Patient Safety Tip of the Week
January 13, 2015 More on Numeracy
Low health literacy is an issue well known to impact health
outcomes. For years when we talked about health literacy we focused on reading
levels and reading comprehension. But in our What’s New in the Patient Safety World columns for June 2012 “Parents'
Math Ability Matters” and November 2014 “Out-of-Hospital
Pediatric Medication Errors” we noted a study (AAP
2012) that showed that parents’ mathematics skills, independent of reading
skills, may play a big role in some pediatric medication errors. The study (Marrese 2012)
showed parents with math skills at the third grade level or below were
five times more likely to measure the wrong dose of medication for their child
than those with skills at the sixth grade level or higher. While about a third of the parents
had low reading skills, 83% had poor “numeracy”
skills, with 27% having skills at or below the third grade level. Parents with
low numeracy may especially prone to make errors in tasks requiring dose
measurement or measurement conversions.
The study highlighted the need to address numeracy skills of
parents when communicating medication instructions. They also provided as an
example having providers review and give parents pictures of dosing instruments
filled to the correct amount for that prescription.
We suspected the same issues likely apply to adult
medication errors as well. Now a new study in adults has demonstrated similar
findings. Wong and colleagues assessed health literacy and numeracy in patients
attending rural and urban rheumatologic practices in Australia (Wong
2014). The study utilized two validated and widely accepted tools for
evaluation of health literacy plus a new practical tool that has not yet been
validated. Word recognition was
assessed using the Rapid Estimate of Adult Literacy in Medicine (REALM).
Comprehension was assessed using the Test of Functional Health Literacy in
Adults (TOFHLA). Practical comprehension and numeracy were then assessed
by asking patients to follow prescribing instructions for 5 common rheumatology
medications (they refer to this new tool as the “Rheumatology Literacy Guide”).
The investigators, somewhat to their surprise, found no
statistically significant difference between the rural and urban populations. REALM scores indicated 15% of patients overall
had a reading level ≤Grade 8 whereas 8% had marginal or inadequate
functional health literacy as assessed by the TOFHLA.
However, most strikingly, they found significant proportions
of the patient populations that incorrectly followed prescribing instructions
for 2 drug regimens commonly prescribed for rheumatology patients. Dosing instructions for ibuprofen and
methotrexate were incorrectly understood by 32% and 21% of patients,
respectively.
That, of course, is
of considerable concern particularly since methotrexate errors can result in
serious adverse patient outcomes (see our What’s New in the Patient
Safety World columns for July 2010 “Methotrexate
Overdose Due to Prescribing Error” and July 2011 “More
Problems With Methotrexate”).
The methotrexate
question was “MTX and folic acid are used to treat rheumatoid arthritis. MTX
comes in 10 mg tablets and folic acid in 0.5 mg tablets. A usual dose of MTX is
10 mg once a week and folic acid 0.5 mg once a day. Please count out how many
of each tablet you would need for 1 week.”
The ibuprofen question was “Ibuprofen is a common
anti-inflammatory medication. It is called a non-steroidal anti-inflammatory or
NSAID. A common adverse effect is indigestion. It therefore needs to be taken
just after a meal. Ibuprofen comes in 200 mg tablets. A common dose is 400 mg
twice per day. How many tablets of ibuprofen per day is that?”
The patients handled instructions for the other three
regimens (tramadol, prednisone, and alendronate) much better.
The two standardized validated tools were not very good at
predicting who would err on the methotrexate or ibuprofen tasks.
The authors recommend the following strategies to address
poor health literacy:
- assessing baseline patient
understanding of their condition before providing information
- use of plain language
rather than medical jargon
- emphasizing <3 main
points that are repeated several times during the consultation
- use of “teach back”
(asking patients to explain or demonstrate what they have been told)
They also refer us to the Health
Literacy Universal Precautions Toolkit developed for AHRQ by the North
Carolina Network Consortium and others.
Wong et al. also stress that patients are often embarrassed about their ability to
understand instructions and often overestimate their reading ability. In fact,
some potential study subjects may have declined participation because of such
embarrassment. So problems with health literacy and numeracy may, in fact, be
underestimates.
They found risk factors for low health literacy that are
similar to those found in the literature: male gender, non-English primary
language, lack of university education, and lack of employment. Interestingly,
they also found an association between low health literacy and low use of the Internet.
But don’t let education level fool you. In our May 7, 2013
Patient Safety Tip of the Week “Drug
Errors in the Home” we described the considerable difficulty even
well-educated patients had following some prescription regimens.
Therefore, use of the “teach
back” technique is very important in ensuring that all patients or their
caregivers really understand the instructions and correct dosing of medications.
“Teach back” does require an investment of time. Practices often find that use
of specially trained physician extenders may be useful in this regard.
Hospitals often use pharmacists in this role. Anecdotally, we have found that
patients are more willing to admit their difficulties following instructions to
someone other than the physician, whether that person is a nurse, PA, NP, or
pharmacist. In fact, we actually most often find out about such difficulties
from our receptionists and other front office staff who deal with our patients
frequently.
References:
American Academy of
Pediatrics (AAP). Parents’ Poor Math Skills May Lead to Medication Errors. AAP
press release April 28, 2012
Marrese C, Dreyer B, Mendelsohn A, Moreira H, Yin
HS. Parent Medication Dosing
Errors: Role of Health Literacy and Numeracy (abstract). Pediatric Academic Societies (PAS) annual
meeting April 28, 2012
http://www.abstracts2view.com/pas/view.php?nu=PAS12L1_4021
Wong PKK, Christie L, Johnston J, et al. Observational Study: How Well Do Patients Understand
Written Instructions?: Health Literacy Assessment in
Rural and Urban Rheumatology Outpatients. Medicine 2014; 93(25): e129
AHRQ. Health Literacy Universal Precautions Toolkit. April
2010
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