Pre-existing diabetes mellitus in patients with multiple myeloma

Type 2 diabetes mellitus is present in approximately 10% of patients at diagnosis of multiple myeloma (MM) and is associated with increased risks of adverse events caused by novel antimyeloma agents. However, the impact of type 2 diabetes on the survival of patients with MM has not been studied.

We enrolled newly diagnosed patients with MM in Taipei Veterans General Hospital between 1999 and 2007 and identified those with pre-existing diabetes. The impact of pre-existing diabetes on patients with MM was evaluated by comparing clinical features, treatments and adverse reactions related to glycaemic control and overall survival (OS) of patients with and without pre-existing diabetes.

Of 310 patients with MM, 73% were men and 40 (12.9%) had pre-existing diabetes. Compared with their non-diabetic counterparts, MM patients with pre-existing diabetes had a significantly higher proportion of renal impairment [(RI), serum creatinine ≥ 2.0 mg/dL] and International Staging System stage III at diagnosis, and a significantly lower proportion of bisphosphonate use and a lower rate of RI reversal (P = 0.087). During the course of the disease, hyperglycaemia and hypoglycaemia of any grade were noted in 23 (67.6%) and 6 (17.6%) of these patients, respectively. Antidiabetic therapy was changed in 10 (29.4%) of 34 evaluable patients. MM patients with pre-existing diabetes had a significantly higher all-cause mortality risk (hazard ratio, 1.509; 95% confidence interval, 1.023-2.225, P = 0.037) compared with their non-diabetic counterparts.

Our study demonstrated the impact of pre-existing diabetes on clinical features and OS in patients with MM.