Inflammatory Serum Markers Predicting Spontaneous Ureteral Stone Passage

Introduction: Ureteral stones pose a high economic and medical burden among Emergency Department (ED) admissions. Management strategies vary from expectant therapy to surgical interventions. However, predictors of spontaneous ureteral stone passage are still not well understood. We aim to explore the role of neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte (PLR) ratios in the spontaneous ureteral stone passage (SSP).

Methods: Chart review was done for 619 patients who presented to our institution's ED with non-febrile renal colic and received a radiological diagnosis of ureteral stone of less than 10 mm. Demographic, clinical, laboratory, and radiological data were collected. The Linear-by-Linear Association test was used to look at the trend among the NLR and PLR quartiles and other demographic variables. Univariate analysis was run for the collected variables. Then, a hierarchal backward multivariate logistic regression was run for each of NLR and PLR variables. To validate the results, bootstrapping was undertaken for each model.

Results: NLR between 2.87 and 4.87 had odds ratio (OR) 2.96 (95% CI 1.80-5.49) and an NLR > 4.87 had 3.63 (2.04-6.69) the odds of retained ureteral stone. A PLR between 10.42 and 15.25 and a PLR > 15.25 had 3.28 (1.79-6.19) and 3.84 (2.28-7.12) the odds of failed SSP, respectively. Other significant variables in the two models are diabetes, urine leukocyte esterase > 10 white blood cell/μl, moderate-to-severe hydronephrosis, and stone size.

Conclusion: NLR and PLR are inversely associated with SSP of ureteral stones. In adjunct with other indicators, NLR and PLR are inflammatory markers that could be used in the clinical decision of ureteral stone management.