Serum homocysteine, folate and vitamin B12 levels in patients with psoriasis: a systematic review and meta‐analysis

• Published in: British journal of dermatology (1951) Vol. 180; no. 2; pp. 382 - 389
• Main Authors: Tsai, T.‐Y., Yen, H., Huang, Y.‐C.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.02.2019
• Subjects: Cardiovascular diseases; Folic acid; Health risk assessment; Homocysteine; Meta-analysis; Psoriasis; Systematic review; Vitamin B; Vitamin B12
• ISSN: 0007-0963; 1365-2133
• DOI: 10.1111/bjd.17034

Summary Background Patients with psoriasis are at increased risk for cardiovascular comorbidities. Previous studies examined the possible contribution of serum homocysteine, folate and vitamin B12 to cardiovascular risks in patients with psoriasis but had conflicting conclusions. Objectives To perform a systematic review and meta‐analysis of studies on serum homocysteine, folate and vitamin B12 levels in patients with psoriasis. Methods Online databases were searched on 15 February 2018 to include studies comparing serum homocysteine, folate and vitamin B12 levels between patients with psoriasis and controls. A random effects model was adopted to estimate odds ratios for dichotomous data and standardized mean differences (SMDs) for continuous data. Results A comprehensive literature search identified 24 studies eligible for inclusion. Compared with controls, patients with psoriasis had a significantly higher serum homocysteine level [SMD 0·41, 95% confidence interval (CI) 0·21–0·61; I2 = 76·7%, 18 studies], a higher prevalence of hyperhomocysteinaemia (odds ratio 3·48, 95% CI 2·08–5·83; I2 = 41·1%, seven studies) and a lower serum folate level (SMD −0·94, 95% CI −1·49 to −0·40; I2 = 95·6%, 14 studies). However, there was no difference in serum vitamin B12 levels between patients with psoriasis and the control group (SMD 0·004, 95% CI −0·49 to 0·50; I2 = 92%, 11 studies). Metaregression analysis revealed a significant inverse correlation between the SMD of homocysteine levels and folate levels. Conclusions Patients with psoriasis might have higher serum homocysteine and lower folate levels than control patients without psoriasis. However, due to significant heterogeneity and other limitations, the associations require further examinations in more studies. What's already known about this topic? Patients with psoriasis are at increased risk for cardiovascular diseases. The possible contribution of serum homocysteine, folate and vitamin B12 to cardiovascular risks in patients with psoriasis has been studied, but the results were inconclusive. What does this study add? Psoriasis was associated with hyperhomocysteinaemia and folate deficiency but not with vitamin B12 deficiency. There was an inverse correlation between serum homocysteine and folate levels. Physicians are encouraged to measure serum homocysteine levels in patients with psoriasis, as hyperhomocysteinaemia may be one of the factors contributing to the elevated cardiovascular risk in patients with psoriasis. Linked Comment:  Gisondi. Br J Dermatol 2019; 180:262–263. Plain language summary available online Respond to this article