Parathyroidectomy does not preserve kidney function in the elderly

Early parathyroidectomy within one year of diagnosis of primary hyperparathyroidism (PHPT) did not reduce the risk of a sustained decline in renal function, as measured by a drop in estimated glomerular filtration rate (eGFR) of at minus 50%, compared to observation (no surgery) in adults 60 years and older.

Early parathyroidectomy, however, was associated with a reduced adjusted risk of this renal function decline in newly diagnosed PHPT patients younger than 60 years of age.

The results, based on data from nearly 43,000 veterans, were published online April 11 in the Annals of Internal Medicine.

“The important finding of our study is that for older adults [age 60 or older] with primary hyperparathyroidism, preservation of renal function should not be a primary consideration when making a decision about whether to undergo parathyroidectomy,” said lead author Carolyn D. Seib, MD. Medscape Medical News in an email.

“It is important that physicians also discuss with their patients the potential long-term benefits of parathyroidectomy related to reduced risk of fractures, kidney stones and cardiovascular disease, and improved quality of life, in addition to the need lifelong monitoring if surgery is refused, comparing them to an individual patient’s risk of surgery,” said Seib, a surgeon at Palo Alto VA Medical Center in California.

“However, in patients younger than 60, early parathyroidectomy may prevent progression to chronic kidney disease (CKD) and should be more strongly considered,” she noted.

Parathyroidectomy, she observed, is a low-risk outpatient surgery for most adults.

“Potential complications of surgery include temporary or permanent hoarseness, hypoparathyroidism (low postoperative parathyroid function), bleeding requiring a return to the operating room, and complications from general anesthesia, all of which are rare” , said Seib.

“Surgery by a high-volume surgeon is associated with a reduced risk of complications, so patients should seek out an experienced parathyroid surgeon,” she emphasized.

Additionally, parathyroidectomy is the only treatment for primary hyperparathyroidism.

Does parathyroidectomy slow the loss of kidney function?

Multidisciplinary guidelines recommend parathyroidectomy, at least in part to mitigate the risk and effects of CKD progression in patients with PHPT and an eGFR less than 60 mL/min/1.73 m²write the researchers.

However, it is unclear whether parathyroidectomy slows the loss of kidney function in adults with PHPT.

The guidelines also state that “Observation for PHPT disease progression may be considered when patients have no obvious end-organ damage (i.e., eGFR >60 mL/min/1.73 m²normal bone mineral density and no history of kidney stones or fractures),” Seib noted.

To fill the evidence gap, the researchers emulated a randomized target trial using observational data.

In this type of study, explains Seib, “although patients are not randomly assigned to a treatment, complex statistical methods are used to adjust for background confounders in an attempt to mimic the random assignment of the treatment and to account for biases that may affect when patients receive treatment.”

Using national data from the Veterans Health Administration, researchers identified 43,697 veterans with a new biochemical diagnosis of PHPT, defined as elevated parathyroid hormone (>65 ng/mL) within 6 months of a elevated serum calcium (> 32.55 mmol/L or > 10.2 mg /dL), from 2000 to 2019.

Of these patients, 3,804 underwent parathyroidectomy within a year of diagnosis of PHPT, and 39,893 did not, and instead a watchful waiting approach was adopted.

To be included in the analysis, patients had to have an eGFR greater than 30 mL/min/1.73 m² for 12 months before diagnosis of PHPT to exclude secondary or tertiary hyperparathyroidism.

The primary endpoint was a sustained decrease in eGFR of at least 50% from baseline.

In the overall cohort, patients had a mean pre-treatment eGFR of 71.8 mL/min/1.73 m². They had an average age of 67, 88% were male and 68% were white.

After a median follow-up of 4.9 years, 6.7% of patients had an eGFR reduction of at least 50%.

The cumulative incidence of this decrease in eGFR was 5.1% at 5 years and 10.8% at 10 years in patients who underwent early parathyroidectomy versus 5.1% and 12.0%, respectively, in patients who did not. operated.

In the overall population, the risk of a decrease of at least 50% in eGFR was similar in the early parathyroidectomy group compared to the observation group (adjusted hazard ratio [HR], 0.98; 95% CI, 0.82, 1.16).

However, a deeper dive showed that parathyroidectomy was associated with a reduced risk of primary outcome in patients younger than 60 (adjusted RR, 0.75; 95% CI, 0.59, 0.93) but not in those aged 60 or over (adjusted RR, 1.08; 95% CI, 0.87, 1.34).

“When you participate in shared decision-making for older people [age 60 and older] with PHPT, clinicians should not consider parathyroidectomy for the potential benefits of preserving renal function,” the researchers reiterate.

“For younger patients, clinicians should discuss the potential benefits of parathyroidectomy in reducing the risk of CKD and associated complications in adults with PHPT,” they conclude.

The study was funded by the National Institute on Aging. Authors did not report any relevant financial relationships.

Ann of Internal Medicine. Published online April 10, 2023. Abstract

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