Steen Andersen

Individual patients show a large variability in albuminuria response to angiotensin receptor blockers (ARB). Identifying novel biomarkers that predict ARB response may help tailor therapy. We aimed to discover and validate a serum metabolite classifier that predicts albuminuria response to ARBs in patients with diabetes mellitus and micro- or macroalbuminuria. Liquid chromatography-tandem mass spectrometry metabolomics was performed on serum samples. Data from patients with type 2 diabetes and microalbuminuria (n = 49) treated with irbesartan 300 mg/day were used for discovery. LASSO and ridge regression were performed to develop the classifier. Improvement in albuminuria response prediction was assessed by calculating differences in R2 between a reference model of clinical parameters and a model with clinical parameters and the classifier. The classifier was externally validated in patients with type 1 diabetes and macroalbuminuria (n = 50) treated with losartan 100 mg/day. Molecular process analysis was performed to link metabolites to molecular mechanisms contributing to ARB response. In discovery, median change in urinary albumin excretion (UAE) was −42 % [Q1–Q3: −69 to −8]. The classifier, consisting of 21 metabolites, was significantly associated with UAE response to irbesartan (p < 0.001) and improved prediction of UAE response on top of the clinical reference model (R2 increase from 0.10 to 0.70; p < 0.001). In external validation, median change in UAE was −43 % [Q1–Q35: −63 to −23]. The classifier improved prediction of UAE response to losartan (R2 increase from 0.20 to 0.59; p < 0.001). Specifically ADMA impacting eNOS activity appears to be a relevant factor in ARB response. A serum metabolite classifier was discovered and externally validated to significantly improve prediction of albuminuria response to ARBs in diabetes mellitus.

Context: The effect of glycemic control on persisting albuminuria remains unclear. Insulin delivery and glucose variability may be important. Objective: This study aimed to investigate the effect of 1-year treatment with sensor-augmented insulin pump (SAP) or multiple daily injections (MDIs) on albuminuria. Design, Patients, and Methods: This was a randomized controlled open-label parallel trial composed of 60 patients with type 1 diabetes with a history of albuminuria and on stable renin-angiotensin system inhibition, were randomly assigned to SAP or MDI. Urine albumin creatinine ratio (UACR) was measured in three urine samples at all visits. Glucose variability and glomerular filtration rate (51Cr-EDTA-GFR) were measured at beginning and study end. Using linear mixed model, change in UACR between groups was analyzed as intention to treat. Main Outcome Measure: Change in UACR was measured. Results: Fifty-five patients (SAP, n = 26; MDI, n = 29) completed the study. Diabetes duration (mean ± SD, 33 ± 12 y), UACR (geometric mean, 99 mg/g; interquartile range, 37–233 mg/g), 51Cr-EDTA-GFR (94 ± 22 mL/min/1.73m2), glycosylated hemoglobin (HbA1c) (9.0 ± 1.1%), glucose variability (calculated as SD), 4.0 ± 1.0 mmol/l; no-group differences (P ≥ .06 for all). After 1 year, change in UACR was mean, −13%; 95% confidence interval, −39 to 22 with SAP vs mean, 30%; 95% CI, −12 to 92% on MDI treatment (unadjusted P = .051; adjusted for HbA1c, P = .04). HbA1c decreased 1.3 ± 1.0 vs 0.6 ± 1.0% (P = .013), glucose variability decreased 0.9 ± 1.1 vs 0.3 ± 1.0 mmol/L (P = .04), and 51Cr-EDTA-GFR declined 5.6 ± 9.6 vs 3.4 ± 13 mL/min/1.73m2 (P = .50) with SAP vs MDI treatment. There were no changes in blood pressure (P ≥ .27). Conclusion: SAP treatment reduced UACR in a randomized controlled trial in type 1 diabetes patients with a history of albuminuria on stable renin-angiotensin system inhibition. Significance was reached after adjustment. SAP treatment reduced HbA1c and glucose variability (calculated as SD).

Aim: The effect of insulin pump [continuous subcutaneous insulin infusion (CSII)] treatment on diabetes complications in a modern clinical setting is largely unknown. We investigated the effect of 4 years CSII treatment on HbA_1c, albuminuria and kidney function compared with multiple daily injections (MDI) in a single‐centre clinical setting.Methods: All patients initiating CSII treatment from 2004 to 2010 and followed for at least 4 years were included in the study: 193 people with Type 1 diabetes were matched (1 : 2) with 386 patients treated with MDI in the same period. Matching was based on diabetes duration, gender, HbA_1c and normo‐, micro‐ or macroalbuminuria at baseline. Urinary albumin/creatinine ratio (UACR) was measured yearly and annual change assessed from linear regression.Results: CSII‐ vs. MDI‐treated patients were comparable at baseline. After 4 years, HbA_1c was 62 ± 11 vs. 68 ± 11 mmol/mol (7.8 ± 1.0 vs. 8.4 ± 1.0%) (P < 0.001). Annual UACR change in CSII‐ vs. MDI‐treated patients was [mean (95% confidence interval)] −10.1 (−13.3; −6.8) vs. −1.2 (−3.6; 0.9)% (P < 0.001). Reduction in UACR was significantly associated with CSII treatment after adjustment for age, gender, diabetes duration, estimated GFR, UACR, mean arterial pressure, HbA_1c, cholesterol, renin–angiotensin–aldosterone system inhibition, anti‐hypertensive treatment and smoking (P < 0.001). This remained significant (P < 0.001) when only including patients on stable renin–angiotensin–aldosterone system inhibition during follow‐up (n = 465).Conclusions: Treatment with CSII over 4 years independently reduced HbA_1c and UACR compared with MDI. Reduced UACR may be due to less glycaemic variability because the effect of CSII on HbA_1c could only partially explain the effect. This needs confirmation in randomized controlled trials.

Background: The use of continuous glucose monitoring (CGM) in clinical decision making in diabetes could be limited by the inaccuracy of CGM data when compared to plasma glucose measurements. The aim of the present study is to investigate the impact of CGM numerical accuracy on the precision of diabetes treatment adjustments. Method: CGM profiles with maximum 5-day duration from 12 patients with type 1 diabetes treated with a basal-bolus insulin regimen were processed by 2 CGM algorithms, with the accuracy of algorithm 2 being higher than the accuracy of algorithm 1, using the median absolute relative difference (MARD) as the measure of accuracy. During 2 separate and similar occasions over a 1-month interval, 3 clinicians reviewed the processed CGM profiles, and adjusted the dose level of basal and prandial insulin. The precision of the dosage adjustments were defined in terms of the interclinician agreement and the intraclinician reproducibility of the decisions. The Cohen’s kappa coefficient was used to assess the precision of the decisions. The study was based on retrospective and blind CGM data. Results: For the interclinician agreement, in the first occasion, the kappa of algorithm 1 was .32, and that of algorithm 2 was .36. For the interclinician agreement, in the second occasion, the kappas of algorithms 1 and 2 were .17 and .22, respectively. For the intraclinician reproducibility of the decisions, the kappas of algorithm 1 were .35, .22, and .80 and the kappas of algorithm 2 were .44, .52, and .32, for the 3 clinicians, respectively. For the interclinician agreement, the relative kappa change from algorithm 1 to algorithm 2 was 86.06%, and for the intraclinician reproducibility, the relative kappa change from algorithm 1 to algorithm 2 was 53.99%. Conclusions: Results indicated that the accuracy of CGM algorithms might potentially affect the precision of the CGM-based insulin adjustments for type 1 diabetes patients. However, a larger study with several clinical centers, with higher number of clinicians and patients is required to validate the impact of CGM accuracy on decisions precision.

To investigate the relationship between arterial stiffness and insulin treatment mode [continuous subcutaneous insulin infusion (CSII) versus multiple daily injections (MDI)] in type 1 diabetes patients. Cross-sectional study, from 2009 to 2011, including 601 Caucasian type 1 diabetes patients, 58 and 543 treated with CSII and MDI, respectively. Arterial stiffness was measured as pulse wave velocity (PWV) (SphygmoCor, AtCor Medical). Adjustment included gender, age, diabetes duration, HbA_1c, heart rate, mean arterial pressure, P-creatinine, urinary albumin excretion rate (UAER), smoking, total daily insulin dose, antihypertensive treatment, previous cardiovascular disease (CVD), total cholesterol and statin treatment. Albuminuria was UAER ≥30 mg/24-h, and CVD included myocardial infarction, revascularization, peripheral arterial disease and stroke. CSII- versus MDI-treated patients were 48 versus 57 % men, 51 ± 11 versus 54 ± 13 years old (mean ± SD), had 33 ± 12 versus 32 ± 16 years diabetes duration and HbA_1c 7.8 ± 0.9 % (62 ± 10 mmol/mol) versus 8.0 ± 1.2 % (64 ± 13 mmol/mol) (P ≥ 0.08 for all). PWV was lower in CSII- versus MDI-treated patients (9.3 ± 2.8 vs. 10.4 ± 3.4 m/s; P = 0.016). In fully adjusted analysis, CSII treatment was significantly (P = 0.038) associated with lower PWV, whereas HbA_1c-level was not (P = 0.93). In type 1 diabetes patients, CSII treatment was associated with lower arterial stiffness independent of other risk factors, while HbA_1c was not. Although glucose variability was not assessed, our results suggest that glucose variability and not HbA_1c-level affect arterial stiffness. This needs confirmation in randomised prospective studies.

Background: Previously the angiotensin II receptor blocker Irbesartan has been demonstrated to reduce the risk for progression from microalbuminuria to macroalbuminuria in type 2 diabetic patients. The purpose of this study was to evaluate the effect of treatment with Irbesartan in type 2 diabetic patients with microalbuminuria on the urinary proteome. Methods: High-resolution capillary-electrophoresis coupled to mass-spectrometry (CE-MS) was used to profile the low-molecular-weight proteome in urine of a subgroup of patients from a two year randomized irbesartan versus placebo therapy trial, which included hypertensive type 2 diabetic patients with microalbuminuria on ongoing antihypertensive medication (IRMA2-substudy). Results: We demonstrate that the therapy with 300 mg Irbesartan daily over a period of two years results in significant changes of the urinary proteome. Both, a classifier developed previously that consists of urinary peptides indicative of chronic kidney disease, as well as several individual peptides changed significantly after treatment. These changes were not observed in the placebo-treated individuals. Most prominent are changes of urinary collagen fragments associated with progression of diabetic nephropathy, indicating normalization in urinary peptides. Conclusion: CE-MS analysis of urine enabled identification of peptides as potential surrogate markers for renoprotection in microalbuminuric type 2 diabetic patients, which show persistent improvement after longterm treatment with Irbesartan. The results suggest that a major benefit of treatment by Irbesartan may be improvement of collagen turnover, reduction of fibrosis. They further suggest that urinary proteome analysis could be utilized to assess potential benefit of therapeutic intervention, providing statistically significant results even on a small population.

It has been suggested that an aldosterone synthase gene polymorphism (CYP11B2 -344T/C) is predictive of the blood pressure lowering effect of angiotensin II receptor blockers in essential hypertension. We investigated whether this polymorphism is predictive of reductions in blood pressure and albuminuria and preservation of glomerular filtration rate (GFR) during short-term and long-term treatment with losartan in 57 hypertensive type-1 diabetic patients with diabetic nephropathy. After a 4-week washout period, patients received losartan (100 mg o.d.) and were followed for a mean follow-up of 36 months. At baseline, after 2 and 4 months, and every 6 months thereafter, GFR (51Cr-EDTA-clearance), albuminuria and 24-h blood pressure were determined. The CYP11B2 -344T/C polymorphism was determined by standard polymerase chain reaction (PCR). The TT, CT and CC genotypes were found in 28 %, 58 % and 14 % of patients, respectively. At baseline albuminuria and blood pressure did not differ between genotype groups. Plasma aldosterone levels (geometric mean (95 % CI)) were similar at baseline: 87 (60-125), 77 (53-112), and 89 (49-161) pg mL(-1) and during follow-up (not significant). After initiation of losartan treatment, comparable mean (SE) reductions in blood pressure and albuminuria were seen in patients with TT, CT and CC genotypes (p >0.6 between groups). After long-term follow-up, there was a tendency towards a difference in systolic blood pressure reduction (p = 0.07, one-way ANOVA), suggesting a poorer response in patients with the CC genotype. No significant difference in rate of decline in GFR (median (range)) was seen between groups (TT, CT, CC): 4.2 (-1.0 to 16.0), 3.2 (-1.6 to 13.8) and 2.6 (-0.1 to 11.0) mL min(-1)year(-1), respectively (p = 0.5). Compared to a previous smaller study of angiotensin II receptor blockade in essential hypertension, we could not confirm that CYP11B2 -344T/C genotypes contribute towards explaining the observed variability in response to treatment with angiotensin II receptor blockers, which could be due to lack of power.