Adherence to metformin in adults with type 2 diabetes: a combined method approach.

BACKGROUND: Medication adherence, one of the most important aspects in the process of optimal medicines use, is unfortunately still a major challenge in modern healthcare, and further research is required into how adherence can be assessed and optimised. The aim of this study was to use a combined method approach of self-report and dried blood spot (DBS) sampling coupled with population pharmacokinetic (PopPK) modelling, to assess adherence to metformin in adult patients with type 2 diabetes. Further aims were to assess metformin exposure levels in patients, determine factors associated with non-adherence with prescribed metformin, and to explore the relationship between adherence and therapeutic outcomes. METHODS: A combined method approach was used to evaluate metformin adherence in patients with type 2 diabetes who had been prescribed metformin for a minimum period of 6 months. Patients were recruited from consultant-led diabetic outpatient clinics at three hospitals in Northern Ireland, UK. Data collection involved self-reported questionnaires [Medication Adherence Report Scale (MARS), Beliefs about Medicines Questionnaire and Centre for Epidemiologic Studies Depression Scale], direct measurement of metformin concentration in DBS samples, and researcher-led patient interviews. The DBS sampling approach was coupled with population pharmacokinetic (PopPK) modelling, which took account of patient characteristics, metformin dosage and type of formulation prescribed (immediate or sustained release). RESULTS: The proportion of patients considered to be adherent to their prescribed metformin, derived from self-reported MARS scores and metformin concentration in DBS samples, was 61.2% (74 out of 121 patients). The majority (n = 103, 85.1%) of recruited patients had metformin exposure levels that fell within the therapeutic range. However, 17 patients (14.1%) had low exposure to metformin and one patient (0.8%) had undetectable metformin level in their blood sample (non-exposure). Metformin self-administration and use of a purchased adherence pill box significantly increased the probability of a patient being classified as adherent based on logistic regression analysis. Both HbA1c and random glucose levels (representing poor glycaemic control) in the present research were, however, not statistically linked to non-adherence to metformin (P > 0.05). CONCLUSIONS: A significant proportion of participating patients were not fully adherent with their therapy. DBS sampling together with the use of a published PopPK model was a useful, novel, direct, objective approach to estimate levels of adherence in adult patients with type 2 diabetes (61.2%).

A retrospective audit of type 2 diabetes patients prescribed liraglutide in real-life clinical practice.

BACKGROUND: In phase 3 trials, the once-daily human glucagon-like peptide-1 analog liraglutide provided effective glycemic control with low rates of hypoglycemia, weight loss, and reduced systolic blood pressure (SBP) in patients with type 2 diabetes. Through a retrospective clinical audit, the authors aimed to assess the clinical effectiveness of liraglutide, from initiation to first hospital visit, when prescribed at a center in Northern Ireland. METHODS: Patients attending Ulster Hospital who were prescribed liraglutide (June 2009-September 2010) and assessed both at baseline and first post-initiation visit were included in the analysis. The primary endpoint was change in glycated hemoglobin (HbA1c) from baseline. Weight, blood pressure, and frequency of hypoglycemic events were also assessed. RESULTS: Data from 193 patients are reported (baseline HbA1c 9.0%, mean age 55.8 years, diabetes duration 8.8 years, 66.8% male). Average time to first visit after initiation was 13.5 weeks, at which point 174 patients (90.2%) were prescribed 1.2 mg liraglutide. Mean change in HbA1c from initiation to first visit was -0.9%, while mean body weight change was -2.4 kg and change in SBP was -2.0 mmHg. Transient gastrointestinal side effects were experienced by 11.9% of patients. The number of patients experiencing minor hypoglycemic events was low (5.7%) and no major events were reported. CONCLUSION: Data from clinical studies translate into clinical practice: liraglutide provided improved glycemic control after 13.5 weeks of treatment, accompanied by weight loss and low incidence of hypoglycemia.

Sustained improvement in vision in a recurrent growth hormone secreting macroadenoma during treatment with octreotide in the absence of marked tumour shrinkage.

Visual improvement following octreotide for growth hormone secreting pituitary macroadenomas is uncommon without tumour shrinkage. A 45-year old lady presented with blurred vision for 12 months. Visual assessment revealed a bitemporal hemianopia and CT scan demonstrated a large pituitary tumour with lateral and suprasellar extension. Acromegaly was confirmed by 75 g glucose tolerance testing. Primary transsphenoidal surgery was performed with normalisation of visual acuity and fields of vision. Post-operatively she had anterior pituitary hormone deficiency. As GH and IGF-1 levels remained elevated she underwent external pituitary irradiation. CT scanning demonstrated tumour shrinkage associated with a modest fall in GH levels. IGF-1 levels remained elevated falling to the age-related upper limit of normal after 5 years. At regular review she had stable visual acuity and fields of vision. She presented as an emergency 7 years from presentation with reduced vision and recurrence of bitemporal hemianopia. An MRI demonstrated a large pituitary adenoma. We therefore undertook a carefully monitored trial of octreotide with great caution with daily reassessment of acuity and fields. A decision was made to proceed to surgery in the event of deterioration or lack of improvement after a short trial over 5-7 days. We observed normalisation of visual acuity and perimetry within 3 days. She then commenced long-acting octreotide (Sandostatin LAR) 20 mg every 28 days. MRI after 1 week showed shrinkage of the tumour by a few millimetres. Five months later repeat MRI failed to show any further improvement in tumour size. However she remains well 29 months from treatment with normal vision and is being monitored carefully as her chosen form of therapy. Somatostatin analogues may be effective as therapy in a selected group of patients with acromegaly and visual loss who are not suitable for pituitary surgery. If used in this way the drug must be given cautiously with frequent detailed ongoing visual assessments. In this present case there has been a restoration of vision but the long-term outlook remains guarded without significant tumor shrinkage.