Oral dissolution therapy proven effective for lucent renal stones regardless of size
Oral dissolution therapy (ODT) effectively treats lucent renal stones regardless of stone size, a recent study has shown.
“The initial response to ODT after 3 months was the key factor in determining the potential oral dissolution therapy response after 6 months,” researchers said. “In addition, treatment compliance in achieving the targeted urine pH and low stone density has an independent role in the ODT response.”
A total of 212 eligible patients agreed to participate between February 2015 and January 2016, of whom 182 complied with ODT and were included in the final analysis. Upon enrolment, mean stone surface area was 1.3 cm2 (range, 0.16–11.84). [J Urol 2019;201:350-357]
At 3 months, 97 (53.2 percent) patients responded to ODT, while 65 (35.7 percent) were partial responders and 20 (11.1 percent) nonresponders. At 6 months, stone-free rate after ODT compliance was 83 percent, including 97 and 54 patients after 3 and 6 months of ODT, respectively.
Regression analysis revealed the following independent predictors of ODT response at 6 months: initial 3-month response to ODT (p=0.001), lower stone density (p=0.03) and higher urine pH 12 weeks after treatment (p=0.01).
“Patients with lucent renal calculi without high-grade obstruction and/or infection are good candidates for a trial of ODT,” researchers said. [Kidney Int 2011;79:385]
The efficacy of ODT in treating lucent renal calculi has been discussed in previous studies, with varying results including a 15–80 percent stone-free rate. [Urology 1977;10:536; J Urol 1976;115:740; Arch Ital Urol Androl 2009;81:188; Urology 2002;59:206; Urol Int 1992;48:81; Hinyokika Kiyo 2003;49:307]
“Most of those studies had a small number of patients and were done retrospectively. Variability in the results of these studies could be attributable to patient number, patient age, the alkalizing agent and the type of endpoint imaging,” researchers noted.
European guidelines strongly recommend ODT, but no standardization recommendation exists for the duration of therapy. [Eur Urol 2012;62:160]
Moran and colleagues applied ODT for 6 weeks, resulting in a 73-percent complete dissolution rate, while Sinha’s team applied the therapy for a mean of 103.6 days and achieved a complete dissolution rate of 15 percent. [Urology 2002;59:206; Arch Ital Urol Androl 2009;81:188]
Trinchieri and colleagues achieved a 37.5-percent complete dissolution rate at week 6 and 62.5 percent after extending the duration to 6 months among partial responders. [Int Braz J Urol 2013;39:103]
The present study enrolled patients with radiolucent renal stones, who were advised to undergo ODT (oral potassium citrate 20 mEq 3 times daily, 3 L daily fluid intake and a dietary regimen). The primary endpoint was the achievement of a 6-month stone-free rate with ODT. Secondary endpoints included a change in stone surface area as measured by noncontrast computerized tomography at 3 and 6 months.
This study was limited by the absence of data on stone analysis in cases requiring secondary intervention, according to researchers.