SAT-808 - Impact of Chronic Kidney Disease on Biochemical and Clinical Outcomes after Parathyroidectomy for Primary Hyperparathyroidism

Background:
Primary hyperparathyroidism (PHPT) affects over 100,000 U.S. patients annually and contributes to urolithiasis, osteoporosis, and chronic kidney disease (CKD). Although parathyroidectomy (PTX) is curative, surgery is often delayed until end-organ damage develops. We evaluated whether preoperative CKD status influences postoperative biochemical and clinical outcomes, hypothesizing greater improvement in patients without CKD.

Methods:
Using the TriNetX Research Network, we identified 19,175 adults with PHPT and hypercalcemia who underwent non-radiofrequency PTX. Patients were stratified by CKD status: CKD (≥3 eGFR (race-adjusted) values < 60 mL/min/1.73 m²; n=3,593) versus non-CKD (≥1 eGFR ≥60; n=15,582). We excluded patients with prior transplant, dialysis, parathyroid malignancy, secondary HPT, or ablation. Outcomes included serum calcium and creatinine (1 month pre-op, 2 weeks, and 1–2 years post-op), osteoporosis (n=2,987), and urolithiasis (n=1,634) documented ≥6 months pre-op. Logistic regression assessed associations between CKD and clinical improvement, adjusting for demographics and BMI. Linear regression evaluated biochemical changes, adjusting for demographics and baseline values.

Results:
CKD patients were older and more frequently male, Black, non-Hispanic, and obese. Osteoporosis resolution was similar between groups (32.6% non-CKD vs 32.7% CKD; p=0.95). Urolithiasis resolution was higher in non-CKD patients (56.3% vs 50.0%; p=0.0288) but not significant after adjustment (OR 0.83, p=0.108). Male sex, Black race, Hispanic ethnicity, and higher BMI were associated with osteoporosis resolution, while black race and unknown ethnicity were associated with higher odds of urolithiasis resolution. Both cohorts (n=16,800) demonstrated significant calcium reductions at 2 weeks, with larger declines among those with higher preoperative calcium. CKD patients had slower early calcium normalization (p < 0.001), though long-term calcium levels were similar. In overlapping presurgical creatinine ranges ( < 1.44 mg/dL), CKD and non-CKD patients showed no adjusted differences at 14 days or 1–2 years. Overall, creatinine decreased to 78% at 14 days and 63% at 1–2 years. Among CKD patients with presurgical creatinine >1.44 mg/dL, creatinine remained at 96% at 14 days and 74% at 1–2 years. Presurgical creatinine strongly predicted postoperative values.

Conclusion: PTX achieves longterm calcium normalization regardless of CKD status, but renal recovery is limited with advancing CKD. Presurgical renal function strongly predicts postoperative outcomes. CKD status did not independently predict osteoporosis or urolithiasis resolution, while demographic factors were stronger predictors. These findings support individualized risk stratification and earlier surgical intervention to preserve renal function before irreversible decline.

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