This study explored the accuracy of healthcare professionals’ estimation of patients’ health literacy and numeracy as compared to patients’ health literacy and numeracy as measured by a validated questionnaire. The study found that 61.1% of HCPs’ health literacy estimations were correct, and where they were incorrect, HCPs were more likely to underestimate than overestimate their patient’s health literacy. In contrast, HCPs were most likely to overestimate health numeracy, accounting for 63.8% of estimations and correctly estimated health numeracy only 13.9% of the time.

Previous studies, mostly conducted in the USA, using composite measures of health literacy and numeracy such as the Test of Functional Health Literacy in Adults (TOFHLA), found that HCPs correctly estimated health literacy 13–61% of the time. These studies have looked at individual healthcare professional groups with the vast majority of studies being completed in doctors [15]. This study looked at the team as an MDT and included all types of HCPs conducting a consultation with the patient. Ours is the first study of its kind to look at the population attending a MBS clinic and including the full breadth of the MDT, including dieticians and nurses and collecting health numeracy data separately to allow for a separate review of health numeracy skills from health literacy.

The patient cohort in this study had a mean age of 41.9 (SD 12.1) years compared to the London regional mean of 36.9 (SD 21.6). The study population disproportionately identified as women as compared to the London region (83.9% vs. 47.6%) and had a greater proportion of individuals with a level 4 qualification or greater (41.9 vs. 33.9%), such as a university degree or professional qualification. More women undergo MBS and that explains the reason why our study population had higher numbers of females.

In this study population, the majority of patients had functional health literacy, however, patients’ scores in health numeracy varied, with just over a third scoring 1 or less. This reflects wider findings on general literacy and numeracy skills by the Organisation for Economic Co-operation and Development (OECD) which demonstrated that in England, a greater proportion of the population has poor numeracy skills than literacy skills [20].

Question 4 of the health numeracy questionnaire tested the patient participants’ ability to read and use a food label and required a range of skills to complete it. Based on the adult numeracy core curriculum, participants were required to use entry level 3 skills to divide a decimal of 2.5 to 1.25 to calculate the number of servings and level 1 skills to multiply a decimal by 10 [21]. The 2011 Skills For Life survey found that only 50.8% of adults aged 16–65 had the basic numeracy skills of level 1 or greater to complete the numeracy skills in this question [22]. In addition, as a worded problem, the question had linguistic demands, and there was increased complexity due to the presence of extraneous information [23]. This question was only answered correctly by 19.4% of participants.

This study demonstrated two key issues to be considered by the reader. Firstly, the poor agreement between HCPs’ perceptions of patients’ health literacy and numeracy is important in considering how HCPs share information with patients and how we recognise when patients need additional support to be part of shared decision-making and follow treatment plans. This is particularly important in this population who are consenting to elective surgery and who will need to be able to successfully follow advice post-surgery to ensure positive outcomes and avoid complications.

Secondly, the level of health numeracy skills in the population may be unexpected to the reader, and it is particularly of note that even within the population attending a MBS clinic, less than a fifth have the skills to interpret a food label. The study population was more qualified than the general population; however, a large proportion were not able to apply everyday health numeracy skills such as reading a thermometer or food label. When consulting with patients, HCPs should be mindful of the health numeracy skill required to take on new information such as percentages when discussing risk or fractions and decimals when discussing dietary advice. These become particularly important as patients undergoing MBS will have discussions related to the proportions of proteins, carbohydrates and fats in the diet they need to follow.

Further research is required to demonstrate the health literacy and numeracy level of patients undergoing MBS in a larger sample size and across multiple centres. Further work should also be undertaken to understand the health numeracy demands along the patient journey pre- and post-op and describe opportunities to build patients’ health numeracy skills and ensure that information is accessible at all skill levels.

There are several limitations to this study. The sample is small and convenient, with patients and HCPs from a single centre. METER was validated in the USA, and as a result, some words in it such as ‘anemia’ and ‘Fam’ would have had different classifications in the UK; participants were informed at the beginning of the questionnaire that it was written in the USA. Patient participants also fed back that the format of METER was particularly difficult if you had dyslexia and so may not accurately measure your health literacy level. METER only tested reading skills and did not test oral health literacy or the ability to understand and act on advice. GHNT-6 did not test all areas of numeracy such as skills around measures of volume, weight and length which are key skills when following advice around diet and weight loss.

There is no clear evidence-based solution on how to assess health literacy and numeracy outside of research in clinical practice. Further, the use of health literacy and numeracy assessment tools outside of research in the clinical setting is complicated by the feasibility of testing patients, the possibility of causing shame and embarrassment for patients and the challenge of selecting a tool, given the large number of health literacy tools that are available [24]. Existing health literacy and numeracy tools have been used in clinical settings, but users should be aware of their limitations and continue to take universal health literacy precautions with all patients [25]. The hope of this study is to raise awareness of this issue and encourage more research in this area in the future for a better understanding of our patients.

This study demonstrates that HCPs’ estimations alone are likely inadequate to identify patients’ health literacy and numeracy needs. HCPs may therefore consider using universal health literacy precautions to support information being accessible to all patients due to the difficulties of identifying patients without functional health literacy and numeracy skills. Broadly, we can look at this in the consultations and education programmes, in our written communications and in supporting self-care. In the consultation and education programmes, we can support patients’ health literacy and numeracy by using the teach-back method; here, you ask patients to explain in their own words what they have understood. In written communication, including leaflets and letters, we can support patients by using everyday language, using images, minimising medical jargon and acronyms and explaining them when they have to be used. Finally, we can support self-care by encouraging questions, using action plan forms with patients to guide and record the management plan and making prescription easier to follow, e.g. “Take 1 tablet by mouth in the morning and in the evening” instead of “Take 1 tablet by mouth two times per day” [26]. When applicable video materials can be used as an educational tool and can be particularly helpful for explaining self-care activities. Finally, patient and public involvement is an important way to gain feedback on existing and changes to educational materials [26].