Serum 1,25(OH)₂ Vitamin D and 25(OH) Vitamin D Ratio for the Diagnosis of Sarcoidosis-Related Uveitis

ABSTRACT

Purpose: The diagnostic workup of uveitis is challenging, with 30 to 50% of cases remaining of undetermined etiology despite multiple investigations. Sarcoid granuloma-related increase of 1,25(OH)₂D levels could be helpful for the diagnosis of ocular sarcoidosis.

Methods: Monocentric retrospective cohort study of patients for whom serum 25(OH)D and 1,25(OH)₂D levels were measured during the etiologic workup of unexplained uveitis in a tertiary referral center. The diagnoses of uveitis’ underlying diseases were established according to international diagnostic criteria.

Results: Fifty-nine patients were included. The diagnosis of defined, presumed or probable sarcoidosis was made in 37% of patients while 41% of cases remained of undetermined origin. The median serum levels of 25(OH)D in patients with ocular sarcoidosis and in those with uveitis due to another cause were 34.50 [21.2–40.8] and 43.20 [32.2–58.3] nmol/L (P=0.02), respectively. In the same subgroups of patients, the median serum levels of 1,25(OH)₂D were 132.4 [107.4–163.9] and 108.0 [84.30–130.5] pmol/l (P=0.02), and the median 1,25(OH)₂D/25(OH)D ratio was 4.17 [3.11–5.09] and 2.56 [1.54–3.37] (P=0.0007) respectively. A 1,25(OH)₂D/25(OH)D ratio >3.5 was associated with the diagnosis of sarcoidosis with a 68 % sensitivity and a 78% specificity and, in univariate analysis, was associated with an abnormal chest CT-scan (OR=5.7, P=0.003), granulomas on bronchial biopsy (OR=14.7, P=0.007) and bronchoalveolar lavage fluid lymphocytosis (OR=12.4, P=0.0006).

Conclusion: The measurement of serum 25(OH)D and 1,25(OH)₂D levels is a useful tool in the etiological workup of patients with unexplained uveitis, since a high 1,25(OH)₂D/25(OH)D ratio is suggestive of ocular sarcoidosis.

Keywords:

• 1
• 25(OH)₂ vitamin D
• 25(OH) vitamin D
• sarcoidosis
• uveitis

Acknowledgments

We thank Corinne Marti and Fanny Kameleddine (DiaSorin Inc France), and Najiba Lahlou, Sylvie Broucke, and Corine Zientek (UF d’hormonologie, Cochin) for their technical assistance.

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.