Metformin may adversely affect orthostatic blood pressure recovery in patients with type 2 diabetes: substudy from the placebo-controlled Copenhagen Insulin and Metformin Therapy (CIMT) trial.

BACKGROUND: Metformin has been shown to have both neuroprotective and neurodegenerative effects. The aim of this study was to investigate the effect of metformin in combination with insulin on cardiovascular autonomic neuropathy (CAN) and distal peripheral neuropathy (DPN) in individuals with type 2 diabetes (T2DM). METHODS: The study is a sub-study of the CIMT trial, a randomized placebo-controlled trial with a 2 × 3 factorial design, where 412 patients with T2DM were randomized to 18 months of metformin or placebo in addition to open-labelled insulin. Outcomes were measures of CAN: Changes in heart rate response to deep breathing (beat-to-beat), orthostatic blood pressure (OBP) and heart rate and vibration detection threshold (VDT) as a marker DPN. Serum levels of vitamin B12 and methyl malonic acid (MMA) were analysed. RESULTS: After 18 months early drop in OBP (30 s after standing) was increased in the metformin group compared to placebo: systolic blood pressure drop increased by 3.4 mmHg (95% CI 0.6; 6.2, p = 0.02) and diastolic blood pressure drop increased by 1.3 mmHg (95% CI 0.3; 2.6, p = 0.045) compared to placebo. Beat-to-beat variation decreased in the metformin group by 1.1 beats per minute (95% CI - 2.4; 0.2, p = 0.10). Metformin treatment did not affect VDT group difference - 0.33 V (95% CI - 1.99; 1.33, p = 0.39) or other outcomes. Changes in B12, MMA and HbA1c did not confound the associations. CONCLUSIONS: Eighteen months of metformin treatment in combination with insulin compared with insulin alone increased early drop in OBP indicating an adverse effect of metformin on CAN independent of vitamin B12, MMA HbA1c. Trial registration The protocol was approved by the Regional Committee on Biomedical Research Ethics (H-D-2007-112), the Danish Medicines Agency and registered with ClinicalTrials.gov (NCT00657943).

Effect of Metformin vs. Placebo in Combination with Insulin Analogues on Bone Markers P1NP and CTX in Patients with Type 2 Diabetes Mellitus.

Preclinical studies have shown a potential osteoanabolic effect of metformin but human studies of how metformin affects bone turnover are few. A post hoc sub-study analysis of an 18-month multicenter, placebo-controlled, double-blinded trial in type 2 diabetes mellitus (T2DM), randomizing participants to metformin versus placebo both in combination with different insulin analogue regimens (Metformin + Insulin vs. Placebo + Insulin). Patients were not treatment naive at baseline, 83% had received metformin, 69% had received insulin, 57.5% had received the combination of metformin and insulin before entering the study. Bone formation and resorption were assessed by measuring, N-terminal propeptide of type I procollagen (P1NP) and C-terminal telopeptide of type I collagen (CTX) at baseline and end of study. The influence of gender, age, smoking, body mass index (BMI), T2DM duration, glycosylated hemoglobin A1c (HbA1c), c-reactive protein (CRP) and insulin dosage was also included in the analyses. The levels of bone formation marker P1NP and bone resorption marker CTX increased significantly in both groups during the trial. P1NP increased less in the Metformin + Insulin compared to the placebo + insulin group (p = 0.001) (between group difference change), while the increases in CTX levels (p = 0.11) were not different. CRP was inversely associated (p = 0.012) and insulin dosage (p = 0.011) was positively related with change in P1NP levels. BMI (p = 0.002) and HbA1C (p = 0.037) were inversely associated with change in CTX levels. During 18 months of treatment with metformin or placebo, both in combination with insulin, bone turnover increased in both groups. But the pattern was different as the bone formation marker (P1NP) increased less during Metformin + Insulin treatment, while change in bone resorption (CTX) was not significantly different between the two groups.

Quality of life, patient satisfaction, and cardiovascular outcomes of the randomised 2 x 3 factorial Copenhagen insulin and Metformin therapy (CIMT) trial - A detailed statistical analysis plan.

Background: The evidence on the effects of metformin and insulin in type 2 diabetes patients on quality of life, patient satisfaction, and cardiovascular outcomes is unclear. Methods: The Copenhagen Insulin and Metformin Therapy (CIMT) trial is an investigator-initiated multicentre, randomised, placebo-controlled trial with a 2 × 3 factorial design conducted at eight hospitals in Denmark. Participants with type 2 diabetes were randomised to metformin (n = 206) versus placebo (n = 206); in combination with open-label biphasic insulin aspart one to three times daily (n = 137) versus insulin aspart three times daily in combination with insulin detemir once daily (n = 138) versus insulin detemir once daily (n = 137).We present a detailed description of the methodology and statistical analysis of the clinical CIMT outcomes including a detailed description of tests of the assumptions behind the statistical analyses. The outcomes are quality of life (Short Form Health Survey (SF-36)), Diabetes Medication Satisfaction Questionnaire, and Insulin Treatment Satisfaction Questionnaire (assessed at entry and 18 months after randomisation) and cardiovascular outcomes including time to a composite of either myocardial infarction, stroke, peripheral amputation, coronary revascularisation, peripheral revascularisation, or death. Discussions: This statistical analysis plan ensure the highest possible quality of the subsequent post-hoc analyses. Trial registration: The protocol was approved by the Regional Committee on Biomedical Research Ethics (H-D-2007-112), the Danish Medicines Agency (EudraCT: 2007-006665-33 CIMT), and registered within ClinicalTrials.gov (NCT00657943, 8th of April 2008).

Effects of 18-months metformin versus placebo in combination with three insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes: A post-hoc analysis of a randomized clinical trial.

Formation of reactive oxygen species has been linked to the development of diabetes complications. Treatment with metformin has been associated with a lower risk of developing diabetes complications, including when used in combination with insulin. Metformin inhibits Complex 1 in isolated mitochondria and thereby decreases the formation of reactive oxygen species. Thus, we post-hoc investigated the effect of metformin in combination with different insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes. Four hundred and fifteen individuals with type 2 diabetes were randomized (1:1) to blinded treatment with metformin (1,000 mg twice daily) versus placebo and to (1:1:1) open-label biphasic insulin, basal-bolus insulin, or basal insulin therapy in a 2 × 3 factorial design. RNA and DNA oxidation were determined at baseline and after 18 months measured as urinary excretions of 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), respectively. Urinary excretion of 8-oxoGuo changed by +7.1% (95% CI: 0.5% to 14.0%, P = 0.03) following metformin versus placebo, whereas changes in 8-oxodG were comparable between intervention groups. Biphasic insulin decreased urinary excretion of 8-oxoGuo (within-group: -9.6% (95% CI: -14.4% to -4.4%)) more than basal-bolus insulin (within-group: 5.2% (95% CI: -0.5% to 11.2%)), P = 0.0002 between groups, and basal insulin (within-group: 3.7% (95% CI: -2.0% to 9.7%)), P = 0.0007 between groups. Urinary excretion of 8-oxodG decreased more in the biphasic insulin group (within-group: -9.9% (95% CI: -14.4% to -5.2%)) than basal-bolus insulin (within group effect: -1.2% (95% CI: -6.1% to 3.9%)), P = 0.01 between groups, whereas no difference was observed compared with basal insulin. In conclusion, eighteen months of metformin treatment in addition to different insulin regimens increased RNA oxidation, but not DNA oxidation. Biphasic insulin decreased both RNA and DNA oxidation compared with other insulin regimens.

Prediction of carotid intima-media thickness and its relation to cardiovascular events in persons with type 2 diabetes.

AIMS: To investigate measures of carotid intima-media thickness (IMT) and conventional cardiovascular (CV) risk factors as predictors of future carotid IMT, and the prediction of CV events during follow-up based on measures of carotid IMT. METHODS: Observational longitudinal study including 230 persons with type 2 diabetes (T2D). RESULTS: Mean age at follow-up was 66.7 (SD 8.5) years, 30.5% were women and mean body mass index (BMI) was 31.8 (4.4) kg/m2. Carotid IMT was measured at baseline, after 18 months of intervention in the Copenhagen Insulin and Metformin Therapy (CIMT) trial and after a mean follow-up of 6.4 (1.0) years. Baseline carotid IMT, carotid IMT after 18 months' intervention, and CV risk factors (age, sex and baseline systolic blood pressure) gave the best prediction of carotid IMT (root mean-squared error of prediction of 0.106 and 95% prediction error probability interval of -0.160, 0.204). CONCLUSIONS: Measures of carotid IMT combined with CV risk factors at baseline predicts attained carotid IMT better than measures of carotid IMT or CV risk factors alone. Carotid IMT did not predict CV events, and the present results do not support the use of carotid IMT as a predictor of CV events in persons with T2D.

Metformin versus placebo in combination with insulin analogues in patients with type 2 diabetes mellitus-the randomised, blinded Copenhagen Insulin and Metformin Therapy (CIMT) trial.

OBJECTIVE: To assess the effect of metformin versus placebo both in combination with insulin analogue treatment on changes in carotid intima-media thickness (IMT) in patients with type 2 diabetes. DESIGN AND SETTING: Investigator-initiated, randomised, placebo-controlled trial with a 2 × 3 factorial design conducted at eight hospitals in Denmark. PARTICIPANTS AND INTERVENTIONS: 412 participants with type 2 diabetes (glycated haemoglobin (HbA1c) ≥ 7.5% (≥ 58 mmol/mol); body mass index >25 kg/m2) were in addition to open-labelled insulin treatment randomly assigned 1:1 to 18 months blinded metformin (1 g twice daily) versus placebo, aiming at an HbA1c ≤ 7.0% (≤ 53 mmol/mol). OUTCOMES: The primary outcome was change in the mean carotid IMT (a marker of subclinical cardiovascular disease). HbA1c, insulin dose, weight and hypoglycaemic and serious adverse events were other prespecified outcomes. RESULTS: Change in the mean carotid IMT did not differ significantly between the groups (between-group difference 0.012 mm (95% CI -0.003 to 0.026), p=0.11). HbA1c was more reduced in the metformin group (between-group difference -0.42% (95% CI -0.62% to -0.23%), p<0.001)), despite the significantly lower insulin dose at end of trial in the metformin group (1.04 IU/kg (95% CI 0.94 to 1.15)) compared with placebo (1.36 IU/kg (95% CI 1.23 to 1.51), p<0.001). The metformin group gained less weight (between-group difference -2.6 kg (95% CI -3.3 to -1.8), p<0.001). The groups did not differ with regard to number of patients with severe or non-severe hypoglycaemic or other serious adverse events, but the metformin group had more non-severe hypoglycaemic episodes (4347 vs 3161, p<0.001). CONCLUSIONS: Metformin in combination with insulin did not reduce carotid IMT despite larger reduction in HbA1c, less weight gain, and smaller insulin dose compared with placebo plus insulin. However, the trial only reached 46% of the planned sample size and lack of power may therefore have affected our results. TRIAL REGISTRATION NUMBER: NCT00657943; Results.

Effects of biphasic, basal-bolus or basal insulin analogue treatments on carotid intima-media thickness in patients with type 2 diabetes mellitus: the randomised Copenhagen Insulin and Metformin Therapy (CIMT) trial.

OBJECTIVE: To assess the effect of 3 insulin analogue regimens on change in carotid intima-media thickness (IMT) in patients with type 2 diabetes. DESIGN AND SETTING: Investigator-initiated, randomised, placebo-controlled trial with a 2 × 3 factorial design, conducted at 8 hospitals in Denmark. PARTICIPANTS AND INTERVENTIONS: Participants with type 2 diabetes (glycated haemoglobin (HbA1c) ≥ 7.5% (≥ 58 mmol/mol), body mass index >25 kg/m(2)) were, in addition to metformin versus placebo, randomised to 18 months open-label biphasic insulin aspart 1-3 times daily (n=137) versus insulin aspart 3 times daily in combination with insulin detemir once daily (n=138) versus insulin detemir alone once daily (n=137), aiming at HbA1c ≤ 7.0% (≤ 53 mmol/mol). OUTCOMES: Primary outcome was change in mean carotid IMT (a marker of subclinical cardiovascular disease). HbA1c, insulin dose, weight, and hypoglycaemic and serious adverse events were other prespecified outcomes. RESULTS: Carotid IMT change did not differ between groups (biphasic -0.009 mm (95% CI -0.022 to 0.004), aspart+detemir 0.000 mm (95% CI -0.013 to 0.013), detemir -0.012 mm (95% CI -0.025 to 0.000)). HbA1c was more reduced with biphasic (-1.0% (95% CI -1.2 to -0.8)) compared with the aspart+detemir (-0.4% (95% CI -0.6 to -0.3)) and detemir (-0.3% (95% CI -0.4 to -0.1)) groups (p<0.001). Weight gain was higher in the biphasic (3.3 kg (95% CI 2.7 to 4.0) and aspart+detemir (3.2 kg (95% CI 2.6 to 3.9)) compared with the detemir group (1.9 kg (95% CI 1.3 to 2.6)). Insulin dose was higher with detemir (1.6 IU/kg/day (95% CI 1.4 to 1.8)) compared with biphasic (1.0 IU/kg/day (95% CI 0.9 to 1.1)) and aspart+detemir (1.1 IU/kg/day (95% CI 1.0 to 1.3)) (p<0.001). Number of participants with severe hypoglycaemia and serious adverse events did not differ. CONCLUSIONS: Carotid IMT change did not differ between 3 insulin regimens despite differences in HbA1c, weight gain and insulin doses. The trial only reached 46% of planned sample size and lack of power may therefore have affected our results. TRIAL REGISTRATION NUMBER: NCT00657943.

Bone mineral content and bone metabolism during physiological GH treatment in GH-deficient adults--an 18-month randomised, placebo-controlled, double blinded trial.

OBJECTIVE: To evaluate the effect of physiological adult growth hormone (GH) replacement on bones. DESIGN: Thirty-six prospective severely growth hormone-deficient (GHD) adults (22 females and 14 males) were randomised to either 18 months of GH (0.03 mU/kg/day) or placebo treatment. METHODS: Bone mineral density and content (BMD, BMC) and body composition were evaluated by dual energy X-ray absorptiometry at baseline and after 6, 12 and 18 months. Serum concentrations of insulin-like growth factor-I (IGF-I), IGF binding protein 3, osteocalcin, carboxyterminal propeptide of type I collagen, carboxyterminal crosslink telopeptide of type I collagen, amino-terminal propeptide of type III procollagen and urine pyridinolin and deoxypyridinolin were determined. RESULTS: IGF-I levels increased from 63.2 microg/l (+/-10.1) to 193.6 (+/- 25.8) microg/l (mean (+/-s.e.)) (P<0.001 compared with placebo). Markers of bone turnover increased significantly from 142% to 227% of baseline values (all P<0.001 compared with placebo). Body composition changes were an increase of lean body mass and a decrease of fat mass resulting in a reduction of percentage body fat of +/- 1.8 (+/- 3.8) in the GH-treated group vs an increase of 1.0 (+/-2.9)) in the placebo-treated group (P=0.002). CONCLUSIONS: No significant difference in BMD or BMC between the GH and placebo groups was found after 18 months. At several sites the variances of changes from baseline were significantly greater in the GH than in the placebo group, indicating an impact of the treatment. From baseline to 6 months an insignificant reduction of total BMD was seen while an increase of BMD was found from 6 to 18 months in the GH group compared with the placebo group. This placebo-controlled trial confirmed the longer term open studies on the effect on bones in patients with GHD, with an initial overrepresentation of bone resorption followed by an increase in BMD which at 18 months had reached baseline level.

Cardiac effects of low-dose growth hormone replacement therapy in growth hormone-deficient adults. An 18-month randomised, placebo-controlled, double-blind study.

OBJECTIVE: To characterise the effect of long-term low-dose growth hormone (GH) treatment on cardiac anatomy and function. METHODS: 20 patients with multiple pituitary hormone deficiencies, including severe acquired GH deficiency (GHD), were randomly assigned to GH or placebo (P) for 18 months. Echocardiographic measurements were performed at baseline and after 6, 12 and 18 months. RESULTS: At baseline, 8 of 20 patients had diastolic dysfunction (6 severe and 2 borderline), while only 1 had systolic dysfunction. None of the investigated parameters of diastolic or systolic function changed during treatment. CONCLUSION: In adult onset GHD, diastolic dysfunction was present in 40% of the patients. None of the investigated values were different after 18 months of GH compared to placebo.

Effect of growth hormone replacement therapy on pituitary hormone secretion and hormone replacement therapies in GHD adults.

OBJECTIVE: We tested the impact of commencement of GH replacement therapy in GH-deficient (GHD) adults on the circulating levels of other anterior pituitary and peripheral hormones and the need for re-evaluation of other hormone replacement therapies, especially the need for dose changes. METHODS: 22 GHD patients were investigated in a double-blind randomized study and 90 GHD patients in an open study at baseline and after 6 and 12 months of GH replacement therapy. RESULTS: In the placebo-controlled trial, the FT(3) levels increased after 6 months in the GH-treated group, and in the open study the FT(3) levels tended to increase. Other hormone concentrations did not change in either part of the study. Four patients required an increase in thyroxine dose, while 2 patients needed dose reduction. One originally euthyroid patient required thyroxine replacement. Two patients with originally conserved pituitary-adrenal function developed ACTH insufficiency. The hydrocortisone dose was increased in 1 and decreased in 1 of the 66 patients with secondary hypocortisolism. None of the females required any adjustment of sex hormone replacement therapy. Two of 37 males needed dose increase of testosterone, while 1 needed dose reduction. CONCLUSION: GH replacement therapy required dose adjustments regarding other hormone replacement therapies in 12.2% (n = 11), while initiation of new hormone replacement was performed in 3.3% (n = 3) of the 90 patients during the 1-year follow-up. Monitoring of pituitary hormone axes is advisable after commencement of GH replacement therapy, since changes of hormone replacement therapy was observed in a small but clinically significant number of patients.