Don't Trust Your Patient('s Med List)

The Gist:  In addition to physician-borne cognitive errors, patients and the system may contribute to medical errors/misdiagnosis in the ED due to unreliable and incomplete medication histories.  The ED patient may be more likely to experience these errors because:  trauma patients generally don't update their medication lists and ensure it's readily accessible prior to getting into a motor vehicle accident or stabbing, critically ill patients often can't communicate well, access to patient information across multiple databases is insufficient (the ED attracts patients who are away from home or at hours when pharmacies/physician offices are closed), etc.  Second guess medication lists.  Take a better medication history, even if there's one listed on the chart, and assume the patient is on medications that you don't know about (I have no evidence for the latter statement other than the fact that omission errors in medication lists are the most common).  There's a great, free full text article by FitzGerald in the British Journal of Clinical Pharmacology that summarizes this problem nicely.  

The case:  A 52 year old female presented with syncope.  She had an episode of syncope and several episodes of near syncope over the prior day.  Overall, she complained of not feeling well.  The patient's vital signs were significant for a blood pressure of 82/50 and a pulse of 58.  Her symptoms worsened when she stood or moved abruptly, which she hasn't been doing much of because she feels terrible.  No other positives on history or physical.  She had a PMH of hypertension (on 3 medications per medical record/history) and diabetes (glucose 125 on metformin).  Patient's IVC had <30% respiratory variation on ultrasound and ECG showed sinus bradycardia and no other changes.

Diagnosis:  Iatrogenic hypotension and bradycardia secondary to anti-hypertensives.  

Outcome:  Patient's blood pressure was stablized and her medications were reviewed and decreased to two anti-hypertensives at relatively small doses.  She was seen for follow-up by her PCP 4 days after hospital discharge, still feeling "weak."  Her blood pressure and pulse were both still low, 90/64 and 58 beats per minute.  In addition to the medications the patient was supposed to be on: metformin, losartan/hydrochlorothiazide, and atenolol, the patient's medication bag contained the following (all blood pressure pills, three of which were beta-blockers):

Apparently, when doses were changed, she filled the new script and added it to what she had at home.  The patient didn't have great medical literacy, a learning point for when we give verbal or written instructions (hence the bottles labeled "STOP" that were then covered with tape).  

The paper:  This month's American Journal of Emergency Medicine has an article, How reliable are patient-completed medication reconciliation forms compared with pharmacy lists?, describing how inaccurate medication reconciliation forms are in the ED setting.  This is not the first study demonstrating the incredible error rates in patient medication lists.

• Prospective study using a convenience sample
• Patient completed medication reconciliation forms and a research assistant tracked down information from patient pharmacies that covered the preceding 3 months
• 484 eligible, n=315 with complete data sets opted to enroll.
• 33 % (n=104) had errors of omission, 12.7% (n=40) had errors of addition, and 18.1% (n=57) had both types of errors

The scope of the problem:  

• In one study, 78% (n=637) of ED medication histories were inaccurate.  This has been corroborated by multiple other studies, summarized in this systematic review (full text).   
• Most susceptible populations:  individuals with extensive medication lists, minimal health literacy, and limited communication capacity

Ways theses errors cause problems:

• Hypersensitivity/Allergic Reactions
• Cause of patient's ailment
• Directly due to drug.  ex:  NSAIDs/ASA/anti-platelet agents/warfarin - bleeding; diuretics - acute kidney insufficiency
• Polypharmacy.  ex: anticholinergic toxicity from multiple medications which could be detected via a complete medication list
• Narrow therapeutic index.  ex:  phenytoin, lithium, digoxin
• Masking signs or symptoms of illness
• Ex:  Beta-blockers or anti-pyretics
• As the case above demonstrated, it's not only important to know a patient's medication list, but precisely how the patient is actually taking the medications.  
• Ex: Metered dose inhalers (MDIs), for example, are frequently used incorrectly (Educating patients in proper use, yet another reason MDIs + spacer should be used instead of nebulizers in asthmatics - albeit, not the crashing, super sick patient).

Solutions  Note: Most papers are targeted at the inpatient services, but a few have targeted the ED to improve medication history accuracy.

• Review patient's medications verbally.  This is still largely inaccurate as demonstrated by the aforementioned study, although apparently better than reading from a patient's list.  
• Assume that the patient is on medications that are not reflected in their medication list/history.  
• When I see a large, swollen lip I presume the patient is on an ACE-I until proven otherwise.  If they have no idea, my assumption doesn't change initial management (airway, airway, airway, and the anaphylaxis cocktail) but it will cause me to pursue whether or not the patient is on an ACE-I and whether or not I get in touch with their PCP.  All too often, the patient eventually remembers being on a pill for years for blood pressure that ends in "-pril" or a family member brings in the offending bottle of pills.
• Careful attention to the ways we obtain medication lists. A RCT by DeWinter et al (n=260) showed that having EPs ask specific medication history questions can significantly reduce ommision errors, which seem to be the most common in the ED.  In this study, the intervention reduced errors from 1.1 per patient to 0.6 per patient (still pretty high) (2). 
• Systems-level changes.  These are likely more expensive, time consuming, and difficult to implement than individual changes but certainly an area for future improvement.  In fact, this is likely the area that will need to change the most to truly address the problem.
• Changes in ED medication reconciliation process that utilizes "waiting" time and are driven by the patient have been proposed.  This BMJ article proposes that patients could organize medications in the waiting room and be provided with a "toolkit" to assemble their medication lists (numbers to reach physician offices, pharmacies, instructions to call home), if needed.  This would be used in line with electronic medical records reconciliations and confirmation by the nurse when the patient is taken to a treatment room (3).  Looks promising but would take some effort to implement (and benefits are not yet proven).
• Use of pharmacists or technicians within the ED to obtain and confirm medication lists has demonstrated improved accuracy in a few studies, including a small Canadian study that achieved excellent results in obtaining accurate medication histories.  Pharmacists and technicians spent about 8-10 minutes per encounter on the phone with the patient's pharmacy in addition to obtaining medication histories from the patients and electronic medical records (4).  This is a pretty expensive option but if you have them, utilize this resource.
• Electronic Medical Records.  These have short-comings as well, as patients don't always take the medications as prescribed and often receive medications from multiple providers that may or may not be reflected in the system.  This is certainly one piece to the puzzle, and a benefit in patients who may not be able to communicate (due to trauma, sickness, or baseline deficit). 

References:
1.  Mueller SK, Sponsler KC, Kripalani S, Schnipper JL.Hospital based medication reconciliation practices: A systematic Review Arch Intern Med. 2012 Jul 23;172(14):1057-69.

2.  De Winter S, et al.  A simple tool to improve medication reconciliation in the emergency department. Eur J Int Med.  2011 Aug;22(4):382-5. 

3.  Hummel J, et al  Qual Saf Health Care.   Medication reconciliation in the emergency department: opportunities for workflow redesign.2010 Dec;19(6):531-5.

4.  Johnston R, et al.  Best possible medication history in the emergency department: comparing pharmacy technicians and pharmacists.  Can J Hosp Pharm. 2010 Sep-Oct; 63(5): 359–365