Ricki Lewis, PhD
January 07, 2019
Four percent of patients undergoing thyroid surgery were readmitted within 30 days, most during the first week, according to findings published online December 10 in Surgery.
Thyroidectomy is a common procedure for which patients are typically discharged within a day. Studies have attributed readmission rates ranging from 0.1% to 11% to several factors: decreased functional status, renal insufficiency, hypocalcemia, hypoalbuminemia, and malignancy.
To extend the findings of studies that had small samples, analyzed data from only one hospital, or did not adequately identify the reasons for readmission, Arturo J. Rios-Diaz, MD, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, and colleagues investigated patient and hospital characteristics associated with increased unplanned readmission following thyroid surgery.
The researchers identified 22,654 patients who had thyroid surgery recorded in the 2014 Nationwide Readmissions Database, 990 of whom (4.37%) had been readmitted within 30 days. That is nearly 1000 patients with side effects severe enough to warrant readmission, the researchers point out.
The primary outcome was 30-day readmission. Secondary outcomes included diagnoses at readmission, indication for thyroid surgery (goiter, thyroid cancer, thyroid function disease, and nontoxic nodular thyroid disease), and how long after discharge a patient was readmitted. A subanalysis considered diagnostic codes that triggered readmission.
Most patients (54.6%) were readmitted within 7 days of surgery, 24.6% within the first 2 days.
The most common diagnoses at readmission were disorders of mineral metabolism, including calcium, iron, copper, magnesium, and phosphorus (36% of readmissions). Hypocalcemia was the most common indication, (26.6%). The subanalysis revealed that calcium-related disorders accounted directly for 22.1% of readmissions.
Damage to the parathyroid glands during thyroid surgery might explain subsequent abnormal calcium levels. Symptoms of hypocalcemia are tingling in the fingers that can progress to tremors and muscle spasms.
Initial thyroid diagnosis and time of readmission after discharge did not influence the risk for readmission. However, 24.6% of readmitted patients had thyroid cancer, raising the possibility that their readmission was actually planned for further treatment of the cancer, but misclassified as unplanned.
Readmitted patients were also more likely than non-readmitted patients to have vocal cord paralysis (5.4% vs 2.8%), wound infection (1.5% vs 0.2%), or other complications (4% vs 1.6%; all P < .05).
Factors associated with an increased odds of readmission included having Medicare (adjusted odds ratio [AOR], 1.47; 95% confidence interval [CI], 1.03 – 2.11) or Medicaid (AOR, 1.44; 95% CI, 1.04 – 1.99); being discharged to inpatient postacute care (AOR, 2.31; 95% CI, 1.48 – 3.62) or to home health care (AOR, 1.78; 95% CI, 1.21 – 2.63); having an Elixhauser comorbidity score of = 4 (AOR, 2.04; 95% CI, 1.27 – 3.26); and hospitalization of 2 or more days after surgery (AOR, 2.70; 95% CI, 1.90 – 3.82).
Readmitted patients compared with non-readmitted patients were more likely to be younger (median, 53.1 years vs not readmitted, 57.5 years), have at least four comorbidities (24.2% vs 17.1%), and to be obese (24.2% vs 17.1%). They were also more likely to have Graves disease (12.2% vs 8.5%) and less likely to have goiter (36.2% vs 44%). Sex, income quartile, type of thyroid surgery, and hospital size and ownership were not associated with readmission.
"The information we gleaned is directly applicable to patient care, and suggests more careful immediate follow-up for patients at high risk for side effects and complications of surgery," coauthor Alliric Willis, MD, associate professor of surgery and codirector of the Jefferson Thyroid and Parathyroid Center, said in the news release. "Surgical thyroid removal is generally a safe operation. However, side effects can be severe enough that patients end up needing readmission to the hospital for treatment. Our study demonstrates that this happens more frequently than one might think. It also identifies the risk factors that can be addressed to prevent these readmissions," he added.
Medicare and Medicaid insurance are risk factors, the researchers suggest, because it may be more difficult for these patients to get prescribed calcium supplements. Patients who had low calcium levels before discharge after surgery and patients hospitalized for 2 or more days after thyroid surgery were also at elevated risk for readmission.
Willis suggested a way to lower the readmission risk. "One solution is to follow up on patients using telehealth in the days immediately after surgery when patients are most at risk for developing hypocalcemia symptoms," he said.
Limitations of the study include reliance on administrative data, recall bias, selection bias, and possible misclassification of patients.
The researchers have disclosed no relevant financial relationships.