Predicted impact of extending the screening interval for diabetic retinopathy: the Scottish Diabetic Retinopathy Screening programme.

AIMS/HYPOTHESIS: The aim of our study was to identify subgroups of patients attending the Scottish Diabetic Retinopathy Screening (DRS) programme who might safely move from annual to two yearly retinopathy screening. METHODS: This was a retrospective cohort study of screening data from the DRS programme collected between 2005 and 2011 for people aged ≥12 years with type 1 or type 2 diabetes in Scotland. We used hidden Markov models to calculate the probabilities of transitions to referable diabetic retinopathy (referable background or proliferative retinopathy) or referable maculopathy. RESULTS: The study included 155,114 individuals with no referable diabetic retinopathy or maculopathy at their first DRS examination and with one or more further DRS examinations. There were 11,275 incident cases of referable diabetic eye disease (9,204 referable maculopathy, 2,071 referable background or proliferative retinopathy). The observed transitions to referable background or proliferative retinopathy were lower for people with no visible retinopathy vs mild background retinopathy at their prior examination (respectively, 1.2% vs 8.1% for type 1 diabetes and 0.6% vs 5.1% for type 2 diabetes). The lowest probability for transitioning to referable background or proliferative retinopathy was among people with two consecutive screens showing no visible retinopathy, where the probability was <0.3% for type 1 and <0.2% for type 2 diabetes at 2 years. CONCLUSIONS/INTERPRETATION: Transition rates to referable diabetic eye disease were lowest among people with type 2 diabetes and two consecutive screens showing no visible retinopathy. If such people had been offered two yearly screening the DRS service would have needed to screen 40% fewer people in 2009.

The effects of acute oesophageal distension on arterial blood pressure, E.C.G. and respiration in dog.

Anginal pain is a common clinical finding during cardiospasm or during pneumatic dilatation of oesophagus to relieve cardiospasm. Thus the present work was taken up to find out any relationship between the oesophagus and the cardiovascular system during experimental distension of the oesophagus in dogs. Pneumatic distension of oesophagus was done in anaesthetised dogs and its effects on arterial blood pressure, E.C.G. and respiration were studied. A fall in arterial blood pressure was observed in almost all dogs during distension. E.C.G. changes like a reduction in the 'R' wave voltage, absence of 'R' wave and a shift in the isoelectric line were observed also during distension. Moreover, oesophageal distension produced a transient apnoea in almost all animals and they seemed to be in a respiratory distress. When the distension was continued, the arterial blood pressure instead of remaining low, came back to the control or even higher level inspite of the presence of distension. Bilateral vagotomy did not abolish the hypotensive effect and E.C.G. changes but abolished the increase of blood pressure during the later part of distension. The cardiovascular changes were considered to be of a reflex nature and besides the vagi, the sympathetics seem to play an important role in this.