Secondary hyperparathyroidism is associated with pulmonary hypertension in older patients with chronic kidney disease and proteinuria

Hyperparathyroidism is associated with pulmonary vascular calcification and pulmonary hypertension (PH) in a chronic kidney failure dog model, and increased prevalence of PH and a PH–hyperparathyroidism relationship in pre-dialysis chronic kidney disease (CKD) and hemodialysis patients are reported. This study investigated the prevalence of PH and relationships between PH and metabolic abnormalities in patients with stage 1–4 proteinuria CKD.

One-hundred and ninety patients (mean age 61 ± 17.4, 116 males) with proteinuria CKD and no coronary diseases, congestive heart failure, smoking history, and pulmonary diseases were enrolled. Estimated glomerular filtration rate was 39.7 ± 23 ml/min. CKD etiology was diabetes mellitus in 52 (27.3 %), chronic glomerulonephritis or tubulointerstitial nephritis in 56 (29.4 %), hypertension in 36 (19 %), and other etiologies (nephrolithiasis, obstructive nephropathy, and amyloidosis) in 46 (25.3 %) patients. Echocardiography was performed, and systolic pulmonary artery pressure (PAP) and left ventricular ejection fraction were determined. Laboratory tests examined lipid parameters, serum albumin, urea, creatinine, calcium, phosphorus, C-reactive protein, parathyroid hormone, ferritin, and hemoglobin levels.

PH (PAP >35 mmHg) was detected in 68 patients (35.9 %). Patients with PH were older (68 ± 12.3 vs. 52.1 ± 16.7, p = 0.03), had lower ejection fractions (51.3 ± 13.4 vs. 60.8 ± 9.1 %, p = 0.003), lower hemoglobin (11.3 ± 1.5 vs. 12.1 ± 1.9, p = 0.05), and higher parathyroid hormone (218 ± 159.3 vs. 127.7 ± 67.4 pg/ml, p = 0.05) levels. The remaining parameters were similar between groups.

Older age, lower ejection fraction, and secondary hyperparathyroidism may contribute to PH in stage 1–4 proteinuria CKD.