Authors from the University of Alberta hypothesized there may be a higher proportion of OSA in kidney stone patients compared to general population. The prevalence of OSA is a show to be approximately 25% and many patients never receive a formal diagnosis.
Pollock and colleagues performed a study to determine the incidence of high-risk patients for OSA, undergoing shockwave lithotripsy. They aimed to examine the potential relationship between OSA and the incidence of kidney stones. Finally, they sought to determine any differences in treatment outcomes between kidney stone patients with and without OSA.
Authors performed a retrospective chart review of patients who underwent SWL between September 2016 and June 2017. Patients completed an 8 question STOP-Bang questionnaire, which divided them into 4 groups: CPAP-compliant (CPAP-C), CPAP-non-compliant (CPAP-NC), high risk (HR) and low risk (LR).
STOP-Bang questionnaire consisted of following questions:
S – Snoring: do you snore loudly?
T – Tired: Do you often feel tired, fatigued, or sleepy during the daytime?
O – Observed: Has anyone observed you stop breathing during your sleep?
P – Blood pressure: do you have high blood pressure, or are you being treated for high blood pressure?
B – BMI: is your BMI greater than 35?
A – AGE: are you over 50 years old?
N – Neck: is your neck circumference greater than 40cm?
G – Gender: are you male?
Pollock reported that high-risk patients had a significant in stone areas compared to low-risk patients, after controlling for BMI (Figure 1). Patients with OSA are an over-represented population of kidney stone formers. Treatment efficacy was reduced in patients with OSA or high risk at OSA compared to patients with low-risk OSA.
Pollock discussed limitations of the study including its retrospective design, and only a minority of patients had relevant metabolic testing done, and not all patients were properly followed up. Further studies are needed to assess the risk of kidney stones in OSA patients, independent of metabolic syndrome. More importantly, data needed to elucidate whether CPAP compliance in OSA patients can reduce the risk of forming kidney stones.
Figure 1.
Figure 2.
Presented by: Brooke Pollock, MD, Division of Urology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
Co-Authors: Lance Wu, Jamey Marrese, Tim Wollin, Dariusz (Derek) Bochinski, Trevor Schuler, Shubha De, Division of Urology, Department of Surgery, University of Alberta, Edmonton, AB, Canada
Written By: Zhamshid Okhunov (Twitter: @OkhunovZham), (Department of Urology, University of California-Irvine) medical writer for UroToday.com at the 73rd Canadian Urological Association Annual Meeting - June 23 - 26, 2018 - Halifax, Nova Scotia