A cross-sectional survey study on the nutrition patterns of patients with peripheral artery disease
Abstract
Summary:Background: Even though nutrition was demonstrated to have an impact on chronic atherosclerotic disease, there is a paucity of corresponding recommendations for patients with peripheral artery disease (PAD). A Mediterranean Diet based on daily intake of fruits and vegetables with high fibre, vegetable oil, and unsalted nuts including fish several times a week may have protective effects. This cross-sectional survey aimed to determine nutritional patterns amongst inpatients with PAD. Methods: All inpatients with symptomatic PAD who underwent revascularisation at a single centre between 1st May 2018 and 31st December 2021 were asked to fill out a questionnaire on nutritional intake. An 8-item frequency rating scale (from never to three times a day) was used for 15 food groups. For 11 of them, an adapted Mediterranean Diet score was calculated using the answers. The descriptive results were stratified by sex and disease stage (intermittent claudication vs. chronic limb-threatening ischaemia). Results: A total of 319 patients (31.7% female, 69.4 years in mean) were included. Thereof, 71.8% reported they did never receive any nutritional information considering their PAD disease. The mean adapted Mediterranean Diet score was 2.7 points (of maximum 11) with most patients not achieving the recommended servings per week for fruits (1.6%), vegetables (1.0%), and unsalted nuts (12.2%). The intake of cereals was sufficient (43.3%). When compared with men, women consumed more fruits and less meat. Conclusions: This survey demonstrated that although healthy nutrition may have a positive impact on patients with PAD, the education and adherence to a Mediterranean Diet was inappropriate. Nutritional patterns should be more focused in future PAD studies to derive specific recommendations and nutritional programmes as well as patient education in clinical practice.
Introduction
Peripheral artery disease (PAD) is a common manifestation of systemic atherosclerosis and affects approximately 237 million people worldwide with increasing prevalence [1, 2]. Due to the involvement of all vascular beds and multiple comorbidities, the five-year amputation and death rates can reach up to 48% in patients with intermittent claudication (IC) and 88% with chronic limb-threatening ischaemia (CLTI) [3]. Recently, the major impact of best medical treatment gained increasing attention by the vascular community [4]. Several practice guidelines emphasised the importance of smoking cessation, supervised exercise therapy as well as optimal pharmacological therapies [5, 6, 7, 8]. Beyond considerations on body weight and obesity as an important part of metabolic syndrome, specific recommendations concerning healthy nutrition remain sparse to date.
Presently, there are no specific dietary guidelines for patients with PAD and the very few available recommendations in disease-related guidelines are only based on expert consensus. However, for the primary prevention of cardiovascular diseases in general, the American College of Cardiology (ACC) and American Heart Association (AHA) in 2019 recommended a healthy diet that includes fruits, vegetables, whole grains, protein-rich foods, and a diet low in saturated fat, trans fat, red meat, refined carbohydrates, and sodium [9].
In a recently published systematic review of studies on that topic, 82 articles on nutrition in patients with PAD were evaluated [10]. Interestingly, the authors suggested that only a few recommendations, e.g., on the Mediterranean Diet and the consumption of nuts, can be generated from high-level comparative effectiveness evidence [10, 11]. Since health behaviour and lifestyle are commonly known to be the Achilles heel of patients with PAD, it appears likely that eating habits are in great need of improvement. However, to date, it remains mostly unknown how patients with PAD subsist in regard of nutrition behaviour.
Certain molecular processes, such as systemic inflammation and increased embedding of low-density lipoprotein (LDL) cholesterol, have been shown to play an important role in the development of atherosclerosis in the past and healthy nutrition may be a game-changer [12, 13, 14, 15]. In a cross-sectional study using the National Health and Nutrition Examination Survey in the US population, an increased intake of vitamins A, C, E, B6, fibre, folic acid, and omega-3 fatty acids, was associated with a significantly lower prevalence of PAD [16].
The current study aimed to collect baseline information on nutritional habits as well as the occurrence of nutritional education in a population invasively treated for symptomatic PAD at a tertiary care centre.
Methods
This was a single-centre sub-study of the prospective multicentre GermanVasc cohort study (NCT03098290) including patients who underwent open-surgical, endovascular, and hybrid invasive revascularisation of symptomatic PAD in Germany [17]. For the current study, we subsequently tried to contact all patients (n=466, 31.8% female) who were enrolled at the study centre during the follow-up duration between 1st May 2018 and 31st December 2020. The interview was conducted by an independent researcher.
All finally contacted patients (n=319) have provided explicit informed consent and agreed to be contacted by telephone for survey-based research related to the previous study. The ethics committee of the Hamburg Medical Association has approved the study (PV5691).
Study population
We included all adult patients suffering from either intermittent claudication (IC, n=189) or CLTI (n=130) including diabetic foot syndrome who were invasively treated by either endovascular, open-surgical, or hybrid revascularisation during the study period.
Study variables
All study variables and their definitions which were available through the prospective GermanVasc cohort study were previously consented by an international Delphi committee and published elsewhere [18, 19, 20]. In the current study, we used a questionnaire on nutritional habits that was driven by the Mediterranean Diet.
The nutrition questionnaire covered quantitative information about how often the patients consume certain foods and beverages. The average frequency of consumption and the portion size as well as the number of beverages consumed within the last 12 months have been set in the questionnaire by nutritional experts. The patients were asked to give only one answer option.
Information about the consumption of the following foods was requested: fruits, vegetables, legumes, cereal products, fish, red meat, poultry, dairy products, butter and/or cream, vegetable oils, unsalted nuts, sweets, salted snacks, sweetened drinks, alcohol.
Possible answer options on frequency were given as an 8-item frequency rating scale which was condensed to 4 categories: “rarely or never”, “once or twice a week”, “three to six times a week”, “at least once a day” and “no answer/I don’t know” (for more details see electronic supplementary material [ESM] 1). Questionnaires on which patients gave several possible answers were excluded.
In addition, yes-no-questions were asked about the intake of vitamin and mineral supplements during everyday life. Regarding the intake of dietary fats, a question about the preferred type of oil used was also created to be able to make a qualitative statement here.
Aside from that, the patients were asked whether they had already received information about a healthy diet as part of their PAD disease and, if so, in what context. Here possible answer options were “no”, “yes, written information (leaflet, brochure)”, “yes, medical advice”, “yes, detailed advice from a nutritionist”, “yes, others” or “no answer/I don’t know”.
As part of the regular evidence-based patient-education, the Mediterranean Diet encouraging fruits, vegetables, cereals, legumes, fish, nuts, and vegetable oils should be recommended to the patients during their initial hospital stay.
Statistical analysis
Patients with mild, moderate, and severe claudication according to the modified Rutherford classification were pooled as IC group. Patients with ischaemic rest pain, ulcer or necrosis, and non-healing amputation were pooled as CLTI group. One person with gender “divers” was excluded. The modified score that was driven by the Mediterranean Diet score was calculated as a summary score of eleven food groups (for more details see ESM 2).
Results
The current study included 319 patients (31.7% women, 69.4 mean age) in four strata by sex and disease stage. A total of 189 (59.2%) patients had IC and 130 (40.8%) CLTI. The baseline characteristics by sex and disease stage are presented in Table I.
A total of 37.0% of the entire cohort reported current smoking at the time being selected for invasive revascularization, and 17.2% were obese. Nearly one third (32.0%) were diagnosed with diabetes, 79.6% with hypertension (see Table I).
Nutritional education
A total of 71.8% of all patients reported that they had not received any information about healthy eating concerning their condition of PAD (Table II). The highest percentage with no information was found in women with CLTI (82.9%). Only 20 of all included patients (6.3%) received advice on healthy eating from a treating physician. Eighteen patients (5.6%) stated that they had received written nutrition information, e.g., brochures or leaflets. Sixteen patients (5.0%) had already received detailed advice from a nutritionist. Thirty-one patients (9.7%) fell into the category “other”, such as e.g., information through the internet, the television etc.
Adapted Mediterranean Diet score
Results for the adapted Mediterranean Diet score are also presented in Table II. The mean adapted Mediterranean Diet score was poor (mean achieved recommended amount of 2.7) whereas 11 points correspond to the recommended nutritional habit. Within all patients, only 1.6% achieved the recommendation for fruit consumption, not even one per cent for vegetables and 2.5% for legume consumption. In contrast to that 43.3% of all patients achieved the score recommendation related to cereal products and 84.6% for poultry intake. Nearly half of all men with IC (47.3%) achieved the recommendation for dairy product consumption. Regarding vegetable oil intake, 31.7% of CLTI women (25.8% for CLTI men) reached the recommendation. Only 12.2% of all patients achieved the recommendation for consumption of unsalted nuts.
Nutrition patterns
The detailed consumption frequencies of the 15 food groups by sex and disease stage are presented in ESM 2 and illustrated in Figure 1.
Fruits and vegetables
When compared with IC patients, the relative intake of fruits was lower in patients with CLTI and in both groups, women consumed more fruits and vegetables than men. Among the entire cohort, 147 patients (46.1%) reported eating fruit at least once a day (ESM 2).
Cereal products
Overall, 83.8% of all patients consumed cereal products at least once a day. The majority here was 90.4% among CLTI women (compared to 76.5% among CLTI men).
Fish
Two-hundred-and-six patients (64.6%) of the whole cohort reported eating fish once or twice a week.
Meat
The prevalence of red meat consumption was higher in CLTI patients. For consumption of red meat such as beef, pork, sheep, or lamb, nearly 70% of all men with CLTI stated a consumption at least three times a week, compared to 51.2% within CLTI women. Within the entire cohort, only 11% of all patients reported red meat consumption never or rarely (<once per week). For poultry consumption, the range of three times a week to several times a day was more than twice as high among men as among women.
Butter and cream
Higher butter consumption was associated with CLTI. In both groups, CLTI men and women more than 60% of the patients consumed butter or cream at least once a day. Thirty-three per cent of the IC men abstained completely from butter and cream (16.7% for IC women, 19.1% for CLTI men and 17.1% for CLTI women).
Unsalted nuts
With 66.5%, most of the included patients reported eating unsalted nuts never or rarely with no predominance of sex or disease stage.
Alcohol
The average of alcohol abstinent women with 64.4% was clearly above their male counterparts (47.7%).
Discussion
The current survey of 319 consecutively treated patients at a tertiary centre illuminated the nutrition habits in a target population that is known for its poor health behaviour and poor long-term outcomes. Firstly, most patients did not achieve the recommended weekly servings referring to the Mediterranean Diet for fruits, vegetables, legumes, fish, and unsalted nuts. On the other hand, 43.3% achieved the recommendation for cereal products, and 84.6% for poultry. Secondly, most patients responded that they had not received any advice concerning healthy eating to improve the long-term course of their disease. In most cases, this usually takes place as part of the secondary prevention handled by nutritionists during rehabilitation programmes. Several explanations for these results could be discussed from a lack of specific interest or knowledge on the side of the patient through limited time for extensive education in everyday clinical practice on the side of the physician. Interestingly, the considerably high rate of active smokers amongst the target population emphasizes that healthy living and risk factor modification remain the Achilles heel of PAD treatment. In a recent cross-sectional survey study including patients with inpatient treatment of symptomatic PAD, 46.6% stated that they had not changed their lifestyle and health behaviour since the index diagnosis, and 33.1% responded that they were not aware of the reasons for all of their medication orders [21].
In the current survey, the consumption of fruits was associated with less advanced disease stages at presentations, while more than 10% reported that they never eat fruits. Thirty-seven percent of the patients stated that they eat fruit every day with a predominance of women. Amongst the patients with a relatively high fruit consumption of more than three times per week, there was a lower prevalence of CLTI, which confirmed findings from a previous study [22].
Also interestingly, we observed a frequent consumption of red meat, butter and cream in patients treated invasively for symptomatic PAD. The high frequency of red meat consumption is mirrored in the observation that the only Mediterranean Diet recommendation that is met by more than 80 percent of the study sample is poultry consumption.
Hence, more than half of the patients stated that they consumed these foods at least once a day. It has been proven that the consumption of saturated fatty acids, such as butter, has a negative effect on the occurrence of PAD, which can be attributed to the resulting high LDL and cholesterol levels in the blood [23, 24]. In this cohort the group of CLTI patients showed a percentage higher consumption of butter and cream compared to the IC group. Taken together, the high total fat intake and association between cholesterol and PAD occurrence previously described in the literature could be confirmed.
More than half of the patients surveyed reported eating red meat, such as beef, pork, mutton, or lamb, four to six times a week. Amongst the entire cohort, 34.9% even said they eat red meat once a day or more often. In addition, the assumption was confirmed that men consume red meat more frequently than women. When compared with IC, patients treated with CLTI eat meat more than twice as often. The previously published connection between meat consumption and a higher incidence of PAD is consistent with this [25, 26].
Taken all together, very few patients were on a Mediterranean Diet, which is defined by a preferred intake of vegetable fats contained in nuts or vegetable oils, as well as seeds, vegetables, fruit, legumes and whole grain products. In addition, moderate consumption of (red) wine, seafood, milk, eggs and poultry and little to no intake of red meat or sweets [10].
Interestingly, available practice guidelines contain only vague advice concerning lifestyle advice and nutrition and do not give any clear recommendation [8].
The European Guideline for Prevention of Cardiovascular Disease recommends a daily intake of 200g of fruit and 200g of vegetables divided into 2-3 portions throughout the day [27]. A meta-analysis on coronary artery disease also reports that each additional serving of fruit and vegetables can reduce the risk of stroke by up to 5% [8, 28]. For metabolic syndrome there are several recommendations as Mediterranean Diet, Mediterranean Dietary Approaches to Stop Hypertension (DASH) diet, plant-based diets, or fasting [29].
In the guideline of the German Nutrition Society there is no concrete recommendation for PAD, but obesity, diabetes, hypertension and coronary heart disease, which are common comorbidities of PAD. They recommended high fibre intake e.g., with whole-grain products and reduced sweets to reduce the risk for cardiovascular diseases [30, 31].
In the German National Nutrition Survey it was reported that the general population in Germany eat less plant-based foods as fruits and vegetables than recommended and too much animal-based food as meat, sausages, milk, and fish [32]. Further, men eat more meat than women [33]. A further result of this study was that nutrition knowledge was higher among women [34] and higher knowledge results in higher consumption of favourable foods as fruits and vegetables.
Although the high-level evidence-base on nutrition and its preventive potential remain sparse, there is increasing data suggesting that a Mediterranean Diet should be recommended for all patients with PAD [10].
The current study has several strengths but also limitations. Firstly, even though this cohort consecutively included all patients eligible during the study period, we cannot rule out that a selection bias affected the central conclusions e.g. patients who died after the index revascularisation. Secondly, a recall bias and self-reported answering has to be considered. There are various external factors interfering with health behaviour. However, due to the very limited evidence base, it appears important to illuminate health behaviour in this vulnerable target population to identify targets to improve the outcomes in a further step. Thirdly, we did not collect data about food allergies e.g. lactose intolerance or personal preferences as vegan/vegetarian lifestyle. For certain nutrition groups, a further subdivision might be reasonable (e.g., cereals into refined carbohydrates vs. whole grains) but the current study followed a pragmatic approach to give an insight into a highly complex research topic. Also, the current survey study did not aim to reveal any associations between nutrition and outcomes. In addition, due to the non-random assignment to nutrition patterns, it is not possible to derive causal relations.
Conclusions
This study provides an overview of the everyday eating habits of symptomatic PAD patients treated invasively in a tertiary care centre. Above all, the results of this study show a poor handling of patient information regarding a healthy diet in the context of secondary prevention to prevent the progression of this atherosclerotic disease, which is important for an adequate therapy. A hospital stay can be served as teachable moment to change nutritional habits.
The current study suggested that there is a need of improvement along with results suggesting that most patients were not sufficiently informed. This can be seen as missed opportunity. It appears reasonable to increase the awareness and patient education to use every single chance to improve the considerably poor outcomes.
Electronic supplementary material
The electronic supplementary material (ESM) is available with the online version of the article at https://doi.org/10.1024/0301-1526/a001005
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