Table 2.

Adjusted incidence rate ratios for all-cause and cardiovascular mortality for patients with serum calcium levels stratified by serum intact parathyroid hormone levels

Outcomes	Serum calcium (mg/dL)	aIRR (95% CI)		Interaction
		iPTH < 300 pg/mL	iPTH ≥ 300 pg/mL
All-cause mortality	< 8.5	0.93 (0.61–1.41)	2.04 (0.94–4.42)	P = 0.119
		P = 0.740	P = 0.070
	≥ 8.5–< 9.5	Ref	Ref
	≥ 9.5	1.65 (1.39–1.96)	1.99 (1.16–3.42)
		P < 0.001	P = 0.012
Cardiovascular mortality	< 8.5	0.84 (0.44–1.57)	2.16 (0.52–9.03)	P = 0.366
		P = 0.580	P = 0.293
	≥ 8.5–< 9.5	Ref	Ref
	≥ 9.5	1.58 (1.22–2.06)	1.83 (1.09–3.07)
		P < 0.006	P = 0.0230

Incidence rate ratios were adjusted for patients’ characteristics (age, sex, primary kidney disease, diabetes, dialysis duration, cardiovascular disease, pulmonary disease, liver disease, malignancy, and history of parathyroidectomy) and time-dependent variables (vitamin D receptor activators, phosphate binders, calcimimetics, serum albumin level, hemoglobin level, body mass index, Kt/V, and dialysate calcium concentration)

aIRR adjusted incidence rate ratio, CI confidence interval, iPTH intact parathyroid hormone, ref reference