Piyawan Kittiskulnam1,2,3, Piyatida Chuengsaman4, Sirarat Katesomboon4, Kearkiat Praditpornsilpa2,3, Kriang Tungsanga3, Somchai Eiam-Ong2,3, Talerngsak Kanjanabuch5,6. 1. Division of Internal Medicine-Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand. 2. Special Task Force for Activating Research in Renal Nutrition (Renal Nutrition Research Group), Office of Research Affairs, Chulalongkorn University, Bangkok, Thailand. 3. Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. 4. Banphaeo-Charoenkrung Peritoneal Dialysis Center, Banphaeo Dialysis Group, Banphaeo Hospital, Bangkok, 10330, Thailand. 5. Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. golfnephro@hotmail.com. 6. Center of Excellence in Kidney Metabolic Disorders, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. golfnephro@hotmail.com.
Abstract
PURPOSE: Progressive decline in lean mass and gain of fat mass are common in patients treated with peritoneal dialysis (PD). It is unclear whether body composition or its longitudinal changes contribute to increased mortality among prevalent PD patients. METHODS: This was a retrospective cohort study. Body composition was assessed using bioelectrical impedance spectroscopy (BIS). Lean and fat tissue indices were derived from lean and fat mass indexed to height-squared, respectively. The patient's baseline BIS results were used to explore its mortality risk prediction for the entire cohort. Among patients with subsequent BIS measurements, changes of lean and fat mass over time were also examined with survival outcomes. RESULTS: Among all participants (n = 555, PD vintage 38 months), higher baseline lean tissue index was associated with lower mortality after adjusting for fat tissue index and confounders (HR 0.90; 95% CI 0.84-0.97, p = 0.01). However, this association was no longer significance after the final adjustment with serum albumin level (p = 0.06). A total of 136 patients had repeated BIS data. After the interval of 10.1 months during two consecutive BIS measurements, there was a strong inverse correlation between the percentage changes of lean and fat tissue indices (r = - 0.73, p < 0.001). The longitudinal changes in lean mass, either high or low categories, were not significantly associated with all-cause mortality. In contrast, patients who were classified as having low values of fat tissue index (below median) from baseline to the next BIS measurements had a lower odds of death in the univariable (HR 0.32; 95% CI 0.12-0.84, p = 0.02) but not in the adjusted models. CONCLUSION: Among prevalent PD patients, higher baseline lean mass was independently associated with better survival. However, the longitudinal changes in lean mass were not significantly associated with mortality. In contrast, the maintenance of low fat status over time appeared to be associated with a lower likelihood of death among PD population.
PURPOSE: Progressive decline in lean mass and gain of fat mass are common in patients treated with peritoneal dialysis (PD). It is unclear whether body composition or its longitudinal changes contribute to increased mortality among prevalent PD patients. METHODS: This was a retrospective cohort study. Body composition was assessed using bioelectrical impedance spectroscopy (BIS). Lean and fat tissue indices were derived from lean and fat mass indexed to height-squared, respectively. The patient's baseline BIS results were used to explore its mortality risk prediction for the entire cohort. Among patients with subsequent BIS measurements, changes of lean and fat mass over time were also examined with survival outcomes. RESULTS: Among all participants (n = 555, PD vintage 38 months), higher baseline lean tissue index was associated with lower mortality after adjusting for fat tissue index and confounders (HR 0.90; 95% CI 0.84-0.97, p = 0.01). However, this association was no longer significance after the final adjustment with serum albumin level (p = 0.06). A total of 136 patients had repeated BIS data. After the interval of 10.1 months during two consecutive BIS measurements, there was a strong inverse correlation between the percentage changes of lean and fat tissue indices (r = - 0.73, p < 0.001). The longitudinal changes in lean mass, either high or low categories, were not significantly associated with all-cause mortality. In contrast, patients who were classified as having low values of fat tissue index (below median) from baseline to the next BIS measurements had a lower odds of death in the univariable (HR 0.32; 95% CI 0.12-0.84, p = 0.02) but not in the adjusted models. CONCLUSION: Among prevalent PD patients, higher baseline lean mass was independently associated with better survival. However, the longitudinal changes in lean mass were not significantly associated with mortality. In contrast, the maintenance of low fat status over time appeared to be associated with a lower likelihood of death among PD population.