r e m e n t s .
It is important to emphasise that previous studies of community diabetic care have equated process of diabetic care received in the case of the community group w ith 'GP care*, and likewise in the case of hospital clinic controls, these studies have equated process of diabetic care received w ith 'hospital clinic care'. They have not examined process of care by location of care in each group. This means that previous studies have not reported the care received by the community group in hospital outpatients, or the consultation rates of hospital diabetic clinic attenders in general practice.
The Islington study revealed a high unprompted annual consultation rate for both groups of patients w ith their general practitioner: 8 per patient in the prompted group v 6 per patient in the hospital clinic group. These rates are high in comparison to the national all-reason annual consultation rate per patient of 3.4 for all ages and 4.4 for those aged 65 to 74 (National Morbidity Statistics 1986). The all-reason consultation rate of diabetic patients is believed to be higher than the average though national statistics have not documented this because consultations are recorded by reason for consultation rather than by specific patients w ith a known diagnosis. However, our results are comparable to the findings of a study of 43 NIDDM patients of the same mean age as Islington study patients; this found an all-reason consultation rate w i t h GPs of 9.6 per patient in the first year of organised diabetic care in two general practices in Southampton (Murphy et al 1992).
Of the unprompted consultations w ith GPs for both groups in the Islington study, consultations in which mention of diabetes was made in the GP notes, or a specific diabetes clinical assessment was
documented, or a diabetic measurement was made or requested were classified as diabetes-related consultations. In the prompted and
hospital clinic group, the average annual diabetes-related
consultation rates were 2 and 3 respectively (see Table 5). For evaluation purposes diabetes-related consultations w i t h GPs were not counted as structured care. Analytically, these consultations constitute ad hoc GP care of diabetes; this consultation rate did not significantly differ between groups. Prompted structured care therefore seemed to have no significant * knock on* effect upon 0 ^ i t h e r the all-reason consultation rate of diabetic patients with
G P s , upon the diabetes-related consultation rate.