Background: Primary hyperparathyroidism (PHPT) is the third most common endocrine disorder, with an estimated prevalence of 1 to 4 per 1000 in the general population. It is well established that vitamin D deficiency co-exists with PHPT. However, there are very few studies that looked at the relationship of the severity of vitamin D deficiency to the clinical and biochemical presentations of PHPT.
Aim: This study evaluated the prevalence of vitamin D deficiency and its relationship to the biochemical and clinical presentations of PHPT.
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. The relationship of the severity of vitamin D deficiency to the clinical and biochemical presentation of PHPT was evaluated.
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. There was a significant inverse correlation between the level of vitamin D and PTH (P= 0.000). There was a high prevalence of osteoporosis (53.35%) across of the entire study population with no between group differences.
Conclusion: Vitamin D deficiency is highly prevalent in patients with PHPT regardless of whether the patients were symptomatic or not. Symptomatic patients were younger compared with those without symptoms. The severity of vitamin D deficiency did not correlate to the severity of symptoms or prevalence of osteoporosis.