The effect of the visceral fat area on the predictive accuracy of C-reactive protein for infectious complications after laparoscopy-assisted gastrectomy

Impact of infectious complications after gastrectomy on non‑gastric cancer‑related deaths

Infectious complications (ICs) have been reported as major causes of postoperative mortality in patients with cancer. However, to the best of our knowledge, the impact of ICs after gastrectomy on non-gastric cancer-related deaths (NGCDs) remains unexplored. The present study aimed to identify the impact of ICs after gastrectomy on NGCDs. A retrospective analysis of 712 patients with gastric cancer who underwent curative gastrectomy was conducted. The participants were categorized into IC and non-IC groups based on the incidence of postoperative IC. Clinicopathological factors and non-gastric cancer-related survival (NGCS) rates were compared between groups. Further NGCD and associated risk factor analyses were performed in a background factor-adjusted cohort using multivariate analysis. Among the 712 patients, 112 developed ICs (Clavien-Dindo classification grade ≥II). In the entire cohort, the IC group had a significantly worse 5-year cumulative incidence of NGCD (17.8 vs. 10.6%; Gray's P=0.021) compared with the non-IC group. Although a number of clinicopathological factors differed between the groups, including patient background, operative factors and tumor factors, the risk factors for NGCD identified in the multivariate analysis were older age, low prognostic nutritional index, low skeletal muscle index and Charlson comorbidity index ≥1, excluding IC incidents. The IC group exhibited more background factors contributing to NGCDs, suggesting a potential increase in NGCD regardless of IC incidence.

Risk factors for infectious complications after gastrectomy in older patients

The present study aimed to identify preoperative and perioperative risk factors for postoperative infectious complications in older patients with gastric cancer. The present retrospective study included 504 patients with gastric cancer aged >65 years who underwent radical gastrectomy. After determining the cutoff values for various perioperative factors in the receiver operating characteristic curve analysis, preoperative and perioperative risk factors for the development of infectious complications after gastrectomy were examined using logistic regression analysis. Of the 504 patients who underwent gastrectomy, 95 (18.8%) developed infectious complications of grade II-V based on the Clavien-Dindo classification. In an analysis restricted to preoperative factors, male sex, low prognostic nutritional index, high visceral fat area and total gastrectomy were independent risk factors for infectious complications after gastrectomy. Among all perioperative factors, a low prognostic nutritional index and long operative duration were identified as independent risk factors for infectious complications after gastrectomy. The patients were divided into five groups according to the number of positive preoperative risk factors for infectious complications, and the incidence of infectious complications differed among the five groups (0 factors, 6.7%; 1 factor, 10.4%; 2 factors, 18.9%; 3 factors, 27.8%; and 4 factors, 47.6%; P<0.001). Older patients with gastric cancer who have a number of preoperative risk factors require careful consideration of the indication for gastrectomy and a shorter operative time to reduce infectious complications.

Investigation of heteroscedasticity in polygenic risk scores across 15 quantitative traits

The polygenic risk score (PRS) could be used to stratify individuals with high risk of diseases and predict complex trait of individual in a population. Previous studies developed a PRS-based prediction model using linear regression and evaluated the predictive performance of the model using the R ² value. One of the key assumptions of linear regression is that the variance of the residual should be constant at each level of the predictor variables, called homoscedasticity. However, some studies show that PRS models exhibit heteroscedasticity between PRS and traits. This study analyzes whether heteroscedasticity exists in PRS models of diverse disease-related traits and, if any, it affects the accuracy of PRS-based prediction in 354,761 Europeans from the UK Biobank. We constructed PRSs for 15 quantitative traits using LDpred2 and estimated the existence of heteroscedasticity between PRSs and 15 traits using three different tests of the Breusch-Pagan (BP) test, score test, and F test. Thirteen out of fifteen traits show significant heteroscedasticity. Further replication using new PRSs from the PGS catalog and independent samples (N = 23,620) from the UK Biobank confirmed the heteroscedasticity in ten traits. As a result, ten out of fifteen quantitative traits show statistically significant heteroscedasticity between the PRS and each trait. There was a greater variance of residuals as PRS increased, and the prediction accuracy at each level of PRS tended to decrease as the variance of residuals increased. In conclusion, heteroscedasticity was frequently observed in the PRS-based prediction models of quantitative traits, and the accuracy of the predictive model may differ according to PRS values. Therefore, prediction models using the PRS should be constructed by considering heteroscedasticity.

Impact of visceral obesity on the short-term outcomes after laparoscopic appendectomy

OBJECTIVE

To investigate the effect of visceral obesity on short-term outcomes after laparoscopic appendectomy (LA).

METHODS

a retrospective study on 441 patients who underwent a LA between July 2019 and July 2020. According to the cutoff visceral fat area (VFA) for visceral obesity, the patients were divided into two groups: visceral obesity group (n = 123) and non-visceral obesity group (n = 318). The general information, comorbidities, perioperative monitoring indicators, and postoperative complications of the patients were collected.

RESULTS

Compared with the non-visceral obesity group, the proportion of overweight patients (56.10%), preoperative white blood cell count (12.92 (9.99, 15.58)*10⁹mg/dl), postoperative white blood cell count (9.71 ± 3.91*10⁹mg/dl), and hospitalization costs (16,220.93 ± 7038.76¥) in the visceral obesity group were significantly different (all p < 0.05). Additionally, multivariate logistic regression analysis revealed that visceral obesity (2.679, 95%CI: 1.155-5.849, p = 0.027), indwelling drainage tube (7.832, 95%CI: 2.151-27.428, p < 0.001), and perforated appendicitis (3.181, 95%CI: 1.195-7.136, p = 0.025) were identified to be independent risk factors for incision infection after LA. The area under receiver operating characteristic (ROC) curve value for VFA predicting incisional infection after LA was 0.770.

CONCLUSIONS

Visceral obesity is one of the independent risk factors for incisional infection after LA, and can be used as one of the reference indicators for prognostic assessment of short-term outcomes after LA.

Risk factors for non-gastric-cancer-related death after gastrectomy in elderly patients

Aim

To identify preoperative factors, especially other diseases that cause death, that are associated with the prognosis of gastrectomy in elderly patients with gastric cancer.

Methods

This retrospective study included a total of 211 consecutive patients aged ≥75 years who underwent radical gastrectomy due to gastric cancer. Time-dependent receiver operating characteristic curve analysis was performed to determine the optimal cutoff values for various perioperative factors. Risk factors for the overall survival and death from other diseases were analyzed using the Cox proportional hazards model.

Results

Among the all perioperative factors, sex, neutrophil-to-lymphocyte ratio, skeletal muscle mass index, and lymph node dissection in accordance with guidelines or not extracted as independent risk factors for death from other diseases. In an analysis restricted to the preoperative factors, sex, neutrophil-to-lymphocyte ratio, and skeletal muscle mass index of the patients were extracted as independent risk factors for death from other diseases and overall survival. We divided the patients into four groups according to the number of preoperative risk factors for death from other diseases and found that the 5-year non-gastric-cancer-related survival was different among the four groups (risk factor 0, 91.7%; risk factor 1, 83.3%; risk factor 2, 56.3%; risk factor 3, 27.2%; P < 0.001).

Conclusion

Male sex, low skeletal muscle mass index, and high neutrophil-to-lymphocyte ratio are risk factors for non-gastric-cancer-related death and the overall survival of elderly patients undergoing gastrectomy. Cautious treatment strategies are needed for elderly gastric cancer patients with many risk factors.

Visceral fat area is a better indicator of surgical outcomes after laparoscopic gastrectomy for cancer than the body mass index: a propensity score-matched analysis

BACKGROUND

The number of overweight gastric cancer patients who are undergoing laparoscopic gastrectomy (LG) has increased in Japan. However, the relationship between obesity and surgical outcomes of LG remains unclear. Therefore, this study aimed to evaluate the effect of visceral fat area (VFA) on surgical outcomes of LG for gastric cancer compared to the body mass index (BMI).

METHODS

This study was a retrospective, cohort study that included 587 patients who underwent LG in our institution between January 2015 and December 2019. The patients were divided into two groups according to VFA (< 100 cm² and ≥ 100 cm²) and BMI (< 25 kg/m² and ≥ 25 kg/m²) values, respectively. Surgical outcomes and postoperative complications were compared between the low and high groups for each VFA and BMI value. Propensity score matching was used to minimize potential selection bias.

RESULTS

After propensity score matching, 144 pairs of patients in the VFA group and 82 pairs of patients in the BMI group were extracted. Operative time (p = 0.003), intraoperative blood loss (p = 0.0006), and CRP levels on postoperative day 1 (p = 0.002) and on postoperative day 3 (p = 0.004) were significantly higher in the high-VFA group than in the low-VFA group. However, these surgical outcomes were not significantly different between the high-BMI and low-BMI groups. There was no strong correlation between VFA and BMI (R² = 0.64). There were no significant differences in postoperative complications between the high and low groups for both VFA and BMI values. On multivariate analysis, high VFA was an independent predictor of operative time, but it was not significantly associated with the incidence of postoperative complications.

CONCLUSION

VFA is a better indicator of longer operative time than BMI. However, increased VFA did not affect postoperative complications.