Risk of Renal Stones During Spaceflight: Countermeasure Development

• Published in: Aviation, space, and environmental medicine space, and environmental medicine, 2010-06, Vol.81 (6), p.606-607
• Main Author: Frey, Mary Anne
• Format: Article
• Language: English
• ISSN: 0095-6562
• DOI: 10.3357/ASEM.2743.2010

The risk of developing renal stones during or after spaceflight is well documented. On Earth, administration of potassium citrate (KCIT) has been shown to be an effective treatment for patients. Therefore, these authors 'investigated KCIT as a countermeasure to minimize the risk of stone formation during ISS and future missions.' There were 30 astronauts and cosmonauts who flew in the NASA-Mir Program or on the International Space Station (ISS) for missions of 93-215 days who participated in the study. Of those, 18 subjects, including all 12 NASA-Mir crewmembers, were controls and 12 ISS crewmembers received the medication: two KCIT 10-mEq pills daily from 3 days before launch until 14 days after return. 'KCIT supplement decreased the risk of renal stone formation during and immediately after spaceflight.' This is primarily shown by the decrease in calcium excretion and higher urinary pH (lower acidity) in the KCIT group, resulting in lower calcium oxalate and uric acid supersatura-tion. The investigators suggest that supplementation with KCIT produced 'a biochemical environment that was less conducive to stone formation.' Protection against renal stone formation in long-duration spaceflight will require a multifaceted risk-mitigation approach. This study has contributed to planning this approach by demonstrating the efficacy of KCIT, which now has been approved as an operational countermeasure for crewmembers on the ISS.