Clinical and biochemical presentation of primary hyperparathyroidism in Kansai District of Japan

Although the number of patients with primary hyperparathyroidism (pHPT) has increased since biochemical screening came to be widely employed, few data are available concerning the clinical analysis of Japanese patients. We therefore tried to determine the recent clinical and biochemical state of Japanese patients with pHPT. Clinical and biochemical data were analyzed in a series of 103 pHPT patients who had been hospitalized in Kobe University Hospital during a 17 year period from 1979 to 1995. The data were obtained from the hospital records and additionally from information through questionnaires performed in 1995. Patients were 29 males and 74 females. The average ages at diagnosis were 53.4 +/- 16.0 (SD) year-old and 53.9 +/- 15.2 year-old, respectively. The major clinical symptoms were nephrolithiasis (35.9%), thirst/polyuria (33.0%), easy fatigability (20.4%) and back pain/lumbago (16.5%), but 19.4% of the patients were asymptomatic. Out of 87 cases who received parathyroidectomy, 10 (11.5%) were diagnosed with parathyroid carcinoma. Age-and sex-corrected bone mineral density (BMD) of the radius was significantly lower in the group with back pain/lumbago than in the group without the symptom. Similarly, radial BMD was lower in the group with a high serum alkaline phosphatase value. Patients with nephrolithiasis had a lower urinary calcium/creatinine ratio (UCa/UCr; 0.305 +/- 0.188 mg/mg) than the patients without nephrolithiasis (0.400 +/- 0.160 mg/mg). This inconsistent result suggests that some important factors except urinary calcium would contribute to urinary stone formation in pHPT. Our data mostly agreed with previous reports on a Caucasian population except for a relatively high prevalence of parathyroid carcinoma, but the negative correlation between nephrolithiasis and urinary calcium was not easily explicable. This finding should be confirmed by analyzing a larger number of cases.