Review of management of type 2 diabetes mellitus

Incidence of lactic acidosis in patients with type 2 diabetes with and without renal impairment treated with metformin: a retrospective cohort study

OBJECTIVE

To determine whether the use of metformin in type 2 diabetic patients with various kidney functions is associated with an increased risk of lactic acidosis (LA).

RESEARCH DESIGN AND METHODS

This study was a retrospective analysis of U.K. patient records from the Clinical Practice Research Datalink database from 1 January 2007 to 31 December 2012. Inclusion criteria were 1) diagnosis of type 2 diabetes before 1 January 2007, 2) treatment with metformin, and 3) at least one assessment of renal function between 2007 and 2012. Renal function was assessed by glomerular filtration rate and categorized as normal (N), mildly reduced (Mi), moderately reduced (Mo), or severely reduced (Se) function. The outcome of the study was LA.

RESULTS

A total of 77,601 patients treated with metformin for type 2 diabetes were identified. There were 35 LA events (10.37 [95% CI 7.22-14.42] per 100,000 patient-years) of which none were fatal and 23 were linked to a comorbidity. No significant difference in the incidence of LA was observed across N, Mi, Mo and Se renal function groups (7.6 [0.9-27.5], 4.6 [2.00-9.15], 17 [10.89-25.79], and 39 [4.72-140.89] cases per 100,000 patient-years, respectively).

CONCLUSIONS

The overall LA incidence rate for patients on metformin in this study was within the range of rates reported in the literature for patients with type 2 diabetes, and no significant difference was observed among patients with N, Mi, Mo, and Se function.

Hospital pharmacists' role in type 2 diabetes management

Focal points

Metformin, heart failure, and lactic acidosis: is metformin absolutely contraindicated?

Many patients with type 2 diabetes are denied treatment with metformin because of “contraindications” such as cardiac failure, which may not be absolute contraindications

Treatment of patients over 64 years of age with type 2 diabetes: experience from nateglinide pooled database retrospective analysis

OBJECTIVE

To evaluate the impact of renal impairment (RI) (estimated creatinine clearance [Cl(cr)] <60 ml/min per 1.73 m(2)) and low baseline HbA(1c) (<7.5%) on comorbidity in patients with type 2 diabetes, and to assess the efficacy and safety of nateglinide monotherapy in these patients and in subgroups of patients over age 64 years (elderly) and elderly with RI.

RESEARCH DESIGN AND METHODS

Retrospective subgroup analyses were performed on pooled data from all completed nateglinide studies (12 randomized, double blind trials and 1 open trial) in patients with type 2 diabetes. A total of 3,702 patients with > or =1 postbaseline safety evaluation received monotherapy with nateglinide (n = 2,204), metformin (n = 436), glyburide (n = 293), or placebo (n = 769). Efficacy (HbA(1c)) was evaluated in pooled data from four studies with similar design using 120 mg nateglinide (n = 544) versus placebo (n = 521). Evaluations were performed in the overall population and subgroups of patients over age 64 years. Specific considerations were given to RI, comorbidity, and baseline HbA(1c).

RESULTS

Patients over age 64 years (n = 1,170) represented 31.6% of the study population. Undiagnosed RI was common in the elderly with 83.4% of all patients being in this subgroup. Patients over 64 years with RI had a higher prevalence of cardio- and microvascular comorbidity compared with the overall population and all patients over age 64 years. Statistically significant HbA(1c) reductions versus placebo were observed with nateglinide in patients over age 64 years and elderly with RI patients at study end point (-0.9% and -1.1% in each subgroup, P < 0.01). Nateglinide was well tolerated with a low incidence of hypoglycemia in all subgroups, including those with RI and low baseline HbA(1c).

CONCLUSIONS

RI and comorbidity are common in patients over age 64 years with type 2 diabetes. Nateglinide was effective and well tolerated in all treated patients. In subgroups in which metformin and long-acting sulfonylureas must be used with caution, nateglinide had a low risk of adverse events and hypoglycemia.

Metformin in patients with type 2 diabetes mellitus: reconsideration of traditional contraindications

BACKGROUND: The strict limiting criteria for the use of metformin in diabetes mellitus stem largely from reports, in the 1970s, of mortality and lactic acidosis associated with phenformin. Data about metformin are less clear and are based mainly on case reports. The aim of this study was to evaluate the safety of continued use of metformin in patients with contraindications to this agent. PATIENTS: Some 393 patients with type 2 diabetes mellitus (serum creatinine 130-220 &mgr;mol/l) were studied. Among them were 266 patients with coronary heart disease (CHD), 94 with congestive heart failure (CHF), and 91 with chronic obstructive pulmonary disease (COPD), all of whom had been treated with metformin. The patients were randomized to either continue or to stop metformin and were then followed for 4 years. RESULTS: Analysis was by intention-to-treat. The patients who stopped taking metformin showed a rise in body mass index and in hemoglobin A1c significantly greater than those who continued the drug. There were no cases of lactic acidosis. Lactic acid values did not differ in the two groups and correlated only with serum creatinine and body mass index. Microvascular diabetic complications, cardiovascular events, and cardiovascular and total mortality were identical in the two groups. CONCLUSIONS: Diabetic patients who are treated with metformin and who tolerate the drug well may continue taking it, even when mild renal impairment develops, possibly up to serum creatinine levels of 220 &mgr;mol/l. There is also no apparent reason why patients with CHD, CHF, and COPD should discontinue metformin.