The predictive value of albumin-based nutritional indices for intestinal ischemia in strangulated abdominal wall hernias: an insight into the novel CALLY Index

Inflammation and nutritional state are both influential factors when it comes to determining the prognosis of surgical patients [1]. Systemic changes arising from acute inflammation may as well affect the immune response and have an impact on the severity of tissue damage and recovery processes [2].

C-reactive protein (CRP) is a positive acute-phase reactant stimulated by proinflammatory cytokines (IL-6, TNF-α, IL-1β) and is therefore a valuable indicator of inflammation [3].

In contrast, serum albumin is regarded as a negative acute-phase reactant that decreases during inflammation and hence reflects a substantial biochemical parameter of the patient's nutritional status [4].

Whereas the CRP levels shoot up, serum albumin levels drop during acute inflammation marking their significance in guiding an appraisal of the severity of inflammation and the general clinical state of a patient.

Another condition frequently observed according to inflammatory response is lymphopenia [5]. A notable decrease in lymphocytes count is visible during acute inflammation. This condition may occur due to the entry of lymphocytes into the margination and redistribution process, the impact of the proinflammatory cytokines on lymphocyte apoptosis, and a boost in the plasma cortisol because of inflammation [6]. Lymphopenia is overtly considered a poor prognosis indicator, notably in sepsis and severe infections, and seems to pose an important biomarker for the determination of disease severity in surgical patients [7].

In this context, modified Glasgow Prognostic Score (mGPS) and Prognostic Nutrition Index (PNI) and the CALLY Index are not merely nutritional assessment indices but are valuable prognostic tools in predicting the clinical course of patients by considering, in addition to nutrition status, the impact of inflammation on prognosis [8‐10].

Incarceration of abdominal hernia, which is capable of giving rise to bowel ischemia and necrosis, is an emergent state in which prompt diagnosis and proper management are key. The incidence of strangulation is one critical factor directly affecting commitment to surgical intervention [11].

Prognostic indicators containing objective measures of inflammatory and immune responses, that is, lymphopenia and significantly raised CRP and declined albumin, could foresee strangulation and requirement of resection in the patient with incarcerated abdominal hernias [12].

The study included 66 (52.8%) female patients. The median age of the population was 67 (58–76) years, and 75% had an ASA3 surgical risk. During the operation, 86 (68.8%) patients had necrosis in the omentum, intestine, or both. Among them, 73 (58.4%) patients had only intestinal ischemia, while 23 (18.4%) had only omental necrosis. Postoperative follow-ups revealed mortality in 12 (9.6%) patients (Table 1).

In the group with intestinal and omental ischemia, 52 (60.5%) patients were female, and the median age was 67 (58–78) years. There were statistically significant differences between the groups in terms of gender (p = 0.011), CRP (8 [4.5–12.3] vs. 74.95 [25–140]) (p < 0.001), albumin (3.98 [3.5–4.3] vs. 3.6 [3–4.02]) (p = 0.008), lymphocyte count (1.43 [1.03–2.11] vs. 1.14 [0.73–1.68]) (p = 0.024), PNI (48.05 [41–53.65] vs. 40.98 [36–47.75]) (p = 0.002), lymphocyte/CRP ratio (0.19 [0.07–0.44] vs. 0.01 [0.006–0.061]) (p < 0.001), CALLY < 2.5 (10 [25.6%] vs. 66 [76.7%]) (p < 0.001), and GPS 2 (6 [15.4%] vs. 37 [43%]) (p < 0.001) (Table 2).

In the multivariate regression analysis of statistically significant parameters, GPS2 (Odds Ratio: 19.299 [1.77–210.454]; p = 0.015) and CALLY < 2.5 (Odds Ratio: 5.397 [1.354–21.513]; p = 0.017) were identified as independent risk factors for intestinal ischemia (Table 3). The CALLY value was assessed through ROC analysis, and a cutoff value of < 2.5 was determined (AUC: 0.828 [0.753–0.902]) (Table 4, Fig. 1).

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Intestinal ischemia in strangulated abdominal wall hernias is a life-threatening condition that requires an early diagnosis and surgical intervention. Systemic inflammation and nutritional status are related to surgical prognosis; thus, various prognostic indices have been studied for their predictive value in ischemic complications. Among these, albumin-based nutritional indices, such as the CALLY Index, Prognostic Nutritional Index, and modified Glasgow Prognostic Score, have been in wide use in malignancies [8‐10] but remain underexplored in acute surgical conditions like incarcerated hernias. Despite the utility of laboratory indices like CALLY and mGPS, instrumental imaging remains essential for definitive diagnosis and surgical planning in cases of suspected intestinal ischemia.

This study is the first to attempt an appraisal of the predictive performance of these indices, particularly the CALLY Index, for intestinal ischemia in strangulated abdominal wall hernias. Our findings indicate that the integration of inflammatory and nutritional markers into risk stratification models may improve clinical decision-making, which could facilitate the early identification of ischemic bowel segments and optimization of surgical outcomes. It should be emphasized that the primary aim of this study was not to detect reversible ischemia but rather to predict cases requiring resection due to irreversible damage, where surgical intervention is mandatory.

The mGPS, is an inflammation- and nutrition based index developed for prognosis in patients with malignancy conditions [13]. This index is calculated using C-reactive protein levels and albumin; such simplicity, rapid assessment, and ease of calculation make this index very valuable in clinical practice. Although a rise in the level of CRP is a manifestation of inflammation, a drop in the level of albumin acts as a negative nutritional indicator in relation to prognosis. The mGPS so far was studied in pancreatic, gastric, colorectal, and gynecological malignancies as a prognostic tool and found to be an effective prognostic marker, but it has not been studied for predicting strangulation and resection in abdominal hernias up to date [14‐16]. Our study is the first one to explore the potential of mGPS for the prediction of strangulation and resection in patients with abdominal hernias. A result suggesting that, other than malignancy, mGPS may also have a potential prognostic value in other surgical and inflammatory conditions.

PNI represents a combination measure of lymphocyte count and albumin level for the prediction of postoperative prognosis in cancer patients [9]. This index evaluates two markers: C-reactive protein, an inflammation marker, and albumin, a nutritional marker, and it is commonly applied in several malignancies. Serum albumin is also an accepted negative acute-phase protein, and earlier studies have shown that low serum albumin levels in ischemic stroke patients are associated with increased mortality and prolonged hospitalization [17]. In our series, we wanted to see the predictive value of PNI, for strangulation and resection in abdominal hernias. By evaluating CRP as an inflammation marker and albumin as a negative acute-phase protein, we hypothesized that PNI will be a major factor in the prognosis of strangulation and resection in abdominal hernia patients with incarceration. Our results suggest that PNI is not an independent predictive factor for strangulation and resection, as no significant association was found between PNI levels and the occurrence of these conditions in our analysis.

The CALLY Index is the multiparametric prognostic score of survival that considers inflammation, nutrition, and the immune response in malignancy and different clinical conditions [18]. This index assesses inflammatory response by the level of CRP, the immune function by lymphocyte count, and nutritional status represented by albumin level to provide a comprehensive judgment of the general clinical condition of the patient. Taken together, these three key parameters provide a more holistic view of disease progression by CALLY in a balanced manner. Although, the estimation of its value initially was tried in hepatocellular carcinoma. It was subsequently directed at being an important parameter for anticipating postoperative outcomes in malignancies involving the stomach, esophagus, and the breast [19, 20]. The utilization of albumin, the negative acute phase reactant in CALLY, is as being considered for uses apart from malignancies much like PNI and mGPS, especially regarding inflammation processes. In this respect, the current study has been designed to assess the prognostic value of the CALLY Index for predicting strangulation and resection in incarcerated abdominal hernias. Multivariate analysis indicated that CALLY was an independent prognostic factor for predicting strangulation and resection in patients with abdominal hernias. This again underlines that inflammation, immune response, and nutritional status are important aspects in the clinical management of abdominal hernias. The CALLY Index, due to its reliance on easily accessible laboratory parameters, can serve as a practical tool in preoperative evaluation, especially when rapid risk stratification is needed in emergency settings. Given its simplicity and objectivity, the CALLY Index could potentially be integrated into clinical decision-making algorithms and artificial intelligence tools to assist emergency physicians in identifying high-risk patients needing resection.

The novelty of this study lies in the fact that this will be the first study investigating the possible role of the immuno-nutritional indexs in predicting strangulation and resection in abdominal hernias; thus, it gives an important contribution to show the possible prognostic value of the CALLY Index, mGPS, PNI in surgical and inflammatory conditions other than malignancies.

There are, however, several limitations that need to be considered despite the significant findings from our study. First, there might be a selection bias due to the retrospective nature of the study. Although our findings are promising, they require confirmation through prospective, multicenter studies with larger sample sizes to ensure broader applicability and clinical integration. The sample size, though sufficient for preliminary analysis, is still relatively small. Larger, multicentric, prospective studies should be carried out to validate our findings and ensure generalizability. Moreover, other potential inflammatory and nutritional markers that could affect prognosis were not included in this study, which might give further insight into the complex interplay of inflammation, nutrition, and surgical outcomes.

This study is the first to investigate the value of the mGPS, PNI and CALLY Index for predicting strangulation and resection in incarcerated abdominal hernias. Of these, mGPS, PNI and CALLY emerged as the independent predictors of resection through multivariate analysis. These observations may suggest that systemic inflammation, immune response, and nutritional status have a crucial role in the prognosis of an incarcerated abdominal hernia and could thus be of assistance in clinical decision-making. However, large-scale prospective studies are needed to present their validation and clinical applicability in routine surgical practice.