Background and aims: Vitamin D deficiency is more common in inflammatory bowel disease (IBD) patients than in the general population. However, there are conflicting data about predictive factors of vitamin D deficiency and its potential association with disease activity. The aims of this study were to determine the prevalence and predictive factors of vitamin D deficiency and to evaluate a possible association with disease activity.
Methods: A prospective observational study was conducted, including patients with IBD from January to July 2016. The Endocrine Society guidelines were considered for defining levels of serum 25-hydroxyvitamin D (25-OH-D) as follows: deficient (< 20 ng/mL, < 10 ng/mL being severe deficiency), insufficient (21-29 ng/mL), and adequate (> 30 ng/mL).
Results: A total of 152 patients (52% men; 47.2 ± 17.3 years) were included, of whom 70% had Crohn's disease (CD). Thirty-seven percent of patients were on immunosuppressors and 17% were on biologics. The majority were outpatients (88.2%). Mean 25-OH-D levels were 17.1 ± 8 ng/mL (CD: 16.7 ± 8 ng/mL vs. ulcerative colitis: 17.6 ± 7 ng/mL, p = 0.1). Inadequate levels were present in 90.8% of patients (deficiency: 68.4%; insufficiency: 22.4%). A significant negative correlation between 25-OH-D levels and age (r = -0.2, p = 0.04), C-reactive protein (CRP) levels (r = -0.22, p = 0.004), and Harvey-Bradshaw index (HBi) (r = -0.32, p = 0.001) was found. Patients with severe deficiency showed a higher CRP (0.6 vs. 1.4 mg/dL, p = 0.03), erythrocyte sedimentation rate (ESR) (22 vs. 31 mm/h, p = 0.03), and HBi (2 vs. 5, p < 0.001) and lower hemoglobin (13.6 vs. 12.7 g/dL, p = 0.02). There was no association between vitamin D deficiency and gender, type, extent, and duration of disease, surgery, and other measures of disease activity, such as ESR, hemoglobin (these 2 items except for severe deficiency), fecal calprotectin, or Truelove and Witts classification.
Conclusions: There is a high prevalence of inadequate levels of vitamin D in IBD patients, particularly deficiency (68.4%). There seems to exist an association between lower levels of vitamin D and higher disease activity, especially in CD.
Introdução: A deficiáncia de vitamina D é mais comum na doença inflamatória intestinal (DII) que na população geral. Contudo, existem dados controversos sobre fatores preditivos da deficiáncia de vitamina D e a potencial associação com a atividade da doença. Os objetivos deste estudo foram determinar a prevaláncia e fatores preditivos da deficiáncia de vitamina D e aferir possível associação à atividade da doença.
Métodos: Desenhou-se um estudo observacional prospetivo incluindo doentes com DII entre janeiro e julho/2016. Foram consideradas as orientações da The Endocrine Society para definir níveis de 25-hidroxivitamina D (25-OH-D) sérica como: deficientes (< 20 ng/mL, sendo <10 ng/mL deficiáncia grave [DG]), insuficientes (21–29 ng/ mL) e adequados (> 30 ng/mL).
Resultados: Foram incluídos 152 doentes (52% homens; 47.2 ± 17.3 anos), dos quais 70% com Doença de Crohn (DC). Do total, 37% estavam medicados com immunossupressores e 17% com biológicos. A maioria (88.2%) estava em ambulatório. O nível sérico de 25-OH-D foi 17.1 ± 8 ng/mL (DC: 16.7 ± 8 ng/mL vs. Colite ulcerosa: 17.6 ± 7 ng/mL, p = 0.1). Verificaram-se níveis inadequados em 90.8% (deficiáncia: 68.4%; insuficiáncia: 22.4%). Registou-se correlação negativa significativa entre níveis de 25-OH-D e idade (r = −0.2, p = 0.04), proteína C-reativa (PCR) (r = −0.22, p = 0.004) e índice Harvey-Bradshaw (iHB) (r = −0.32, p = 0.001). Doentes com DG apresentaram níveis mais elevados de PCR (0.6 vs. 1.4 mg/dL, p = 0.03), velocidade de sedimentação (VS) (22 vs. 31 mm/h, p = 0.03) e iHB (2 vs. 5, p < 0.001), e mais baixos de hemoglobina (13.6 vs. 12.7 g/dL, p = 0.02). Não se verificou associação entre deficiáncia de vitamina D e sexo, tipo, extensão e duração da doença, cirurgia, e outras medidas de atividade da doença como VS, hemoglobina (estas duas exceto para DG), calprotectina fecal ou classificação Truelove e Witts.
Conclusões: Registou-se prevaláncia alta de níveis inadequados de vitamina D na DII, particularmente de deficiáncia (68.4%). Parece existir associação entre níveis mais baixos de vitamina D e maior atividade da doença, nomeadamente na DC.
Keywords: Crohn disease; Disease activity; Epidemiology; Inflammatory bowel disease; Ulcerative colitis; Vitamin D.