Incidence and Characteristics of Patients Readmitted for Hypoparathyroidism After Thyroidectomy for Differentiated Thyroid Cancer in California.

Abstract

Post-thyroidectomy hypoparathyroidism is a common complication and is usually managed outpatient. The aim of this study was to identify the incidence and characteristics associated with inpatient readmissions for postoperative hypoparathyroidism after thyroidectomy for cancer. The California Cancer Registry and Health Care Access and Information databases were linked to identify patients with differentiated thyroid cancer who underwent a total thyroidectomy between 2005 and 2018, with subsequent inpatient readmission for hypoparathyroidism within 2 years. Cumulative incidence and Cox proportional hazards models were used to evaluate factors associated with readmission. Among 49,892 thyroidectomy patients, 572 (1.15%) required readmission for hypoparathyroidism. Median time to first readmission for hypoparathyroidism was 6 days, with 59.5% of readmissions occurring within 1 month. The 2-year cumulative incidence was higher for younger patients (age 18-40: 1.54% and 95% confidence interval [CI]: 1.34%-1.75%). In multivariable analysis, several factors were significantly associated with readmission for hypoparathyroidism including: female sex (hazard Ratio [HR] 1.56 and CI: 1.24-1.96), Hispanic (HR 1.54 and CI: 1.26-1.88) or Asian ethnicity (HR 1.48 and CI: 1.17-1.86), Charlson Comorbidity Index (CCI) (1: HR 1.26 and CI: 1.02-1.56; > 1: HR 1.39 and CI: 1.03-1.89), having > 4 lymph nodes (LN) removed (HR 1.88 and CI: 1.59-2.23), and patients < 65 years old with Medicaid/public insurance (HR 1.39 and CI: 1.09-1.76). Being in the highest SES neighborhood was associated with a decreased risk of readmission for hypoparathyroidism when compared to the lowest SES neighborhoods (HR 0.67 and CI: 0.49-0.92). Most readmissions for hypoparathyroidism occur soon after surgery for thyroid cancer. Patients at risk for readmission for hypoparathyroidism include those who are women, of Hispanic or Asian ethnicity, have an increased CCI, > 4 LN removed, < 65 years old with public insurance, or come from a lower SES.