Use of maximal dosage renin-angiotensin-aldosterone system inhibitors in a real life population of complicated type 2 diabetes - contraindications and opportunities

OBJECTIVE

Pharmacological inhibition of the renin-angiotensin-aldosterone-system (RAASi) is the cornerstone of hypertension treatment, renoprotection and secondary prevention of cardiovascular disease in patients with type 2 diabetes. Although there is a dose-dependent effect of RAASi with optimum protection when using maximal dose, little is known on actual use of maximal dosage RAASi in clinical practice. Here we investigate prevalence of maximal dosage RAASi, and contraindications for, optimizing RAASi dosage, in patients with complicated type 2 diabetes in a real-life clinical setting.

RESEARCH DESIGN AND METHODS

We performed a retrospective analysis in 668 patients included in the DIAbetes and LifEstyle Cohort Twente (DIALECT). We grouped patients according to no RAASi, submaximal RAASi and maximal RAASi use. All potassium and creatinine measurements between January 1st 2000 and date of inclusion in DIALECT were extracted from patients files. We identified determinants of maximal RAASi use vs. submaximal RAASi use with multivariate logistic regression analysis.

RESULTS

Mean age was 64 ± 10 years and 61% were men. In total, 460 patients (69%) used RAASi, and 30% used maximal RAASi. Maximal RAASi use was not statistically different between different indications for RAASi (i.e. hypertension, diabetic kidney disease, coronary heart disease and cerebrovascular disease; P > 0.05). Per patient, 2 [1-4] measurements of potassium and 20 [13-31] measurements of creatinine were retrieved, retrospective follow-up time was - 3.0 [-1.4 to -5.7] years. Pre-baseline hyperkalemia > 5.0 mmol/l and acute kidney injury were found in 151 (23%) patients and 119 patients (18%), respectively. Determinants of maximal RAASi were prior acute kidney injury (OR 0.51 (0.30-0.87)), increased albuminuria (OR 1.89 (1.17-3.08)) and total number of used antihypertensives (OR 1.66 (1.33-2.06)).

CONCLUSIONS

Maximal dose RAASi is used in almost one third of complicated type 2 diabetes patients in a real-life setting. The prevalence of contraindications is considerable, but relative in nature, suggesting that it is worthwhile to explore strategies aimed at maximizing RAASi while circumventing the alleged contraindications.

Simultaneous quantification of dabrafenib and trametinib in human plasma using high-performance liquid chromatography-tandem mass spectrometry

Dabrafenib (Tafinlar(®)) and trametinib (Mekinist(®)) are registered for the treatment of patients with BRAF V600 mutation positive unresectable or metastatic melanoma. To support therapeutic drug monitoring (TDM) and clinical pharmacological trials, an assay to simultaneously quantify dabrafenib and trametinib in human plasma using liquid chromatography tandem mass spectrometry was developed and validated. Human plasma samples were collected on an outpatient base and stored at nominally -20°C. Analytes and internal standards (stable isotope labeled compounds) were extracted with TBME. After snap freezing the samples in a dry ice-ethanol bath, the organic layer was transferred to a clean tube and evaporated under a gentle stream of nitrogen gas. The dry extract was then reconstituted with 100μL acetonitrile and 5μL of the final extract was injected and separated on a C18 column with gradient elution, and analyzed with triple quadrupole mass spectrometry in positive-ion mode. The validated assay ranges from 50 to 5000ng/mL for dabrafenib and 0.5-50ng/mL for trametinib were linear, and correlation coefficient (r(2)) of 0.996 or better. At all concentrations of both analytes the biases were within ±15% of the nominal concentrations and precisions were ≤15%. All results were within the acceptance criteria of the latest US FDA guidance and EMA guidelines on method validation. Dabrafenib was found to degrade under the influence of light in different organic solvents and at least seven degradation products were detected. In conclusion, the described method to simultaneously quantify dabrafenib and trametinib in human plasma was successfully validated and applied for therapeutic drug monitoring in cancer patients treated with dabrafenib and trametinib.