Medical or Common Knowledge? Knowledge of Medical Professionals on Obesity Diagnosis Criteria and Treatment

The World Health Organization (WHO) defines obesity as a chronic disease resulting from excessive, abnormal accumulation of body fat in excess of its physiological needs, which may impair health and increase the risk of premature death [1]. For over 20 years, obesity has been classified as an epidemic [1]. Nevertheless obesity remains under-identified and undertreated [2, 3]. A cross-sectional study of the National Health and Nutrition Examination Survey (NHANES) showed that only 40% of adults with overweight or obesity reported that they received counseling to lose weight [4]. Proper diagnosis of obesity, its severity, obesity complications, and their effective treatment requires an interdisciplinary healthcare approach. The development of academic knowledge concerning obesity pathology, diagnosis, and treatment is increasing [5]. Nevertheless, it is not clear whether this translates into clinical practice. Obesity management should be multidisciplinary, involving physicians, surgeons, psychologists, nutrition experts, nurses, and physiotherapists.

Despite the high prevalence rates of obesity in the population, the disease does not seem to be regularly diagnosed in general practice [6]. There are many barriers to the appropriate treatment of obesity: negative attitudes toward patients with obesity and medical professionals’ view of themselves as not being prepared to treat obesity are two such barriers [7, 8]. Even professionals who specialize in obesity have a weight bias [9, 10].

In the USA, approximately one-quarter to one-third of the medical schools included little to no coverage of rudimentary treatments for obesity and also did not prioritize development of future curricula in obesity [11]. Knowledge of obesity management is not routinely assessed in medical school examinations [12]. Therefore, the finding that 70% of medical professionals have never received any education related to obesity should not be surprising, although it should be alarming [13].

Many prominent scientific societies have presented guidelines regarding diagnostic and therapeutic procedures related to obesity [14‒17]. Clinical care and practice related to obesity is currently inconsistent with evidence-based recommendations [18]. Authors of an international consensus statement for ending the stigma associated with obesity have highlighted the gap between scientific evidence and misconceptions in the public narrative, such as “obesity is primarily caused by voluntary overeating and a sedentary lifestyle,” “body weight = calories in – calories out,” “obesity is a lifestyle choice,” “obesity is a condition, not a disease,” “severe obesity is usually reversible by voluntarily eating less and exercising more” [19]. Such public narrative may become common knowledge. Fan et al. [20] showed that 60% of nurses obtained information about bariatric surgery from the mass media, while only 5.6% obtained such information from medical school education. Mass media and social platforms are the most direct and common ways university students obtain information [21]. The media serve to influence, reflect, and reinforce social norms, attitudes, and beliefs about weight. Weight bias is thought to be perpetuated by the media via idealization of body types that are inconsistent with being overweight and via underrepresentation and stereotyping of people living with overweight and obesity [22].

Previous publications assessed the knowledge of various groups of medical professionals – physicians, nurses, or physiotherapists; however, there are no publications that compare all these groups. Thus, the goal of this study was to assess knowledge of healthcare professionals (HCPs) on obesity, in particular the criteria for diagnosis and conservative and surgical treatment. Self-assessment of knowledge about the diagnosis and treatment of obesity was evaluated, and it was verified whether the self-rated knowledge level correlated with the actual level of knowledge.

This cross-sectional study was conducted in Poland among active HCPs (N = 184) (including physicians, nurses, physiotherapists, and paramedics) who had contact with adult patients with obesity. The quantitative data were gathered with the use of the Computer-Assisted Web Interview method [23]. The study was positively evaluated and approved by the Independent Bioethics Commission for Research at the Medical University of Gdansk (NKBBN/694/2019–2020). Data were collected from January 2019 to September 2020.

Social media, professional self-government channels, and “snowball sampling” were used to recruit respondents. The invitation to participate in the study was sent to HCPs and instigated by medical institutions via mailing. The study was conducted under the patronage of the Polish Patients’ Rights Ombudsman and was supported by the Team for Counteracting Discrimination of Patients with Obesity at the Office of the Patient Ombudsman. Participation in the study was voluntary and fully anonymous. Voluntary consent for participation in the study was confirmed by each participant. No sensitive data were collected as part of the study. The study manual contained information on the study’s purpose and form. HCPs could withdraw from participation in the study at any point, and their responses were not included in the analysis. HCPs were informed that sending a fully completed survey was tantamount to consent to participate in the study. We also made sure the data collected were safe. No sensitive data were collected during the study.

The research survey consisted of three sections. In the first section, “knowledge about obesity,” respondents were asked to subjectively assess their own knowledge (9 closed questions based on a Likert scale) about obesity and attitudes to statements relating to patients living with obesity (12 closed questions in which responses were based on a Likert scale). This section also included a knowledge test analyzing knowledge of obesity treatment guidelines adopted in Poland (10 closed questions with a single-choice question). The second section addressed the situation of patients living with obesity in medical institutions. It contained fourteen closed questions and one open-ended question. The last section dealt with the relationship between medical personnel and patients living with obesity and consisted of 18 closed questions. The independent variables for this study were 12 questions relating to gender, age, place of residence, seniority and place of work, occupation, degree, weight, height, and participation in educational programs.

In the presented study, we focused on presenting the results obtained from the analyses on the first section. Due to the extent and multifaceted nature of obesity, the analysis was limited to two areas: the diagnosis and the treatment of obesity. For the diagnosis, there were four indicator questions, while there were six for treatment. These questions were related to body mass index (BMI) definition, BMI values, visceral obesity definition, bariatric surgery indications, choice of treatment method, role of diet and physical activity, knowledge of new anti-obesity drugs, length of obesity pharmacotherapy, financing of bariatric procedures, goals of bariatric treatment.

The content of the questions was agreed on by specialist doctors from the Team for Counteracting the Discrimination against People with Obesity at the Patients’ Rights Ombudsman in Poland. Correct answers were determined in accordance with the Polish recommendations for the diagnosis and treatment of obesity [5]. Knowledge-related questions were single-choice questions with four answer options. HCPs’ self-rated knowledge level was assessed with the use of a five-point scale, in which 1 indicated a “complete lack of knowledge,” while 5 indicated “high level of knowledge.”

The data obtained were analyzed using SPSS v.26 (IBM SPSS, Inc., Armonk, NY, USA) and Statistica 13.3 (TIBCO, Palo Alto, CA, USA) software. In the analysis of relationship between the noncontinuous variables and statistical heterogeneity of groups, Pearson’s χ² test, the Mann-Whitney U test, and the Kruskal-Wallis H test were used. The level of correlation between the self-assessed knowledge on obesity and the actual knowledge on obesity was defined with Spearman’s method. p < 0.05 was adopted as a statistical significance threshold.

Among the respondents (N = 184), 65.7% were women. Overall, 55.4% were inhabitants of large cities (over 100,000 inhabitants). Young professionals – under 29 years old – comprised the largest group of respondents (42.4%). One in three respondents (30.4%) was between 30 and 45 years old, while 27.2% were aged 46 years and older. Half of the respondents (52.2%) were doctors, 20.7% were nurses and midwives, 19.0% were physiotherapists, and 8.2% were other medical professionals (including paramedics and technicians). Half of the participants (51.5%) reported a hospital as their main workplace. Almost a quarter (22.8%) of respondents were employed in outpatient primary care, while 3.3% were employed in specialist clinics. About half (47.3%) had work experience of up to 5 years, while 23.9% had work experience of 5–20 years. Every fourth respondent (28.8%) had work experience exceeding 20 years. Characteristics of the respondents are presented in Table 1.

Among all answers to the questions regarding knowledge on obesity, 67.1% were correct, with respondents providing correct answers to questions concerning obesity diagnosis more frequently (70.1%) than to questions concerning treatment methods (64.6%). The largest number of correct answers concerned the definition of BMI (98.9%) and healthy BMI which is in the 18.5 kg/m² to 24.9 kg/m² range (89.1%). The smallest number of correct answers pertained to the diagnostic criteria for visceral obesity and the pharmacological treatment of obesity (38.6%) (Fig. 1).

Each of the respondents with the lowest level of knowledge on obesity as disease (N = 18, 9.8% of respondents) gave four correct answers. The respondents with the highest level of knowledge (N = 7, 3.8% of the study population) answered all 10 questions correctly. The distribution of correct answers is presented in Table 2.

It has been observed in our study that workplace and participation in training sessions had the largest impact on the level of knowledge on obesity. On average, the respondents who worked in hospitals answered 7 questions correctly, and the median was 7, while the ones who worked in outpatient centers answered 6.4 questions correctly, and the median was 6 (U = 3,297.0, z = −2.62, p = 0.009). The respondents who had participated in training sessions on obesity answered a larger number of questions correctly than did those who had not taken part in such sessions (M = 7.1 and Me = 7 vs. M = 6.6 and Me = 6, respectively; U = 2,892.5, z = −2.2, p = 0.026).

The respondents’ age also had an impact on the level of the obesity knowledge. A low level of knowledge was present more often in respondents under 29 years old (51.3%) than in respondents aged 30 years and more (39.6%) (χ² = 6.546; df = 2; p = 0.03).

Additional differences were observed in reference to particular questions. For instance, older respondents (30 years or older) knew the regulations on bariatric surgery procedure reimbursements more often than did young respondents (69.8% vs. 55.1%; χ² = 4.184; df = 1; p = 0.04). Similarly, hospital employees were more familiar with the regulations on reimbursement than were employees of outpatient centers (70.5% vs. 56.2%; χ² = 4.085, df = 1; p = 0.04).

No statistically significant impact of a respondent’s levels of knowledge on obesity of different medical professions was noticed.

The respondents were not confident of their own knowledge of obesity diagnosis (2.8/5) and treatments (2.3/5; statistica: U = 11,694, z = 5.12923, p < 0.0001). Respondents who participated in training related to obesity had a lower regard of their own skills (knowledge on diagnosis: 2.6/5 and knowledge on treatment: 2.0/5: statistica: U = 279.5, z = 2.63, p = 0.008) than those who did not take part in such training sessions (knowledge on diagnosis: 2.9/5 and knowledge on treatment: 2.4/5; statistica: U = 2,751.5, z = 2.6, p = 0.005). The impact of the respondents’ type of medical profession on the level of self-assessment was not observed.

Medical professionals’ own assessment of their knowledge on obesity treatment was negatively correlated with their actual level of knowledge in this field. This correlation was moderately strong but statistically significant (rho = −0.2308; p = 0.002).

Given that overweight and obesity is highly prevalent in many societies, practically every HCP has daily contact with patients with excessive body weight. Our research showed that 32.9% of HCPs did not have sufficient knowledge. This raises concerns about providing healthcare services and compliance with applicable standards on obesity diagnosis and treatment.

The highest number of correct answers (99%) was related to the definition of BMI, a parameter dating back to the 19th century [24]. Previous studies have shown that BMI is the most widely known marker for assessing obesity [25, 26]. Additionally, 97% of answers related to a question about the role of diet modification and physical activity in obesity were correct; however, this knowledge has also been understood since centuries. These results complement findings from previous studies that knowledge of diet modification and physical activity is greater than knowledge about pharmacotherapy or bariatric surgery [18, 27]. Knowledge of BMI values cannot be considered as being exclusively in the medical domain. These values were established years ago and are widely available in public sources, such as lifestyle magazines and even primary school textbooks. A Chinese study showed that nurses obtained information about obesity treatment mostly from mass media, such as television, websites, newspaper, and magazines [20]. The media serve to influence, reflect, and reinforce social norms, attitudes, and beliefs about obesity. The prejudices against obesity presented in the mass media may negatively contribute to HCP’s diagnostic and therapeutic decisions.

The most problematic questions for the HCPs pertained to specialist knowledge: modern pharmacotherapy (39%), indications for bariatric surgery (51%), or the definition of visceral obesity (44%). These results were comparable to those of previous studies [12, 28].

We speculate that the competencies of HCPs related to obesity are limited to common knowledge, which does not necessarily translate into diagnostic and therapeutic success. The argument supporting this hypothesis is the fact that we found no statistically significant differences in the level of knowledge of different medical professions. In Norway, studies about obesity knowledge among first-year medical students were surprisingly similar to that of final-year students. It is also worth pointing out that first-year students answered a few more questions correctly than did final-year students [29]. However, in another study conducted in Switzerland, there were small but significant differences between the levels of knowledge about obesity of physicians and nurses, with physicians demonstrating better knowledge [13].

The knowledge deficits shown in our study potentially reduces patients’ chance for an accurate diagnosis and effective treatment. There is not only a low percentage of medical professionals who know the criteria for the diagnosis of visceral obesity (44%) but also a significant (more than twofold) discrepancy between the knowledge of these criteria and the knowledge of the criteria for diagnosing obesity based on BMI (89.1%). Such a condition may not only contribute to the misdiagnosis of central obesity in people with a normal body weight but also is associated with a higher likelihood of underestimating the risk of complications (primarily metabolic and cardiovascular) in people with a relatively small excess of body weight in general but with central adipose tissue accumulation [30, 31]. It should be emphasized that central adipose tissue deposition is also one of the most important factors determining the choice of a therapeutic strategy, including referral for bariatric surgery [32].

Similarly, there is a discrepancy between the level of knowledge about the importance of diet modification and physical activity (97.3%) and the level of knowledge about the criteria for referral to bariatric surgery (51.1%), financing of such surgical procedures (63.6%), and modern anti-obesity pharmacotherapy (38.6%). A Greek study also confirmed that lack of knowledge about bariatric surgery seems to be the main reason for the limited penetration of this surgery [24, 25]. This may contribute to patients persisting ineffectively for a long time (with HCPs’ approval) in futile attempts to reduce body weight by lifestyle modification only. This may have a negative impact not only on the self-esteem and mental health of patients with obesity but also may contribute to obesity complications.

Most HCPs declared a negative or neutral self-assessment of their own competence in the areas of the diagnosis and treatment of obesity. This may by associated with a feeling of insecurity and may result in avoiding the topic of obesity during interviews with a patient, as shown in previous studies [6]. Stigmatization of obesity, blaming patients for it, may result in reluctance to talk about weight loss [33].

It should be noted that HCPs’ self-rating was incorrect and in particular, that their self-rating of their knowledge about treatment was negatively correlated (the correlation was weak although significant) with the knowledge actually presented. The worst-educated HCPs overestimated their competence, while the best-educated HCPs judged themselves harshly. On the one hand, this may favor the implementation of suboptimal therapeutic strategies, and on the other hand, it may discourage better educated HCPs from acting. However, educational interventions focused on obesity diagnosis and treatment have clearly demonstrated success in improving HCPs’ attitudes and skills in caring for patients with obesity [34]. We should be aware of the possibility that HCPs who consider themselves as knowledgeable and competent may not seek additional training to expand their skills under the concept that they possess those skills. Finding a way to reach this group of HCPs will be challenging due to their high self-esteem, unsupported by modern medical knowledge. Patients in their care are treated with common knowledge rather than evidence-based medicine.

We speculate that many HCPs perceive the problem of obesity through the prism of common knowledge, i.e., respondents who know BMI values and recommendations for changing diet and physical activity are to some extent convinced that this information has already exhausted the knowledge on obesity treatment. However, respondents who have participated in training on obesity were aware that obesity treatment is a complex issue that requires specific medical knowledge. Therefore, they lower self-assessment of knowledge on obesity.

The limitation of the study was the low number of respondents. Patients living with obesity face many barriers. Among them, a significant obstacle in the effective diagnosis and treatment of obesity may be related to the HCP’s deficits in medical knowledge on these topics. In this study, HCPs had a moderate level of knowledge about obesity. They had more knowledge about obesity diagnosis than about its treatment. The self-assessment indicated that the majority of HCPs considered their level of knowledge to be insufficient, which may affect their confidence in addressing, and may lead to avoidance of the topic, with a patient with obesity. Treatment knowledge needs to be increased, particularly among primary and outpatient HCPs. More attention should also be paid to obesity treatment methods in undergraduate education as younger HCPs were more often uninformed in this regard. Awareness of these deficits should prompt investigation of whether undergraduate and postgraduate training programs for HCPs contain a sufficient amount of current knowledge on obesity treatment and addressing this if needed.

We would like to thank the Ombudsman, the Commissioner for Patient’s Rights, the Polish Association for the Study on Obesity, OD-WAGA Foundation for People with Obesity as well as the media patron “poradnikzdrowie.pl.” We wish to extend our appreciation to all study participants who made this research possible.

Ethical Review Board: This study protocol was reviewed and approved by the Independent Bioethics Committee for Scientific Research at Medical University of Gdansk, approval number: NKBBN/694/2019-2020. Participation in the study was voluntary and fully anonymous. Participants were informed that sending a fully completed survey was tantamount to consent in the study. It was approved by the Independent Bioethics Committee for Scientific Research at Medical University of Gdansk, approval number: NKBBN/694/2019-2020.

The authors have no conflicts of interest to declare.

The authors received no specific funding for this work.

Study design: Aleksandra Mojkowska, Krzysztof Sobczak, and Katarzyna Leoniuk. Data collection: Krzysztof Sobczak and Katarzyna Leoniuk. Methodology: Krzysztof Sobczak, Katarzyna Leoniuk, and Michał Henzler. Manuscript preparation: Aleksandra Mojkowska, Krzysztof Sobczak, Katarzyna Leoniuk, Michał Henzler, and Marek Jackowski. Supervision: Aleksandra Mojkowska.

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.

Krzysztof Sobczak: ORCID number, 0000-0002-8354-2299.