Chung DY et al, 2015: Impact of colic pain as a significant factor for predicting the stone free rate of one-session shock wave lithotripsy for treating ureter stones: a Bayesian logistic regression model analysis.
Chung DY, Cho KS, Lee DH, Han JH, Kang DH, Jung HD, Kown JK, Ham WS, Choi YD, Lee JY.
Department of Urology, Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
Department of Urology, Gangnam Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
Department of Urology, Severance Check-Up, Yonsei University Health System, Seoul, Korea.
Department of Urology, Yangpyeong Health Center, Yangpyeong, Korea.
Department of Urology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
Abstract
PURPOSE: This study was conducted to evaluate colic pain as a prognostic pretreatment factor that can influence ureter stone clearance and to estimate the probability of stone-free status in shock wave lithotripsy (SWL) patients with a ureter stone.
MATERIALS AND METHODS: We retrospectively reviewed the medical records of 1,418 patients who underwent their first SWL between 2005 and 2013. Among these patients, 551 had a ureter stone measuring 4-20 mm and were thus eligible for our analyses. The colic pain as the chief complaint was defined as either subjective flank pain during history taking and physical examination. Propensity-scores for established for colic pain was calculated for each patient using multivariate logistic regression based upon the following covariates: age, maximal stone length (MSL), and mean stone density (MSD). Each factor was evaluated as predictor for stone-free status by Bayesian and non-Bayesian logistic regression model.
RESULTS: After propensity-score matching, 217 patients were extracted in each group from the total patient cohort. There were no statistical differences in variables used in propensity- score matching. One-session success and stone-free rate were also higher in the painful group (73.7% and 71.0%, respectively) than in the painless group (63.6% and 60.4%, respectively). In multivariate non-Bayesian and Bayesian logistic regression models, a painful stone, shorter MSL, and lower MSD were significant factors for one-session stone-free status in patients who underwent SWL.
CONCLUSIONS: Colic pain in patients with ureter calculi was one of the significant predicting factors including MSL and MSD for one-session stone-free status of SWL.
PLoS One. 2015 Apr 22;10(4):e0123800. doi: 10.1371/journal.pone.0123800. eCollection 2015. FREE ARTICLE
Comments 1
The idea behind the study was that “Ureter stones in patients with colic pain are unlikely to be impacted as they do not have enough time to develop surrounding edema” Consequently their disintegration and fragment passage should be better than that of impacted stones.
Similar work has been published by Tombal et al. ( Prospective Randomized Evaluation of Emergency Extracorporeal Shock Wave Lithotripsy (ESWL) on the Short-Time Outcome of Symptomatic Ureteral. Stones Europ Urol 2005; 47: 855-859) and Seitz et al. (Rapid Extracorporeal Shock Wave Lithotripsy for Proximal Ureteral Calculi in Colic versus Noncolic Patients. Europ Urol, 2007; 52: 1223-1228). In these studies ESWL showed better results than medical or delayed treatment when done within 6 hours of emergency department admittance or within 24 hours resp.
In the present study the inclusion criteria were not very detailed “ 4–20 mm single, radiopaque calculi located within the ureter on non-contrast computed tomography (NCCT), presenting within a month of treatment and without evidence of stone migration.” Also the way colic was defined in the present paper was unusual: “The colic pain as the chief complaint was defined as subjective flank pain during physical examination”
The authors put an emphasis on statistics representing 25% of the references.
Among other statistical techniques they also used propensity score matching (PSM) which controls only for observed variables. Bias due to unregistered confounders may increase. There are no details about medical treatment in either patient group; pain medication was probably applied in the pain group and it cannot be excluded that this had an influence on the outcome.