Table 1.
Eligibility criteria for the PRECOVID trial
| Inclusion criteria | Exclusion criteria |
|---|---|
| Vitamin D deficiency (serum 25(OH)D < 50 nmol/l) | Severe vitamin D deficiency (serum 25(OH)D <15 nmol/l), |
| Postbronchodilator FEV1/FVC < 0.70, FEV1 < 80 % and diagnosis COPD confirmed by a physician | Use of a supplement containing more than 400 IU vitamin D per day |
| Recent COPD exacerbation | Use of maintenance dose oral corticosteroids |
| ≥10 packyears of smoking | Diagnosed asthma |
| Age ≥ 40 years | Diagnosed osteoporosis |
| Written informed consent | Self-reported history of hypercalcaemia or nephrolithiasis |
| Ability to comply with all study requirements. | Self-reported presence of sarcoidosis |
| Diagnosed chronic kidney disease stage 4 or higher (eGFR ≤ 29 ml/min/1.73 m2) | |
| Interfering malignant diseases | |
| Life expectation of less than 1 year on the basis of concurrent disease | |
| Current participation in a clinical rehabilitation program | |
| Pregnant or lactating women, or subjects who intend to become pregnant within the study period | |
| Potentially unreliable patients and those judged by the investigator to be unsuitable for the study | |
| Serious mental impairment i.e. preventing to understand the study protocol or comply with the study aim |
25(OH)D 25-hydroxyvitamin D, FEV 1 Forced Expiratory Volume in one second, FVC Forced Vital Capacity, eGFR estimated Glomerular Filtration Rate with the MDRD formula