Symptoms of Secondary Hyperparathyroidism in Patients Receiving Maintenance Hemodialysis: A Prospective Cohort Study.

RATIONALE & OBJECTIVE: Although multiple lines of evidence suggest a negative impact of secondary hyperparathyroidism on patients with kidney failure treated by hemodialysis, it is uncertain whether patients can detect associated symptoms. The objective was to determine whether changes in parathyroid hormone (PTH) levels are associated with changes in symptoms within this patient population.

STUDY DESIGN: Prospective cohort.

SETTING & PARTICIPANTS: 165 adults with hyperparathyroidism secondary to kidney failure diagnosed, a range of dialysis vintages, and receiving regular hemodialysis from a US single-provider organization.

EXPOSURE: Change in PTH levels over 24 weeks.

OUTCOMES: 19 putative symptoms of secondary hyperparathyroidism measured up to 4 times using a self-administered questionnaire that assessed severity on a 5-level ordinal scale.

ANALYTICAL APPROACH: Longitudinal associations between changes in PTH levels and symptom severity were assessed using generalized additive models.

RESULTS: The 165 participants studied represented 81% of enrollees (N=204) who had sufficiently complete data for analysis. Mean age was 56 years and 54% were women. Increases in PTH levels over time were associated (P<0.1) with worsening of bone aches and stiffness, joint aches, muscle soreness, overall pain, itchy skin, and tiredness, and the effects were more pronounced with larger changes in PTH levels.

LIMITATIONS: Findings may have been influenced by confounding by unmeasured comorbid conditions, concomitant medications, and multiple testing coupled with a P value threshold of 0.10.

CONCLUSIONS: In this exploratory study, we observed that among patients with secondary hyperparathyroidism, increases in PTH levels over time were associated with worsening of 1 or more cluster of symptoms. Replication of these findings in other populations is needed before concluding about the magnitude and shape of these associations. If replicated, these findings could inform clinically useful approaches for measuring patient-reported outcomes related to secondary hyperparathyroidism.