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.

SUBJECT/PATIENTS

A 2517 patient dataset was utilised from an international multi-centre 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 United Kingdom, Ireland, Australia, and New Zealand. Inclusion criteria mandated a non-contrast CT-KUB.

METHODS

SSP was defined as the 'absence of the need for intervention'. The model was developed using logistic regression and backwards selection (to achieve lowest AIC) 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%). Mean age (±[SD]) was 47 (±14.7) years and 1892 were male (75.2%). At the end of the modelling process, gender: male (OR 0.8, 95%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 >5-7mm (OR 0.2, 95%CI 0.16-0.25, p<0.0001), stone size >7mm (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 NSAID use (OR 1.3, 95%CI 0.99 - 1.71, p=0.06), and rectal NSAID use (OR1.17, 95%CI 0.9 - 1.53, p=0.24) remained. 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 online calculator via www.BURSTurology.com and could allow clinicians and patients to make a more informed decision on pursuing conservative management versus early intervention.

Clinical and Radiological Predictors of Early Intervention in Acute Ureteral Colic

PURPOSE

Acute ureteric colic (AUC) is generally one of the most common reasons for emergency department attendance. Expectant management is recommended in non-complicated ureteral calculi. However, data regarding the optimal duration of observation or indications of early intervention (EI) are not well understood. This article describes the clinical and radiological factors that promote EI in AUC.

PATIENTS AND METHODS

This was an observational and retrospective cohort study. Patients with AUC diagnosed based on non-contrast computerized tomography (NCCT) between 2019 and 2020 were enrolled in the study. These patients were classified into two main categories: spontaneous passage of stone (SSP) and EI. In addition, a comparative analysis was performed to identify clinical and radiological variables that promote EI.

RESULTS

One-hundred and sixty-one patients were included. High WBCs are associated with a significant increase in EI. Forty-three percent (n=37) of patients with serum WBCs higher than 10 had an EI, while 23% had SSP (n=17;p<0.001). High CRP level is also significantly associated with EI (n=36; 86%; p<0.001). Upper and middle ureteral calculi are statistically associated with EI (n=54; 62%) in comparison to the SSP cohort (n=22; 30%;p<0.001). EI is also linked to the maximal length of ureteric calculi (MCL) of 9 mm (6-13mm), and HU density of stone of 700 (430-990) H.U (p<0.001). Ureteric stone volume of 0.2 (0.06-0.3) cm³ is significantly associated with EI (p<0.001). Ureteral wall thickness of 3 (2-3 mm), the presence of extrarenal pelvis (n=20; 23%), and AP diameter of renal pelvis 18 (13-28 mm) are all significantly associated with a higher rate of EI (p<0.001). Multiple binary logistic regression analysis showed that MCL is the strongest predictor of EI.

CONCLUSION

MCL is an independent and robust predictor of EI in AUC. Biochemical variables and radiological characteristics can also act as an adjunct to promote EI.

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

OBJECTIVES

To assess the relationship of white blood cell count (WBC) and other routinely collected inflammatory and clinical markers including stone size, stone position, and medical expulsive therapy use (MET), with spontaneous stone passage (SSP) in a large contemporary cohort of patients with acute ureteric colic, as there are conflicting data on the role of WBC and other inflammatory markers in SSP in patients with acute ureteric colic.

PATIENTS AND METHODS

Multicentre retrospective cohort study coordinated by the British Urology Researchers in Surgical Training (BURST) Research Collaborative at 71 secondary care hospitals across four countries (UK, Republic of Ireland, Australia, and New Zealand). In all, 4170 patients presented with acute ureteric colic and a computed tomography confirmed single ureteric stone. Our primary outcome measure was SSP, as defined by the absence of need for intervention to assist stone passage (SP). Multivariable mixed effects logistic regression was used to explore the relationship between key patient factors and SSP.

RESULTS

In all, 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 count, nor C-reactive protein (CRP) predicted SSP, with an adjusted odds ratio (OR) of 0.97 (95% confidence interval [CI] 0.91-1.04, P = 0.38), 1.06 (95% CI 0.99-1.13, P = 0.1) and 1.00 (95% CI 0.99-1.00, P = 0.17), respectively. MET also did not predict SSP (adjusted OR 1.11, 95% CI 0.76-1.61). However, stone size and stone position were significant predictors. SSP for stones <5 mm was 89% (95% CI 87-90) compared to 49% (95% CI 44-53) for stones ≥5-7 mm, and 29% (95% CI 23-36) for stones >7 mm. For stones in the upper ureter the SSP rate was 52% (95% CI 48-56), middle ureter was 70% (95% CI 64-76), and lower ureter was 83% (95% CI 81-85).

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, nor CRP, helps determine the likelihood of SSP. We also found no overall benefit from the use of MET. Stone size and position are important predictors and our present findings represent the most comprehensive SP rates for each millimetre 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.