The prognostic value of albuminuria for the development of cardiovascular disease and retinopathy: a 5-year follow-up of 451 patients with type 2 diabetes mellitus

The aim of the present study was to evaluate the risk for vascular morbidity or death and retinopathy in relation to urinary albumin concentration. To that end, we performed a 5-year follow-up study of all type 2 diabetic patients attending the outpatient-clinic. A total of 444 (98.4%) out of 451 adult patients initially studied were evaluated for the degree of retinopathy and levels of HbA1c blood pressure, serum creatinine and urinary albumin. Vascular morbidity and causes of death were registered by one and the most severe event only. Forty-seven patients developed atherosclerotic vascular disease, i.e. myocardial infarction (n = 19), cerebrovascular disease (n = 20), or amputation (n = 8), and 42 died. The observed annual mortality rate was 22.1/1000 compared to an expected rate of 13.6/1000 for the general population with corresponding age and sex. Urinary albumin concentration was found to be a prognostic marker for the development of vascular disease and death in patients treated with insulin at baseline (P < 0.01), whereas this was not the case in patients treated with diet and/or oral agents at baseline. However, insulin treatment per se was not associated with an increased mortality or mortality or morbidity. Urinary albumin concentration was not correlated with incidence or progression of retinopathy regardless of type of diabetes treatment. In conclusion, this study showed that albuminuria was a prognostic factor for vascular morbidity and death in type 2 diabetic patients treated with insulin but not in patients treated with diet or oral agents. Furthermore, albuminuria was not a predictor for incidence or progression of retinopathy.

The importance of early diagnosis of treatable diabetic retinopathy for the four-year visual outcome in older-onset diabetes mellitus

The four-year visual outcome was retrospectively studied in patients with older-onset diabetes mellitus and diabetic retinopathy in need of laser treatment. Visual acuity in 53 patients examined by ophthalmologists who referred the patients for an evaluation of retinopathy before laser treatment, was compared to that of 47 patients examined by ophthalmologists who also performed the photocoagulation. The number of eyes that became blind (visual acuity < or = 6/60) during the four-year period was higher (23/90 vs 9/91; p < 0.01) among referred patients, whereas the number of retinal examinations per patient during the three-year period prior to laser treatment did not differ between the two groups. Among referred patients, 13% had not been ophthalmologically examined before the treatment-requiring retinopathy was found. Corresponding figure for those examined at the laser centre was 23%. Severe macular oedema in regularly examined patients was more common among referred patients (9/30 vs 1/32; p < 0.01). The results indicate that screening for diabetic retinopathy in older-onset diabetes was not performed satisfactorily. In addition, laser treatment was delayed in older-onset diabetic patients controlled by ophthalmologists who referred patients for photocoagulation, resulting in an increased incidence of legally blind eyes. The study also stresses the importance of carrying out knowledge of when and how to diagnose early sight-threatening diabetic retinopathy to ophthalmologists referring patients for laser treatment.

Restitution of neurophysiological functions, performance, and subjective symptoms after moderate insulin-induced hypoglycaemia in non-diabetic men

The restoration of cognitive function was studied in 10 healthy men aged 26 years (25.5 +/- 1.2 years; mean +/- SD) after insulin-induced hypoglycaemia (arterialized blood glucose 2.5 +/- 0.4 mmol l-1) for 62 +/- 8 min. Another group of six men participated in a single blind sham study for comparison. The hypoglycaemic event caused a significant increase (p = 0.006) in serum adrenaline levels. Ratings of adrenergically mediated symptoms increased during hypoglycaemia (p = 0.006), as did neuroglycopenic symptoms (p = 0.002), although neuroglycopenia ratings increased in both studies. During hypoglycaemia, P300 amplitudes in a relatively demanding visual search task decreased (p = 0.02), whereas easier tasks were unaffected. The amplitudes were restored after 40 min of normoglycaemia. Reaction time deteriorated after restoration of normoglycaemia, suggesting an effect of hypoglycaemia on learning. Thus, hypoglycaemia at a blood glucose level that is common among patients treated with insulin causes clear cognitive dysfunction, although restoration of the cognitive dysfunction to normal was fast.

Greater reduction of urinary albumin excretion in hypertensive type II diabetic patients with incipient nephropathy by lisinopril than by nifedipine

A double-blind, randomised, parallel group, multicentre, multinational study compared the effects of 12 months' treatment with lisinopril (10-20 mg once daily) or nifedipine retard tablets (20-40 mg twice daily) in 239 males (aged 18-75 years) and 96 post-menopausal females (aged 40-75 years). They all had a history of clinically stable type II diabetes > 3 months, microalbuminuria and early diabetic nephropathy (a urinary albumin excretion (UAE) rate ranging from 20 to 300 micrograms/min) and a sitting diastolic blood pressure (DBP) 90-100 mm Hg (Korotkoff phase V) inclusive at both entry and after 3-4 weeks' placebo treatment. The aim of treatment was to achieve a reduction in sitting DBP to < 90 mm Hg 24-30 h after the last dose of lisinopril or 12-18 hours after the last dose of nifedipine and to evaluate the effect of these treatments on UAE over 12 months. The effect of the two treatments on ambulatory blood pressure (BP) was also evaluated in a subset of patients. Management of diabetes with oral hypoglycaemic drugs, diet and insulin alone or in combination was permitted. Median UAE fell on lisinopril from 65.5 (range 20-297) micrograms/min at baseline to 39.0 (2-510) micrograms/min after 12 months. On nifedipine median UAE fell from 63.0 (range 20-289) micrograms/min at baseline to 58.0 (9-1192) micrograms/min after 12 months. The estimated median difference between the effects of the two treatments was 20 micrograms/min (P = 0.0006). Over 12 months both treatments produced similar falls in sitting BP from 163 +/- 17/99 +/- 6 mm Hg (mean +/- s.d.) to 147 +/- 18/88 +/- 10 mm Hg for lisinopril and from 161 +/- 18/97 +/- 5 mm Hg to 150 +/- 18/88 +/- 9 mm Hg for nifedipine. Ambulatory BP was assessed in a subset of patients and using areas under the BP-time curve (AUC) a comparison of the effects of the two treatments showed no between-treatment differences. Creatinine clearance, glycaemic control (HbA1c) and lipid profiles did not change significantly during either treatment. Frequency of withdrawals and adverse events were similar for both treatments. We conclude that lisinopril has a significantly more beneficial effect on UAE than nifedipine despite similar effects on both BP and glycaemic control in type II diabetic patients with hypertension.

Plasma beta-hexosaminidase isoenzymes A and B exhibit different relations to blood glucose levels in a population of Type 1 diabetic patients

The activity of lysosomal enzymes, such as beta-hexosaminidase (Hex), is increased in the plasma and serum of diabetic patients. A positive association has been shown between enzyme activity and glycated proteins, indicating an association with the degree of metabolic control. Several isoenzymes of Hex exist. Studies have reported different proportions of the isoenzymes in plasma from diabetic patients, compared with healthy subjects. In the present study, Hex isoenzymes were examined in 76 Type 1 diabetic patients, of mean age 37.4 years (SD 12.9) compared with 38 age- and sex-matched healthy control subjects in an attempt to evaluate the influence of long- and short-term changes in blood glucose levels on these isoenzymes. The results show that Hex A activity (p<0.01), but not Hex B activity, was higher in the diabetic patients. Hex A activity was positively associated with both the actual blood glucose levels (r = 0.48, p<0.001) and haemoglobin A1c (HbA1c) (r = 0.43, p<0.001), while Hex B activity was associated with the level of HbA1c only (r = 0.42, p<0.001). Both Hex A and B activities were also positively associated with early signs of diabetic nephropathy (e.g. urinary excretion of Hex, fractional albumin excretion ratio and urinary albumin). There was no association between Hex A and B activities and different degrees of retinopathy. In conclusion, the present study demonstrates an association between Hex A and B and metabolic parameters in diabetes as well as with clinical signs of early diabetic nephropathy, but no association with the degree of retinopathy. Furthermore, Hex A seems to be more influenced than Hex B by short-term changes in blood glucose levels.

Decreasing incidence of major amputation in diabetic patients: a consequence of a multidisciplinary foot care team approach?

The purpose of this retrospective study was to evaluate the changes in diabetes-related lower extremity amputations following the implementation of a multidisciplinary programme for prevention and treatment of diabetic foot ulcers in a 0.2 million population with a 2.4% prevalence of diabetes. All diabetes-related primary amputations from toe to hip from 1 January 1982 to 31 December 1993 were included. In 294 diabetic patients, 387 primary major (above the ankle) or minor (through or below the ankle) amputations were performed, constituting 48% of all lower extremity amputations. The annual number of amputations at all levels decreased from 38 to 21, equalling a decrease of incidence from 19.1 to 9.4/100,000 inhabitants (p = 0.001). The incidence of major amputations decreased by 78% from 16/1 to 3.6/100,000 inhabitants (p < 0.001). The absolute number of amputations with a final level below the ankle showed no increase, but their proportion increased from 28 to 53% (p < 0.001) and the reamputation rate decreased from 36 to 22% (p < 0.05) between the first and last 3-year period. Thus, a substantial long-term decrease in the incidence of major amputations was seen as well as a decrease in the total incidence of amputations in diabetic patients. Seventy-one per cent of the amputations were precipitated by a foot ulcer. These findings indicate that a multidisciplinary approach plays an important role to reduce and maintain a low incidence of major amputations in diabetic patients.

The cerebral vascular response to a rapid decrease in blood glucose to values above normal in poorly controlled type 1 (insulin-dependent) diabetes mellitus

The effect of rapid lowering of blood glucose on cerebral blood flow (CBF) was studied in 10 Type 1 (insulin-dependent) diabetic patients (age 23.5 +/- 3.8 years; mean +/- S.D.) with longstanding, poor metabolic control (HbAlc 11.2 +/- 1.0%; normal value 4.0-5.3%) using an intravenous xenon 133 single photon emission computed tomography technique. After a fall in blood glucose, during 81 +/- 11 min (mean +/- S.E.M.), from 18.2 +/- 1.4 mmol/l to 9.2 +/- 0.9 mmol/l CBF was unchanged, but increased from its initial value of 48.8 +/- 2.9 ml/100 g per min to 57.1 +/- 2.4 ml/100 g per min (P < 0.001) when the blood glucose level was restored. The CBF was higher in the right compared to the left hemisphere at all measurements (1.8 +/- 0.5 ml/100 g per min, P < 0.01; 1.9 +/- 0.5 ml/100 g per min, P < 0.05; 2.1 +/- 0.7 ml/100 g per min, P < 0.05, respectively). The change in CBF was inversely correlated with time for fall of blood glucose, but there was no correlation with absolute levels of blood glucose. The respiratory end-tidal PCO2 decreased during the low blood glucose level, but there was no correlation between the PCO2 and CBF. The cerebral volume was unchanged during the study. The results indicate that in patients with chronic hyperglycemia a rapid fall in blood glucose may cause a rise in CBF of the same magnitude as previously shown during absolute hypoglycemia in patients with well controlled diabetes mellitus and in normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical characteristics in relation to final amputation level in diabetic patients with foot ulcers: a prospective study of healing below or above the ankle in 187 patients

The aim of this study was to describe the clinical characteristics in relation to final amputation level in diabetic patients with foot ulcers. In a prospective series, 187 consecutively presenting patients were investigated. From admission until final outcome, the patients were treated by a multidisciplinary team both as in- and out-patients. All the patients had one or more signs of neuropathy and 171 had evidence of peripheral vascular disease. Healing with an amputation below the ankle occurred in 74 patients, 88 patients healed with an amputation above the ankle, and 25 patients died unhealed. Amputation above the ankle was associated with high age, living in an institution, a limited walking capacity, cerebrovascular disease, congestive heart failure, and a low hemoglobin level. Amputation below the ankle was associated with diabetes diagnosis before 30 years of age and diabetes duration. In conclusion, older age, history of cerebrovascular disease and low hemoglobin level are associated with above ankle amputation level in diabetic patients with foot ulcers. However, level selection cannot be based upon these factors only, since some patients at high age, with cerebrovascular disease or with a low hemoglobin value, healed with an amputation below the ankle. None of these factors per se should be taken as a cause to choose a primary amputation above the ankle, unless amputation is supported by the total clinical picture, including local characteristics, such as type and localization of ulcer, and signs of peripheral vascular disease. More attention should be paid to biological than to chronological age.

Increased catalase levels and hypoxanthine-enhanced nitro-blue tetrazolium staining in rat retina after ischemia followed by recirculation

In the present study, using retinal ischemia as a model, we examined if different periods of ischemia and recirculation influenced the generation of reactive oxygen species, i.e. in hydrogen peroxide generation and nitroblue tetrazolium (NBT) reduction. Ischemia was induced for 30 and 90 min by ligation of the optic nerve with the vessels and recirculation was established by removing the ligature. The rats were sacrificed after 15 min or 3 days of recirculation. The retinas were separated from the pigment epithelium for measurements of catalase activity and examination of NBT staining. Compared to controls, the catalase activity was increased after 30 and 90 min of ischemia followed by 15 min of recirculation, and after 90 min of ischemia followed by 3 days of recirculation. As in controls, NBT staining was observed, both after 30 and 90 min of ischemia followed by 15 min of recirculation, in photoreceptors, in both plexiform layers, in some ganglion and glial cells, and, occasionally, in cells in the inner nuclear layer. Opposite to controls, addition of hypoxanthine to the NBT solution resulted in an increased staining in vessels in the inner nuclear layer in retinas subjected to 30 min of ischemia followed by 3 days of recirculation. The increased catalase activity suggests an increased amount of this free radical scavenger after ischemia followed by short-term and long-term recirculation. The hypoxanthine-enhanced NBT staining of blood vessel walls after ischemia followed by long-term recirculation indicates an activation of xanthine oxidase and an increased production of NBT reductants, some of which may represent oxygen free radicals.

Lack of association between plasma homocysteine levels and microangiopathy in type 1 diabetes mellitus

The reactive vascular-injuring amino acid homocysteine was previously shown to be increased in plasma in diabetic patients with clinical signs of nephropathy. In this study, plasma homocysteine was measured in type 1 diabetic patients with normoalbuminuria (n = 22), microalbuminuria (n = 40) and proteinuria (n = 14) in order to investigate whether plasma homocysteine levels are increased already at the stage of incipient nephropathy, i.e. microalbuminuria. Furthermore, patients were characterized according to the degree of retinopathy. Plasma homocysteine in the whole population (n = 76) was related to B-Folate (r = 0.38, p < 0.01), S-Creatinine (r = 0.55, p < 0.001), S-Urea (r = 0.37, p < 0.01), U-Albumin (r = 0.46, p < 0.001), urinary N-acetyl-beta- glucosaminidase (r = 0.40, p < 0.001), systolic blood pressure (r = 0.36, p < 0.01) and diabetes duration (r = 0.44, p < 0.001). There were no differences in plasma homocysteine levels between patients with normoalbuminuria (8.0 +/- 1.7 mumol l-1; mean +/- SD) and those with microalbuminuria (9.1 +/- 3.4 mumol l-1). However, patients with clinical signs of nephropathy had higher plasma homocysteine levels (12.9 +/- 5.7 mumol l-1, p < 0.01) compared to the other two groups. There was no association between plasma homocysteine levels and different degrees of retinopathy. Thus, the present study does not show any relation between plasma homocysteine levels and early stages of diabetic nephropathy or retinopathy indicating that elevated concentrations of plasma homocysteine does not explain the increased risk for atherosclerosis observed in patients with microalbuminuria.

Influence of intensified insulin regimen on quality of life and metabolic control in insulin-dependent diabetes mellitus

Seventy-eight non-randomized patients with IDDM, aged 33.8 +/- 9.6 years (mean +/- S.D.), with a duration of diabetes of 16.6 +/- 9.5 years and a HbA1c level of 8.0% +/- 1.5 at baseline were included in the study. The effects of a change from a 3-dose insulin regimen using conventional syringes to a treatment mode using 4 injections per day with a pen injector on metabolic control, perceived distress from diabetes on everyday life and correspondence between expectations and experiences of treatment during a 1-year trial were assessed. The experience measures were registered at baseline and after 3 and 12 months, respectively. HbA1c levels were measured every 3 months. Neither the metabolic control nor the body mass index or rate of hypoglycemic episodes changed during the study period. However, the patients experienced a decreased distress from diabetes, which appeared during the first 3 months and remained unchanged thereafter. The expectations of advantages from the intensified insulin therapy were generally high and were mostly either fulfilled or exceeded by experiences. We conclude that multiple insulin injection therapy, under routine treatment conditions, is subjectively preferable to patients and has favourable effects on their quality of life although something more is required in order to also achieve an improvement of metabolic control.

Local signs and symptoms in relation to final amputation level in diabetic patients. A prospective study of 187 patients with foot ulcers

Local signs and symptoms were evaluated in 187 consecutively presenting diabetic patients undergoing amputation for foot ulcers. From admission until final outcome the patients were treated by the same multidisciplinary team both as in- and out-patients. At the time of amputation, the types of lesions were superficial/deep ulcer (n 17), ulcer with deep infection, but without gangrene (n 40), and gangrene with or without infection (n 130). Healing after a minor amputation (below the ankle) occurred in 74 patients, while 88 patients healed after a major amputation (above the ankle), and 25 patients died before healing had occurred. Deep infection and presence of popliteal or pedal pulses were associated with healing after minor amputation and so were ulcers on the small toes, metatarsal head area and midfoot. Pain, progressive gangrene, intermittent claudication, and decubital and multiple ulcers were related to healing after major amputation. In a logistic regression analysis, pain, progressive gangrene and intermittent claudication remained. However, none of these factors excluded healing of a minor amputation and thus selection of amputation level in diabetic patients with foot ulcers cannot be based upon these factors exclusively.

Nitro blue tetrazolium staining and hydrogen peroxide production in the rat retina in vitamin E deficiency and after light exposure

Nitro blue tetrazolium (NBT) staining in normal rat retina was previously found to be affected by inhibition of free radical-related enzyme systems, indicating that NBT might be useful as a marker of free radicals. The aim of the present study was to investigate NBT staining in rat retina in vitamin E deficiency and after blue light exposure, and also to measure hydrogen peroxide (H2O2) production indirectly by measuring catalase activity under these conditions. Vitamin E deficiency resulted in morphological changes in the retina and increased NBT staining in the photoreceptors and in the outer plexiform layer. Light exposure caused increased staining in the inner segments of photoreceptors. The increased staining was not clearly influenced by addition of the free radical scavengers superoxide dismutase and catalase. The catalase activity was not influenced by light exposure, while it was increased in vitamin E-deficient retina compared to controls. The results indicate that reducing systems as measured by NBT were activated in the retina under these conditions. However, to what extent the reductants represent free radicals still has to be established using other methods.

Urinary excretion rate of NC1 and Tamm-Horsfall protein in the microalbuminuric type I diabetic patient

Fifty-six type I diabetic patients with microalbuminuria (albumin excretion rate 20-200 micrograms/min) were characterized as to sex, age, duration of diabetes, smoking habits, blood pressure, glomerular filtration rate, urinary NC1 (the carboxy-terminal domain of collagen IV), and Tamm-Horsfall protein excretion rate. Albumin excretion rate was considered a sign of glomerular damage, NC1 excretion rate a measure of renal basement membrane turnover, and Tamm-Horsfall protein excretion rate a marker for distal tubular function. There were no differences between males and females and between smokers and nonsmokers with respect to blood pressure, body-mass index, albumin excretion rate, glomerular filtration rate, excretion rate of NC1, and Tamm-Horsfall protein. As a group, the patients with microalbuminuria had normal glomerular filtration rate, excretion rate of NC1, and Tamm-Horsfall protein. The latter was influenced by glycosylated hemoglobin (HbA1c) levels, especially so in patients with an albumin excretion rate less than the median value of 53.0 micrograms/min (r = -0.61, p < 0.01). Furthermore, both excretion rate of NC1 and Tamm-Horsfall protein were increased in patients with high glomerular filtration rate > or = 130 mL min-1 1.73 m-2). There was no association between glomerular filtration rate and HbA1c levels. As glomerular filtration rate is related to kidney size, these observations suggest that patients with a high glomerular filtration rate have an increased mass and turnover of tubular basement membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

A four-year follow-up study on the incidence of diabetic retinopathy in older onset diabetes mellitus

Out of 369 diabetic patients with an age at onset of diabetes > or = 30 years previously studied, 325 (88%) were included in an ophthalmological follow-up examination 4 years later. In patients treated with oral drugs at baseline, the incidence of any type of retinopathy was 30.8% and of severe retinopathy 5.7%. All patients who developed severe retinopathy received insulin during the follow-up period. At baseline, duration of diabetes, diastolic blood pressure, and signs of nephropathy (p < 0.05 in all cases) as well as degree of metabolic control (p < 0.01) differed between patients who developed retinopathy and those who did not. At follow-up, there were no longer any differences regarding degree of metabolic control and diastolic blood pressure. In patients treated with insulin at baseline, the incidence of any type of retinopathy was 41.0% and of severe retinopathy 16.1%. At baseline, duration of diabetes (p < 0.01), degree of metabolic control, and insulin dosage (p < 0.05 in both cases) differed between patients who developed retinopathy and those who did not. At follow-up, there was no longer any difference in insulin dosage.

A 5-year follow-up study on the incidence of retinopathy in type 1 diabetes mellitus in relation to medical risk indicators

OBJECTIVES

The aim of the present study was to describe the 5-year incidence of retinopathy in type 1 diabetes mellitus and to characterize risk indicators for the development and progression of retinopathy.

DESIGN

A cross-sectional study of type 1 diabetic patients taken care of at a medical department.

SETTING

All type 1 diabetic patients attending the Department of Internal Medicine, University Hospital, Lund, during a 2-year period were offered ophthalmological examination.

SUBJECTS

A total of 396 out of 461 (85.9%) initially examined type 1 diabetic patients formed the basis for this 5-year follow-up study.

MAIN OUTCOME MEASURES

The degree of retinopathy was based on fundus photography or biomicroscopy. Degree of metabolic control was assessed by HbA1c levels, signs of nephropathy by albumin creatinine clearance ratio and urinary albumin levels. Blood pressure was measured in the supine position. Duration of diabetes, age, and insulin dosage were registered.

RESULTS

The incidence of retinopathy was 47.2% and progression from background to severe retinopathy occurred in 41%. Risk indicators for the development of retinopathy were duration of diabetes (P < 0.001), degree of metabolic control (P < 0.001), insulin dosage (P < 0.05) and signs of nephropathy based on measurements of albumin creatinine clearance ratio (P < 0.01) and urinary albumin concentration (P < 0.05). Two risk indicators could be identified for progression of retinopathy, i.e. the degree of metabolic control (P < 0.01) and diastolic blood pressure (P < 0.05).

CONCLUSIONS

The results suggest that apart from poor metabolic control, development of retinopathy in type 1 diabetes is associated with long diabetes duration and clinical signs of diabetic nephropathy. Progression of retinopathy is associated with poor metabolic control and elevated diastolic blood pressure levels.

The five-year incidence of blindness after introducing a screening programme for early detection of treatable diabetic retinopathy

The incidence of moderate visual impairment and blindness due to diabetic retinopathy was studied 5 years after introducing a screening system for early detection of treatable retinopathy. Photocoagulation was performed in patients with clinically significant macular oedema, severe preproliferative, and proliferative retinopathy. Eighty-eight percent of 470 Type 1 and 88% of 388 Type 2 diabetic patients were still available for follow-up. In the Type 1 group, the five-year incidence of blindness and moderate visual impairment were 0.5% and 1.2%, respectively. Corresponding figures for the Type 2 diabetic patients were 0.6% and 1.7%, respectively. The majority of patients with loss of vision had severe retinopathy at baseline. Among those who entered the screening programme with no or mild retinopathy, loss of vision occurred in only one of the Type 1 and four of the Type 2 diabetic patients. It is concluded that the risk for visual impairment and blindness due to diabetes can be substantially reduced by using programmes for early detection of and effective treatment of diabetic retinopathy.

Distal blood pressure as a predictor for the level of amputation in diabetic patients with foot ulcer

The predictive value of distal blood pressure measurements for the level of amputation was studied prospectively in 161 consecutive diabetic patients with foot ulcers. The patients were treated as outpatients except for periods of surgery and when complications requiring hospital care occurred. All patients were treated pre- and postoperatively by the same multidisciplinary foot care team. Either ankle or toe blood pressure measurement was available in 86% of the patients. Incompressible arteries, ulcer or gangrene at the measuring site, previous amputation, poor general condition, and an emergency situation were factors that excluded standardized ankle and toe blood pressure measurements in 24% and 27% of the patients, respectively. An absolute lower ankle pressure level of 50 mm Hg was found, below which a minor amputation was never sufficient to achieve healing. An ankle pressure below 75 mm Hg was seldom sufficient, and at or above that pressure level, the ankle pressure had no predictive value in this respect. At a toe pressure below 15 mm Hg, a minor amputation was seldom sufficient. Ankle and toe pressure indices gave no further information.

Long-term prognosis for diabetic patients with foot ulcers

OBJECTIVE

To evaluate the recurrence of foot ulcers as well as the cumulative amputation and mortality rates in diabetic patients with previous foot ulcers.

DESIGN

A prospective study of consecutively presenting diabetic patients admitted to the Department of Internal Medicine because of foot ulcer with a median follow-up of 4 years.

SETTING

A multidisciplinary foot-care team.

POPULATION

Five-hundred-and-fifty-eight consecutive diabetic patients with foot ulcers treated between 1 July 1983 and 31 December 1990 were followed to final outcome. Out of these patients, 468 healed either primarily (n = 345) or after minor or major amputations (n = 123) and 90 died before healing had occurred. Those 468 patients who healed were included in this prospective study from the time of healing.

MAIN OUTCOME MEASURES

Patients were followed according to a standardized protocol with registration of foot lesions, amputation, morbidity and mortality. Clinical examination was performed twice yearly.

RESULTS

After 1, 3 and 5 years of observation 34%, 61% and 70% of the patients, respectively, had developed a new foot ulcer. The recurrence rate of foot lesions was slightly higher among patients who previously had had an amputation (P < 0.05, P < 0.01 and non-significant, respectively). Among patients with previous primary healing the cumulative amputation rates were 3%, 10% and 12% after 1, 3 and 5 years of follow-up compared with 13%, 35% and 48% among those who previously healed after amputation, irrespective of previous amputation level (P < 0.001 at all time-points). All amputations except three were initiated by a foot ulcer deteriorating to deep infection or progressive gangrene. The long-term survival ratio was lower among patients healed after previous amputation (80%, 59%, 27%) compared with patients with previously primary healing (92%, 73%, 58%) after 1, 3 and 5 years of observation, respectively (P < 0.001, P < 0.01 and P < 0.001 respectively). The mortality rate was twice as high among primarily healed and four times as high among patients with amputation compared to an age- and sex-matched Swedish population.

CONCLUSION

These findings stress the need for life-long surveillance of the diabetic foot at risk and the necessity of preventive foot care among diabetic patients with previous foot lesions, and particularly among those who had had a previous amputation.

The influence of hypoglycaemia on regional cerebral blood flow and cerebral volume in type 1 (insulin-dependent) diabetes mellitus

The effect of moderate hypoglycaemia (venous blood glucose 2.0 +/- 0.2 mmol/l; mean +/- SD) on regional cerebral blood flow and cerebral volume was studied in a group of ten right-handed patients with Type 1 (insulin-dependent) diabetes mellitus (age 26.0 +/- 2.4 years, duration 18.4 +/- 3.8 years) using an intravenous Xenon 133 single photon emission computed tomography technique. After 10 min of hypoglycaemia, global cerebral blood flow had increased to 55.8 +/- 4.5 ml.100 g-1.min-1 compared to the initial normoglycaemic flow of 49.5 +/- 3.7 ml.100 g-1.min-1 (p < 0.01). A further increase in global cerebral blood flow to 59.5 +/- 4.5 ml.100 g-1.min-1 (p < 0.05) occurred 15 min after normalization of the blood glucose level. The global cerebral blood flow change from before hypoglycaemia to after recovery was inversely related to the initial glucose level. No change in the relative distribution of the regional cerebral blood flow was found between the measurements. The cerebral blood flow was significantly higher in the right hemisphere compared with the left hemisphere (2.3, 1.6 and 2.2%, respectively; p < 0.05) in all measurements. Deeper hypoglycemia was associated with a more pronounced decrease in brain volume, while the length of the restitution time after hypoglycaemia correlated with a volume increase. Due to influences with opposite effects there was no mean change in the brain volume.

Nitro blue tetrazolium staining: a morphological demonstration of superoxide in the rat retina

Nitro blue tetrazolium (NBT) is an artificial electron acceptor which has been suggested to be a useful tool in studies of free radicals. To establish whether NBT could be useful in morphological demonstration of free radicals in the retina, the staining pattern was examined in normal rat retina and after incubation with the free radical scavenger superoxide dismutase or with inhibitors of free radical protective enzymes, such as potassium cyanide, dicoumarol, and aminotriazole. After 60 min incubation in 1 mM NBT, staining was observed in photoreceptors, in some cells in the inner nuclear and ganglion cell layers, and in glial cells. Staining also appeared in the plexiform layers and occasionally in small blood vessels. Addition of superoxide dismutase caused a decreased staining of the inner parts of the retina. The inhibitors of free radical scavengers caused a dose-dependent increase in staining of the inner parts of the retina and, at high concentrations of potassium cyanide, of the photoreceptors. Thus, NBT seems indeed to be useful in morphological studies of free radicals in the retina.

Day and night variation in ambulatory blood pressure in type 1 diabetes mellitus with nephropathy and autonomic neuropathy

The objective was to study ambulatory blood pressure and heart rate variability between day and night in patients with type 1 (insulin-dependent) diabetes mellitus with different degrees of diabetic nephropathy, and to evaluate the influence of autonomic neuropathy and type of antihypertensive treatment. Twenty type 1 diabetic patients with diabetic nephropathy and antihypertensive treatment were studied with 24-h ambulatory blood pressure monitoring using an oscillometric method. They were compared with eight insulin-treated diabetic patients with short duration of diabetes (1-5 years) and with 10 apparently healthy subjects. The degree of autonomic neuropathy was evaluated by measuring the RR-interval during deep breathing and uprising. The 24-h blood pressure was generally higher in patients with diabetic nephropathy compared to those other two groups. These patients also had a lower ratio between day and night in diastolic blood pressure compared to the control subjects (1.15 +/- 0.12 vs. 1.25 +/- 0.76, P < 0.05) and heart rate compared to the diabetic patients without nephropathy, as well as the control subjects (1.15 +/- 0.08 vs. 1.26 +/- 0.09 vs. 1.27 +/- 0.08, P < 0.01, respectively). All patients with diabetic nephropathy had clinical signs of autonomic neuropathy as judged by RR-interval measurements during deep breathing and uprising.

The predictive value of albuminuria for cardiovascular and renal disease. A 5-year follow-up study of 476 patients with type I diabetes mellitus

A 5-year follow-up study of 476 type I adult diabetic patients previously studied cross sectionally revealed that, during the observation period, 19 patients died and 30 developed cardiovascular or renal disease, such as myocardial infarction (n = 8), cerebrovascular disease (n = 3), amputation (n = 6), and renal insufficiency (n = 13). The patients were registered by one and the most-severe event only. The yearly death rate was 8.0 per 1000, compared with the expected death rate of 2.0 for people with corresponding age and sex in the general population. In patients with renal insufficiency, one also had myocardial infarction, and one had had an amputation. The ages of patients who died, with myocardial infarction, cerebrovascular disease, amputation, or renal insufficiency, were 44.2 +/- 12.7, 41.3 +/- 6.6, 43.7 +/- 13.2, 45.3 +/- 15.7, and 40.8 +/- 9.8 years, respectively. Urinary albumin concentration in a single early morning urine sample was found to be a strong prognostic marker for the development of cardiovascular disease or death. In contrast, age, gender, age at onset and duration of diabetes, levels of blood pressure, serum creatinine, and HbA1c, or presence of hypertension, as well as changes in blood pressure and hBa1c, during the observation period did not influence the survival or incidence of cardiovascular disease. However, blood pressure and HbA1c were associated with increased urinary albumin concentrations during the follow-up period.

Tubular secretion of Tamm-Horsfall protein is decreased in type 1 (insulin-dependent) diabetic patients with diabetic nephropathy

Signs of glomerular, proximal and distal tubular dysfunction as well as metabolic control were studied in type 1 diabetes mellitus. To that end, the urinary excretion rates of albumin, sodium, phosphate and Tamm-Horsfall protein as well as HbA1c levels were measured in 20 patients with different degrees of diabetic nephropathy (positive Albustix for several years). Eight diabetic patients with short duration of diabetes and without any diabetic complications and 10 apparently healthy subjects were studied for comparison. The HbA1c levels in the three groups were 8.6 +/- 1.2, 5.9 +/- 2.2 and 4.1 +/- 0.4%, respectively (mean +/- SD). Duration of diabetes in the two diabetic groups were 27 +/- 7 and 3 +/- 1 years, respectively. The urinary protein levels were measured by enzyme-linked immunoassays. The fractional clearance of sodium (1.9 +/- 1.9%; p < 0.001) and phosphate (27 +/- 11%; p < 0.01) were increased in patients with diabetic nephropathy compared to diabetic patients without nephropathy (0.6 +/- 0.2 and 16 +/- 4%) and healthy control subjects (0.6 +/- 0.1 and 16 +/- 4%, respectively). Tamm-Horsfall protein excretion rate was decreased in both diabetic groups (15.0x/3.1 and 37.9x/1.9 micrograms/min, geometric mean x/tolerance factor, p < 0.001 and p < 0.05, respectively) compared to the healthy subjects (63.8x/1.3 micrograms/min). Furthermore, patients with diabetic nephropathy had a lower excretion rate of Tamm-Horsfall protein (15.0x/3.1 micrograms/min) compared to patients without signs of nephropathy (37.9x/1.9 micrograms/min, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The association between clinical risk factors and outcome of diabetic foot ulcers

OBJECTIVE

The aim of the study was to describe the association between clinical risk factors in diabetic patients with food ulcers in relation to outcome.

DESIGN

A prospective study of 314 consecutively presenting diabetic patients with foot ulcers referred to the Department of Internal Medicine between July 1, 1983 and June 30, 1987. All patients were followed to final outcome.

SETTING

All patients were treated by the same multi-disciplinary foot care team at the Department of Medicine, both as in- and out-patients. Healing was defined as intact skin for at least 6 months.

RESULTS

One hundred and ninety-seven patients healed primarily, 77 after amputation, and 40 died unhealed. Signs of macroangiopathy were more common among patients who healed after amputation. The outcome was strongly related to age, though 43% of the patients with an age over 80 years healed primarily. There was no difference in smoking habits between patients who healed primarily and those who required amputation to heal. Diabetic nephropathy was found in 26% of the patients and was strongly associated with amputation. Presence of retinopathy was found in 54% of the patients, but this finding was not related to the outcome. There were no differences in short-term metabolic control as assessed by hemoglobin A1c levels between patients who healed primarily and those who healed after amputation.

CONCLUSION

The presence of diabetic foot ulcers was strongly associated with age and diabetic complications such as multiple cardiovascular disease and nephropathy, which were important factors related to amputation.