Biomedical subjects
Publications and source records attributed to R W Newton.
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AIMS: To examine the impact of a new national retinal screening programme on screening attendance, technical quality of images, and referrals to the ophthalmology clinic. METHODS: Results from the previous ad hoc retinal screening service were compared with data from the first year of the new Scottish Diabetes Retinal Screening Programme in Dundee, which was administered according to criteria recommended by the Health Technology Board Scotland. RESULTS: Of 5150 patients invited for screening, 10.3% of patients did not attend. Overall, 4574 patients underwent single-field digital retinal photography and 25.4% required mydriasis for an adequate image. After screening, 1.9 and 90.5% were recalled for repeat photography at 6 months and 1 year, respectively, whilst 4.6% were ungradable and 3.0% were referred to the ophthalmology clinic. Compared with the last 18 months of the previous scheme, with the new programme a smaller proportion of patients were referred to ophthalmology (3.0 vs. 5.9%; P < 0.001, difference 2.9%: 95% confidence interval 2.1-3.7%). Moreover, the attendance was higher (89 vs. 82%; P < 0.01) and there were fewer ungradable images (4.6 vs. 7.1%; P < 0.001). CONCLUSIONS: Introduction of a systematic retinal screening programme can reduce the proportion of patients referred to the ophthalmology clinic, and use ophthalmology services more efficiently.
AIMS AND METHODS: Thyroid function tests were initially carried out on 122 children with Down's syndrome aged 6-14 years and then repeated four to six years later in 103 adolescents (85% of the group of 122) when they were aged 10-20 years (median 14.4 years). At the second test two were hypothyroid and two with isolated raised thyroid stimulating hormone (IR-TSH) were receiving thyroxine. RESULTS: At the first test there were 98 (80%) euthyroid children: 83 were retested and four (5%) had IR-TSH. At the first test 24 had IR-TSH: 20 were retested and 14 (70%) had become normal. Seventeen with IR-TSH on initial testing had a thyrotrophin releasing hormone test within three months; TSH had become normal in eight (47%) of these children. There was no association between reported clinical symptoms and IR-TSH, but there were clear symptoms in one of the two with definite hypothyroidism. CONCLUSIONS: The likelihood ratio for a positive result on second testing when raised TSH and positive antibody status on first testing are combined is 20. This suggests initial testing results could be used as a basis to select a subgroup for further testing at say five yearly intervals unless new symptoms emerge in the interim. It also suggests that yearly screening (as recommended by the American Academy of Pediatrics, 2001) is probably not justified in the first 20 years of life.
OBJECTIVES: To study serial measures of maximum QT interval corrected for heart rate (QTc) and QT dispersion (QTD) and their association with cardiac mortality patients with non-insulin dependent diabetes and to compare QT abnormalities with other mortality predictors (ankle brachial pressure index (ABPI) and autonomic function tests) in their ability to predict cardiac death. SETTING: Teaching hospital. METHODS AND PATIENTS: QT interval analysis, heart rate (RR) variation in response to deep breathing and standing, and ABPI were analysed in 192 patients with non-insulin dependent diabetes. Cardiac death was the primary end point. RESULTS: Mean (SD) follow up was 12.7 (3.2) years (range 1.2-17.1 years). There were 48 deaths, of which 26 were cardiac. QTc and QTD were individually significant predictors of cardiac mortality throughout the follow up period (p < 0.001). The predictability of QT parameters was superior to the predictability of ABPI and RR interval analysis. Temporal changes in QT parameters showed that the mean absolute QT parameter was a significant predictor of cardiac death (p < 0.001), whereas an intraindividual change in QT parameter over time was not predictive. CONCLUSION: QT abnormalities seem to exist at the point of diagnosis of diabetes and do not appear to change between then and the subsequent cardiac death. Furthermore, the analysis of QT interval is superior to ABPI and the RR interval in identifying diabetic patients at high risk of cardiac death.
The potential efficacy of temporal and extratemporal resection in patients with partial epilepsy uncontrolled by anti-epileptic drugs is undisputed. However, there are still uncertainties about which patients will benefit most. A systematic review of the available literature has been undertaken by four pairs of reviewers to assess the overall outcome of epilepsy surgery and to identify factors better correlated to seizure outcome. A Medline search for studies on epilepsy surgery published since 1984 was performed. Studies were included if they had a well-defined population and design, a sample size of at least 30 patients, an MRI performed in least 90% of cases, an expected duration of follow-up of at least one year, and a post-operative outcome measured as seizure remission. A good outcome was considered as seizure control or seizure-free status for at least one year or Engel class I. Based on the review of 47 articles meeting all the eligibility criteria, febrile seizures (odds ratio, OR, 0.48; 95% confidence interval, CI, 0.27-0.83), mesial temporal sclerosis (OR 0.47; 95% CI 0.35-0.64), tumors (OR 0.58; 95% CI 0.42-0.80), abnormal MRI (OR 0.44; 95% CI 0.29-0.65), EEG/MRI concordance (OR 0.52; 95% CI 0.32-0.83), and extensive surgical resection (OR 0.24; 95% CI 0.16-0.36) were the strongest prognostic indicators of seizure remission (positive predictors); by contrast, post-operative discharges (OR 2.41; 95% CI 1.37-4.27) and intracranial monitoring (OR 2.72; 95% CI 1.60-4.60) predicted an unfavorable prognosis (negative predictors). Firm conclusions cannot be drawn for extent of resection, EEG/MRI concordance and post-operative discharges for the heterogeneity of study results. Neuromigrational defects, CNS infections, vascular lesions, interictal spikes, and side of resection did not affect the chance of seizure remission after surgery. Despite a number of limitations, the results of the review provide some insight into the selection of the best surgical candidates in clinical practice but raise concerns on the quality of published reports, and may serve as the basis for the identification of better standards to assess surgical outcome in observational studies.
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AIMS: To estimate the incidence of death and macrovascular complications after a first myocardial infarction for patients with Type 2 diabetes. RESEARCH DESIGN: In a retrospective, incidence cohort study in the Tayside Region of Scotland we studied all patients hospitalized with a diagnosis of first acute myocardial infarction from 1 April 1993 to 31 December 1994. The primary endpoint was time to death. Secondary endpoints were 2-year incidence of hospital admission for angina, myocardial infarction, stroke, heart failure, coronary angiography, coronary artery bypass graft (CABG) and percutaneous transluminal coronary angioplasty (PTCA). RESULTS: The 147 patients with Type 2 diabetes had significantly worse survival with an increase in relative hazard of 67% compared with non-diabetic patients. After adjustment for age, sex, smoking status, prior heart failure, prior angina, delay to hospitalization, site of infarction, drug therapy with aspirin, beta-blockers, streptokinase and hyperlipidaemia and treated hypertension, Type 2 diabetes was still associated with a 40% higher death rate compared with people without diabetes (P < 0.05) There was no significant difference in death rates in those aged over 70 years, but an indication of a trend in younger individuals with a four-fold increase in death rate in those with diabetes aged < 60 years, compared with a rate ratio of 2.6 in those with diabetes aged 61-70 years. CONCLUSIONS: Among hospitalized patients with first acute myocardial infarction, Type 2 diabetes mellitus is consistently associated with increased mortality and increased hospital admission for heart failure. The estimated 4-year survival rate is only 50%. Our results indicate that younger subjects with Type 2 diabetes and acute myocardial infarction are a high-risk group deserving of special study, and support the argument for aggressive targeting of coronary risk factors among patients with Type 2 diabetes.
AIMS: To determine the changes in oral hypoglycaemic therapy and the time to incidence of insulin therapy in people with Type 2 diabetes. METHODS: A retrospective incidence cohort was constructed of 1305 subjects with Type 2 diabetes, who obtained a first prescription for oral hypoglycaemic medication between 1 July 1993 and 31 December 1994 in Tayside, Scotland. The primary endpoint of changes in oral hypoglycaemic therapy and time to insulin was determined up to the end of the follow-up, on 31 December 1995. RESULTS: Overall, 9.4% of subjects switched to insulin, while 11% of those initially on sulphonylurea, and 6% of those initially on metformin switched to insulin therapy. Approximately three-quarters (72%) remained on the same class of drug throughout the study period (median follow-up 588 days). Only 9% died during the follow-up and this did not differ appreciably by drug group. Males were more likely to switch to insulin compared with females (10.3% vs. 8.5%), and those who switched were slightly younger with a mean age of 58 years compared with a mean age of 60 years of those who did not switch. The median time of switching to insulin was 186 days or approximately 6 months for this cohort, giving a rate of switching to insulin of 5.84% per year. Poorer glycaemic control (HBA1c) and low body mass index (BMI) were associated with switching to insulin. CONCLUSIONS: Following initial therapy with oral hypoglycaemic medication in the population, switching to insulin occurred at a rate of 5.84% per year. Switching to insulin was associated with being younger, male, having low BMI and higher HbA1c.
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OBJECTIVES: To investigate the relationship between in-shoe plantar foot pressure and the co-ordinated activity of five lower limb muscles of diabetic patients, who are known to have a higher risk of foot morbidity. DESIGN: A portable six channel electromyographic system has been designed, developed and synchronised in real time with a 16 channel piezoelectric transducer in-shoe pressure measuring device, Gaitscan. BACKGROUND: So far, no one has tried to establish a relationship between in-shoe foot pressure distribution and muscle activity of the lower limb in diabetes. The measurement of phasic muscle activity has been related to foot pressure and compared to a control group of normal volunteers. METHODS: Twenty nine diabetic subjects and 22 healthy non-diabetic volunteers have been studied by recording electromyography of lower leg muscles and in-shoe foot pressure measurements simultaneously. RESULTS: In diabetic subjects, the period of contact pressure was greater than in normal control subjects (P<0.003). The initial forefoot time to contact with the ground was shorter in diabetics when compared to controls, indicating a faster forefoot contact. Of the dorsiflexor muscles, the Anterior Tibialis, normally contracting eccentrically at heel strike, was subject to a measurable delay in the initiation of contraction, of mean difference of 180 ms (P<0.001), in diabetic subjects when compared to the normal controls. CONCLUSIONS: The late firing of Tibialis Anterior means that its normal modulating role in lowering the foot to the ground after heel strike through eccentric contraction is disturbed. The result is that the foot reaches the foot flat stage in a less ordered manner, subjecting it to high plantar pressures. RELEVANCE: The results obtained may assist in planning realignment procedures of the foot and help prevent development of ulcers on the sole of the foot in high risk diabetic subjects.
To investigate the hypothesis that diabetes induces nephrogenic diabetes insipidus, we studied the urine-concentrating ability in response to vasopressin (AVP) in 12 patients with insulin-dependent diabetes mellitus (IDDM) and 12 nondiabetic controls. Subjects were euglycemic-clamped, and after oral water loading, AVP was infused intravenously for 150 min. AVP induced a greater (P<0.001) rise in urine osmolality in controls (67.6+/-10.7 to 720+/-31.1 mosmol/kg, P<0.001) than in IDDM patients (64.3+/-21.6 to 516.7+/-89.3 mosmol/kg, P<0.001). Urinary aquaporin-2 concentrations after AVP infusion were higher in controls (611.8+/-105.6 fmol/mg creatinine) than in IDDM (462.0+/-94.9 fmol/mg creatinine, P = 0. 003). Maximum urine osmolality in IDDM was inversely related to chronic blood glucose control, as indicated by Hb A(Ic) (r = -0.87, P = 0.002). To test the hypothesis that improved glycemic control could reverse resistance to AVP, 10 IDDM subjects with poor glycemic control (Hb A(Ic) >9%) were studied before (B) and after (A) intensified glycemic control. Maximum urine osmolality in response to AVP increased with improved glycemic control (B, 443.8+/-49.0; A, 640.0+/-137.2 mosmol/kg, P<0.001), and urinary aquaporin-2 concentrations after AVP increased from 112.7 +/-69 to 375+/-280 fmol/mg creatinine (P = 0.006), with improved glycemic control. Poorly controlled IDDM is associated with reversible renal resistance to AVP.
AIMS: The influence of socio-economic status on the prevalence of Type 1 and Type 2 diabetes mellitus, and on obesity, was explored using routinely collected healthcare data for the population of Tayside, Scotland. METHODS: Among 366,849 Tayside residents, 792 and 5,474 patients with Type 1 and Type 2 diabetes, respectively, were identified from a diabetes register. The Carstairs Score was used as a proxy for socio-economic status. This is a material deprivation measure derived from the UK census, using postcode data for four key variables. Odds ratios for diabetes prevalence, adjusted for age, were determined for each of six deprivation categories (1 - least deprived, 6/7 - most deprived). The mean body mass index (BMI) in each group was also determined, and the effect of deprivation category explored by analysis of covariance, adjusting for age and sex. RESULTS: The prevalence of Type 2 diabetes, but not Type 1 diabetes, varied by deprivation. People in deprivation category 6 and 7 were 1.6-times (95% confidence interval 1.4-1.8) more likely to have Type 2 diabetes than those least deprived. There was no relationship between deprivation and BMI in Type 1 diabetes (P = 0.36), but there was an increase in BMI with increasing deprivation in Type 2 diabetes (P < 0.001; test of linearity P < 0.001). CONCLUSIONS: The study confirms the relationship between deprivation and the prevalence of Type 2 diabetes. There are more obese, diabetic patients in deprived areas. They require more targeted resources and more primary prevention.
OBJECTIVES: To investigate patterns of self monitoring of blood glucose concentration in diabetic patients who use insulin and to determine whether frequency of self monitoring is related to glycaemic control. SETTING: Diabetes database, Tayside, Scotland. SUBJECTS: Patients resident in Tayside in 1993-5 who were using insulin and were registered on the database and diagnosed with insulin dependent (type 1) or non-insulin dependent (type 2) diabetes before 1993. MAIN OUTCOME MEASURES: Number of glucose monitoring reagent strips dispensed (reagent strip uptake) derived from records of prescriptions. First recorded haemoglobin A1c concentration in the study period, and reagent strips dispensed in the previous 6 months. RESULTS: Among 807 patients with type 1 diabetes, 128 (16%) did not redeem any prescriptions for glucose monitoring reagent strips in the 3 year study period. Only 161 (20%) redeemed prescriptions for enough reagent strips to test glucose daily. The corresponding figures for the 790 patients with type 2 diabetes who used insulin were 162 (21%; no strips) and 131 (17%; daily tests). Reagent strip uptake was influenced both by age and by deprivation category. There was a direct relation between uptake and glycaemic control for 258 patients (with recorded haemoglobin A1c concentrations) with type 1 diabetes. In a linear regression model the decrease in haemoglobin A1c concentration for every extra 180 reagent strips dispensed was 0.7%. For the 290 patients with type 2 diabetes who used insulin there was no such relation. CONCLUSIONS: Self monitoring of blood glucose concentration is associated with improved glycaemic control in patients with type 1 diabetes. Regular self monitoring in patients with type 1 and type 2 diabetes is uncommon.
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AIMS/HYPOTHESIS: To test the hypothesis that subnormal thirst sensation could contribute to the development of the hypernatraemia characteristic of hyperosmolar coma, we studied osmoregulation in survivors of hyperosmolar coma. METHODS: Eight survivors of hyperosmolar coma, eight control subjects with Type II (non-insulin-dependent) diabetes mellitus and eight healthy control subjects underwent water deprivation during which measurements of thirst, plasma osmolality and vasopressin were taken. RESULTS: Water deprivation caused greater peak plasma osmolality in the hyperosmolar coma group (301.7 +/- 2.7 mmol/kg) than in Type II diabetic (294.3 +/- 3.2 mmol/kg, p < 0.01) or control group (296.9 +/- 3.0 mmol/kg, p < 0.01) and a greater increase in plasma vasopressin concentration (hyperosmolar coma, 5.8 +/- 1.3 pmol/l, Type II diabetes, 1.8 +/- 1.3 pmol/l, p < 0.001, control subjects, 2.2 +/- 1.8 pmol/l, p < 0.001). Thirst ratings were lower following water deprivation in the hyperosmolar coma group (3.5 +/- 0.8 cm) than in Type II diabetes (7.7 +/- 1.6 cm, p < 0.001) or control subjects (7.4 +/- 1.3 cm, p <0.001), and the hyperosmolar group patients drank less in 30 min following water deprivation (401 +/- 105 ml) than Type II diabetic (856 +/- 218 ml, p < 0.001) or control subjects (789 +/- 213 ml, p < 0.001). CONCLUSION/INTERPRETATION: Survivors of hyperosmolar coma have subnormal osmoregulated thirst and fluid intake, which might contribute to the hypernatraemic dehydration typical of the condition.
PURPOSE: Detection of diabetic retinopathy by screening is a major public health concern. Fundus photography has been shown to be a useful screening tool for the detection of diabetic retinopathy. In this paper the authors assess the incidence of blind and partially sighted registration due to diabetic eye disease in patients screened by a mobile fundus photography unit and identify the factors that contributed to loss of vision in the registered group. METHODS: A retrospective review of blind and partially sighted registrations between 1990 and 1995 was performed in a diabetic population screened by a mobile fundus photography unit in a region with a population of 390,000. The incidence of blind and partially sighted registration in the screened diabetic population was calculated. In the registered group, cause of visual loss, accuracy of photograph reporting, delay in laser treatment, adequacy of laser treatment and non-attendance rates at ophthalmic clinics were assessed. RESULTS: Of the 5390 patients screened by the mobile unit over 6 years, 68 (210 per 10(5) patient-years) were registered blind or partially sighted, but in only 17 patients (53 per 10(5) patient-years) was this as a result of diabetes. The factors contributing to loss of vision were found to be failure of laser treatment, rapidly progressive disease and poor patient attendance. CONCLUSIONS: As the majority of visual impairment in patients with diabetes is not due to diabetic retinopathy, this has important implications for screening programmes and may make the St Vincent Declaration targets difficult to achieve. The rate of new blind and partially sighted registration due to diabetes in the screened population was low at 53 per 10(5) patient-years (95% confidence interval, 29-76).
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