Quality of life in hypoparathyroidism

Hypoparathyroidism is a rare endocrine disorder where deficiency (or lack of effect) of parathyroid hormone results in disordered mineral metabolism leading to hypocalcemia and hyperphosphatemia. Many patients with this disorder have physical, emotional and cognitive complaints suggestive of impaired quality of life (QOL). Several recent studies have demonstrated that hypoparathyroid patients treated with calcium and vitamin D (conventional therapy) have reduced QOL compared to either suitable controls or general population. QOL has also been studied during treatment with PTH1-84, which has been FDA approved in the USA as an adjunct to calcium and vitamin D in patients not adequately controlled on conventional therapy. In open label studies, PTH therapy has resulted in dramatic improvements in SF-36 scores. In placebo-controlled, double-blinded studies the effect of PTH on QOL has been less striking. In one such study there was no improvement, possibly due to high incidence of hypercalcemia in the PTH-treated group. In contrast, in the pivotal trial leading to PTH1-84 approval, were hypercalcemia was less common, SF36 scores improved in the PTH-treated but not in the placebo group although between-group differences were not statistically significant. In the same study, patients who started with lower baseline QOL scores had greater improvements, suggesting that patients with poor wellbeing may be particularly suitable for this new therapy. In the future, it will be necessary to develop disease specific instruments to better define the nature of QOL impairments in this disease. In addition, further studies should focus on the possible relationship between biochemical variables and QOL parameters during treatment with different regimens.