The diabetic pen contains a pre-measured dose of insulin in a disposable cartridge. Users push a button on the pen and the proper dose of medication is injected through a needle, explained senior author Dr. Rajesh Balkrishnan, of Ohio State University in Columbus.

"Diabetics who use syringes must carefully measure their insulin, so there is a risk of getting too much or too little," Balkrishnan said in a statement.

The researchers compared 1,162 patients who started insulin therapy with a syringe to 168 who began their therapy with a pen.

The study, published in the journal Clinical Therapeutics, found 53 percent of the pen users taking their medications properly and about 50 percent of syringe users doing so.

However, the study found the annual average healthcare costs were nearly $17,000 lower for insulin pen users than for syringe users at $31,764 a year -- due to fewer hospital and outpatient costs and total diabetes-related costs, which include treatment for vision problems, foot ulcers and circulatory problems.