Doctors sometimes remove the parathyroid gland to treat a condition called hyperparathyroidism, which affects hormone balance in the body. However, new research shows that more than half of patients still have high hormone levels even after surgery. Scientists studied 261 patients over 10 years to understand why this happens. They found that people with kidney problems and certain other factors were more likely to have this issue. Understanding these patterns helps doctors predict which patients might need extra monitoring or different treatment approaches after surgery.

The Quick Take

  • What they studied: Why some patients still have high parathyroid hormone levels more than a year after having their parathyroid gland surgically removed
  • Who participated: 261 patients (average age 56 years) who had parathyroid surgery between 2010 and 2019 at a major hospital in Brazil. Most had normal weight, and doctors tracked their hormone levels before surgery and up to 18 months after
  • Key finding: More than half of the patients (over 50%) still had elevated parathyroid hormone levels 18 months after surgery. Patients with kidney problems and lower vitamin D levels were more likely to have this issue
  • What it means for you: If you’re considering parathyroid surgery, talk with your doctor about kidney function and vitamin D levels beforehand. You may need closer follow-up monitoring after surgery, especially if you have kidney concerns. This doesn’t mean surgery won’t help, but it helps set realistic expectations

The Research Details

Researchers looked back at medical records from 261 patients who had parathyroid surgery at a major hospital in Southern Brazil over a 10-year period (2010-2019). They collected information about each patient’s age, weight, kidney function, vitamin D levels, and hormone measurements taken before surgery and multiple times after surgery (up to 18 months). They compared patients whose hormone levels returned to normal after surgery with those whose levels stayed high, looking for patterns that might explain the difference.

The study examined data from 3 months before surgery through 18 months after surgery. Doctors measured parathyroid hormone levels, calcium levels, kidney function, and vitamin D at different time points. This allowed them to see how these measurements changed over time and which factors predicted whether hormone levels would normalize or stay elevated.

This research approach is important because it uses real-world patient data from a specialized center that performs many of these surgeries. By looking at actual outcomes over several years, researchers can identify patterns that might not show up in smaller studies. Understanding which patients are at risk for persistent hormone elevation helps doctors make better treatment decisions and set appropriate expectations with patients before and after surgery.

This study has several strengths: it includes a reasonably large number of patients (261), follows them for a substantial time period (up to 18 months after surgery), and uses data from a specialized center experienced with these procedures. However, it’s a retrospective study, meaning researchers looked back at existing records rather than following patients forward in a controlled way. The study was conducted at a single hospital in Brazil, so results may not apply equally to all populations. The researchers used statistical methods to account for multiple factors, which strengthens their conclusions about what predicts persistent hormone elevation.

What the Results Show

The most striking finding was that more than half of all patients (over 50%) still had elevated parathyroid hormone levels 18 months after surgery. This was higher than many doctors might expect, suggesting that persistent elevation is quite common after this procedure.

When researchers compared patients with normal hormone levels to those with high levels, they found important differences. Patients with persistent elevation had lower vitamin D levels and lower initial parathyroid hormone levels at the time of surgery. Interestingly, the amount of hormone reduction after surgery was different between groups, with kidney function playing a key role.

The study identified kidney function as a critical factor. Patients with reduced kidney function (measured by glomerular filtration rate) showed larger changes in parathyroid hormone levels after surgery compared to those with normal kidney function. These patients also started with higher hormone levels before surgery but didn’t show as much improvement after the procedure.

Several other findings provide context: age, body weight, and pre-surgery calcium levels did not significantly differ between patients who improved and those who didn’t. This suggests that these common factors aren’t the main predictors of surgical success. Vitamin D levels emerged as important—patients with higher vitamin D were more likely to have normal hormone levels after surgery. The study also found that calcium levels after surgery were associated with hormone changes, suggesting that the body’s overall mineral balance matters for hormone regulation.

Previous research has suggested that persistent hormone elevation occurs in 20-30% of patients after parathyroid surgery. This study found rates over 50%, which is notably higher. This difference might be because this hospital is a specialized center that treats more complex cases, or because they followed patients longer than some other studies. The finding that kidney function predicts outcomes aligns with other research showing that kidney disease complicates parathyroid hormone regulation. The importance of vitamin D in predicting success is consistent with growing evidence about vitamin D’s role in parathyroid health.

This study looked backward at existing medical records rather than following patients forward in a controlled study, which can introduce bias. The study was conducted at a single specialized hospital in Brazil, so results may not apply to all populations or healthcare settings. Some patients may have been lost to follow-up or had incomplete records, which wasn’t fully detailed in the study. The researchers couldn’t determine whether persistent elevation was due to incomplete surgery, disease in other parathyroid tissue, or other biological factors. Additionally, the study couldn’t explain why kidney function affects outcomes so significantly, only that it does.

The Bottom Line

If you have primary hyperparathyroidism and are considering surgery: (1) Have your kidney function and vitamin D levels checked before surgery—these appear to predict outcomes; (2) Discuss with your doctor whether you’re at higher risk for persistent elevation based on these factors; (3) Plan for follow-up hormone testing at 3, 6, 12, and 18 months after surgery rather than assuming one test is enough; (4) If you have kidney disease, work with your doctor on a comprehensive plan that addresses both parathyroid and kidney health. Confidence level: Moderate—this is based on one center’s experience and should be confirmed with your own doctor.

This research is most relevant for: people diagnosed with primary hyperparathyroidism considering surgery, people with kidney disease who also have parathyroid problems, and doctors who treat these conditions. If you have normal kidney function and normal vitamin D levels, you may have a better chance of complete surgical success, though individual results vary. If you have kidney disease or low vitamin D, this information helps explain why you might need closer monitoring after surgery.

Hormone levels typically show the most change in the first 3 months after surgery. However, this study shows that changes can continue for up to 18 months. If your hormone levels haven’t normalized by 6 months, they’re less likely to normalize on their own. Most doctors recommend checking levels at 3 months, 6 months, and 12 months post-surgery to establish the pattern for your individual case.

Want to Apply This Research?

  • If you’ve had or are planning parathyroid surgery, track your parathyroid hormone levels, calcium levels, vitamin D levels, and kidney function (GFR) at each doctor’s visit. Record the date and values in a simple spreadsheet or health app. This creates a personal record showing whether your levels are improving, stable, or worsening over the 18-month period after surgery.
  • Set calendar reminders for follow-up blood tests at 3, 6, 12, and 18 months after surgery. Before each appointment, note any symptoms (fatigue, bone pain, kidney issues). Share this symptom log with your doctor to help them understand how your body is responding. If you have low vitamin D, work with your doctor on supplementation and track your vitamin D levels to see if improvement helps normalize parathyroid hormone.
  • Create a simple chart in your health app showing hormone levels over time with a target range marked. This visual helps you and your doctor see trends. Set up alerts if results fall outside expected ranges. If you have kidney disease, also track kidney function (GFR) alongside parathyroid hormone, as the study shows these are connected. Share this data with your healthcare team at each visit to guide treatment decisions.

This research describes patterns observed in one hospital’s patient population and should not replace personalized medical advice from your doctor. Parathyroid surgery outcomes vary significantly between individuals based on many factors not fully captured in any single study. If you have primary hyperparathyroidism or are considering parathyroid surgery, discuss these findings with your endocrinologist or surgeon who understands your complete medical history, kidney function, and individual risk factors. This information is educational and does not constitute medical advice. Always consult with qualified healthcare professionals before making treatment decisions.