Development and internal validation of a clinical nomogram for predicting major postoperative pulmonary complications following radical cystectomy: a retrospective cohort study

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Bladder urothelial carcinoma requiring radical cystectomy (n=456). Intervention: Dynamic perioperative predictive nomogram (age, smoking history, ASA physical status III–IV, preoperative serum albumin, FEV1%pred, and intraoperative net fluid balance). Primary outcome: Incidence of major postoperative pulmonary complications (PPCs) within 30 days (apparent C-index 0.824, 95% CI 0.758-0.890).

Q: What does this research mean for the field?

A dynamic perioperative nomogram integrating age, smoking history, ASA status, serum albumin, FEV1%pred, and intraoperative net fluid balance accurately predicts major postoperative pulmonary complications after radical cystectomy with high discrimination (C-index 0.824). Novelty: ClaimNovelty.METHODOLOGICAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Jing Feng; Juan Zhang

doi:10.21037/tau-2026-0459

August 1, 2026Translational Andrology and UrologyOpen Access

Development and internal validation of a clinical nomogram for predicting major postoperative pulmonary complications following radical cystectomy: a retrospective cohort study

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Key result

Novel perioperative nomogram predicts major post-cystectomy pulmonary complications with a C-index of ~0.82.

apparent C-index 0.824
95% CI 0.758-0.890
n=456

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Why the study?

Radical cystectomy is associated with a considerable risk of major postoperative pulmonary complications, and generic surgical risk models may not adequately account for procedure-specific characteristics of RC.

Key Points

To develop and internally validate a dynamic perioperative nomogram combining preoperative factors with intraoperative net fluid balance to predict major postoperative pulmonary complications following radical cystectomy.
Retrospective cohort study of N=456 patients undergoing radical cystectomy between January 2020 and June 2025.
Variable selection was performed using least absolute shrinkage and selection operator (LASSO) penalized regression across 10 multiply imputed datasets, followed by multivariable logistic regression.
Internal validation and optimism correction were conducted using 1,000 bootstrap resamples, with clinical utility evaluated via decision curve analysis.
Major postoperative pulmonary complications occurred within 30 days in 32 of 456 patients (7.0%).
Six independent predictors were identified: age (aOR=1.07 per year; 95% CI: 1.02–1.13; P=0.01), smoking history (aOR=2.41; 95% CI: 1.08–5.38; P=0.03), ASA physical status III–IV (aOR=2.65; 95% CI: 1.18–5.95; P=0.02), serum albumin (aOR=0.83 per 1 g/L; 95% CI: 0.74–0.93; P=0.002), FEV1%pred (aOR=0.94 per 1%; 95% CI: 0.90–0.98; P=0.003), and intraoperative net fluid balance (aOR=1.16 per 100 mL; 95% CI: 1.06–1.28; P=0.001).
The nomogram achieved an apparent C-index of 0.824 (95% CI: 0.758–0.890), an optimism-corrected C-index of 0.811, and favorable calibration (Hosmer-Lemeshow P=0.60) with positive net benefit between 4% and 65% threshold probabilities.

Study Design

Type

Cohort (n=456)

Multicenter

No

Structured PICO

P

Population

456 adults (mean age 66.9 years, 19.3% female) undergoing elective open or robot-assisted radical cystectomy for bladder cancer, followed for 30 days postoperatively to assess the incidence of major pulmonary complications.

E

Exposure

Development and internal validation of a dynamic perioperative nomogram integrating 6 variables (age, smoking history, ASA physical status III-IV, preoperative serum albumin, FEV1%pred, and intraoperative net fluid balance) to update risk near the end of surgery.

O

Outcome

Incidence of major postoperative pulmonary complications (PPCs) occurring within 30 days following radical cystectomy, defined as a composite of pneumonia, respiratory failure, acute respiratory distress syndrome, or clinically significant atelectasis.composite

Main Result

Effect estimate: apparent C-index 0.824 (95% CI 0.758-0.890)

A dynamic perioperative nomogram combining preoperative factors and intraoperative net fluid balance showed strong discriminative ability for predicting major pulmonary complications after radical cystectomy, offering a potential tool for guiding immediate postoperative respiratory care.

Limitations

Single-center retrospective design introduces potential selection and information bias and limits model transportability.
Only 32 major PPC events occurred, which limits the stability of regression coefficients and may cause optimistic performance.
Inclusion of intraoperative net fluid balance prevents purely preoperative application.
Residual confounding due to inconsistently available data on ventilation parameters, analgesia, respiratory physiotherapy, and surgical technique variations.
Low event count (32 events) relative to candidate predictors, posing a risk of overfitting despite internal validation.
Model was evaluated only in the development cohort and requires external validation in larger independent cohorts.
Single-center retrospective cohort design.

Implication

May aid perioperative risk stratification after cystectomy; leaves open external validation before clinical adoption.

Abstract

Background: Radical cystectomy (RC) is associated with a considerable risk of major postoperative pulmonary complications (PPCs). Generic surgical risk models may not adequately account for the procedure-specific characteristics of RC. This study aimed to develop and internally validate a dynamic perioperative nomogram that combines preoperative characteristics with an intraoperative variable to estimate the individualized risk of major PPCs following RC for bladder cancer. Methods: A retrospective cohort study was conducted on 456 patients who underwent RC between January 2020 and June 2025. The least absolute shrinkage and selection operator (LASSO) regression and multivariable logistic regression analyses were utilized to screen independent perioperative predictors. These robust predictors were subsequently incorporated to construct a visual nomogram. Model performance was comprehensively evaluated in terms of discrimination (Harrell's C-index), calibration, and clinical utility via decision curve analysis (DCA). Internal validation was performed using 1,000 bootstrap resamples to assess optimism-corrected performance. Results: Among the 456 included patients, 32 (7.0%) developed major PPCs within 30 days postoperatively. Six independent predictors were identified and integrated into the nomogram: age, smoking history, American Society of Anesthesiologists (ASA) physical status, preoperative serum albumin level, forced expiratory volume in one second percentage of predicted value (FEV1%pred), and intraoperative net fluid balance. The nomogram demonstrated excellent discrimination with an apparent C-index of 0.824 [95% confidence interval (CI): 0.758-0.890] and an optimism-corrected C-index of 0.811. The bootstrap-corrected calibration curve showed high concordance between predicted and observed probabilities (Hosmer-Lemeshow P=0.60). DCA suggested a positive net benefit relative to the treat-all and treat-none strategies across threshold probabilities of 4% to 65% within the study cohort. Conclusions: This internally validated dynamic perioperative nomogram showed preliminary discrimination and calibration for estimating major PPC risk after RC within the study cohort. Because intraoperative net fluid balance is required, the model is intended for risk updating near the end of surgery rather than purely preoperative assessment. It may provide a preliminary basis for planning postoperative surveillance and respiratory care, but external validation in larger independent cohorts is required before clinical implementation.

Discussion

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Cite This Study

Feng et al. (2026) conducted a cohort in Bladder urothelial carcinoma requiring radical cystectomy (n=456). Dynamic perioperative predictive nomogram (age, smoking history, ASA physical status III–IV, preoperative serum albumin, FEV1%pred, and intraoperative net fluid balance) was evaluated on Incidence of major postoperative pulmonary complications (PPCs) within 30 days (apparent C-index 0.824, 95% CI 0.758-0.890). An internally validated dynamic perioperative nomogram integrating six clinical and intraoperative variables demonstrated excellent discrimination with an apparent C-index of 0.824 for predicting major postoperative pulmonary complications after radical cystectomy.

synapsesocial.com/papers/6ad0fce415427f6a84040368 https://doi.org/10.21037/tau-2026-0459

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Development and internal validation of a clinical nomogram for predicting major postoperative pulmonary complications following radical cystectomy: a retrospective cohort study

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Development and internal validation of a clinical nomogram for predicting major postoperative pulmonary complications following radical cystectomy: a retrospective cohort study

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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