Variation in National Opioid Prescribing Patterns Following Surgery for Kidney Stones

Abstract

Background: Opioid misuse is a significant public health problem. As initial exposures to opioids are frequently encountered through the management of postoperative pain, we examined patterns of opioid prescribing following surgical treatment for nephrolithiasis.

Methods: We identified patients with nephrolithiasis in the national Women Veterans Cohort Study (WVCS) who were treated surgically by diagnosis and procedure codes. Using standard conversion factors, we calculated the morphine milligram equivalent (MME) dose prescribed. We used descriptive statistics to characterize opioid prescription across management strategy and multivariable regression to examine clinical and demographic characteristics associated with dispensed dose.

Results: We identified 22,609 patients diagnosed with kidney stones during 1999-2014, 1,976 of whom were treated surgically and 1,582 (80.1%) of whom received an opioid prescription. The median age was 39 years, and 1,366 (90%) were male; 1,314 (86.3%) were treated with ureteroscopy, 172 (11.3%) with extracorporeal shockwave lithotripsy, and 36 (2.4%) with percutaneous nephrolithotomy. The median number of days supplied per opioid prescription (interquartile range) was 10 (5-14), and patients were dispensed a median of 180 (140-300) MME. A total of 6.4% of patients received ≥50 MME/d. On multivariable analysis, comorbid diagnosis of post-traumatic stress disorder (PTSD) was associated with higher total dispensed dose, whereas surgery type was not.

Conclusions: We observed substantial variation in opioid prescribing following surgical treatment of nephrolithiasis. Although type of surgical intervention did not impact opioid dosing, patients with a diagnosis of PTSD were more likely to receive higher doses. This work can inform efforts to improve the safety and efficacy of postoperative opioid prescribing.