Summary
In this mixed-methods study, we investigated the value of measuring waist circumference in primary care. Currently, this is not standard practice in primary care in the Netherlands. A waist circumference measurement was recorded in only 6.7% of the GP records of patients aged ≥18 years. Incidence rates of recorded waist circumference decreased from 2012 to 2023 from 47 to 3 per 1000 person-years.
Barriers to GPs measuring waist circumference were feeling discomfort, the inability to measure it accurately, lack of measuring tape, and perceived uselessness. Facilitators included the availability of measuring tape and the comprehension that increased waist circumference is a cardiovascular risk factor. Nevertheless, when waist circumference was measured, this was typically in the range of BMI for patients without obesity but with a large waist and increased CVD risk may be identified.
We showed that measuring waist circumference as a screening tool is a valuable measurement in the identification of patients at increased risk of CVD. Selecting patients with an increased waist circumference for cardiovascular risk assessment identified 89% of those at intermediate and 93% of those at high predicted cardiovascular risk.
Importantly, among patients without obesity, but with an increased waist circumference, 43% had an increased risk of CVD and would not have been identified if only patients with obesity (>30 kg/m2) are screened. Given the time constraints and largely demand-driven nature of primary care, it may serve as a less burdensome alternative to assessing multiple risk factors for selecting patients eligible for cardiovascular risk assessment, making risk assessment more targeted and time efficient.
Strengths and limitations
Strengths of this study are the mixed-methods approach, which ensures that both quantitative and qualitative data were collected. This allows for a broad interpretation of the research results and ultimately, well-tailored interventions that lead to improvements and a more efficient approach in cardiovascular risk management in current practice.
Other strengths of this study are the access to a large population (n = 676 708) with routine healthcare data. We also identified barriers and facilitators using a well-established theoretical framework (Theoretical Domains Framework).21 Additionally, we had access to extensive and uniform measurements of all information needed for calculating the 10-year cardiovascular risk with SCORE2. Several limitations should be taken into account though. In the routine heathcare data, measured waist circumference could have been missed because analysis was limited within the structured electronic health records, as we did not include free-text data. It is likely that more waist circumferences have been recorded in free text in the electronic health records, as not all GPs translate their medical assessment to accurately coded recordings. This would have led to an underestimation of available recorded waist circumference. It is important to note that routine healthcare data were used. To use these data accurately, we evaluated the data for extreme and non-adequate values and inconsistent records. Only less than 1% of the values were removed, as they may represent measurement or recording errors.
For the qualitative study, focus groups could have yielded socially acceptable answers. Additionally, GPs who attended the focus groups might have had a special interest in obesity and may have been more motivated to optimise the care for patients with obesity. However, only two GPs expressed having a special interest in obesity or lifestyle medicine (Supplementary Table S2).
The first limitation in the NEO study may be the oversampling of individuals with a BMI ≥27 kg/m2. This may have led to overestimation of the number of patients with an intermediate or high risk of CVD that can be identified by an increased waist circumference. However, patients who are overweight are more likely to visit their GP for other complaints than patients who are not overweight,26,27 and therefore the NEO study population might be viewed as a typical population visiting general practice.
The second limitation in the NEO study is that some individuals in our risk assessment population may already be identified by their GP and monitored accordingly; for example, those with self-reported diabetes, pre-existing CVD, or chronic obstructive pulmonary disease. We included these individuals in our analysis since we were uncertain whether the baseline diagnosis in the NEO study fully aligns with real-life medical records of GPs, leaving it unclear whether these individuals have been identified by their GP. For individuals not yet identified by their GP, measuring waist circumference could be a valuable tool to identify those at increased risk in general practice.
A third limitation of the NEO study is that our study population consists of individuals aged 45–65 years, which limits generalisability to other age groups. However, this age range is appropriate for determining eligibility for cardiovascular risk assessment, as preventive interventions are most effective in this age group. Finally, most participants of the NEO study were White, and because body fat distribution may differ between ethnicities, the results of this study cannot be extrapolated to other ethnic groups.
Comparison with existing literature
The decrease in recorded waist circumference from 2012 to 2023 may be explained by revisions in the Dutch cardiovascular risk management guidelines. Until 2011, both BMI and waist circumference were recommended as part of the physical examination.28 After 2011, the guidelines shifted focus to BMI, with waist circumference listed as an optional additional measurement,29,30 possibly owing to its greater intra- and inter-observer variability compared with BMI.31 The 2024 updated guidelines reintroduced waist circumference alongside the BMI as part of the physical examination, but waist circumference has not been included as a criterion for cardiovascular risk assessment eligibility.1 This might be because it was shown that measuring waist circumference does not improve the prediction of CVD risk beyond established factors such as age, sex, blood pressure, lipids, and smoking behaviour.4
However, our results suggest that measuring waist circumference could help as a screening tool to select patients for cardiovascular risk assessment and identify patients at intermediate and high predicted cardiovascular risk, supporting consideration of its role as a screening tool in future guideline updates.
The low measurement rates in our study are consistent with findings from other countries (Canada, the UK, and the US), where waist circumference is also rarely recorded.13–16 These trends contradict the increasing awareness that knowledge of waist circumference has added value for risk assessment.7,32–35 So, the barriers for measuring waist circumference should be overcome to ease implementation in practice and support guideline adherence.
Previous studies investigated the barriers and facilitators for measuring waist circumference.13,17 We confirmed some of the barriers reported by these studies: the discomfort felt by GPs,13,17 the perceived usefulness of a measurement,17 and the lack of measuring tapes.13 In our qualitative study, the most important barriers mentioned were that GPs felt measuring waist circumference had no consequence for further management and that they believed they could visually assess an increased waist circumference. This is particularly important for patients without obesity, in whom an increased waist circumference may be less visible but who are at increased risk of CVD.
Also, considering patient perspectives, Dunkley et al, showed that most patients would not feel uncomfortable or embarrassed about having their waist measured. They perceived waist measurement as useful and acceptable, and it could provide an opportunity for open communication with the doctor about health risks and lifestyle changes.17
Our results are in line with findings from two other studies that investigated the role of waist circumference in identifying patients at increased risk of CVD,36,37 and showed that waist circumference (with cut-offs of 80 cm for women and 94 cm for men) can effectively identify individuals at increased risk, highlighting its value in general practice. Comparing these studies, however, requires careful consideration, as they used different endpoints, such as individual risk factors (for example, hypertension, cholesterol), or other prediction models than the SCORE2 model used in our study, which is currently widely adopted in Europe.
Furthermore, our findings suggest that the population with an increased waist circumference, in addition to the high number of patients identified at high predicted risk, also showed a high observed risk, deeming this population suitable for cardiovascular risk assessment eligibility. The high number of patients identified at high predicted cardiovascular risk by measuring waist circumference can be explained by the strong association between waist circumference and visceral fat, which is associated with CVD.7,32–35
Waist circumference is a simple, quick, and non-invasive method to assess abdominal adiposity that is easy to perform in a clinical setting.7,32,34 Besides, it is a low-cost, low-risk tool, also useful in settings where other assessments, for example, cholesterol concentrations or blood pressure measurements, are not — or less readily — available.
Even in well-resourced practices, waist circumference can help prioritise patients for further evaluation, reducing the need for multiple separate measurements and supporting a more targeted and time-efficient use of blood tests and blood pressure assessments. It could serve as an opportunistic screening tool (that is, when patients visit their GPs for unrelated reasons) in primary care, thereby facilitating the selection of individuals eligible for cardiovascular risk assessment. Furthermore, waist circumference could also be applied as a screening method in community-based settings, such as pharmacies, gyms, or health fairs, to identify individuals who may need further cardiovascular risk assessment.
We previously showed that selecting patients who are overweight or obese for cardiovascular risk assessment by the GP may help to identify 70% of patients with a treatment indication who were not yet receiving treatment to prevent CVD.38 Our present findings may further help to identify patients at increased risk of CVD by measuring waist circumference in those patients who are overweight but with no apparent obesity, enabling further treatment.
Additionally, waist circumference is a measurement that can aid patients to recognise their own condition as it may lead to active attempts and successful weight loss.39 Furthermore, it could be used to know which patients should seek and be offered weight management and it enables the effects of weight management and healthy behaviours to be monitored.7,40