Kidney Week

Abstract: PUB031

Clinical Meaning of Absolute PTH Levels Depends on Longitudinal Stability in Maintenance Hemodialysis

Session Information

• Publication Only

Category: Bone and Mineral Metabolism

• 502 Bone and Mineral Metabolism: Clinical

Authors

• Kim, Do Hyoung, Hallym University Kangnam Sacred Heart Hospital, Yeongdeungpo-gu, Seoul, Korea (the Republic of)

Do Hyoung Kim, MD, PhD, FASN

• Lee, Sua, Hallym University Kangnam Sacred Heart Hospital, Yeongdeungpo-gu, Seoul, Korea (the Republic of)

Sua Lee, MD, PhD

• Kim, Soh Yeon, Hallym University Kangnam Sacred Heart Hospital, Yeongdeungpo-gu, Seoul, Korea (the Republic of)

Soh Yeon Kim, DrMed

• Kim, Eunjung, Hallym University Dongtan Sacred Heart Hospital, Hwaseong-si, Gyeonggi-do, Korea (the Republic of)

Eunjung Kim, MD

• Choi, Gwangho, Chuncheon Sacred Heart Hospital, Chuncheon-si, Gangwon-do, Korea (the Republic of)

Gwangho Choi, MD

• Oh, Dong-jin, Myongji Hospital, Goyang-si, Gyeonggi-do, Korea (the Republic of)

Dong-jin Oh

Background

The clinical meaning of absolute parathyroid hormone (PTH) levels may differ according to longitudinal PTH stability in hemodialysis (HD). We evaluated associations of PTH stability assessed by time in target range (TTR) with nutritional and body composition outcomes, with subgroup analyses by baseline PTH.

Methods

This prospective observational study included 108 maintenance HD patients. Patients were divided into low- and high-TTR groups using the median TTR for PTH (target 150–300 pg/mL). Phase angle (PhA), overhydration (OH), and lean tissue index (LTI) were assessed by bioimpedance spectroscopy during follow-up. Within each TTR group, patients were further stratified by median baseline PTH. Multivariable linear regression analyses were adjusted for age, sex, body weight, albumin, phosphorus, PTH, C-reactive protein, and Kt/V.

Results

Median TTR was 33.4%. Compared with the low-TTR group, the high-TTR group had lower PhA (3.98±0.97 vs. 4.73±1.15°, P=0.001), higher OH (2.92±1.43 vs. 2.31±1.27 L, P=0.029), and lower LTI (12.82±3.13 vs. 14.41±3.04 kg/m², P=0.017). In multivariable analyses, higher TTR was independently associated with higher OH (β=0.013, P=0.034) and lower PhA (β=−0.009, P=0.012). In subgroup analyses, among patients with low TTR, higher baseline PTH was associated with lower OH (1.75±1.26 vs. 2.80±1.08 L, P=0.004) and higher PhA (5.11±1.13 vs. 4.39±1.08, P=0.035). In contrast, among patients with high TTR, OH and PhA did not differ according to baseline PTH level.

Conclusion

Higher PTH TTR was associated with less favorable body composition and volume-related measures in maintenance HD patients. The association between absolute PTH level and these outcomes differed according to longitudinal PTH stability, suggesting that absolute PTH values may need to be interpreted in the context of longitudinal variability rather than as isolated measurements. These findings warrant further prospective validation.

PTH Time in Target Range, Phase Angle, and Overhydration.
Scatter plots showing associations of PTH TTR with phase angle and overhydration in maintenance hemodialysis patients.