{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T10:17:00Z","timestamp":1788171420727,"version":"build-2803163510"},"reference-count":33,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T00:00:00Z","timestamp":1787875200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Clin. Med.","JCM"],"abstract":"<jats:p>Background\/Objectives: Acute obstructive pyelonephritis (AOP) is a urological emergency requiring urgent decompression. We aimed to develop and internally validate an interpretable admission-based score (AP-Score) to predict the likelihood of undergoing percutaneous nephrostomy (PCN) and to test whether it outperforms hydronephrosis grade alone. Methods: We retrospectively analyzed 231 adults with AOP treated with antibiotics alone, double-J stenting, or PCN at a single center. Four admission variables (temperature, C-reactive protein [CRP], serum creatinine, and hydronephrosis grade) were evaluated by multivariable logistic regression and likelihood ratio testing. Discrimination was compared against hydronephrosis grade alone using the DeLong test; calibration and clinical usefulness were assessed, and optimism was estimated using 1000 bootstrap resamples. Results: In the likelihood ratio test, while adding CRP to hydronephrosis grade significantly improved model fit (p &lt; 0.001), serum creatinine provided a smaller additional contribution (p = 0.013). The AP-Score (0\u20138 points) combined these three variables included in the model; in the categorical model, the grade of hydronephrosis and CRP appeared as independent predictors, whereas creatinine was included due to its contribution on a continuous scale. The score achieved an AUC of 0.830 (95% CI 0.771\u20130.886), performing significantly better than the model using only the grade of hydronephrosis (AUC 0.772; \u0394AUC = +0.058, DeLong p = 0.010; IDI = 0.061, p = 0.002). The optimism-corrected AUC was calculated as 0.827, and calibration was found to be adequate (Hosmer\u2013Lemeshow p = 0.342). A threshold value of \u22654 points yielded a sensitivity of 85.3% and a specificity of 65.0% (OR = 10.79, 95% CI 5.12\u201322.70); no patients scoring 0\u20131 points (n = 37) underwent nephrostomy. Conclusions: The AP-Score\u2014which combines a structural parameter (degree of hydronephrosis) with two systemic markers (CRP and creatinine)\u2014is a simple and well-calibrated score that performs significantly better than the degree of hydronephrosis alone. The AP-Score was also associated with additional clinical outcomes, suggesting that it captures aspects of the underlying clinical course in addition to local treatment patterns. However, because the primary endpoint reflects the drainage modality selected under a single-center institutional protocol, the score should be considered hypothesis-generating until externally validated in independent, preferably multicenter cohorts with different drainage practices.<\/jats:p>","DOI":"10.3390\/jcm15176662","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T09:21:19Z","timestamp":1788168079000},"page":"6662","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Development and Internal Validation of the AP-Score for Predicting Percutaneous Nephrostomy Use in Acute Obstructive Pyelonephritis"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1587-6796","authenticated-orcid":false,"given":"Hakan","family":"\u015e\u0131\u011fva","sequence":"first","affiliation":[{"name":"Urology Clinic, Van Training and Research Hospital, Van 65300, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0792-1075","authenticated-orcid":false,"given":"Mehmet","family":"Sevim","sequence":"additional","affiliation":[{"name":"Urology Clinic, Van Training and Research Hospital, Van 65300, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9990-1516","authenticated-orcid":false,"given":"Arif Mehmet","family":"Duran","sequence":"additional","affiliation":[{"name":"Urology Clinic, Van Training and Research Hospital, Van 65300, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-6318-6719","authenticated-orcid":false,"given":"Muhammed","family":"Tosun","sequence":"additional","affiliation":[{"name":"Urology Clinic, Van Training and Research Hospital, Van 65300, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-4252-3534","authenticated-orcid":false,"given":"\u00d6mer","family":"B\u00fcy\u00fcktepe","sequence":"additional","affiliation":[{"name":"Urology Clinic, Van Training and Research Hospital, Van 65300, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"supervision","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3099-3317","authenticated-orcid":false,"given":"Fatih","family":"G\u00f6kalp","sequence":"additional","affiliation":[{"name":"Urology Clinic, Osmaniye Training and Research Hospital, Osmaniye 80000, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"project-administration","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"803","DOI":"10.1007\/s00345-013-1166-4","article-title":"Predictors of septic shock in obstructive acute pyelonephritis","volume":"32","author":"Tambo","year":"2014","journal-title":"World J. Urol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1258\/ar.2011.110507","article-title":"Serious acute pyelonephritis: A predictive score for evaluation of deterioration of treatment based on clinical and radiologic findings using CT","volume":"53","author":"Kim","year":"2012","journal-title":"Acta Radiol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1055\/s-0039-3401842","article-title":"Emergent Percutaneous Nephrostomy for Pyonephrosis: A Primer for the On-Call Interventional Radiologist","volume":"37","author":"Florido","year":"2020","journal-title":"Semin. Interv. Radiol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"229","DOI":"10.48083\/OZUL6913","article-title":"Predictors for Retrograde Ureteral Stenting Failure as an Initial Drainage Method for Emergent Complicated Acute Calculus Obstructive Uropathy","volume":"2","author":"Elbaset","year":"2021","journal-title":"Soc. Int. Urol. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"710","DOI":"10.21037\/tau-20-1208","article-title":"Machine learning-assisted decision-support models to better predict patients with calculous pyonephrosis","volume":"10","author":"Liu","year":"2021","journal-title":"Transl. Androl. Urol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1587","DOI":"10.1007\/s00240-024-01587-y","article-title":"Machine learning constructs a diagnostic prediction model for calculous pyonephrosis","volume":"52","author":"Yang","year":"2024","journal-title":"Urolithiasis"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1526","DOI":"10.1016\/j.juro.2017.12.052","article-title":"Performance of Quick Sequential (Sepsis Related) and Sequential (Sepsis Related) Organ Failure Assessment to Predict Mortality in Patients with Acute Pyelonephritis Associated with Upper Urinary Tract Calculi","volume":"199","author":"Fukushima","year":"2018","journal-title":"J. Urol."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Hsu, J.-T., Lin, C.-M., Hung, S.-F., Chung, S.-D., and Cheng, P. (2025). Optimizing antibiotic duration and percutaneous nephrostomy timing in urosepsis complicated by upper ureteral stones: A retrospective study. BMC Urol., 25.","DOI":"10.1186\/s12894-025-01868-7"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1016\/j.annemergmed.2015.08.019","article-title":"External Validation of the STONE Score, a Clinical Prediction Rule for Ureteral Stone: An Observational Multi-institutional Study","volume":"67","author":"Wang","year":"2015","journal-title":"Ann. Emerg. Med."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Tsai, Y.-C., Huang, Y.-H., Niu, K.-Y., Tsai, Y.-C., Chen, C.-B., and Yen, C.-C. (2024). Development of a predictive nomogram for sepsis in patients with urolithiasis-related obstructive pyelonephritis. Medicina, 60.","DOI":"10.21203\/rs.3.rs-4397502\/v1"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Hu, M., Zhong, X., Cui, X., Xu, X., Zhang, Z., Guan, L., Feng, Q., Huang, Y., and Hu, W. (2018). Development and validation of a risk-prediction nomogram for patients with ureteral calculi associated with urosepsis: A retrospective analysis. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0201515"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Sugizaki, Y., Utsumi, T., Ishitsuka, N., Noro, T., Suzuki, Y., Iijima, S., Somoto, T., Oka, R., Endo, T., and Kamiya, N. (2025). Predicting Urosepsis in Ureteral Calculi: External Validation of Hu\u2019s Nomogram and Identification of Novel Risk Factors. Diagnostics, 15.","DOI":"10.3390\/diagnostics15091104"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1326","DOI":"10.12669\/pjms.37.5.3951","article-title":"Etiology of hydronephrosis in adults and children: Ultrasonographic assessment in 233 patients","volume":"37","author":"Alshoabi","year":"2021","journal-title":"Pak. J. Med. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1186\/s43055-022-00799-9","article-title":"Importance of the Hounsfield unit value measured by computed tomography in the differentiation of hydronephrosis and pyonephrosis","volume":"53","author":"Barsoum","year":"2022","journal-title":"Egypt. J. Radiol. Nucl. Med."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"g7594","DOI":"10.1136\/bmj.g7594","article-title":"Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD): The TRIPOD statement","volume":"350","author":"Collins","year":"2015","journal-title":"BMJ"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"S253","DOI":"10.1016\/j.jvir.2015.12.646","article-title":"Nephrostomy for nephrolithotomy: Basic review with tips and tricks for challenging cases","volume":"27","author":"Mahon","year":"2016","journal-title":"J. Vasc. Interv. Radiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1055\/s-0032-1326932","article-title":"Emergent percutaneous nephrostomy for the diagnosis and management of pyonephrosis","volume":"29","author":"Li","year":"2012","journal-title":"Semin. Interv. Radiol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2621","DOI":"10.12659\/MSM.894153","article-title":"Scoring systems in assessing survival of critically ill ICU patients","volume":"21","author":"Sekulic","year":"2015","journal-title":"Med. Sci. Monit."},{"key":"ref_19","first-page":"10841","article-title":"Does qSOFA score predict ICU admission and outcomes in patients with obstructed infected ureteral stones?","volume":"28","author":"Stokes","year":"2021","journal-title":"Can. J. Urol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"410","DOI":"10.1016\/j.jvir.2015.11.045","article-title":"Quality improvement guidelines for percutaneous nephrostomy","volume":"27","author":"Dariushnia","year":"2016","journal-title":"J. Vasc. Interv. Radiol."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Yu, Y., Hu, J., Liu, W., Peng, Z., Wang, M., Zhou, X., and Xi, H. (2022). Performing percutaneous nephrolithotomy under modified local anesthesia. Front. Surg., 9.","DOI":"10.3389\/fsurg.2022.922158"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"895","DOI":"10.1016\/j.urology.2004.06.029","article-title":"Percutaneous nephrostomy versus indwelling ureteral stents in extrinsic ureteral obstruction in advanced malignancies","volume":"64","author":"Ku","year":"2004","journal-title":"Urology"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1016\/j.urols.2012.07.008","article-title":"Comparison between the use of percutaneous nephrostomy and internal ureteral stenting in the management of long-term ureteral obstructions","volume":"23","author":"Chang","year":"2012","journal-title":"Urol. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"6613","DOI":"10.1038\/s41598-021-86136-y","article-title":"Percutaneous nephrostomy versus retrograde ureteral stenting for acute upper obstructive uropathy: Systematic review and meta-analysis","volume":"11","author":"Azwadi","year":"2021","journal-title":"Sci. Rep."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"424","DOI":"10.1177\/03915603251316702","article-title":"Nephrostomy (PCN) versus nephroureteral stent (Double JJ); An ongoing battle","volume":"92","author":"Trinh","year":"2025","journal-title":"Urologia"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"571","DOI":"10.1259\/bjr\/38306763","article-title":"Nephrostomy insertion for bilateral ureteric obstruction caused by prostate cancer","volume":"82","author":"Nariculam","year":"2009","journal-title":"Br. J. Radiol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"17562872221078773","DOI":"10.1177\/17562872221078773","article-title":"Evaluation of early scoring predictors for expedited care in patients with emphysematous pyelonephritis","volume":"14","author":"Chawla","year":"2022","journal-title":"Ther. Adv. Urol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"891","DOI":"10.1080\/14787210.2023.2237192","article-title":"SIRS, SOFA, qSOFA and NEWS in the diagnosis of sepsis and prediction of adverse outcomes: A systematic review and meta-analysis","volume":"21","author":"Qiu","year":"2023","journal-title":"Expert Rev. Anti-Infect. Ther."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Chen, C.-C., Hsieh, M.-S., Hu, S.-Y., Huang, S.-C., Tsai, C.-A., and Tsai, Y.-C. (2022). Performance of scoring systems in predicting clinical outcomes of patients with emphysematous pyelonephritis: A 14-year hospital-based study. J. Clin. Med., 11.","DOI":"10.3390\/jcm11247299"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"880","DOI":"10.1016\/j.juro.2007.05.017","article-title":"Risk factors for mortality in emphysematous pyelonephritis: A meta-analysis","volume":"178","author":"Falagas","year":"2007","journal-title":"J. Urol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1111\/bju.15225","article-title":"Prognostic scoring system and risk stratification in patients with emphysematous pyelonephritis: An 11-year prospective study at a tertiary referral centre","volume":"127","author":"Krishnamoorthy","year":"2020","journal-title":"BJU Int."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"774","DOI":"10.21037\/tau.2016.07.02","article-title":"Emphysematous pyelonephritis: The impact of urolithiasis on disease severity","volume":"5","author":"Sanford","year":"2016","journal-title":"Transl. Androl. Urol."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Lu, Y.-C., Chiang, B.-J., Pong, Y.-H., Huang, K.-H., Hsueh, P.-R., Huang, C.-Y., and Pu, Y.-S. (2014). Predictors of failure of conservative treatment in emphysematous pyelonephritis. BMC Infect. 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