Diabetes is a big problem in the US — and thus, it is a big focus of doctors, researchers and pharmaceutical companies alike. New medications and developments alter how diabetes is treated.
A new study aimed to measure how outpatient visits for diabetes were being managed in the US.
The study found that both visits using two or more medications and the amount of money spent on these medications have increased in recent years.
Led by Lydia W. Turner, MHS, of the Department of Epidemiology at the Bloomberg School of Public Health in Baltimore, Maryland, this study focused on the treatment of type 2 diabetes in ambulatory care. Also called "outpatient" care, ambulatory care means the patient does not stay at the hospital or clinic overnight.
In type 2 diabetes, the body does not use the hormone insulin (which helps the body use glucose for energy) properly, resulting in high blood glucose levels. According to the American Diabetes Association (ADA), in 2011, an estimated 25.6 million Americans age 20 or over (11.3 percent of this age group) had diabetes.
"The prevalence and burden of diabetes have made it a target ripe for pharmaceutical development, and during the past decade several important changes in the marketplace have occurred," Turner and colleagues wrote.
According to these researchers, glitazones, or thiazolidinediones, began to be used at high rates in the early 2000s to treat diabetes, but worries related to cardiovascular risks slowed their use in the late 2000s. Examples of glitazones include pioglitazone (brand name Actos) and rosiglitazone (Avandia), which recently had restrictions related to heart troubles removed by the FDA.
Long-acting insulin injections taken once per day have seen increased development and use by patients in recent years. These medications include insulin glargine (Lantus) and insulin detemir (Levemir).
The authors of this study also explained that during the past 10 years, the US Food and Drug Administration (FDA) approved several new types of treatment for type 2 diabetes, including injectable incretin mimetics (GLP-1 agonists), DPP-4 inhibitors and SGLT-2 inhibitors.
GLP-1 agonists, including exenatide (Byetta) and liraglutide (Victoza), work to stimulate the pancreas to create insulin and slow the emptying of the stomach, decreasing appetite. DPP-4 inhibitors are used specifically for type 2 diabetes, and include linagliptin (Tradjenta), saxagliptin (Onglyza) and sitagliptin (Januvia).
SGLT-2 inhibitors, like canagliflozin (Invokana), lower the body's rate of reabsorption of filtered glucose, leading to an increase of glucose excretion through the urine.
Turner and colleagues used data from the IMS Health National Disease and Therapeutic Index, which is a national evaluation of ambulatory physician practices, to identify visits made by diabetes patients 35 years old or older. These researchers also used the IMS Health National Prescription Audit of pharmacy dispensing to examine data about expenditures for medication. The data was then used to estimate nation-wide totals.
Turner and team found that ambulatory diabetes visits increased from an estimated 23 million in 1997 to an estimated 35 million in 2007. However, the number of visits fell slightly to 31 million in 2012.
These researchers found a continuous decline in sulfonylurea use from an estimated 61 percent of treatment visits (meaning a visit where one or more pharmaceutical treatment was used for diabetes) in 1997 to 22 percent of treatment visits in 2012.
Sulfonylureas, including glimepiride (Amaryl) and tolazamide (Tolinase), cause the pancreas to produce insulin and help the body use the hormone effectively.
The researchers also found that use of the medication biguanide increased from 24 percent of treatment visits in 1997 to 53 percent of treatment visits in 2012.
Biguanides work to lower the amount of glucose absorbed from food and produced by the liver. One example of a biguanide is metformin (Fortamet, Glucophage). Gastrointestinal issues like diarrhea and cramps are a common side effect of these medications.
Use of glitazone medications increased from 6 percent of treatment visits in 1997 to 41 percent in 2005, but declined to 16 percent in 2012.
Use of DPP-4 inhibitors increased steadily since they were approved by the FDA in 2006, to a rate of 21 percent of treatment visits in 2012. GLP-1 agonists, introduced around the same time, were used in 4 percent of treatment visits in 2012.
Visits that used two or more medications increased by a large amount — almost 40 percent from 1997 to 2012.
The amount of money spent on medications increased 61 percent between 2008 and 2012, which the authors of this study noted was driven mostly by the use of insulin glargine and DPP-4 inhibitors.
"Treatment of diabetes has grown in complexity while older treatments continue to be replaced or supplemented by newer therapies," these authors wrote.
This study was published online November 6 in Diabetes Care.
Two of the study's authors have served as board members or consultants for IMS Health, one in a paid role and the other in an unpaid role.