Association of Calcium and Phosphate Levels with Incident Chronic Kidney Disease in Patients with Hypoparathyroidism: A Retrospective Case-Control Study

Table 2

Association between albumin-corrected serum calcium and development of CKD.

	Patients with CKD (n = 150), n	Control patients without CKD (n = 150), n	Matched groups			Adjusted analyses
			Odds Ratio	95% CI	value	Odds Ratio	95% CI	value
Proportion of measurements outside of 2.00–2.25 mmol/L (8.0–9.0 mg/dL)^†
≥67%	63	27	3.39	1.81–6.38	<0.001^‡	3.46	1.82–6.56	<0.001^‡
33% to <67%	51	62	1.40	0.75–2.61	0.29	1.36	0.72–2.56	0.34
<33%	36	61	1.00	(Reference)	—	1.00	(Reference)	—
Proportion of measurements above 2.00–2.25 mmol/L (8.0–9.0 mg/dL)^†
≥67%	25	11	2.61	1.21–5.59	0.01^‡	2.85	1.30–6.28	<0.01^‡
33% to <67%	37	31	1.47	0.85–2.53	0.17	1.53	0.87–2.70	0.14
<33%	88	108	1.00	(Reference)	—	1.00	(Reference)	—
Proportion of measurements below 2.00–2.25 mmol/L (8.0–9.0 mg/dL)^†
≥67%	26	10	2.75	1.21–6.25	0.02^‡	2.68	1.16–6.15	0.02^‡
33% to <67%	31	37	0.78	0.43–1.42	0.42	0.71	0.38–1.33	0.29
<33%	93	103	1.00	(Reference)	—	1.00	(Reference)	—

CCI: Charlson comorbidity index; CI: confidence interval; CKD: chronic kidney disease. Models were run for the proportion outside, above, and below the range. Matching for groups was 1:1 based on age ± 5 years, sex, index date ± 1 year, and exposure window duration. Adjusted models were adjusted for the following baseline characteristics: age (continuous variable), index year (continuous variable), race (White vs Black, Asian, multi, other, or unknown), hypertension, type 2 diabetes, any acute hypoparathyroidism event (event of cardiac dysrhythmia, hypercalcemia, hypocalcemia, laryngeal spasm, muscle spasm, other convulsions, palpitations, tachycardia, tetanic cataract, or tetany), and CCI. ^†The target range for albumin-corrected serum calcium in patients with chronic hypoparathyroidism is defined as 2.00–2.25 mmol/L (8.0–9.0 mg/dL), which is different from the normal population reference range (2.15–2.55 mmol/L; 8.6–10.2 mg/dL). ^‡Denotes any value < 0.05.