Heterogeneity in the Reporting of Disease Characteristics and Treatment Outcomes in Studies Evaluating Treatments for Nephrolithiasis

Background and Purpose: There is no standardization in the nephrolithiasis literature regarding preoperative or postoperative evaluation of patients who are undergoing treatment for stone disease. This may hinder comparisons of efficacy of different treatment modalities. We evaluated heterogeneity in the literature of preoperative and postoperative evaluations of patients who were undergoing surgical treatment for nephrolithiasis. Materials and Methods: A systematic PubMed search was performed for 2006 to 2008 using search terms kidney stones, ureteral stones, nephrolithiasis, ureterolithiasis, ureteroscopy (URS), shockwave lithotripsy (SWL), and percutaneous nephrolithotomy (PCNL). Articles that evaluated treatment outcomes were included, and information regarding preoperative and postoperative evaluation was collected. Results: One hundred and fifty-four studies were included. Preoperative stone burden was evaluated using CT (42), ultrasonography (US) (42), plain radiography of the kidneys, ureters, and bladder (KUB) (92), multiple modalities (52), and no mention (45). Stone burden was reported as maximum diameter (105), surface area (32), volume (6), other (1), and no mention (10). Treatment modalities included URS (46), PCNL (71), SWL (50), and multiple modalities (9). Postoperative imaging included CT (37), US (67), KUB (115), multiple modalities (70), other (11) and no mention (19). Radiographic outcomes included strict stone free (114) and presence of residual fragments (RF) (64). There was wide variation in the size of RF reported (<1 mm through <7 mm). "Stone free'' included the presence of RF in 18 studies. Treatment "success'' was defined to include RF of various sizes. Reported clinical outcomes included stone-related events (46) and surgery (90). Conclusions: There is extensive variability in the reporting of preoperative disease characteristics and postoperative outcomes in studies that evaluate treatments for nephrolithiasis. Standardization of these criteria is essential for more meaningful comparisons of treatment modalities and outcomes for different disease subgroups.