The clinical and cost effectiveness of surgical interventions for stones in the lower pole of the kidney: the percutaneous nephrolithotomy, flexible ureterorenoscopy and extracorporeal shockwave lithotripsy for lower pole kidney stones randomised controlled trial (PUrE RCT) protocol

Abstract

Introduction: Renal stones are common, with a lifetime prevalence of 10% in adults. Global incidence is increasing due to increases in obesity and diabetes, with these patient populations being more likely to suffer renal stone disease. Flank pain from stones (renal colic) is the most common cause of emergency admission to UK urology departments. Stones most commonly develop in the lower pole of the kidney (in ~35% of cases) and here are least likely to pass without intervention. Currently there are three technologies available within the UK National Health Service to remove lower pole kidney stones: extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and flexible ureterorenoscopy (FURS) with laser lithotripsy. Current evidence indicates there is uncertainty regarding the management of lower pole stones, and each treatment has advantages and disadvantages. The aim of this trial is to determine the clinical and cost effectiveness of FURS compared with ESWL or PCNL in the treatment of lower pole kidney stones.

Methods: The PUrE (PCNL, FURS and ESWL for lower pole kidney stones) trial is a multi-centre, randomised controlled trial (RCT) evaluating FURS versus ESWL or PCNL for lower pole kidney stones. Patients aged ≥16 years with a stone(s) in the lower pole of either kidney confirmed by non-contrast computed tomography of the kidney, ureter and bladder (CTKUB) and requiring treatment for a stone ≤10 mm will be randomised to receive FURS or ESWL (RCT1), and those requiring treatment for a stone >10 mm to ≤25 mm will be randomised to receive FURS or PCNL (RCT2). Participants will undergo follow-up by questionnaires every week up to 12 weeks post-intervention and at 12 months post-randomisation. The primary clinical outcome is health status measured by the area under the curve calculated from multiple measurements of the EuroQol five dimensions five-level version (EQ-5D-5L) questionnaire up to 12 weeks post-intervention. The primary economic outcome is the incremental cost per quality-adjusted life year gained at 12 months post-randomisation.

Discussion: The PUrE trial aims to provide robust evidence on health status, quality of life, clinical outcomes and resource use to directly inform choice and National Health Service provision of the three treatment options.

Trial registration: ISRCTN: ISRCTN98970319. Registered on 11 November 2015.

Keywords: Extracorporeal shockwave lithotripsy; Flexible ureterorenoscopy; Lower pole stone; Percutaneous nephrolithotomy; Renal stone.

Fig. 1

Forest plot demonstrating the meta-analysis of percutaneous nephrolithotomy (PCNL) versus extracorporeal shockwave lithotripsy (ESWL) for the outcome of stone-free rate at 3 months for lower pole stones ≤20mm. Albala and colleagues (2001) [13] and Yuruk and colleagues (2010) [26] reported outcomes for lower pole stones <20 mm. Albala and colleagues [13] also reported outcomes for stones ≤10 mm and 11–20 mm (see Table 1 in Donaldson and colleagues [28]). CI confidence interval, df degrees of freedom, M-H Mantel–Haenszel

Fig. 2

Forest plot demonstrating meta-analysis of flexible ureterorenoscopy (FURS) versus extracorporeal shockwave lithotripsy (ESWL) for the outcome of stone-free rate for lower pole stones at 3 months. Sener and colleagues (2014) [32] and Pearle and colleagues (2005) [27] included stones ≤10mm; Singh and colleagues (2014) [33] included stones 10–20 mm; Kumar and colleagues (2013) [29] and Salem and colleagues (2013) [31] included stones ≤20 mm. Kumar and colleagues [29] reported results for stones 0–9.99 mm and 10–20 mm individually, whilst Salem and colleagues [31] only reported results for stones ≤20 mm. All studies reported the stone-free rate at 3 months, except Singh and colleagues [33] who reported the stone-free rate at 1 month. CI confidence interval, df degrees of freedom, M-H Mantel–Haenszel

Fig. 3

The clinical and cost effectiveness of interventions for stones in the lower pole of the kidney: the percutaneous nephrolithotomy (PCNL), flexible ureterorenoscopy (FURS) and extracorporeal shockwave lithotripsy (ESWL) for lower pole kidney stones randomised controlled trial (PUrE RCT). EQ-5D-5L EuroQol five dimensions five-level version questionnaire, NRS Numeric Rating Scale, SF-12 12-item short-form survey