AIMS To evaluate the plasma values of vitamin B12 in a population of patients with type 2 diabetes or impaired glycemic regulation, outpatients in a Diabetes Unit in Campania Region (Italy), in order to highlight any factors that could be correlated with vitamin deficiency, in particular metformin treatment.

METHODS We divided our patients into two groups: those who were in long-term treatment with metformin and those who did not received such therapy, in each group we reported the plasma values of vitamin B12 along with other factors that are known as possible interferents with the vitamin, in particular the use of proton pump inhibitors or H2-antagonists, the age and the years of the diabetic disease, as well as creatininemia and glycated hemoglobin.

RESULTS Patients chronically treated with metformin have significantly lower plasma values of vitamin B12 than patients who did not use these medications, and similarly have more often a true vitaminic deficiency (< = 200 pg/ml), further confirming these data, we found a negative, statistically significant correlation between B12 values and drug dosage and years of therapy. According to our data, age, years of diabetes and glycated hemoglobin were also statistically significant predictors of lower plasma values of vitamin, and the use of gastroprotectors is correlated with lower average values, albeit not statistically significant (P = 0.06).

CONCLUSIONS Chronic metformin therapy is the most important predictor of low plasma B12 values, in fact even at multivariate analysis, correcting the data for all the above mentioned variables, this relationship remained significant, while for the other factors taken into consideration, statistical significance was lost. We conclude that vitamin B12 deficiency is very frequent in subjects with diabetes receiving metformin, especially if at higher dosages and for longer periods, in these patients the plasma dosage of the vitamin is strongly recommended. Among patients using metformin, the use of proton pump inhibitors and anti-H2, while reducing the average values of plasma B12 levels, does not seem to have a significant additive effect, whereas among who do not take metformin the effect of these drugs is more pronounced and significantly reduce the average level of vitamin when compared with patients who do not take gastroprotectors.

KEY WORDS metformin; vitamin B12 deficiency.

AIM OF THE STUDY Management of diabetes in oncological patients has critical aspects. Even if the treatment of patients with combined diabetes and cancer is getting more and more common, no shared strategies or dedicated guidelines exist, at present. This study aims at analyzing the characteristics of the population referred and the activities carried out in a centre specifically dedicated to the management of diabetes in oncological patients.

DESIGN AND METHODS The study retrospectively evaluated the population referred to a dedicated Centre in a tertiary university hospital in Turin, Italy, between January 2013 and December 2017. The clinical features at presentation, the cancer therapies, and the clinical management of diabetes of 167 consecutive patients have been analyzed. Furthermore, we evaluated the compliance to the process indicators as well as to the outcome indicators issued in the Clinical Pathway for the management of diabetes in cancer patients, edited by the Oncology Network of Piemonte and Valle d’Aosta.

RESULTS The clinical features of the population referred to the Centre were very heterogeneous. About 80% of the patients were treated with corticosteroids, while 11% were treated with targeted therapies that could potentially affect their glucose metabolism. Insulin was the most commonly prescribed drug during the first visit and thereafter. As for the other antidiabetic drugs, metformin was the second mostly used treatment, followed by pioglitazone, DDP-4 inhibitors, SGLT-2 inhibitors, and glinides. The process and outcome indicators have all been complied to.

CONCLUSIONS Diabetes management in patients with cancer often reveals to be challenging due to the complexity of the clinical situation of patients, their nutritional problems, the cancer and supportive therapies (especially glucorticoids). Insulin therapy proved to be the most widely used treatment because of its efficacy, flexibility, and positive effects over fatigue and appetite. Other antidiabetic therapies can also be effective, albeit paying particular attention to liver, kidney, and pulmonary functions and to their tolerability. The clinical assistance to patients with both diabetes and cancer must be individualized and should involve the caregivers. The prognosis and the goal to achieve should be considered in order to define the most appropriate glycaemic target, the frequency of blood glucose monitoring, and the choice of antidiabetic therapy. A growing and closer cooperation among oncologists and endocrinologist comes out to be essential to achieve this goal.

KEYWORDS diabetes mellitus, cancer, appropriateness, care pathways.