Prediction of hypocalcemia after using 1- to 6-hour postoperative parathyroid hormone and calcium levels: an analysis of pooled individual patient data from 3 observational studies.
BACKGROUND
Parathyroid hormone (PTH) levels up to 6 hours postthyroidectomy have been shown to have excellent predictive power in determining hypocalcemia. In this study, we investigate the usefulness of combining calcium and PTH to increase the predictive power.


METHODS
Individual patient data were obtained from 3 studies (152 patients) that fulfilled our criteria (using PTH assay within hours postthyroidectomy to predict symptomatic hypocalcemia).


RESULTS
Changes in combined PTH and calcium threshold levels checked 1 to 6 hours after thyroidectomy were excellent in predicting postoperative hypocalcemia. A decrease in PTH of 60%, coupled with a simultaneous decrease in calcium of 10%, 5 to 6 hours postoperatively resulted in a sensitivity and specificity of 100%. However, combined PTH and calcium threshold changes were not significantly better than using PTH threshold changes alone.


CONCLUSIONS
Threshold changes in serum calcium and PTH, checked hours after surgery, can be used together to accurately predict whether a patient will become hypocalcemic after thyroidectomy.
Department of Otolaryngology-Head and Neck Surgery, Boston University Medical Center, Boston, Massachusetts, USA.
Jeffrey Saad
JS
Jumaily
J Pieter
JP
Noordzij
Alex G
AG
Dukas
Stephanie L
SL
Lee
Victor J
VJ
Bernet
Richard J
RJ
Payne
Ian K
IK
McLeod
Michael P
MP
Hier
Martin J
MJ
Black
Paul D
PD
Kerr
Marco
M
Raffaelli
Rocco
R
Bellantone
Celestino P
CP
Lombardi
Mary S
MS
Dietrich
D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood* / Q000378:metabolism; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006996:Hypocalcemia / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D015994:Incidence; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood* / Q000378:metabolism; D011182:Postoperative Care / Q000379:methods; D011237:Predictive Value of Tests; D011336:Probability; D012372:ROC Curve; D012042:Registries; D018570:Risk Assessment; D013965:Thyroidectomy / Q000009:adverse effects* / Q000379:methods; D013997:Time Factors
D015415:Biomarkers; D010281:Parathyroid Hormone; D002118:Calcium