Scottish Care Information-Diabetes Collaboration Research Articles

Trajectories of BMI before and after diagnosis of type 2 diabetes in a real-world population.

Few studies have examined the clinical characteristics associated with changes in weight before and after diagnosis of type 2 diabetes. Using a large real-world cohort, we derived trajectories of BMI before and after diabetes diagnosis, and examined the clinical characteristics associated with these trajectories, including assessing the impact of pre-diagnosis weight change on post-diagnosis weight change. We performed an observational cohort study using electronic medical records from individuals in the Scottish Care Information Diabetes Collaboration database. Two trajectories were calculated, based on observed BMI measurements between 3 years and 6 months before diagnosis and between 1 and 5 years after diagnosis. In the post-diagnosis trajectory, each BMI measurement was time-dependently adjusted for the effects of diabetes medications and HbA1c change. A total of 2736 individuals were included in the study. There was a pattern of pre-diagnosis weight gain, with 1944 individuals (71%) gaining weight overall, and 875 (32%) gaining more than 0.5 kg/m2 per year. This was followed by a pattern of weight loss after diagnosis, with 1722 individuals (63%) losing weight. Younger age and greater social deprivation were associated with increased weight gain before diagnosis. Pre-diagnosis weight change was unrelated to post-diagnosis weight change, but post-diagnosis weight loss was associated with older age, female sex, higher BMI, higher HbA1c and weight gain during the peri-diagnosis period. When considering the peri-diagnostic period (defined as from 6 months before to 12 months after diagnosis), we identified 986 (36%) individuals who had a high HbA1c at diagnosis but who lost weight rapidly and were most aggressively treated at 1 year; this subgroup had the best glycaemic control at 5 years. Average weight increases before diagnosis and decreases after diagnosis; however, there were significant differences across the population in terms of weight changes. Younger individuals gained weight pre-diagnosis, but, in older individuals, type 2 diabetes is less associated with weight gain, consistent with other drivers for diabetes aetiology in older adults. We have identified a substantial group of individuals who have a rapid deterioration in glycaemic control, together with weight loss, around the time of diagnosis, and who subsequently stabilise, suggesting that a high HbA1c at diagnosis is not inevitably associated with a poor outcome and may be driven by reversible glucose toxicity.

Type 1 diabetes incidence in Scotland between 2006 and 2019.

To describe type 1 diabetes incidence in Scotland between 2006 and 2019. Repeated annual cross-sectional studies of type 1 diabetes incidence were conducted. Incident cases were identified from the Scottish Care Information-Diabetes Collaboration (SCI-DC), a population-based register of people with diagnosed diabetes derived from primary and secondary care data. Mid-year population estimates for Scotland were used as the denominator to calculate annual incidence with stratification by age and sex. Joinpoint regression was used to investigate whether incidence changed during the study period. Age and sex-specific type 1 diabetes incidence over the whole time period was estimated by quintile of the Scottish Index of Multiple Deprivation (SIMD), an area-based measure, in which Q1 and Q5 denote the most and least deprived fifths of the population, respectively, with quasi-Poisson regression used to compare incidence for Q5 compared to Q1. The median (IQR) age of the study population of 14,564 individuals with incident type 1 diabetes was 24.1 (12.3-42.4) years, 56% were men, 23% were in Q1 and 16% were in Q5. Incidence of T1DM was higher in men than women overall (at around 22 and 17 per 100,000, respectively) and in under 15 year olds (approximately 40 per 100,000 in both sexes) than other age groups and was similar across the study period in all strata. There was an inverse association between socio-economic status and type 1 diabetes incidence for 15-29, 30-49 and 50+ year olds [incidence rate ratio (IRR) for Q5 compared to Q1; IRR (95% CI) 0.52 (0.47-0.58), 0.68 (0.61-0.76) and 0.53(0.46-0.61), respectively] but not for under 15 year olds [1.02 (0.92-1.12)]. Incidence of type 1 diabetes varies by age, sex and socio-economic status and has remained approximately stable from 2006 to 2019 in Scotland.

In a cohort of individuals with type 2 diabetes using the drug sulfasalazine, HbA1c lowering is associated with haematological changes.

Several small studies indicate the sulphonamide component of the drug sulfasalazine lowers HbA1c. We investigated reduction of HbA1c following incident prescription of sulfasalazine and related aminosalicylates, lacking the sulphonamide group, in an observational cohort. Individuals in the Scottish Care Information Diabetes Collaboration (SCI-Diabetes) with type 2 diabetes and incident prescription for an aminosalicylate drug (sulfasalazine, mesalazine, olsalazine or balsalazide) were identified. Baseline and 6-month HbA1c were required for eligibility, to calculate HbA1c response. To investigate association with haemolysis, change in components of full blood count was assessed. Paired t-tests compared difference in baseline and treatment HbA1c measures and other clinical variables. In all, 113 individuals treated with sulfasalazine and 103 with mesalazine (lacking the sulphonamide group) were eligible, with no eligible individuals treated with olsalazine or balsalazide. Baseline characteristics were similar. Mean (SD) HbA1c reduction at 6months was -9±16mmol/mol (-0.9±1.4%) (p<0.0001) in those taking sulfasalazine with no reduction in those taking mesalazine (2±16mmol/mol (0.2±1.4%). Sulfasalazine but not mesalazine was associated with a mean (SD) increase in mean cell volume of 3.7±5.6fl (p<0.0001) and decrease in red cell count of -0.2±0.4×10-12 /L (p<0.0001). In this observational, population-based study, sulfasalazine initiation was associated with a 6-month reduction in HbA1c . This correlated with haematological changes suggesting haemolytic effects of sulfasalazine. Haemolysis is proposed to contribute to HbA1c lowering through the sulphonamide pharmacophore. This suggests that HbA1c is not a reliable measure of glycaemia in individuals prescribed sulfasalazine.

The cost of prevalent and incident cardiovascular disease in people with type 2 diabetes in Scotland: data from the Scottish Care Information-Diabetes Collaboration.

To compare costs for three groups of people with type 2 diabetes, those at high risk of future cardiovascular disease, those without cardiovascular disease and those with established cardiovascular disease, and to also compare costs incurred by people with type 2 diabetes with an incident cardiovascular disease event with those who remain incident event-free over a 3-year period. Data about people with type 2 diabetes in Scotland were obtained from the Scottish Care Information Diabetes registry. Data linkage was used to retrieve information on healthcare utilization, care home use and deaths. Productivity effects were estimated for those of non-pensionable age. We estimated costs over 12months (prevalent cardiovascular disease) and 3years from incident cardiovascular disease event. Mean annual cost per person with established cardiovascular disease was £6900, £3300 for a person at high risk of future cardiovascular disease, and £2500 for a person without cardiovascular disease and not at high risk. In year 1, the cost of an incident cardiovascular disease event was £16 700 compared with £2100 for people without an incident event. Over 2years, the cumulative costs were £21 500 and £4200, and by year 3, £25 000 and £5900, respectively. Cardiovascular disease in people with type 2 diabetes places a significant financial burden on healthcare and the wider economy. Our results emphasize the financial consequences of cardiovascular disease prevention strategies.

Visit-to-Visit HbA1c Variability Is Associated With Cardiovascular Disease and Microvascular Complications in Patients With Newly Diagnosed Type 2 Diabetes.

To investigate the association between visit-to-visit HbA1c variability and cardiovascular events and microvascular complications in patients with newly diagnosed type 2 diabetes. This retrospective cohort study analyzed patients from Tayside and Fife in the Scottish Care Information-Diabetes Collaboration (SCI-DC) who were observable from the diagnosis of diabetes and had at least five HbA1c measurements before the outcomes were evaluated. We used the previously reported HbA1c variability score (HVS), calculated as the percentage of the number of changes in HbA1c >0.5% (5.5 mmol/mol) among all HbA1c measurements within an individual. The association between HVS and 10 outcomes was assessed using Cox proportional hazards models. We included 13,111-19,883 patients in the analyses of each outcome. The patients with HVS >60% were associated with elevated risks of all outcomes compared with the lowest quintile (for example, HVS >80 to ≤100 vs. HVS ≥0 to ≤20, hazard ratio 2.38 [95% CI 1.61-3.53] for major adverse cardiovascular events, 2.4 [1.72-3.33] for all-cause mortality, 2.4 [1.13-5.11] for atherosclerotic cardiovascular death, 2.63 [1.81-3.84] for coronary artery disease, 2.04 [1.12-3.73] for ischemic stroke, 3.23 [1.76-5.93] for heart failure, 7.4 [3.84-14.27] for diabetic retinopathy, 3.07 [2.23-4.22] for diabetic peripheral neuropathy, 5.24 [2.61-10.49] for diabetic foot ulcer, and 3.49 [2.47-4.95] for new-onset chronic kidney disease). Four sensitivity analyses, including adjustment for time-weighted average HbA1c, confirmed the robustness of the results. Our study shows that higher HbA1c variability is associated with increased risks of all-cause mortality, cardiovascular events, and microvascular complications of diabetes independently of high HbA1c.

OP96 Applying Missing Data Methods to Routine Data: A Prospective Population-Based Register of People with Diabetes

BackgroundResearch using data from large population-based datasets is often hindered by the presence of non-trivial proportions of missing data. Numerous approaches for handling missing data are available, each of which...

Incidence of Major Amputation for Diabetes in Scotland Sets a Target for Us All

In this issue, Kennon et al. (1) report the incidence of amputation in diabetes across Scotland. Their findings are expressed both in terms of the total population (which is primarily a measure of national disease burden and much influenced by the changing prevalence of diagnosed diabetes) and the population with diabetes: the “at risk” population. The advantage of expressing amputation in terms of those at risk is that the results can be used as an indication of the quality of disease management, even though the data require careful interpretation (2). Unfortunately, it is not possible to calculate incidence in the population at risk without reliable information on the prevalence of diabetes in the community or country being studied, and such information is rarely available. The study by Kennon et al. (1) is, therefore, a tribute to those who created the Scottish Care Information–Diabetes Collaboration (SCI-DC) (3). However, if a reliable national database of diabetes does not exist, other—potentially less reliable—approaches must be used, including 1 ) hospital discharge coding, which has traditionally been flawed by underrecording of diabetes but is improving with increased awareness of the contribution made by diabetes to the disease burden of all nations, and 2 ) the study of particular communities, with populations selected by health care provider or insurance/reimbursement scheme (Medicare, Veterans Health Administration [VHA], etc.) or by locality (4–7). By use of the SCI-DC database, Kennon et al. (1) report that the incidence of major amputation in people with known …

Risk of Cardiovascular Disease and Total Mortality in Adults with Type 1 Diabetes: Scottish Registry Linkage Study

Randomized controlled trials have shown the importance of tight glucose control in type 1 diabetes (T1DM), but few recent studies have evaluated the risk of cardiovascular disease (CVD) and all-cause mortality among adults with T1DM. We evaluated these risks in adults with T1DM compared with the non-diabetic population in a nationwide study from Scotland and examined control of CVD risk factors in those with T1DM. The Scottish Care Information-Diabetes Collaboration database was used to identify all people registered with T1DM and aged ≥20 years in 2005-2007 and to provide risk factor data. Major CVD events and deaths were obtained from the national hospital admissions database and death register. The age-adjusted incidence rate ratio (IRR) for CVD and mortality in T1DM (n = 21,789) versus the non-diabetic population (3.96 million) was estimated using Poisson regression. The age-adjusted IRR for first CVD event associated with T1DM versus the non-diabetic population was higher in women (3.0: 95% CI 2.4-3.8, p<0.001) than men (2.3: 2.0-2.7, p<0.001) while the IRR for all-cause mortality associated with T1DM was comparable at 2.6 (2.2-3.0, p<0.001) in men and 2.7 (2.2-3.4, p<0.001) in women. Between 2005-2007, among individuals with T1DM, 34 of 123 deaths among 10,173 who were <40 years and 37 of 907 deaths among 12,739 who were ≥40 years had an underlying cause of death of coma or diabetic ketoacidosis. Among individuals 60-69 years, approximately three extra deaths per 100 per year occurred among men with T1DM (28.51/1,000 person years at risk), and two per 100 per year for women (17.99/1,000 person years at risk). 28% of those with T1DM were current smokers, 13% achieved target HbA(1c) of <7% and 37% had very poor (≥9%) glycaemic control. Among those aged ≥40, 37% had blood pressures above even conservative targets (≥140/90 mmHg) and 39% of those ≥40 years were not on a statin. Although many of these risk factors were comparable to those previously reported in other developed countries, CVD and mortality rates may not be generalizable to other countries. Limitations included lack of information on the specific insulin therapy used. Although the relative risks for CVD and total mortality associated with T1DM in this population have declined relative to earlier studies, T1DM continues to be associated with higher CVD and death rates than the non-diabetic population. Risk factor management should be improved to further reduce risk but better treatment approaches for achieving good glycaemic control are badly needed. Please see later in the article for the Editors' Summary.

The effect of deprivation and HbA1c on admission to hospital for diabetic ketoacidosis in type 1 diabetes

Diabetic ketoacidosis is a potentially life-threatening complication of diabetes and has a strong relationship with HbA(1c). We examined how socioeconomic group affects the likelihood of admission to hospital for diabetic ketoacidosis. The Scottish Care Information - Diabetes Collaboration (SCI-DC), a dynamic national register of all cases of diagnosed diabetes in Scotland, was linked to national data on hospital admissions. We identified 24,750 people with type 1 diabetes between January 2005 and December 2007. We assessed the relationship between HbA(1c) and quintiles of deprivation with hospital admissions for diabetic ketoacidosis in people with type 1 diabetes adjusting for patient characteristics. We identified 23,479 people with type 1 diabetes who had complete recording of covariates. Deprivation had a substantial effect on odds of admission to hospital for diabetic ketoacidosis (OR 4.51, 95% CI 3.73, 5.46 in the most deprived quintile compared with the least deprived). This effect persisted after the inclusion of HbA(1c) and other risk factors (OR 2.81, 95% CI 2.32, 3.39). Men had a reduced risk of admission to hospital for diabetic ketoacidosis (OR 0.71, 95% CI 0.63, 0.79) and those with a history of smoking had increased odds of admission to hospital for diabetic ketoacidosis by a factor of 1.55 (95% CI 1.36, 1.78). Women, smokers, those with high HbA(1c) and those living in more deprived areas have an increased risk of admission to hospital for diabetic ketoacidosis. The effect of deprivation was present even after inclusion of other risk factors. This work highlights that those in poorer areas of the community with high HbA(1c) represent a group who might be usefully supported to try to reduce hospital admissions.

Inpatient costs for people with type 1 and type 2 diabetes in Scotland: a study from the Scottish Diabetes Research Network Epidemiology Group.

The rising prevalence of diabetes worldwide has increased interest in the cost of diabetes. Inpatient costs for all people with diabetes in Scotland were investigated. The Scottish Care Information-Diabetes Collaboration (SCI-DC), a real-time clinical information system of almost all diagnosed cases of diabetes in Scotland, UK, was linked to data on all hospital admissions for people with diabetes. Inpatient stay costs were estimated using the 2007-2008 Scottish National Tariff. The probability of hospital admission and total annual cost of admissions were estimated in relation to age, sex, type of diabetes, history of vascular admission, HbA(1c), creatinine, body mass index and diabetes duration. In Scotland during 2005-2007, 24,750 people with type 1 and 195,433 people with type 2 diabetes were identified, accounting for approximately 4.3% of the total Scottish population (5.1 million). The estimated total annual cost of admissions for all people diagnosed with type 1 and type 2 diabetes was £26 million and £275 million, respectively, approximately 12% of the total Scottish inpatient expenditure (£2.4 billion). Sex, increasing age, serum creatinine, previous vascular history and HbA(1c) (the latter differentially in type 1 and type 2) were all associated with likelihood and total annual cost of admission. Diabetes inpatient expenditure accounted for 12% of the total Scottish inpatient expenditure, whilst people with diabetes account for 4.3% of the population. Of the modifiable risk factors, HbA(1c) was the most important driver of cost in type 1 diabetes.

General practitioners' and nurses' experiences of using computerised decision support in screening for diabetic foot disease: implementing Scottish Clinical Information - Diabetes Care in routine clinical practice

The Scottish Care Information - Diabetes Collaboration (SCI-DC) developed a computer-based information system to create a shared electronic record for use by all involved in the care of patients with diabetes mellitus. The objectives of this study were to understand primary care practitioners' views towards screening for diabetic foot disease and their experience of the SCI-DC system. We conducted an exploratory study using qualitative methods. Semi-structured interviews were audiotape-recorded, transcribed and subjected to thematic analysis. Seven practice nurses and six general practitioners (GPs) with special responsibility for diabetes care in NHS Lothian participated. Primary care clinicians reported good systems in place to screen for diabetes-related complications and to refer their patients to specialist care. Foot ulceration was rarely observed; other diabetes related conditions were seen as a higher priority. Most had heard of the SCI-DC foot assessment tool, but its failure to integrate with other primary care information technology (IT) systems meant it was not used in these general practices. Adoption of the SCI-DC foot assessment tool in primary care is not perceived as clinically necessary. Although information recorded by specialist services on SCI-DC is helpful, important structural barriers to its implementation mean the potential benefits associated with its use are unlikely to be realised; greater engagement with primary care priorities for diabetes management is needed to assist its successful implementation and adoption.

Scottish Foot Ulcer Risk Score Predicts Foot Ulcer Healing in a Regional Specialist Foot Clinic

To determine whether patients developing ulcers had previously been identified as being at high risk of ulceration using the Scottish Care Information-Diabetes Collaboration (SCI-DC) ulcer risk score and whether the risk score predicts ulcer healing. All patients attending the diabetes foot clinic with an ulcer had been assessed for foot ulcer risk using the SCI-DC risk calculator, which categorizes patients into low, moderate, or high risk of ulceration. Information on foot pulses, neuropathy, foot deformity, previous ulcer, ulcer site, depth, and presence of sepsis was recorded and related to ulcer outcome. Patients were followed up until outcome was achieved (median 3 months [range 1-33]). Of patients attending the clinic with a foot ulcer (mean [+/-SD] age 67.3 +/- 12.7 years, 68% male), 68% were previously recognized to be at high risk of foot ulceration, and 98% were high or moderate risk. Of 221 ulcers, the healing rate was 75% overall but was lower for high-risk patients compared with other patients (68 vs. 93%; P < 0.0001). Of the remainder, 3% became chronic ulcers, 12% required minor or major amputation, and 10% died with their ulcer. In multivariate analysis, absent pulses, neuropathy, increased age, and deep ulcers were associated with poor healing. The combination of neuropathy and ischemia was particularly associated with poor outcome of an ulcer (61% healing). The Scottish foot ulcer risk score predicts both ulcer development and ulcer healing. The risk score can be a useful initial guide to determine the likelihood of poor healing. The individual criteria contributing to this overall risk are similar to other studies.