1,721,015 research outputs found
Florence Nightingale diagrams of deaths in England & Wales
No full textWhen time-series data is plotted as a normal x-y plot with the time variable along the x axis it is difficult to identify seasonality or other factors that may influence the data.
Florence Nightingale used a form of radial plots to display data from the Crimean War and to demonstrate that better hygiene would reduce the death rate amongst soldiers could be reduced by better hygiene.
Plotting the weekly numbers of deaths using this radial form demonstrates the variability during the first months of the year – deaths from “Aussie flu” in the first weeks of 2018. The increase in the number of deaths from the first week in April 2020 can clearly be seen.
Radial plots are available in all the main stats packages (Radar plots in Excel, several procedures in R, proc gradar in SAS, RADAR in STATA)
Rapid and simultaneous detection of multiple mutations by pooled and multiplex single nucleotide primer extension: Application to the study of insulin-responsive glucose transporter and insulin receptor mutations in non-insulindependent diabetes
No full textThe application of molecular scanning techniques to the detection of potentially pathogenic mutations in candidate genes in patients with non-insulin-dependent diabetes has revealed a number of molecular variants of uncertain pathophysiologic significance. The determination of the significance of such variants requires large-scale population studies of the prevalence of the mutant in affected and control groups. Herein, we describe two adaptations of the technique of single nucleotide primer extension (SNuPE) which allow the simultaneous examination of large numbers of alleles at multiple loci. The usefulness of these adaptations is illustrated by their application to the simultaneous detection of three point mutations, two in the tyrosine kinase domain of the insulin receptor and one in the insulin-responsive glucose transporter(GLUT4)in a highly insulin-resistant NIDDM population. By pooling genomic or amplified DNA and performing the SNuPE reactions with three primers of different length we could readily examine 300 alleles on a single 20 lane gel. Using pooled SNuPE, we also examined a large British Caucasian control population for the prevalence of GLUT4II e 383, a variant which has previously been reported only in NIDDM. GLUT4 II e 383 was detected in 2/42 of the highly insulin-resistant NIDDM subjects and 4/240 middleaged blood donors. Family studies and examination of the expressed mutant transporter will be necessary to establish whether this mutation is of functional significance. Pooled and multiplex SNuPE are powerful techniques with wide applicability to population genetic studies of specific mutaitions.</p
UKPDS58: modeling glucose exposure as a risk factor for photocoagulation in type 2 diabetes
No full textIn type 2 diabetes, the risk of retinopathy, and of retinal photocoagulation, rises with time after diagnosis of diabetes. In this paper, mathematical modeling shows that this ageing effect is attributable to the rise in glycemia with time since diagnosis of diabetes. Mathematical models were fitted to data from 3648 patients from the UK Prospective Diabetes Study (UKPDS). A proportional hazards model, in which time and glycemia measured by HbA1c are independent risk factors for photocoagulation, was compared to a model in which time does not contribute except through a measure of cumulative glucose exposure. Since likelihood ratio tests cannot be applied to non-nested models, graphical methods were used to compare the two models. The glucose exposure model was able to fit variation in survival with time at least as well as the proportional hazards model. The proportional hazards model, however, seriously underestimates the differences in two groups of different mean HbA1c. We conclude that duration of diabetes and HbA1c level better predict risk for photocoagulation when treated as two components of cumulative glucose exposure, than when treated as independent risk factors.</p
Epidemiological issues in diabetic retinopathy.
No full textThere is currently an epidemic of diabetes in the world, principally type 2 diabetes that is linked to changing lifestyle, obesity, and increasing age of the population. Latest estimates from the International Diabetes Federation (IDF) forecasts a rise from 366 million people worldwide to 552 million by 2030. Type 1 diabetes is more common in the Northern hemisphere with the highest rates in Finland and there is evidence of a rise in some central European countries, particularly in the younger children under 5 years of age. Modifiable risk factors for progression of diabetic retinopathy (DR) are blood glucose, blood pressure, serum lipids, and smoking. Nonmodifiable risk factors are duration, age, genetic predisposition, and ethnicity. Other risk factors are pregnancy, microaneurysm count in an eye, microaneurysm formation rate, and the presence of any DR in the second eye. DR, macular edema (ME), and proliferative DR (PDR) develop with increased duration of diabetes and the rates are dependent on the above risk factors. In one study of type 1 diabetes, the median individual risk for the development of early retinal changes was 9.1 years of diabetes duration. Another study reported the 25 year incidence of proliferative retinopathy among population-based cohort of type 1 patients with diabetes was 42.9%. In recent years, people with diabetes have lower rates of progression than historically to PDR and severe visual loss, which may reflect better control of glucose, blood pressure, and serum lipids, and earlier diagnosis
Disengagement and loss to follow-up in intravitreal injection clinics for neovascular age-related macular degeneration
Full text linkBackground/Objectives
Timely assessment and treatment of patients with neovascular AMD (nAMD) are crucial to preservation of vision. Loss to follow up (LTFU) in these patients is a problem but this has not been systematically investigated.
Subjects/Methods
A retrospective review of electronic medical records of patients with nAMD first treated with anti-VEGF therapy from 1st Jan 2014 to 31st Dec 2018, was conducted in January 2021. Any patient not seen for more than 12 months was classed as no longer attending.
Results
Of the 1328 patients who attended between 2014 and 2018, 348 had failed to attend and were eligible for inclusion in this study. Reasons noted for discontinuation of care: discharged by clinician (33.3%), died (20.7%), moved to another unit outside of area (17.5%), stopped attending due to ill-health (13.5%), discharged due to failure to attend (5.6%) and patient choice to no longer attend (4.6%). There were 16 (4.6%) who did not receive any further appointments despite clinician request for follow-up. After 5 years, 50.5% of patients were no longer attending for treatment. Age was a factor in failure to attend, with 7 out of 12 patients aged >100 years no longer being followed up, compared to 1 out of 11 of 50–59 year-olds.
Conclusions
When analysing visual outcomes in an AMD service it is important to characterise the patients who are lost to follow up. The outcomes for this group may be avoidably poor and understanding the factors influencing LTFU rate is crucial to addressing shortcomings in a hospital AMD service
Repeated significance tests for clinical trials with a fixed number of patients and variable follow-up.
No full textGroup-sequential tests may be applied to trials in which the number of patients is fixed, a response variable is measured for each patient at successive follow-up visits, and the accumulated responses are compared across treatment groups. The standard theory is inapplicable because the increments in the accumulated responses are no longer independent. An adjustment can be made to allow for the ratio of between-patient to within-patient variance and for possible first-order autocorrelation. The method is illustrated by reference to a dental trial
Macula service evaluation and assessing priorities for anti-VEGF treatment in the light of COVID-19
No full textPurpose: to assess the treatment position of all patients who have had an anti-VEGF injection in 2020, prior to the UK lockdown on 23 March. To assess methods of service quality evaluation in setting benchmarks for comparison after the situation stabilized. To consider what proportion could be delayed based on national guidelines and varying vision parameters. Finally, to measure how many patients actually attended. Method: a retrospective analysis of data collected from our electronic medical record was performed. Age, sex, reason for injection, visual acuity (VA) for both treated and untreated eyes and number of injections were recorded. The proportion of patients and eyes with ≥ 70 letters were calculated as an assessment of quality of service provision. The proportion of patients that could be delayed was estimated based on published guidelines and varying the parameters of difference between treated and untreated eyes. Finally, the number of patients who actually attended was recorded. Results: about 3364 eyes (2229 neovascular age-related macular degeneration (nAMD), 427 diabetic macular oedema (DMO), 599 retinal vein occlusion (RVO) and 109 other) from 2924 patients were analysed. At the last appointment with injection, 64.4% of patients achieved ≥ 70 letters in their better-seeing eye. Mean VA of the treated eye was 61.5 letters, and 36.9% achieved ≥ 70. The mean number of injections was 16, 90% with aflibercept. Of the patients receiving treatment to one eye, 57.6% was receiving treatment to their worse seeing eye. In 18.2% this eye was > 20 letters worse and in 5.07% > 40 letters worse than the untreated eye. Using Royal College of Ophthalmologists (RCOphth) guidelines, (treat nAMD 8 weekly, delay majority of RVO and DMO) 24.8% would be delayed. From 2738 appointments during the first 4 weeks of lockdown (booked prior to lockdown), doctors rescheduled 1025 and patients did not attend 820, leaving 893 who were seen (33%). Conclusions: assessing the treatment position of patients prior to COVID-19 lockdown enables objective stratification for prioritization for continued treatment. If RCOphth guidelines were followed 24.8% could be delayed and if treating the worse seeing eye up to 57.6%. Many scheduled patients elected not to attend, with 67% not seen in the first 4 weeks. The impact of non-attendance and delays may be evaluated later.</p
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