The Preferred Insulin for the Elderly

Long-acting forms of insulin seem to be the best choice for elderly patients diagnosed with type 2 diabetes.

A study published in JAMA Internal Medicine shows that insulin detemir and insulin glargine had a lower risk of hypoglycemia development in the elderly than NPH insulin. Both insulin glargine and insulin detemir are long-acting insulins, whereas NPH insulin is intermediate-acting. The study was conducted with approximately 575,000 participants. The purpose of this study was to determine the probability of hospital visits in elderly patients with type 2 diabetes who were on long-acting insulin versus NPH due to hypoglycemia.  

Of the 575,000 patients, 26,402 were on NPH insulin, 141,588 were on insulin detemir, and the remaining 407,018 patients were on insulin glargine. In an intermediate check-in of 0.37 years, 7,347 hospital visits for hypoglycemia were recorded. Of these 7,347 visits, 460 were for NPH, 1,693 were for detemir, and 5,194 were for glargine. Insulin glargine induced low blood sugar in 1.28 percent, insulin detemir caused low blood sugar in 1.20 percent, and insulin NPH initiated hypoglycemia in 1.74 percent. Patients starting glargine and detemir had a 30 percent decreased risk of going to the E.R. for low blood sugar. There were significantly fewer patients on NPH insulin than there were on glargine and detemir, yet the percentages of hypoglycemia-induced hospital visits were relatively similar. If the study had an equal number of people on NPH as on the other two insulins, the hospitalization rate would have increased. 

One of the benefits of prescribing insulin glargine and insulin detemir to older adults is the dosing. Because both of these insulins are long-acting, they are typically dosed once daily. Once-daily dosing is excellent for elderly adults as they sometimes have issues with keeping up with their medications. If an elderly patient was on an insulin regimen that required multiple injections daily, they might not be able to keep track. If they end up taking too many doses, this could cause them to experience hypoglycemia. 

This study had its limitations. The research was lacking laboratory data. Because there was no laboratory data, researchers could not adjust for glycemic control at baseline. Making such adjustments would help account for variations in the study. The missing information would also allow doctors to decide the necessity of starting a patient on insulin therapy. Regardless of the lacking information, it is advised that physicians initiate a long-acting insulin therapy instead of insulin NPH.  

Although insulin NPH is not the preferred drug of choice, that does not make it a bad option. Physicians need to exercise caution when prescribing it and assess a patient’s risk of developing hypoglycemia. If a patient is at an increased risk of developing hypoglycemia, their doctor should prescribe alternative insulin instead of insulin NPH. When starting older patients on insulin therapy, doctors should be completely transparent with their patients. The patient should be aware of all the risks and potential side effects that could result from insulin use. Patients should also be mindful of the benefits they can receive from the medicine. Together, the physician and patient can determine whether the benefits outweigh the risk and if insulin therapy is right for them.  

Practice Pearls: 

• Insulin detemir and insulin glargine have a lower risk of hypoglycemia development in the elderly than NPH insulin. 
• When compared, insulin detemir and glargine resulted in fewer hospitalizations for hypoglycemia than insulin NPH. 
• Physicians need to exercise caution when prescribing insulin and assess a patient’s risk of developing hypoglycemia. 

Marie C. Bradley, Ph.D., MPharm, MScPH; Yoganand Chillarige, MPA, et al. Severe Hypoglycemia Risk with Long-Acting Insulin Analogs vs. Neutral Protamine Hagedorn Insulin. JAMA Internal Medicine, March 01, 2021. 

Reuters staff. Less Risk of Severe Hypoglycemia with Long-Acting Insulin Analogs in Elderly. Medscape, March 2, 2021. 

Oluwatayo Ishola, PharmD Candidate, South College School of Pharmacy