I’m slowly getting back into the story around the "ePrescribing/PDA/last mile to the doctors office" issue.  I’ll be writing more about this later, but I’ve been talking around with some people in the know. From my conversations I smell a slow take off in something that wasn’t a big deal when I was a hard core researcher into physician computing-use in 1999 & 2000. 

The last real numbers that I’ve seen are about a year and a half old.  Manhattan Research, in some non-public data from 2002 suggests that 40% of doctors had a PDA, and some 75% of those used them for reference, while some 20% of those with a PDA used them for other work activities beyond reference–which presumably includes a lot of ePrescribing.  I’ve back of the envelope triangulated those numbers with ePocrates’ claim that 250,000 doctors have downloaded their drug reference manual for PDAs and that 25% of US doctors use it as their prime drug information source (over the Physicians Desk Reference, etc).  (The full ePocrates study is here although the group was selected form current ePocrates users by the look of it!).  Assuming that ePocrates is doing a little double-counting in who’s downloaded their app, from combining the numbers you end with roughly 200,000 docs out of roughly 500,000 in practice with PDAs. Of those roughly 150,000 are using them for reference and of those about 30-40,000 are doing something more than that.

Now remember that was early 2002 data, and we are dealing with a growing market. The 2000 data from the Harris study I designed was that ~3% of docs (or 15,000) were using handhelds for ePrescribing, while ~9% (or 45-50,000) were using a computer for ePrescribing (presumably mostly in hospitals).  Harris’ early 2002 data collected in their Vital Signs study for BCG  asking slightly different questions said that about 16% of physicians were using ePrescribing and 21% were likely to in the next 18 months. So if three-quarters of those ePrescribers are using computers (probably mostly in a hospital) it still leaves 25-30,000 using PDAs for ePrescribing in early 2002. So a total guess-timate is that by now we are probably close to 75% above  that number–perhaps 45-50,000 using a PDA for ePrescribing?  (Anyone with more recent numbers, please let me know–I’ll be discreet!!)

Now there are lots of "yeahbuts" here, including that the computer use of ePrescribing in the practice may be mostly for refills and mostly handled by the nurse or clerk, and we don’t have much information about share of script volume written electronically. In other words are docs using it only when they visit the hospital? For that matter in the average doc’s mind, does "writing an electronic Rx" really mean just telling a nurse to type the order in the CPOE system.  Plus it’s very likely that the group using PDAs is skewed heavily towards younger and hospital-based doctors (i.e. residents and maybe attendings at teaching hospitals), who not coincidentally have been in the engine of the CPOE train, and are probably of less interest for pharma companies and health plans. But it does appear that the carriages behind the PDA engine are filling up, and that some technophobic docs are at least thinking about leaving the caboose.

For more about PDA use by clinicians, take a look at this article in Healthcare Data Management, which is long on issues but short on numbers.