Identifying a critical skeletal muscle threshold and systemic predictors for acute urinary retention in benign prostatic hyperplasia with sarcopenia: an internally validated model.

BACKGROUND

The concurrent presentation of benign prostatic hyperplasia (BPH) and sarcopenia complicates the clinical evaluation of acute urinary retention (AUR). This study aimed to identify clinical predictors and explore non-linear associations with AUR risk in this specialized comorbidity.

METHODS

A retrospective cohort of 328 adult males with comorbid BPH and sarcopenia was analyzed. Stabilized inverse probability of treatment weighting (IPTW) was utilized to adjust for baseline confounding. Feature selection was conducted via Lasso penalization (lambda.1se threshold) to prevent overfitting. Non-linear relationships were evaluated using restricted cubic splines (RCS) with three fixed knots. The predictive model underwent internal validation via 1,000 bootstrap resamples.

RESULTS

Multivariable weighted logistic regression identified older age and catheterization history as potential risk factors for AUR, whereas higher skeletal muscle index (SMI) and pharmacological treatments (5-ARIs, alpha-blockers) were associated with reduced risk. RCS analysis indicated a significant non-linear relationship (P-non-linear = 0.002), suggesting a sharp increase in AUR probability when SMI declined below a critical threshold. The internally validated model exhibited an area under the curve of 0.789 and adequate calibration.

CONCLUSIONS

Identifying specific muscle depletion thresholds and selective clinical indicators may assist in stratifying AUR risk among patients with BPH and sarcopenia.