Health-related quality of life in T1DM patients after high-dose cholecalciferol supplementation: data from a pilot clinical trial

BACKGROUND: Type 1 Diabetes Mellitus (T1DM) impacts health-related quality of life (HRQoL). Cross-sectional studies suggest that low levels of vitamin D (VD) may impair HRQoL, however, the effect of VD supplementation on quality of life in T1DM patients has not yet been clarified. Our study evaluated the effects of high-dose VD supplementation on HRQoL in T1DM. METHODS: We performed a prospective study with 64 patients receiving cholecalciferol (4000 IU/day for patients with 25-OH-vitamin D [25(OH)D] between 30 and 60 ng/mL, and 10,000 IU/day for those with 25(OH)D below 30 ng/mL) for 12 weeks, as part of a research protocol. HRQoL was assessed with EuroQol instruments (EQ-5D and EQ-VAS). RESULTS: There was an improvement in global EQ-5D index, and analysing specifically the EQ-5D domains, we observed an improvement in mobility (1.3 ± 0.6 versus 1.1 ± 0.3, p < 0.01). Evaluating possible outcome influencing variables, we detected a reduction in albuminuria at the end of the trial, without changes in BMI, lipids, blood pressure, glycemic control and insulin doses. We found correlations between final albuminuria and the dimensions: mobility (r = 0.6; p < 0.01), personal care (r = 0.7; p < 0.01), pain and discomfort (r = 0.6; p < 0.01) and habitual activities (r = 0.6; p < 0.01), suggesting an association between albuminuria reduction and the impact of VD supplementation on HRQoL. CONCLUSION: Our data showed that high doses of cholecalciferol supplementation can improve HRQoL in patients with T1DM, and the reduction of albuminuria seems to be an important factor in this context. Trial registration: (ISRCTN32601947), 03/06/2017 retrospectively registered.