What is the efficacy of initiating metformin (metformin hydrochloride) therapy in a 93-year-old patient with newly diagnosed prediabetes (impaired glucose regulation)?

From the Guidelines

Starting metformin for a 93-year-old patient with newly diagnosed prediabetes is generally not recommended. The potential benefits of metformin in this age group are limited compared to the risks of side effects, including gastrointestinal disturbances, vitamin B12 deficiency, and rarely lactic acidosis 1. For elderly patients, especially those over 90, management should focus on modest lifestyle modifications like gentle physical activity as tolerated and simple dietary changes to limit excessive carbohydrate intake. Blood glucose monitoring should be less stringent, with higher acceptable targets to avoid hypoglycemia, which can be particularly dangerous in the elderly. The American Geriatrics Society and other medical organizations suggest less aggressive glycemic targets for very elderly patients, recognizing that the time to benefit from preventive interventions often exceeds life expectancy, while the harms of medication can be immediate 1. Quality of life considerations should take precedence over strict glycemic control in this age group. Instead of medication, regular follow-up to monitor for progression to diabetes and addressing cardiovascular risk factors may be more beneficial.

Some key points to consider in the management of prediabetes in the elderly include:

• Focusing on lifestyle modifications rather than medication 1
• Avoiding hypoglycemia, which can be dangerous in the elderly 1
• Considering the patient's quality of life and life expectancy when making treatment decisions 1
• Monitoring for progression to diabetes and addressing cardiovascular risk factors 1
• Being aware of the potential side effects of metformin, including gastrointestinal disturbances and vitamin B12 deficiency 1

Overall, the decision to start metformin in a 93-year-old patient with prediabetes should be made on a case-by-case basis, taking into account the patient's individual needs and circumstances. However, in general, lifestyle modifications and regular follow-up are likely to be a safer and more effective approach than medication in this age group.

From the Research

Efficacy of Metformin in Prediabetes

The efficacy of initiating metformin therapy in a 93-year-old patient with newly diagnosed prediabetes is a topic of debate.

• Metformin has been shown to decrease the risk of diabetes among individuals with prediabetes by 3.2 cases per 100 person-years during 3 years 2.
• However, metformin is most effective for women with prior gestational diabetes and for individuals younger than 60 years with body mass index of 35 or greater, fasting plasma glucose level of 110 mg/dL or higher, or HbA1c level of 6.0% or higher 2.
• A study found that targeted pathophysiologic therapy based on oral glucose tolerance test-derived measures of insulin sensitivity and β-cell function can be implemented in general internal medicine and endocrine practice and is associated with marked improvement in glucose tolerance and reversion of prediabetes to normal glucose tolerance in more than 50% of patients 3.
• Another study suggested that metformin should not be used to treat prediabetes, as approximately two-thirds of people with prediabetes do not develop diabetes, even after many years, and people who meet the glycemic criteria for prediabetes are not at risk for the microvascular complications of diabetes 4.

Considerations for Metformin Prescription

When considering metformin prescription for patients with prediabetes, the following points should be taken into account:

• Metformin prescription rates among patients with prediabetes are low, with only 2.4% of patients receiving a metformin prescription within 1 year of a laboratory-confirmed prediabetes result 5.
• Patients who are obese or aged < 60 years are more likely to receive a metformin prescription, but prescription rates are still low in these groups 5.
• The American Diabetes Association has highlighted metformin therapy as a consideration for individuals with BMI ≥ 35 kg/m2, those aged < 60 years, and women with a history of gestational diabetes 5.

Metformin Therapy in Older Adults

There is limited evidence on the efficacy and safety of metformin therapy in older adults with prediabetes.

• A study found that metformin is generally well-tolerated and safe, but decades of clinical use have demonstrated that metformin can have adverse effects, particularly in older adults 6.
• The study by 2 did not provide specific guidance on the use of metformin in older adults with prediabetes, but suggested that lifestyle modification is associated with a larger benefit than metformin.