I just read an article in a "throwaway" diabetes journal titled "Insulin Pens for Type 2 Diabetes." Although this article isn't on-line, there's a very similar article (published by the same authors!) in Diabetes Care, Factors Affecting Use of Insulin Pens by Patients With Type 2 Diabetes.
I was surprised at the very narrow and misleading focus of the authors on the situation about pen use in the United States. For instance, there's the claim in the throwaway that pens "are used by less than 20% of people who use insulin." Of course, they mean in the sample they chose, which happened to be in the United States. But the abstract in Diabetes Care never mentions the US as the source of the data; if you look at the full-text of the article, you finally can find that information.
Interestingly, in both the throwaway and in Diabetes Care, the authors don't even mention the usage patterns for insulin pens in the rest of the world. In Europe, many insulins come only in pens, and many patients are completely unfamiliar with the use of vials and syringes. One authoritiy is quoted as saying "I'd say 90 percent of the diabetic patients in Europe use the pen over the syringe."
I won't go into the reasons for pen use in Europe vs. syringe use in the U.S. -- many of them are self-evident, although lack of physician familiarity and cost are two obvious ones to mention.
More of a concern, and the focus of this essay: don't believe everything you read. If you did, you'd think that everyone in the world (a) speaks English, (b) measures weight in pounds and distances in miles, (c) is not using an insulin pen.