BALTIMORE – Research into how primary hyperparathyroidism and parathyroidectomy affect sleep quality has been limited, but investigators at the Medical College of Wisconsin, Milwaukee, reported that primary hyperparathyroidism does indeed disrupt sleep patterns and that curative surgery can improve sleep quality in a third of patients.
“Today, most patients with primary hyperparathyroidism have what is considered asymptomatic disease,” Justin La reported at the annual meeting of the American Association of Endocrine Surgeons. “However, recent studies demonstrate that many of these asymptomatic patients commonly exhibit neuropsychological problems, including sleep disturbances.” Mr. La is a fourth-year medical student at the Medical College of Wisconsin.
Justin La
This prospective study, led by Dr. Tina Yen, recruited patients between June 2013 and September 2015 and compared 110 patients who had parathyroidectomy for primary hyperparathyroidism (PHPT) with 45 controls who had thyroidectomy for benign euthyroid disease between June 2013 and September 2015.
“Multiple studies, including recent meta-analyses, have demonstrated lower quality of life in patients with primary hyperparathyroidism and have suggested that patients, regardless of symptoms or degree of hypercalcemia, report varying degrees of improvement after parathyroidectomy,” Mr. La said. “In contrast there is a relative paucity of literature on the effects of primary hyperparathyroidism on sleep quality and changes after parathyroidectomy.”
He noted studies from both the University of Texas M.D. Anderson Cancer Center, Houston, and the University of Wisconsin–Madison had demonstrated a 44%-63% incidence of sleep disturbance preoperatively and improvement postoperatively in patients with PHPT who had parathyroidectomy (Endocr Pract. 2007 Jul-Aug;13:338-44; World J Surg. 2014 Mar;38:542-8; Surgery. 2009 Dec;146:1116-22).
“However, these studies were limited by small sample sizes and lack of a control group,” La said.
The latest study had subjects complete questionnaires inquiring about quality of life and sleep patterns at three different intervals: before surgery; and 1 and 6 months after surgery. The study used the Medical Outcomes Study SF-36 to assess quality of life and the Pittsburgh Sleep Quality Index (PSQI) to evaluate sleep quality. The PSQI rates sleep quality on a scale of 0 to 21; a score of 5 or higher indicates poor sleep quality.
“Compared to the preoperative scores, sleep scores after parathyroidectomy were lower, signifying better sleep quality among the 105 patients who completed 1-month postoperative surveys and the 94 patients who completed the 6-month surveys,” La said.
Before surgery, PHPT patients had worse sleep quality than their thyroid counterparts with PSQI scores of 8.1 vs. 5.3, respectively. After surgery, sleep quality scores between the two groups were similar, with mean PSQI scores of 6.3 vs. 5.3 at 1 month after surgery for the parathyroid and thyroid groups, respectively, and 5.8 vs. 4.6 for the two groups at 6 months.
Also, the proportion of patients in both groups who had poor sleep quality after surgery showed no statistical difference. At 1 month after surgery, 50% of patients in the parathyroid group and 40% in the thyroid group continued to have poor sleep quality, La said. However, when comparing preoperative with postoperative sleep scores, 37% in the parathyroid group had a noticeable improvement in their sleep scores, while only 10% of the thyroid group demonstrated improvement.
The researchers also evaluated physical and mental function in the two groups. “Preoperative overall health status was significantly worse in the parathyroid group,” La said. At 1 and 6 months after parathyroidectomy, only two physical components, physical functioning and bodily pain, remained worse in the PHPT patients. Compared with preoperative scores, PHPT patients showed statistically significant improvement in all four mental components at both postoperative periods. “In contrast, the thyroid group demonstrated no significant changes in the preoperative to postoperative scores in all eight components,” La said.
“Our study adds to the body of literature suggesting that asymptomatic patients with primary hyperparathyroidism are unlikely to be truly asymptomatic,” La said. “All patients with primary hyperparathyroidism should be referred for surgical consultation, particularly those with neurocognitive symptoms.”
He also said that patients should be counseled that improvement in sleep quality and quality of life, if they are to occur, typically are seen within 1 month after surgery.
Mr. La, Dr. Yen, and the study coauthors had no relationships to disclose.