Evaluation of Patient Treatment Preferences for 15-20mm Kidney Stones: A Conjoint Analysis - Beyond the Abstract

Ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) are two surgical treatment options for the management of intermediate-size (15-20mm) kidney stones. Given there are differences between these two procedures in surgical technique, stone-free rates, and complication risks to name a few distinctions, physician to patient counseling often plays an important role in the shared decision-making process before deciding on which procedure is the best option for the patient. While there are a number of factors urologists take into consideration before operating (anatomical factors, stone characteristics), in the case of intermediate-size kidney stones, where URS and PCNL are often both reasonable options the ultimate choice often comes down to individual patient preference.

To better understand patient treatment preferences and how much importance patients place on specific treatment attributes of URS and PCNL, we performed a conjoint analysis of patients in our kidney stone clinic. This type of survey-based statistical analysis is commonly used in market research to study how consumers make decisions on which products to buy and determine which product attributes are most influential on a consumer’s choice of product. For example, before introducing a new product to the market (for example – a television), product attributes are identified (screen size, features, brand name, cost, etc.), and survey respondents are given a series of hypothetical product options and asked to choose their preferred option. The data collected is used to determine the relative importance of each product attribute and guide product development.

Interestingly, in the medical field, treatment options can similarly be viewed as consumer products with patients weighing several treatment attributes or even comparison shopping before deciding on which treatment is best for them. As such, conjoint analysis has been successfully used across multiple medical specialties to determine the relative importance of various treatment attributes. In urology, conjoint analysis modeling has been applied to men with urethral stricture disease deciding between open urethroplasty or endoscopic urethrotomy treatment. Hampson and colleagues found that patients prioritize procedure success above other treatment attributes, though younger patients valued less invasive treatment (in many cases more than treatment success). Given these interesting findings, we decided to apply conjoint analysis methodology to patients with kidney stone disease to better understand what treatment attributes are most important to patients undergoing URS or PCNL.

The final cohort size of our study was relatively small (n=58) due to some recruitment challenges related to the COVID-19 pandemic. Despite this, our conjoint analysis revealed some interesting trends. Patients prioritized the stone-free rate as the most important treatment attribute. But because other treatment attributes (complication risk, length of hospitalization, etc.) also carried weight for patients, there was ultimately nearly equal preference for URS and PCNL for the treatment of 15-20mm kidney stones. In other words, if these stone surgeries were the only two products in a store, the market share would be roughly 50/50. Interestingly, we found that younger patients leaned more towards a preference for PCNL (more invasive and higher chance of being stone free postoperatively), and older patients URS (less invasive and lower chance of being stone-free postoperatively). We hope that these findings can be useful to urologists in how they plan their discussions with patients and encourage more shared decision making in this field. Further work in kidney stone treatment preference is certainly warranted with larger cohorts of patients and additional treatment attributes, something our group continues to work on. We look forward to others using this potentially interesting method on other urology projects in the future as well.

Written by: Kyle Spradling, MD, Urology Resident, Stanford University, Department of Urology, Stanford, California, Twitter: @SpradlingKyle


  1. Hampson, Lindsay A., Tracy K. Lin, Leslie Wilson, Isabel E. Allen, Thomas W. Gaither, and Benjamin N. Breyer. "Understanding patients’ preferences for surgical management of urethral stricture disease." World journal of urology 35, no. 11 (2017): 1799-1805.
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