PTH and hydrops fetalis: In a 3.5-year follow-up study of 148 HF outpatients with a mean age of 68 years in Denmark, both vitamin D and PTH were also significantly associated with all-cause mortality, with aHR of 1.9 (95% CI, 1.1–3.4) for 25(OH)D < 30 ng/mL and 2.0 (95% CI, 1.0–3.8) for PTH > 4.45 pM (42.0 pg/mL), respectively [5].