Kidney Week

Abstract: PUB032

The PTH-Nutrition Paradox: Mild PTH Elevation Is Associated with Preserved Phase Angle and Protein Intake in Patients on 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 nutritional implications of lower-target versus mildly elevated parathyroid hormone (PTH) levels in hemodialysis (HD) remain unclear. We evaluated whether mild PTH elevation was associated with nutritional and body composition measures compared with lower-target PTH over a 3-year period.

Methods

This prospective cohort study included 64 maintenance HD patients followed from 2019 to 2022. Patients were stratified by 3-year averaged intact PTH into a lower-target group (150≤PTH<300 pg/mL, n=28) and a mild-elevation group (300≤PTH<600 pg/mL, n=36). Outcomes included phase angle (PhA), creatinine-to-body surface area ratio (Cr/BSA), albumin, normalized protein catabolic rate (nPCR), and achievement of nPCR ≥1.0 g/kg/day. Longitudinal associations were assessed using linear mixed-effects models. Binary outcomes were assessed using Firth penalized logistic regression.

Results

Age and sex were similar between groups, whereas diabetes was more frequent in the lower-target group. In time-averaged analyses, the mild-elevation group had higher PhA (4.52±1.09° vs. 3.94±0.83°, P=0.017), Cr/BSA (492.7±93.9 vs. 434.4±107.3 μmol/L/m², P=0.027), and lean tissue index (13.9±3.5 vs. 12.4±2.3 kg/m², P=0.044). The proportion achieving nPCR ≥1.0 g/kg/day was also higher in the mild-elevation group (72.2% vs. 32.1%, P=0.002). In fully adjusted longitudinal models including age, sex, diabetes, baseline body mass index, baseline Kt/V, calcium, and phosphorus, mild PTH elevation remained associated with higher PhA (β=0.38, 95% CI 0.01–0.75; P=0.047) and nPCR (β=0.12, 95% CI 0.00–0.24; P=0.042). In fully adjusted Firth logistic regression, mild PTH elevation was independently associated with achieving nPCR ≥1.0 g/kg/day (OR 9.35, 95% CI 2.34–48.47; P=0.001).

Conclusion

Mild PTH elevation was associated with a more favorable nutritional and muscle-related phenotype than lower-target PTH in maintenance HD patients, particularly reflected by higher PhA and a greater likelihood of adequate protein intake. These findings suggest that PTH values should be interpreted together with nutritional and body composition status rather than as isolated biochemical targets.