Atrial fibrillation (AF) is estimated to affect about 2–4% of the adult population, and the incidence is projected to continue to increase up to 4-fold by 2050 (1–3). Both malnutrition and overweight and obesity are challenges to modern public health in developed and developing countries (4). Excess body weight is associated with high cardiovascular risk, risk of prolonged hospitalization and mortality (5–7). Despite knowledge on the subject, malnutrition remains one of the most common causes of death in developing countries. In 70% of cases, nutritional deterioration occurs during hospitalization (8, 9). Several publications indicate an association between AF incidence and overweight and obesity. Studies show a relationship between AF risk and body weight; overweight and underweight were associated with higher arrhythmia events during the follow-up period. It was confirmed that body mass index (BMI), waist circumference, hip circumference and body surface area, among others, were independent predictors of atrial fibrillation (10–12). Thacker et al. observed that higher BMI was an independent factor in arrhythmia progression from paroxysmal or persistent AF to fixed AF, in contrast to other factors (13). Also, a higher BMI score is an independent factor in the progression of arrhythmias from paroxysmal to sustained atrial fibrillation, in contrast to other cardiovascular risk factors (14). Pathak et al. showed that a 10% weight loss in obese patients resulted in a sixfold greater likelihood of maintaining sinus rhythm than patients with no change in body weight values (15). Although some researchers have described a phenomenon occurring among AF patients called the “obesity paradox” concerning deaths from all causes and those from cardiovascular causes, there is an inverse relationship between overweight/obesity and better cardiovascular prognosis at long-term follow-up (16, 17). There are studies showing gender differences in AF (18, 19). However, data on the relationship between nutritional status, gender and length of hospitalization in AF are scarce. This thread has not been sufficiently explored, justifying the need for such observations.

The aim of this study is to assess the prognostic impact of NRS-2002 and body mass index on length of hospital stay (LOHS) among patients with AF relative to their sex.

The impact of nutritional status on CVD is widely reported in the scientific literature. Its effects can range from the risk of cardiovascular events, presentation of symptoms, condition treatment methods, length of hospitalization and influence patient prognosis. The association of obesity with AF and the effect of weight reduction on its course is well known (22). It is also known that being underweight can be an independent risk factor for AF, and the association of BMI with AF risk takes a “U” shape (23). Scientific reports are also increasingly pointing out the gender differences present in atrial fibrillation (24). However, to the best of our knowledge, this study is one of the few to evaluate gender differences in the effect of nutritional status on the length of hospitalization in patients with AF, highlighting the complexity of this problem.

In the study, a multivariate linear regression model showed that malnutrition risk, as determined by the NRS-2002 scale, was a significant independent predictor of prolonged LOHS in men (B = 1.285, p = 0.005). No such effect was demonstrated in women. We also noted no effect of BMI score on LOHS for either sex. A study by Cheng et al. confirmed the impact of malnutrition on clinical outcomes, which showed that moderate to severe malnutrition is an independent predictor of adverse prognosis among older adult patients with non-valvular AF (25). The impact on LOHS was also evaluated in the work of Alturi et al., where it was shown that protein-calorie malnutrition in patients with AF could prolong hospital stay by 2.76 days (26). When comparing the groups in relation to the risk of malnutrition, statistically significant differences in the length of hospitalization in both men and women were not registered. However, the length of hospitalization is prolonged in the group of men with NRS ≥ 3 (6.4 vs. 4.33), which, although not statistically significant, may be clinically relevant and affect the total cost of treatment.

The risk of malnutrition can be studied using several different tools. Zhu et al. evaluated the effect of malnutrition assessed by the nutritional status score (CONUT score) and geriatric nutritional risk index (GNRI) on AF recurrence in patients after ablation procedures. They found that malnourished patients were more likely to experience AF recurrence (27). Malnutrition can also affect the increased risk of complications. Kim et al. showed that it increases the risk of complications in AF patients undergoing catheter ablation. The overall complication rate was more marked among malnourished women (7.1%) than malnourished men (3.7%) (28). Monitoring patients’ nutritional status is essential to the medical care process, as it can deteriorate during a hospital stay (29). The assessment should be performed at the time of admission to the hospital and during hospitalization. This is because it has been shown that a drop in category on the Subjective Global Assessment (SGA) or significant weight loss during the first week of hospitalization may be associated with a greater likelihood of a longer hospital stay (30).

In our study, only males had malnutrition risk according to NRS-2002 as a significant independent predictor of LOHS. Although this hypothesis requires further research, it may be influenced by different body fat content relative to gender. It is indicated that with similar BMI, the body fat percentage in men is lower than in women (31). In our study, we also found no effect of BMI on LOHS in either sex, which seems to confirm the lack of reflection of body composition in the BMI parameter. This is because it does not consider body fat, muscle mass or water content but only the patient’s weight-to-height ratio.

Researchers identify multiple determinants of prolonged hospital stay for patients with AF. Independent predictors of LOHS include acute coronary syndromes, acute decompensated heart failure, heart failure with reduced ejection fraction, and elevated NT-proBNP levels (32). Sex differences in AF are related to comorbidities, the influence of sex hormones, differences in electrophysiology, endothelial dysfunction, and pro-inflammatory signalling, among other factors (33). Researchers indicate that women with AF have a larger left atrial diameter, which affects their mortality (34), prolonged hospitalization time compared to men after ablation (35), and a higher risk of AF recurrence after radiofrequency catheter ablation (35). Women with AF also report poorer overall quality of life (36). Although in our study, BMI results were not a factor in the length of hospitalization, it should be noted that many authors show a positive association between the occurrence of AF and obesity, overweight and underweight (37–39). Also, in the study we conducted, there were no deaths; however, it is worth noting that increasingly researchers are pointing to gender differences in the incidence of mortality and the course of atrial fibrillation (40, 41). Renoux et al. showed that AF mortality was higher in males (10.0, 95% CI 9.8 to 10.1) than in females (8.5, 95% CI 8.3 to 8.6) (40). Our findings of gender differences in the effects of BMI and NRS on LOHS in patients with AF justify the need for further prospective studies in this area, highlighting the complexity of factors affecting the length of hospitalization.

The risk of malnutrition according to the NRS-2002 directly predicts the length of hospital stays in men but not women. The study did not find a relationship between body mass index and length of hospital stay in both women and men. Because the number of participants were at risk of malnutrition, these results should be interpreted within the context of each patient. Additional independent predictors of length of hospitalization for female patients independent predictors of length of hospitalization are age, persistent AF, hypertension and in male patient’s age, persistent AF, permanent AF, history of stroke and hypertension. Undoubtedly, the impact of NRS-2002 and BMI results in patients hospitalized in the cardiology department due to atrial fibrillation relative to sex requires further investigation.

The original contributions presented in this study are included in the article, further inquiries can be directed to the corresponding author.

AK and MC: conceptualization, methodology, validation, formal analysis, resources, writing-original draft preparation, and writing-review and editing. AK and KŁ: software. MC, BU, AM, KŁ, and JS: investigation. AK: data curation. AK and AM: visualization. MC: supervision. KŁ: project administration. JS: funding acquisition. All authors contributed to the article and approved the submitted version.

The study was funded by the Ministry of Science and Higher Education of Poland under the statutory grant of the Wroclaw Medical University (SUBZ.E250.23.020).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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