There is a high prevalence of type 2 diabetes in older adults, especially those living in long-term care.
Insulin therapy is often an important treatment strategy for managing type 2 diabetes since people with the disease can’t produce enough insulin or can’t use insulin efficiently.
One form of insulin therapy called sliding scale insulin, however, has remained controversial for use in older adults because it doesn’t control blood sugar very well.
This article explains what sliding scale insulin is and whether it should be used to control diabetes in older adults living in long-term care.
Challenges of managing diabetes in older adults
The high prevalence of diabetes in older adults is due to a number of age-related changes, such as increased fat, decreased muscle mass, and chronic low-grade inflammation.
Managing diabetes in older adults living in long-term care remains challenging due to their coexisting chronic medical conditions, such as cognitive impairment, depression, and functional limitations (1).
Consequently, the presence of coexisting illnesses and functional impairments have excluded older adults from studies seeking to find best-practice recommendations for managing diabetes.
This lack of research has led to widespread variability and inconsistency among treatments — particularly insulin therapy — by health care providers for older adults with diabetes.
What is sliding scale insulin?
Sliding scale insulin has been around since the early 1930s, and is still widely used today because it’s easy and convenient (2).
Simply put, sliding scale insulin is an estimate of how much insulin needs to be provided for a given blood sugar level with the help of a predefined rubric.
For example, if a person has a blood sugar level between 201-250 mg/dL, they might receive 4 units of insulin, and for a blood sugar level between 251-300 mg/dL, they could receive 6 units of insulin.
In this way, sliding scale insulin therapy is a reactive way of treating hyperglycemia — or high blood sugars — after it has occurred rather than preventing it.
Hyperglycemia in older adults can cause urinary incontinence, dehydration, confusion, and poor wound healing (3).
The downsides of sliding scale insulin
Insulin given on a sliding scale does not mimic your body’s normal production of insulin, thereby leading to fluctuations in blood sugars.
Normal insulin production involves basal insulin secretion to keep blood sugars stable throughout the day, and spikes of insulin secretions with meals to increase the uptake of nutrients — including sugar — into your cells.
Because sliding scale treats high blood sugar after it has already occurred, instead of preventing it, the reactive nature of this therapy can also lead to rapid changes in blood sugar levels.
For example, one study in nursing home residents showed that the incidence of hypoglycemic — or low blood sugar — events was nearly three times greater in those on sliding scale insulin compared with those not on the insulin therapy (7).
Hypoglycemia is the most important risk factor in determining blood sugar goals in older adults.
Consequences of hypoglycemia in older adults can be serious and, when left untreated, lead to heart attacks, falls, or even death (8).
Due the higher risk of hypoglycemia without evidence suggesting improvements in hyperglycemia, the American Geriatrics Society Beers Criteria for Potentially Inappropriate Medication Use in Older Adults advises against the sole use of sliding scale insulin (9).
A better approach
Despite its convenience and ease of use, many organizations, including the American Diabetes Association and American Geriatrics Society recommend against the sole use of sliding scale insulin for managing diabetes in older adults (10, 11).
Instead, experts recommend basal insulin, with mealtime insulin added as needed according to what and how much people want to eat. This recommendation better mimics normal insulin production and controls blood sugars more effectively.
Basal insulin is a longer acting form of insulin that keeps blood sugars stable through the day. Added to this is rapid-acting insulin given at mealtimes and correction doses as needed to account for higher blood sugar levels.
A study in 64 nursing home residents with type 2 diabetes found that compared with sliding scale insulin, basal with meal time insulin resulted in significantly lower average fasting blood sugar levels after 21 days (12).
Researchers of the study concluded that switching to basal with meal time insulin is feasible, safe, and effective in the long-term care setting.
Nonetheless, treatment recommendations and goals of care for older adults with diabetes should be individualized based on their life expectancy, coexisting medical conditions, functional status, and risk of hypoglycemia (13).
Additionally, these recommendations and goals should be made with the person and include person-centered care from an interdisciplinary team, consisting of physicians, pharmacists, nurses, dietitians, food service managers, social workers, and physical therapists.
Diabetes is a common yet difficult disease to manage in older adults living in long-term care.
The general consensus among many organizations is to avoid the sole use of sliding scale insulin and instead, transition to basal insulin and mealtime insulin, which better mimics normal insulin production.
In accordance with the resident, the interdisciplinary team can develop a plan of care that includes treatment plans and goals for diabetes management that can lead to improved health outcomes and quality of life.