Observational study of the efficacy of prolonged-release metformin in people with prediabetes

Cost saving analysis of prediabetes intervention modalities in comparison with inaction using Markov state transition model-A multiregional case study

BACKGROUND

Prediabetes management is a priority for policymakers globally, to avoid/delay type 2 diabetes (T2D) and reduce severe, costly health consequences. Countries moving from low to middle income are most at risk from the T2D "epidemic" and may find implementing preventative measures challenging; yet prevention has largely been evaluated in developed countries.

METHODS

Markov cohort simulations explored costs and benefits of various prediabetes management approaches, expressed as "savings" to the public health care system, for three countries with high prediabetes prevalence and contrasting economic status (Poland, Saudi Arabia, Vietnam). Two scenarios were compared up to 15 y: "inaction" (no prediabetes intervention) and "intervention" with metformin extended release (ER), intensive lifestyle change (ILC), ILC with metformin (ER), or ILC with metformin (ER) "titration."

RESULTS

T2D was the highest-cost health state at all time horizons due to resource use, and inaction produced the highest T2D costs, ranging from 9% to 34% of total health care resource costs. All interventions reduced T2D versus inaction, the most effective being ILC + metformin (ER) "titration" (39% reduction at 5 y). Metformin (ER) was the only strategy that produced net saving across the time horizon; however, relative total health care system costs of other interventions vs inaction declined over time up to 15 y. Viet Nam was most sensitive to cost and parameter changes via a one-way sensitivity analysis.

CONCLUSIONS

Metformin (ER) and lifestyle interventions for prediabetes offer promise for reducing T2D incidence. Metformin (ER) could reduce T2D patient numbers and health care costs, given concerns regarding adherence in the context of funding/reimbursement challenges for lifestyle interventions.

Metformin for diabetes prevention: update of the evidence base

We have conducted a narrative review based on a structured search strategy, focusing on the effects of metformin on the progression of non-diabetic hyperglycemia to clinical type 2 diabetes mellitus. The principal trials that demonstrated a significantly lower incidence of diabetes in at-risk populations randomized to metformin (mostly with impaired glucose tolerance [IGT]) were published mainly from 1999 to 2012. Metformin reduced the 3-year risk of diabetes by -31% in the randomized phase of the Diabetes Prevention Program (DPP), vs. -58% for intensive lifestyle intervention (ILI). Metformin was most effective in younger, heavier subjects. Diminishing but still significant reductions in diabetes risk for subjects originally randomized to these groups were present in the trial's epidemiological follow-up, the DPP Outcomes Study (DPPOS) at 10 years (-18 and -34%, respectively), 15 years (-18 and -27%), and 22 years (-18 and -25%). Long-term weight loss was also seen in both groups, with better maintenance under metformin. Subgroup analyses from the DPP/DPPOS have shed important light on the actions of metformin, including a greater effect in women with prior gestational diabetes, and a reduction in coronary artery calcium in men that might suggest a cardioprotective effect. Improvements in long-term clinical outcomes with metformin in people with non-diabetic hyperglycemia ("prediabetes") have yet to be demonstrated, but cardiovascular and microvascular benefits were seen for those in the DPPOS who did not vs. did develop diabetes. Multiple health economic analyses suggest that either metformin or ILI is cost-effective in a community setting. Long-term diabetes prevention with metformin is feasible and is supported in influential guidelines for selected groups of subjects. Future research will demonstrate whether intervention with metformin in people with non-diabetic hyperglycemia will improve long-term clinical outcomes.