Greater than age-predicted functional deficits in older patients with primary hyperparathyroidism

To compare the functional capacity of "asymptomatic" patients with primary hyperparathyroidism (PHPT) with normative values of healthy age-matched subjects.

Eighteen asymptomatic patients with PHPT met the study inclusion criteria: age >55 years, serum calcium concentration elevated ≤1 mg/dL above normal, inappropriate elevation of parathyroid hormone (PTH) level, and no objective symptoms of PHPT. Functional capacity was assessed by (1) a 6-minute walk test, (2) time to complete 2 sit-to-stand maneuvers, (3) gait velocity, and (4) forward reach. Serum calcium, 25-hydroxyvitamin D, and PTH levels were measured by standard laboratory assays. Functional outcomes of the study patients were compared with age-matched normative values (unpaired t test) and correlated with these biomarkers. Because these patients often have weakness, fatigue, and malaise, we hypothesized that their functional capacity would be compromised relative to that of healthy, age-matched persons.

The mean age of the patients was 65.6 years, and the mean serum calcium, PTH, and 25-hydroxyvitamin D levels (and standard deviations) were 10.36 ± 0.37 mg/dL, 122.22 ± 39.54 pg/mL, and 44.4 ± 14.27 ng/mL, respectively. Relative to normative values of healthy, age-matched subjects, these patients had comparable 6-minute walk distances but required a 37% longer time to complete a repeated sit-to-stand maneuver (P<.05), demonstrated a 52% slower gait speed (P<.001), and had a greater forward reach (P=.05).

Our findings suggest that older asymptomatic patients with PHPT may have significant functional deficits that can affect their safety and quality of life. Therefore, their functional capacity should be routinely evaluated, and identified deficits should be treated with appropriate interventions.