OBJECTIVES: To determine whether shock wave lithotripsy (SWL) increases the prevalence of hypertension (HTN) at intermediate follow-up.
METHODS: All patients were treated with the Medstone STS electrohydraulic lithotripter, and the data were recorded prospectively in a centralized database. The data on the development of HTN after SWL was obtained from a questionnaire mailed to the patients who had undergone SWL from November 1999 and January 2002. Controls matched for age, sex, and body mass index were obtained from the National Health and Nutrition Examination Survey, using the demographic, body measurements, medical conditions, and blood pressure data sets. Two sets of matching controls were used to compare the prevalence of HTN between our patients and the NHANES population at SWL and at the follow-up point.
RESULTS: A total of 2041 patients responded to the questionnaire, with a median follow-up of 6 years. No statistically significant difference was found in the HTN prevalence between the patients and matched controls at SWL (26.7% vs 28.0%). At the follow-up point, the prevalence of HTN was greater in our patients (37.8%) than in the controls (32.5%, P = .0009). Of our patients, 15% have developed de novo HTN compared with the predicted rate of 6.25% from the matched controls. Male gender, age, and a greater body mass index were associated with the development of HTN, but none of the SWL parameters (number of shocks, bilateral vs unilateral, and multiple SWL sessions) were significantly associated with HTN.
CONCLUSIONS: The results of our study have indicated a small, but significant, increase in the risk of developing HTN after SWL using a third-generation electrohydraulic lithotripter at intermediate follow-up.
Copyright © 2011 Elsevier Inc. All rights reserved.
Urology. 2011 Jul;78(1):22-5. doi: 10.1016/j.urology.2010.11.006. Epub 2011 Jan 22
PMID: 21256538 [PubMed - as supplied by publisher]
The authors weaken their conclusion »a small, but significant, increase exists in the risk of developing HTN after receiving SWL« by stating at the end of their comment section: »our study could not establish a causal relationship between SWL and HTN.« They also rightly comment »If calculus disease per se predisposes to HTN, the increased risk of HTN demonstrated in our study might be a reflection of this predisposition and not a direct result of SWL.«