A Retrospective Cohort Study Evaluating the Prevalence of Vitamin D Deficiency and its Impact on the Biochemical and Clinical Presentations of Patients with Primary Hyperparathyroidism (PHPT)

Background: Primary Hyperparathyroidism (PHPT) is the third most common endocrine disorder, with an estimated prevalence of 1 to 4 per 1,000 in the general population. It is well established that vitamin D deficiency co-exists with PHPT. However, there are very few studies that have compared the prevalence of vitamin D deficiency between symptomatic and asymptomatic PHPT patients. Aim: This research evaluated the prevalence of vitamin D deficiency in patients with PHPT, and compared the prevalence of vitamin D deficiency in patients with symptomatic and asymptomatic disease. Methods: This observational cohort study employed a retrospective design where clinical records of 400 new patients referred to the metabolic bone clinics for investigation of hypercalcaemia, between 2010 and 2017, were reviewed. The study population was grouped as ‘asymptomatic’ or ‘symptomatic’ based on the absence or presence of at least one classical hypercalcaemia-related symptom. Results: PHPT is more prevalent in women with female to male ratio of 4.4:1. Symptomatic patients were significantly younger compared to the asymptomatic group (60.97 year+15.356 vs 65.88 years+13.924, p=0.001). There was a high prevalence of vitamin D deficiency (64.25%) with no difference between the symptomatic and asymptomatic groups. The prevalence of osteoporosis was 53.35% whilst the prevalence of renal stone was 13.54% with no between group differences. Conclusion: PHPT is more common in women than in men. Symptomatic patients were younger compared with those without symptoms. Vitamin D deficiency is highly prevalent in patients with PHPT regardless of whether the patients were symptomatic or not.