Factors associated with spontaneous stone passage in a contemporary cohort of patients presenting with acute ureteric colic. Results from the MIMIC Study (A Multi-centre cohort study evaluating the role of Inflammatory Markers in patients presenting with acute ureteric Colic)

Objectives There is conflicting data on the role of white blood cell count (WBC) and other inflammatory markers in spontaneous stone passage in patients with acute ureteric colic. The aim of the study was to assess the relationship of WBC and other routinely collected inflammatory and clinical markers including stone size, stone position and Medically Expulsive Therapy use (MET) with spontaneous stone passage (SSP) in a large contemporary cohort of patients with acute ureteric colic. Subjects and Methods Multi‐centre retrospective cohort study coordinated by the British Urology Researchers in Surgical Training (BURST) Research Collaborative at 71 secondary care hospitals across 4 countries (United Kingdom, Republic of Ireland, Australia and New Zealand). 4170 patients presented with acute ureteric colic and a computer tomography confirmed single ureteric stone. Our primary outcome measure was SSP as defined by the absence of need for intervention to assist stone passage. Multivariable mixed effects logistic regression was used to explore the relationship between key patient factors and SSP. Results 2518 patients were discharged with conservative management and had further follow up with a SSP rate of 74% (n = 1874/2518). Sepsis after discharge with conservative management was reported in 0.6% (n = 16/2518). On multivariable analysis neither WBC, Neutrophils or CRP were seen to predict SSP, with an adjusted OR of 0.97 [95% CI 0.91 to 1.04, p = 0.38], 1.06 [95% CI 0.99 to 1.13, p = 0.1] and 1.00 [95% CI 0.99 to 1.00, p = 0.17], respectively. Medical expulsive therapy (MET) also did not predict SSP [adjusted OR 1.11 [95% CI 0.76 to 1.61]). However, stone size and stone position were significant predictors. SSP for stones 7mm. For stones in the upper ureter the SSP rate was 52% [95% CI 48 to 56], middle ureter was 70% [95% CI 64 to 76], and lower ureter was 83% [95% CI 81 to 85]. Conclusion In contrast to the previously published literature, we found that in patients with acute ureteric colic who are discharged with initial conservative management, neither WBC, Neutrophil count or CRP help determine the likelihood of spontaneous stone passage. We also found no overall benefit from the use of MET. Stone size and position are important predictors and our findings represent the most comprehensive stone passage rates for each mm increase in stone size from a large contemporary cohort adjusting for key potential confounders. We anticipate that these data will aid clinicians managing patients with acute ureteric colic and help guide management decisions and the need for intervention

Nomogram predicting the probability of spontaneous stone passage in patients presenting with acute ureteric colic

Objectives To develop a nomogram that could predict spontaneous stone passage (SSP) in patients presenting with acute ureteric colic who are suitable for conservative management. Patients and Methods A 2517 patient dataset was utilised from an international multicentre cohort study (MIMIC, A Multi-centre Cohort Study Evaluating the role of Inflammatory Markers In Patients Presenting with Acute Ureteric Colic) of patients presenting with acute ureteric colic across 71 secondary care hospitals in the UK, Ireland, Australia, and New Zealand. Inclusion criteria mandated a non-contrast computed tomography of the kidneys, ureters, and bladder. SSP was defined as the ‘absence of the need for intervention’. The model was developed using logistic regression and backwards selection (to achieve lowest Akaike's information criterion) in a subset from 2009–2015 (n = 1728) and temporally validated on a subset from 2016–2017 (n = 789). Results Of the 2517 patients, 1874 had SSP (74.5%). The mean (SD) age was 47 (14.7) years and 1892 were male (75.2%). At the end of the modelling process, gender: male (odds ratio [OR] 0.8, 95% confidence interval [CI] 0.64–1.01, P = 0.07), neutrophil count (OR 1.03, 95% CI 1.00–1.06, P = 0.08), hydronephrosis (OR 0.79, 95% CI 0.59–1.05, P = 0.1), hydroureter (OR 1.3, 95% CI 0.97–1.75, P = 0.08), stone size >5–7 mm (OR 0.2, 95% CI 0.16–0.25, P 7 mm (OR 0.11, 95% CI 0.08–0.15, P < 0.001), middle ureter stone position (OR 0.59, 95% CI 0.43–0.81, P = 0.001), upper ureter stone position (OR 0.31, 95% CI 0.25–0.39, P < 0.001), medical expulsive therapy use (OR 1.36, 95% CI 1.1–1.67, P = 0.001), oral nonsteroidal anti-inflammatory drug (NSAID) use (OR 1.3, 95% CI 0.99–1.71, P = 0.06), and rectal NSAID use (OR 1.17, 95% CI 0.9–1.53, P = 0.24) remained. The concordance-statistic (C-statistic) was 0.77 (95% CI 0.75–0.80) and a nomogram was developed based on these. Conclusion The presented nomogram is available to use as an on-line calculator via www.BURSTurology.com and could allow clinicians and patients to make a more informed decision on pursuing conservative management vs early intervention