Spinal tuberculosis (STB), a relatively common form of tuberculosis, primarily affects the spine and has been traced back to ancient times (1). It accounts for 1 to 3% of all tuberculosis cases and is present in approximately 50 to 60% of musculoskeletal tuberculosis cases (2, 3). STB is becoming a significant public health concern with the increase in global migration and drug-resistant strains (4, 5). The disease often has a chronic and occult onset, leading to delayed diagnosis (6). Clinical manifestations vary but commonly include back pain, sometimes accompanied by systemic symptoms (7). The destruction of vertebral bodies and the development of kyphosis can result in severe complications, such as paraplegia, making it one of the most hazardous pathological changes in the musculoskeletal system (8). STB in the elderly has increased due to the aging of the population (9). However, managing elderly STB becomes more complex due to compromised physiology, medical comorbidities, and potential drug interactions (10–12). In addition, nerve damage and paralysis can occur even during the early stage of this disease due to spinal degeneration and stenosis (13). Surgery in the elderly carries additional risks, including longer operative times, increased blood loss, and the need for extended segment fixation due to osteoporosis and degenerative spine (14, 15). Therefore, it is of great significance to find an indicator to evaluate elderly STB patients at admission for predicting potential adverse prognosis.

The anticipation of surgical intervention for STB is affected by many variables, among which nourishing status is the critical factor (16). Two nutritional biomarkers, controlling nutritional status score and prognostic nutrition index, have been proven to be independent predictors of adverse outcomes of STB postoperatively (17). The geriatric nutritional risk index (GNRI) developed by Bouillanne et al. (18) is an assessment tool used to evaluate the nutritional status and risk of malnutrition in elderly individuals. A mounting of literature has proven that GNRI is a good predictive value for adverse outcomes such as morbidity, mortality, length of hospital stay, and complications in different diseases (19–22). However, the correlation between the GNRI and surgical outcomes in elderly STB patients has not been reported. The aim of this study was to evaluate whether the perioperative GNRI can be used as an effective biomarker for predicting prognosis in elderly STB patients undergoing surgical intervention.

A total of 91 patients (Mean age 70.49 ± 3.91 years, 44 males, 47 females) were included in the study (Table 1). ROC curve analysis demonstrated GNRI <98.63 g/dL as a cut-off value for predicting unfavorable clinical prognosis with a sensitivity of 73.08% and a specificity of 81.54% (Figure 1). The AUC of the GNRI score was 0.832 (95% CI 0.745–0.919). Thus, for the final analysis, 31 patients were included in the low GNRI cohort, and 60 patients were included in the high GNRI cohort (Table 1). The low GNRI group had a higher CCI score (2.06 ± 0.73 vs. 1.40 ± 1.14, p < 0.001), more likely to receive red blood cell transfusions treatment (48.39% vs. 25.00%, p = 0.024) and a higher prevalence of overall complications (74.19% vs. 28.13%, p < 0.001). Among the complications, pneumonia (29.03% vs. 8.33%, p = 0.022) was the most common and statistically different.

Depending on the clinical cure standard at 1 year, twenty-six (28.57%) patients had an unfavorable result, and sixty-five (71.43%) patients had a favorable result in our research. The GNRI in the unfavorable clinical prognosis group was significantly lower compared with the favorable clinical prognosis group (96.21 ± 6.95 vs. 106.69 ± 8.19, p < 0.001) (Table 2). The correlation between clinical prognosis and basic clinical characteristics was explored by a univariate analysis 1 year postoperatively. The results showed that patients in the unfavorable group were older (71.92 ± 4.30 vs. 69.92 ± 3.62, p = 0.027), had a higher CCI score (2.03 ± 0.87 vs. 1.46 ± 1.19, p = 0.018), were more inclined to red blood cell transfusions therapy (53.85% vs. 24.61%, p = 0.007) and had a higher rate of pneumonia (34.62% vs. 7.69%, p = 0.024) and pneumothorax (19.23% vs. 1.54%, p = 0.009) complications (Table 2). In the multivariate analysis of unfavorable outcomes, lower GNRI (odds ratio [OR] 1.141, 95% confidence interval [CI] 1.050–1.241, p = 0.002) was the only variable that significantly predicted unfavorable STB clinical prognosis outcomes (Table 3).

As the understanding and techniques for treating STB continue to advance, the primary goal of surgical treatment has shifted towards eradicating TB lesions, relieving spinal nerve compression, reconstructing spinal stability, addressing spinal deformities, and ultimately improving the quality of life for elderly patients (24, 25). However, malnutrition and frailty, which are prevalent and interconnected among geriatric individuals, pose potential risk factors for adverse postoperative outcomes (14, 26). In the context of spine surgery, malnutrition has been associated with complications such as delirium, surgical site infections, and wound dehiscence (27, 28). Among elderly patients with cervical spondylotic myelopathy, preoperative malnutrition has been closely linked to the increased occurrence of cervical kyphosis following laminoplasty (29). Additionally, individuals with latent tuberculosis are prone to tuberculosis reactivation and progression to active tuberculosis when malnutrition sets in and cellular immune function declines (30). Active tuberculosis requires increased energy expenditure, necessitating an additional 20–30% of daily caloric intake (31). Consequently, malnutrition is considered a widespread risk factor for tuberculosis. Recurrent infections further exacerbate nitrogen loss and worsen nutritional status, rendering individuals more susceptible to infections. This vicious cycle poses particular harm to geriatric patients (32). Therefore, our study focuses on evaluating the prognostic value of preoperative nutritional status in elderly patients undergoing STB surgery. This retrospective, single-center study revealed that geriatric patients with lower GNRI scores had worse outcomes and experienced a higher incidence of complications compared to those with higher GNRI scores at the 1-year follow-up. Multivariate analysis demonstrated that GNRI scores independently predicted adverse postoperative outcomes in elderly patients with STB.

The GNRI, an index used to predict mortality risk based on nutritional status, is applicable to all patients, including elderly individuals with age-related malnutrition (18). Extensive literature supports the strong correlation between the GNRI and various nutritional evaluations, enabling it to effectively forecast short- and long-term clinical outcomes (33, 34). This index relies on objective parameters such as serum albumin concentration and weight loss. In addition, the GNRI stands out as a cost-effective and efficient tool for assessing nutritional status upon admission, making it suitable for routine evaluation in population-based settings (35). Moreover, due to its association with nutrition-related factors, the GNRI can aid in the prevention of complications related to underlying malnutrition, such as bedsores and infections, ultimately improving the prognosis for undernourished patients (36). Numerous studies have demonstrated the utility of the GNRI for screening malnutrition in patients with chronic diseases like peritoneal dialysis, heart failure, cancer, and stroke. In these cases, a low GNRI is indicative of an unfavorable prognosis, including poor functional outcomes, higher prevalence of complications, and increased mortality rates (34, 37–39). Building on our study, the GNRI can effectively guide perioperative treatment and nursing for elderly patients with STB, facilitating personalized care. Comprehensive assessment and management of nutritional status before surgery are crucial in preventing postoperative functional decline and unfavorable surgical outcomes, as malnutrition can be modified as a risk factor prior to the procedure. Additionally, patients with gastrointestinal dysfunction should receive early provision of parenteral nutrition to ensure targeted caloric support.

It is important to acknowledge the limitations of our study. Firstly, it is a retrospective, single-center study with a small sample size. Secondly, while trace elements have been implicated in influencing tuberculosis infection and immunity, our study did not include their measurement. Due to the low content of vitamins and trace elements, sensitive technology is necessary for accurate analysis, and precautions must be taken to avoid contamination during measurement. Moreover, our assessment only focused on preoperative nutritional status, neglecting postoperative nutritional evaluation. Consequently, further prospective studies are required to explore the correlation between the GNRI and the prognosis of elderly patients with STB.

This study demonstrated that a lower GNRI is linked to negative outcomes in elderly patients with STB. The GNRI serves as a cost-effective and easily accessible set of biomarkers that can assist in identifying individuals with poor prognoses, who would benefit from early nutritional intervention. These significant findings should be further investigated through prospective studies to validate their implications.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving humans were approved by Ethics Committee of West China Hospital of Sichuan University. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

YH and RW conceptualized and designed the study and drafted the initial manuscript. QX carried out the initial analyzes, and reviewed and revised the manuscript. GF and LL coordinated and supervised data collection, critically reviewed, and revised the manuscript for important intellectual content. All authors contributed to the article and approved the submitted version.

The authors acknowledge the funding support from the National Natural Science Foundation of China (Nos. 82072434 and 82272546). The organizations had no involvement in the study design, collection, analysis, or interpretation of data, in the writing of the manuscript, or in the decision to submit the manuscript for publication.

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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